Abstracts of 11th C1-inhibitor Deficiency & Angioedema Workshop

s of 11th C1-inhibitor Deficiency & Angioedema Workshop Hungary, 23–26 May 2019 Published: 13 August 2019 © The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. I0 Dear Colleagues, Between 23 and 26 May 2019, the international scientific conference on angioedemas—conditions belonging to the group of orphan diseases and resulting in a life-threatening condition—will be held on the eleventh occasion in Budapest (2019.haenetworkshop.hu). This year, the word ‘angioedema’ has been added to the title of this event (organised every two years in Hungary starting from 1999), which now reads “11th C1-INH Deficiency & Angioedema Workshop”. This designation better reflects the agenda of the 4-day long conference, because it has become a forum for discussing topics also on other bradykinin-mediated hereditary and acquired angioedemas, in addition to C1-inhibitor deficiency. Based on the 82 submitted abstracts, the programme includes 36 oral and 46 poster presentations. These will be supplemented by the lectures delivered by Patricia Pozo-Rosich (Barcelona, Spain) on the relationship between migraine and angioedema, as well as by Michael Kirschfink (Heidelberg, Germany) on the standardization of the laboratory methods applied for complement testing. Furthermore, Avner Reshef (Ashkelon, Israel) will summarize the prodromal symptoms of angioedema. By tradition, the agenda of the conference comprises consensus meetings and roundtable discussions intended to facilitate the adoption of international guidelines. This year, Anastasios E. Germenis will moderate the roundtable session “International consensus on the use of genetics in the management of hereditary angioedema”, whereas Teresa Caballero will lead the discussion on “International consensus on the gynecologic and obstetric management of female patients with hereditary angioedema—updates”. Further, the ‘HAE Global Registry’ Work Group (established to develop an international database on hereditary angioedema), led by Marco Cicardi, will hold its meeting here. The geographical distribution and professional background of the participants are variegated. Approx. 330 delegates have registered from all over the world, from 39 countries in total. Researchers, medical professionals, drug development specialists, members of patients’ organisations, and nurses will all be represented in the audience, which has become an active and creative community over the past two decades. The delegates of the International Hereditary Angioedema Nursing Organization will hold a consultative meeting on improving the stateof-the-art care of angioedema patients in the ‘Nurse Meeting’ session of the Workshop, under the moderation by Iris Leibovich-Nassi. Generous support by CSL Behring, Pharming, Biocryst, Kalvista and Sobi made it possible to organize a high level scientific conference. This educational activity is supported by an independent medical educational grant from Shire (Takeda). The support referred to above has again enabled us to present the “For HAE Patients” award, as well as to give the “Grant for Young Investigators” to four presenters under the age of 35 years. In 2019, the ‘For HAE Patients’ award goes to Teresa Caballero (Madrid, Spain), who will deliver a presentation in the festive session of the first conference day, and her accomplishments will be reviewed by Henriette Farkas (Budapest, Hungary) beforehand. The closing feature of the Workshop will be the presentation of the ‘Grant for Young Investigators’ to the four winners (elected by a 7-member jury) by Peter J. Späth, Chair of the Jury. Finally, Allen Kaplan will summarize for the audience all the topics and findings discussed at this Workshop. The programme and the submitted abstracts including those by the invited speakers will be published again in the greatly esteemed Allergy, Asthma, & Clinical Immunology, in order to make them available to an even broader range of professionals interested in this subject. Henriette Farkas and Lilian Varga Chairs of 11th C1-inhibitor Deficiency & Angioedema Workshop

Both migraine and C1-INH-HAE are genetically-driven paroxysmal disabling diseases, which are characterized by recurrent unpredictable episodic attacks. In rare cases, C1-INH-HAE is manifested with neurological symptoms, including cephalalgia which does not respond to conventional treatment. The complement system has important function in the regulation of bradykinin release within the brain. Some of the inflammatory molecules in migraine can be measured indirectly (serum, CSF) using ELISAs. This is different from C1-INH-HAE, where conventional laboratory tests are of diagnostic value. In respect of treatment options: in migraine, treatment is broad, and recently a new class of drugs has been developed, and proven to be effective and safe, targeting CGRP and preventing migraine attacks, however, there may be non-responders. The pathophysiology shares the presence of inflammatory molecules which lead to pain in migraine and angioedema attacks in C1-INH-HAE. Therapeutic options of both diseases are to be personalized and target-driven. In addition to its role as an inhibitor of C1r and C1s of the classical pathway and MASP1 and MASP2 of the lectin pathway, C1-INH is the major inhibitor of factor XIIa and kallikrein. The lack of inhibition of these enzymes results in excessive bradykinin generation, which in turn mediates increases vascular permeability, leading to angioedema. In the past decades complement analysis has undergone a tremendous development in part expanding beyond specialized laboratories. However, improving diagnostic strategies requires the correct choice of analytes and the use of well-characterized methods that will yield consistent results between laboratories. In the diagnosis of the various types of angioedema, as in many fields of immunodiagnostic, there is considerable need for consensus and standardization of analytical methods, which will be a major challenge in the future. In recent years, laboratories specializing in complement analysis have joined with the International Complement Society and the IUIS to coordinate efforts to standardize and improve complement testing, ongoing efforts show first promising results (http://iuiso nline .org/index .php?optio n=com_conte nt&view=artic le&id=64&Itemi d=69). Since that time eight rounds of external quality assessment, now covering 18 parameters, also including those to better characterize angioedema patients (C4, C1-inhibitor [protein, function], autoantibodies to C1-inhibitor) have been completed. It is recommended to extend this efforts to a more comprehensive analysis of parameters of the clotting and kallikrein-kinin systems for better defining the pathophysiological background and to distinguish angioedema with C1-inhibitor deficiency from primary angioedema. Signs and symptoms (Prodromes) which antedate swelling attacks have been noted since early descriptions of Hereditary Angioedema (HAE). Regrettably, no consensual definition of a prodrome exists, contributing to ambiguity and disagreement among medical disciplines and researchers. Heralding signals occurs in other diseases, mostly characterized by a chronic and undulating course. For instance, in Schizophrenia, bipolar disorders, and some neurodegenerative diseases, early signs of abnormal behavior, occurring few years before a psychotic crisis, are regarded as a prodrome. In Migraine, a prodromal stage with subtle symptoms precedes the attacks. Early emotional changes, physical symptoms and visual 'Aura' , are regarded as premonitory and predict oncoming paroxysm of headaches. In Herpes Zoster, a prodrome occurs 48-72 h before the typical vesicular rash, and intense pain in the involved dermatome precedes the rash in more than 90% of cases. Prodromes have also been described in Familial Mediterranean Fever (FMF) and Capillary-leak Syndrome (Clarckson's syndrome). A renewed interest in prodromes preceding HAE took place a decade ago, followed by an extensive literature search and some preliminary explorations. Further studies and expert opinions affirmed the fact that prodromes are more frequent than realized. Our group has recently designed and analyzed a new instrument to evaluate HAE prodromes. In this study 84% of the patients reported ever having a prodrome, and 87% said that they could predict an oncoming attack by experiencing a prodrome. A significant correlation was found between the perception of prodrome and ability to predict an oncoming attack. This data corroborates other studies reporting similarly high rate of association. Despite consistent patient reports, prodrome's remains elusive, and their precise nature and mechanisms are unknown. It could be hypothesized that they represent an early surge of angioedema mediators, such as complement fragments or factor XII-dependent contact system kinins. Indeed, bradykinin was detected in the stromal and endothelial cells of prodromal Erythema Marginatum skin rash. Additionally, evidence of early activation of the kallikerin-kinin system, with high kininogenase activity, proenzyme consumption, high-molecular weight kininogen cleavage and C1-INH function alteration, occurring before visible angioedema, was recently demonstrated. In another study, C4 depletion and higher than baseline C4a levels, were detected hours before the onset of an attack. In summary, albeit frequently reported, prodromes have not been adequately investigated, and systematic tools for their evaluation are missing. Accurate prodrome evaluation is critical for early diagnosis of attacks and timing of medical interventions, particularly in an era when effective drugs are available for self-treatment.
Mutations of C1inh are present in some patients with hereditary angioedema with normal C1-inhibitor (HAE-nl-C1inh), but the underlying disease mechanism remains unclear. There is no accepted biomarker for this disease. In 1989 while developing a new purification procedure for the human complement protein C2 1 we isolated a then unidentified plasma protein with a molecular weight of 120 Kd. It appeared related to the contact system of coagulation because incubating plasma at 4 °C in glass tubes led to cleavage of the protein. Plasma deficient in high-molecular-weight kininogen (HMWK) and kallikrein when treated similarly did not show cleavage of the protein. If a mixture of HMWK and prekallikrein was added to deficient plasma, the glycoprotein was cleaved after contact activation 2 . In 1994, Xiao Ping Pu and colleagues isolated a similar protein from plasma 3 . Using a partial cDNA sequence, they suggested that their protein had closely related sequence homologies to the heavy chains of the inter-α-trypsin inhibitor (ITI) superfamily 4 . This group of 6 separate proteinase inhibitors is characterized by the presence of a common light chain, and is susceptible to proteolysis by the enzymes they inhibit. ITI heavy chain 4 (ITIH4) is different from the other members of the group of ITI proteins because it is the only member that has no light chain and circulates as a free isoform. ITIH4 is also the only kallikrein sensitive protein among this group and has a molecular weight of 120 KD. We isolated our protein and identified it as IATI heavy chain 4. We examined fragmentation of the protein in plasma from normal, patients with HAE types 1 and 2 and patients with HAE-nl-C1inh. ITIH4 is fragmented in almost all patients with HAE types 1 and 2 and is intact in almost all normals and patients with HAE-nl-C1inh. On incubation of patient plasma in plastic tubes at 4 °C the protein is intact in normal and cleaved in plasma of patients with HAE-nl-C1inh. We studied C1inh in the same samples. C1inh was at low levels or was cleaved in HAE type 1 or 2 disease. It was normal structurally and functionally in normal and patients with HAE-nl-C1inh. However on incubation in plastic at 4 °C the C1inh was cleaved and lost function in patients with HAE-nl-C1inh but not in normals. Antiserum to this protein is commercially available and we propose that study of its cleavage pattern provides a new means for the laboratory diagnosis of HAE-nl-C1inh.
Background: Hereditary Angioedema (HAE) is a rare autosomal dominant disorder characterized by potentially fatal swelling of the larynx. In addition, abdominal angioedema can lead to misdiagnosis and needless surgical intervention, along with narcotic dependence. The prevalence of HAE is estimated at roughly 1:50,000 individuals, however, the overall epidemiological data for this disorder remains scarce and inadequate. The main gene linked to HAE pathogenesis is SERPING1, the gene that encodes for C1-INH. Less commonly observed are mutations in F12, the gene that encodes the Coagulation Factor XII (Hageman Factor). Very recently two other genes have also been described: PLG and ANGPT1 Objectives: We sought to examine the clinical features as well as the molecular genetic defects observed in HAE in the Saudi population. Methods: Thirty-six (36) patients with a diagnosis of HAE, who were being followed at the Immunology clinics at King Faisal Specialist Hospital (both Riyadh and Jeddah) were included in the study after informed consent. This study is RAC approved. (RAC # 2080 025) Results: HAE diagnosis was based on the classic clinical presentation of angioedema without urticaria as well as characteristic lab features. 38.8% of the patients were males and the mean age was 31.08 years. Initial molecular screening was performed for the SERPING1 gene. For cases that were negative for this gene, primers were then designed against all coding regions of F12, PLG and ANGPT1 for PCR analysis. Twenty-six (26) patients were found to have mutations in SERPING1 gene, of which the most common was NM_000062:c.1397G>A:p.R466H (Table 1). In addition, one novel mutation (NM_000062:c.1202T>A:I401N) was uncovered in a single Saudi family. All negative cases have been screened for F12, PLG and ANGPT1 gene mutations, but thus far, no such mutations have been found. Conclusions: Molecular analysis of this HAE cohort has revealed consistent autosomal dominant inheritance and the presence of SERPING1 mutations in > 50% of patients. Although some mutations have been found across multiple families, R466H is the only mutation which appears to dominate the HAE genetic landscape in the region. The lack of observed mutations in F12, PLG and ANGPT1 suggest that there are no prevalent founder mutations in these genes in the local population. Unsolved pedigrees are being prioritized for whole exome sequencing.
performed and these patients were re-evaluated after 72-96 h from discharge for clinical and biochemical assessment. Conclusions: Increased levels of CRP and D-Dimer, probably rising from extravascular activation of the coaugulation pathway rather than from the vascular district, may be frequently detected on acute attacks of urticaria and/or angioedema. Although both the biomarkers seem well correlate with disease activity, they are not predictive of systemic phlogosis and thromboembolism. As CRP and D-D do not affect therapeutic strategies in urticaria and AE, these tests should not be included among ER screening analyses but in cases of strong pretest probability for inflammation and thromboembolism. The study was approved by the local Ethical Committee (protocol number 4314/AO/17) Nearly 62% of this group were diagnosed by age 10 (M > F, P < 0.05). Preliminary questionnaire was constructed, based on the literature and investigator's experience. Six new instruments were used to reach a robust evaluation scale. Data from the preliminary interviews was used to test the instrument's construct and internal validity. In the 2 nd phase, patients were interviewed to obtain data on prodromes and attacks. After final refinement of the instrument, a retrospective and prospective data were obtained and statistical analysis was performed to study prodromes and attacks associations. Results: In the 1st phase, 165/197 (84%) reported ever having a prodrome, 143/165 (87%) could predict an oncoming attack by experiencing a prodrome. There was a significant correlation between the perception of prodrome and ability to predict an oncoming attack (p < 0.01, r = .79). The Internal validity of the new questionnaire, constructed based on the preliminary study, was high, as well as its internal reliability (Cronbach's α = .70 to .96). Prodromes and attacks, analyzed for each body system cluster, were highly correlated (r = .33, p < .01). In the 2 nd phase, 66 patients (33.5%) completed a questionnaire that covers 'clusters' of body systems, affected by both events. Differences between the clinical dimensions of prodromes (i.e. pain, severity, impairment, dysfunction, duration), were evaluated by one-way MANOVA with repeated measurements, and shown to be segregated from attacks on all dimensions [F (4, 56) = 45.7, P < .001, Eta 2 = .77] Conclusions: A questionnaire-based PRO instrument for the evaluation of HAE prodromes and attacks was designed and tested. The high internal validity and reliability makes it useful for studying clinical expressions of HAE. A prodrome/attack evaluation instrument can be useful in the diagnosis of oncoming attacks and timing of medical interventions.

O10 Psychosocial burden of hereditary angioedema in a Canadian cohort
Julia Hews-Girard 1,2,* , M. Dawn Goodyear 1,2 Methods: Seventeen patients, ≥ 18 years, with a confirmed diagnosis of HAE type 1 or 2 (  There are scarce data about Hereditary Angioedema (HAE) with C1-INH deficiency in pediatric patients. Although symptoms of HAE begin early in life, diagnosis of the disease is delayed in this period of life. In addition, several new therapies are still restricted to older ages. Considering the restricted access to diagnosis and therapy in developing countries, we evaluated clinical and laboratorial characteristics and therapy of pediatric patients from Brazilian reference centers. Methods: Medical records of HAE patients aged less than 18 years old, whose diagnosis was confirmed by quantitative and/or functional C1-INH, were included. The following data were collected: age of diagnosis, age at onset of symptoms, prodromes, symptoms, triggering factors, diagnostic tests and treatment. Descriptive statistical analysis was performed. The study was approved by ethical committee. Results: 96 participants (52 M:44F) from 17 reference centers on HAE were included: 50% from southeast, 23% from northeast, 16% from midwest, and 11% from south of Brazil. Family history was present in 72/96 patients. Twenty percent of the patients were asymptomatic. Age at onset of symptoms was < 1 year of age in 27%; 1-5 years in 45%; 6-10 years in 21% and 11 to < 18 years in 7%. Median age at diagnosis was 7 years old. Prodromes were reported among 25% of the patients: local burning in 10%; serpiginous erythema in 7%; fatigue and nausea in 2% each and irritability in 5.2%. Angioedema attacks affected: face (5%); lips (13%); tongue (11%); eyelid (6%); ear (2%); neck (1%); hands (19%); arms (15%); legs (5%); genitals (7%); upper airways (3%) epigastric pain and/or abdominal pain (55%). One fourth of the patients had no trigger factor identified. Severity of attacks were mild in 32%; moderate in 40% and severe in 26%. Misdiagnosis included: allergy 16% and helminthiasis 5%. Previous ER visits were reported by 56.3%. Surgical intervention (appendectomy) prior to HAE diagnosis occured in 4%. Long term prophylaxis was introduced in 54% (53/96): tranexamic acid in 76% (40/53); danazol in 13% (7/53) and oxandrolone in 11% (6/53). Androgens were used in 4/13 under 12 years of age. Short-term prophylaxis was prescribed in 10/96 (tranexamic acid 6/10; danazol 3/10 and plasma derived C1-INH 1/10). 32/96 patients received specific treatment of acute attacks, including Icatibant to 4/32; fresh frozen plasma to 15/32; plasma derived C1-INH to 11/32 and tranexamic acid to 13/32 patients. Conclusions: Although more than 80% of the patients had family history and several members affected, there was a delay in diagnosis. Abdominal pain and surgical interventions were less frequent than reported in adulthood. Attenuated androgens were prescribed for pediatric patients, probably due to restricted access to on demand therapy. Only recently Icatibant was licensed for use in children, nevertheless it had been previously used in our population. Educational programs should focus on Pediatricians, aiming at reducing delayed diagnosis and providing appropriate therapy. Background: Short-term prophylaxis (STP) in HAE is commonly administered to prevent breakthrough attacks after minor surgical trauma, such as dental procedures. This purpose of this study was to identify clinical determinants predictive of HAE breakthrough attacks after STP. Methods: A cross-sectional questionnaire survey distributed to HAE subjects (n = 250) obtained information related to STP use outcomes after dental procedures. Patient demographics, comorbidities and their treatment, as well as the frequency, severity and location of their prior HAE attacks were compared between HAE groups with vs. without breakthrough attacks after STP. Analysis was performed using univariate Chi square test of association followed by multivariate generalized linear regression and decision trees after checking for multicollinearity. Results: A higher proportion of HAE subjects with a history of moderate to severe dental procedure-related HAE attacks were on LTP (i.e., 78.8% vs 57.1%; p = 0.002) and received STP during dental procedures (68.2% vs. 40.8%; p = 0.0001) compared to subjects with none to mild attacks.Overall 20 out of 120 subjects being treated with STP reported breakthrough attack after dental procedures (18/20 were on LTP). C1Inh was the most commonly used STP agent being administered to 91 of 120 subjects. Comorbid conditions including 'hypertension' , 'hypercholesterolemia' , 'chronic rhinitis' and use of 'supplementary oxygen' , taking 'phenytoin' and 'immunosuppressant' medications as well as having 'dentures' were significantly associated with a 'history of post-procedure HAE attacks' . After checking for multicollinearity in the univariate analysis, the significant factors used in the multivariate analysis were 'history of procedural angioedema attacks' , 'younger age (< 25.9)' , and comorbid 'asthma' . The above comorbid conditions as well as severity of previous attacks, prodromes, frequency of routine dentist visits, avoidance of dental check-ups/cleanings or procedures because of potential HAE attacks and having dentures were not significantly associated with the occurrence of breakthrough attacks. Conclusion: Young age (< 26), history of post-procedural HAE attacks and comorbid asthma are significant risk factors for breakthrough HAE attacks following dental procedures despite STP and LTP. The significant association of post-dental procedure HAE breakthrough attacks with asthma implies that HAE subjects with comorbid asthma may represent a distinct HAE phenotype which requires further investigation (Table 1). Note: Use of corticosteroids, supplementary oxygen, phenytoin and immunosuppressants (i.e., medications for comorbidities) were significantly associated with breakthrough attacks but were determined to have multicollinearity with history of procedure-related angioedema and therefore, were not included in the multivariate analysis. 30% (20 of 120) subjects receiving STP had breakthrough attacks. About 30% (17 of 57 who received STP) of those with previous history of post-procedural angioedema attacks vs. 3% of those without such history reported breakthrough attacks. About 41% of those with history of asthma vs. 12.6% of those without such history reported breakthrough attacks (  Activation of the lectin pathway of complement is initiated by mannose-binding lectin (MBL)-associated serine proteases 1 and 2 (MASP-1 and MASP-2). MASP-1 and MASP-2 circulate in the blood as zymogens in complex with pattern recognition molecules (PRMs), such as MBL, other collectins, and ficolins. The third serine protease of the lectin pathway (MASP-3), which is also complexed with PRMs, was shown to be the major physiological activator of pro-factor D (pro-FD) in the blood, linking the alternative and the lectin complement pathways. We have demonstrated earlier that only activated MASP-3 is capable of converting pro-FD to factor D (FD), and indeed the major form of MASP-3 in the blood is the active form. The activation mechanism of MASP-3, however, remains unclear. In vitro MASP-1 can activate MASP-3, and C1-inhibitor is the major physiological regulator of MASP-1. We hypothesized that if MASP-1 is the physiological activator of MASP-3 then individuals with low C1-inhibitor levels would exhibit altered MASP-3 activation. The activation state of endogenous MASP-3 was detected by Western blot, whereas in other experiments fluorescently labeled recombinant MASP-3 variants were used. We found that a significant portion of fulllength, labeled MASP-3 became "activated" (cleaved) in hirudin-plasma in the matter of hours even when the inactive S664A variant was used. The activation was less efficient, but still occurred, when the N-terminally truncated catalytic fragment was used. On the other hand, we found that the ratio of active MASP-3 in type I HAE patients was virtually identical with that in healthy individuals, namely 82 ± 3%, versus 81 ± 4%. This indicates that a protease other than MASP-1 is responsible for the activation of MASP-3. To confirm this assumption we monitored the cleavage of labeled MASP-3 in the presence or absence of a MASP-1-specific inhibitor. Again, no difference was observed.

Determinants of breakthrough attacks in hereditary angioedema patients undergoing dental procedures
In conclusion, our results imply that a protease is present in the blood that converts MASP-3 to the active form. The activation is not autoactivation because the inactive variant got cleaved as well. Activation is more pronounced with the full length protein implying that binding of MASP-3 to PRMs might be necessary for efficient activation. Activation of MASP-3 is probably carried out by a protease not inhibited by C1-inhibitor. Background: Bradykinin is considered as the major mediator of edema in HAE, but we have only limited knowledge about the triggering factors and the initiation of the attacks. Bacterial infections are considered as one of the risk factors for the onset of attacks and during these the complement system becomes activated. We have previously demonstrated that the most abundant enzyme of the complement lectin pathway, mannan-binding lectin-associated serine protease 1 (MASP-1), which is naturally inhibited by C1-inhibitor, directly increases endothelial permeability and activates the expression of permeability related genes. Therefore, we wanted to investigate how bacterial LPS, bradykinin and MASP-1 can interact with one another to influence endothelial permeability.

Results and methods:
We measured the mRNA level of BDKRB1 and 2 with qPCR and found that MASP-1 upregulated the level of BDKRB2, while LPS increased the expression of both bradykinin receptors. In concert with this, the MASP-1 or LPS pretreated cells showed significantly greater Ca 2+ -mobilization to bradykinin than those that were not pretreated (measured with fluorescence microscopy). LPS also induced the mRNA level of PAR2, which is a receptor of MASP-1 on endothelial cells, and we demonstrated that MASP-1 elicited grater Ca + -mobilization after LPS pretreatment.
To measure the endothelial permeability, we used the modified X-per-T method. The LPS pretreatment could significantly increase endothelial permeability in response to MASP-1.

Conclusion:
Our findings highlight that significant interaction can occur amongst endothelial cell activators (between MASP-1 and LPS, LPS and bradykinin and MASP-1 and bradykinin) in the regulation of endothelial cell permeability. These synergistic interactions may give us a more detailed picture on the pathogenesis of HAE and highlight the importance of MASP-1 as a potential additional factor triggering edematous attacks. For this purpose, we used a transwell in vitro model with a filter covered by primary human endothelial cells (EC), in the upper chamber we add the fluorescent-BSA and the stimuli and the BSA leaked into the lower chamber was evaluated using a Fluorescence reader. We found that the presence of C1-INH (BehrinertP) was able to block the endothelial permeability induced by the plasma collected from patients during attack (APL) in the majority of the patients. To mimic the in vivo situation we stimulated the EC with the APL for 30 min and then the SN was collected and used to stimulate the ECs in the transwell model. In that case the inhibition of the leakage by C1INH was not seen in all the patients. This observation was further confirmed by using the plasma collected from patients before and 1 h after the clinical treatment with C1-INH. The addition of C1-inhibitor from 10 min before the addition of APL and till 10 min after the addition of APL resulted efficient in the inhibition of endothelial leakage, while the use of C1-inhibitor 20 min after the contact between the APL and the EC resulted completely inefficient. Then we added the antagonist of B1 BK receptor (R954) or the antagonist of B2 BK receptor (Icatibant) and they both resulted able to block the permeabilizing effect of the SN. This inhibition resulted even stronger using a combination of both antagonists.
On the basis of these results, we conclude that the inhibition of endothelial leakage induced by APL stimulation by C1-INH indicates the involvement of that molecule in controlling the onset of AE attacks, although the inability of C1-INH to completely block the permeabilizing effect of the SN indicates that after the activation of the cells there are other molecules involved. The most plausible is BK but also other related metabolites can interact with specific receptors. The effectiveness of the treatment seems to be correlated with the time of treatment, as soon is treated the patient C1-INH is perfectly working but after the activation of the kinin system antagonists of kinins receptors seem to be more efficient in reducing the vascular permeability. Patients are eagerly awaiting next generation treatments for hereditary angioedema (HAE), asking for oral treatment to replace the burden of current injectables. Pharvaris is developing PHA-022121 as a first-in-class novel proprietary small-molecule antagonist of the B2 receptor, for oral on-demand treatment of acute HAE attacks and for prophylactic prevention of attacks. PHA-022121 is entering clinical phase I studies in Q2 2019, was optimized and developed by Pharvaris, a company founded by the team which successfully developed Firazyr the only approved and widely used B2 antagonist for on demand treatment. Based on preclinical studies, PHA-022121 demonstrates excellent drug-like physicochemical properties, primary activity, oral bioavailability and metabolic stability. PHA-022121 shows sub-nanomolar potency in a calcium mobilization assay using recombinant human B2 receptors expressed in a mammalian cell line (0.15 nM) and at endogenous human B2 receptors in the human umbilical vein model (pA2 value corresponding to 0.35 nM). The compound is several thousand-fold selective for the B2 receptor versus the B1 receptor as well as against 130 other molecular targets (including GPCRs, ion channels, enzymes and transporters). Oral bioavailability is high in rat and monkey. In a proof of concept study, PHA-022121 potently inhibits bradykinin-induced haemodynamic changes in freely moving monkeys. The onset of activity was 1 h or less (first time point measured), which was faster than icatibant. PHA-022121 also partially prevents carrageenan-induced paw edema in rat with a longer duration of action as compared to icatibant. Based on experimental data and modeling, Pharvaris expects that a single daily pill of less than 30 mg will provide therapeutic efficacy for at least 24 h. Pharvaris plans to develop PHA-022121 as an oral on-demand and prophylactic treatment of HAE attacks. Background: Approved acute treatments for angioedema attacks in hereditary angioedema (HAE) are administered parenterally, including plasma kallikrein inhibitors. Guidelines recommend at-home on-demand treatment. BCX7353, an orally administered kallikrein inhibitor with fast onset and sustained duration of action, may improve access to self-administered treatment and allow earlier dosing after symptom onset. Methods: BCX7353 doses for evaluation of efficacy in HAE subjects were selected using pharmacokinetic (PK) and pharmacodynamic (PD) evidence from the first-in-human trial in healthy subjects (dose range: 30 to 1000 mg). Separately, plasma concentrationtime profiles, plasma kallikrein inhibition (KKI)-time profiles, and PK-PD relationships of orally administered BCX7353 (750 mg) were evaluated in 6 HAE subjects. We separately conducted a proof-ofconcept clinical trial (ZENITH-1) using a 3-part, dose-de-escalation, randomised-sequence, double-blind, placebo-controlled, 3-period crossover design. Subjects were randomised in each part to 2 treatments with BCX7353 (at the same dose level) and 1 with placebo; for each treatment, subjects confirmed the attack with the investigator before dosing. This trial tested on-demand at-home treatment of angioedema attacks with 750, 500, and 250 mg doses of BCX7353 in 58 subjects with HAE. Subjects recorded symptoms and interventions using standardised questions and visual analogue scales (VAS) for skin swelling, skin pain, and abdominal pain in a diary. Results: Drug levels (   Here we report ATN-249's pharmacokinetics (PK) and safety from a 14-day multiple ascending dose study and its in vitro potency relative to an approved plasma kallikrein inhibitor. Materials and methods: Healthy participants received multiple doses of ATN-249 100 mg QD, 200 mg QD, 400 mg QD, 300 mg BID, or placebo for 14 days (6 ATN-249:2 placebo in each dose cohort). Serial blood draws and urinalysis were conducted to calculate PK parameters. Adverse events (AEs) were assessed. Separately, the potency of ATN-249 and lanadelumab, a subcutaneously administered plasma kallikrein inhibitor, were tested in biochemical inhibition and contact activation assays in human plasma as well as in a semi-quantitative Western blot assay evaluating attenuation of cleaved kininogen. Results: PK parameters following 14-day QD regimens were dose proportional (Table 1). With repeated dosing over 14-days, trough concentrations were on average approximately 200 ng/mL (460 nM) and generally exceeded 527 ng/mL (1.2 µM) for 400 mg QD and 300 mg BID regimens, respectively. Average concentrations at steady-state (C avg ) were approximately 683 ng/mL (1.57 µM) and 1198 ng/mL (2.7 µM) for the 400 mg QD and 300 mg BID regimens, respectively. Across treatment and placebo cohorts, the most common AEs were headache, contact dermatitis secondary to ECG lead placement, and nausea. All AEs were self-limited and not related to study drug. Mean ATN-249 trough concentrations for the 400 mg QD and 300 mg BID dosages exceeded expected therapeutically relevant concentrations and were greater than those demonstrating attenuation of cHMWK   Hereditary angioedema (HAE) represents a rare disease connected with inherited predisposition for angioedema (AE) development in various locations. More frequently, different forms of acquired angioedema can be seen in daily clinical practice. Isolated angioedema can be also a rare clinical phenotype of chronic spontaneous urticaria. Diagnostic approach and treatment strategies differ among different forms of AE. We present a rare and unique case of 67-year-old man with negative family history for angioedema or urticaria. There were no significant diseases in the history before the onset of angioedema. He was treated for benign prostatic hyperplasia and recurrent urinal infections. At the age of 66 years, he was admitted to the hospital for severe abdominal pain, which was evaluated as acute idiopathic pancreatitis. Abdominal CT scan revealed abdominal lymphadenopathy and small lymphocytic lymphoma/chronic lymphocytic leukaemia was diagnosed. Patient was regularly followed-by haematologist without any treatment (watch&wait). 4 month after the attack of pancreatitis, recurrent facial angioedema with tongue swelling was observed and patient had at least 3 attacks of acquired angioedema I type was confirmed (with haematooncological background) and following 2 facial attacks were successfully treated with icatibant with rapid relief of symptoms within 2 h after application. Besides typical symptoms of AAE, recurrent symptoms of generalised urticaria associated with intense pruritus were observed. Treatment with desloratadine was initiated (from single dose up to 4-times increased dose), but without any clinical effect. UAS7 score was permanently above 28 points and therefore a treatment with omalizumab was initiated. After second application of omalizumab, complete remission of urticaria was succeeded.

O24
Hereby, we present a unique case of two separated diseases -acquired angioedema of I type and chronic spontaneous urticaria. Despite their similarities, two therapeutic strategies were used for achievement of clinical control over the symptoms. We would like to point out the possible clinical co-existence of two rare diseases, what should be taken into account during the differential-diagnostic algorithm of angioedema in clinical practice.  1%) had Angiopoetin 1 mutation, 21/181 (11.6%) the mutation was unknown and 17/181 (9.4%) weren't tested yet (Table 1). Eight symptomatic patients with F12 mutation (8/141, 5.6%) underwent surgical procedures due to angioedema: laparotomy, 4 (2.8%); laparoscopy, 3 (2.1%); tracheostomy, 1 (0.7%). Among symptomatic patients with unknown mutation, 2 were submitted to laparotomy (2/38; 5.3%). Thirteen (13/181, 7.2%) were admitted in ICU during attacks at least once and 3/181 (1.7%) died due to HAE attacks. Of the symptomatic patients, 38/181 (21%) did not receive any specific treatment. The patients treated (143/181, 79%) were 116/143 (81.1%) with F12 mutation, 25/143 (17.5%) with unknown mutation and 2/143 (1.4%) with Angiopoietin 1 mutation. Among the patients who underwent specific treatment: 45/143 (31.5%) only stopped or modified contraceptives; 32/143 (22.4%) were medicated during the attacks only and 66/143 (46.1%) received long term prophylactic treatment. Short term prophylaxis was performed for 28/143 (19.6%). Tables 3 and 4 refer to drugs used for on-demand treatment and prophylaxis.  A central venous access was placed initially for home self-infusion in two patients. One of these patients developed sepsis secondary to central venous access contamination. Another patient suffered from headache secondary to fast pdhC1INH infusion and then home self-infusion with a pump was started with good tolerance. This patient also had facial malar erythema with Cinryze ® but tolerated Berinert ® . No viral seroconversion was detected. One patient died due to a breast cancer unrelated to pdhC1INH. No other sideeffects were observed. The patient or a relative were trained in IV pdhC1INH self-administration in all the cases. Conclusion: pdhC1INH LTP was more frequently needed by women, proved to be an effective, safe and well tolerated alternative in patients with contraindications for administration of conventional LTP, including pregnancy and lactation. Background: Hereditary angioedema due to C1-inhibitor deficiency (HAE-C1-INH) is a rare autosomal dominant inherited disease. The recurrent swelling attacks such as subcutaneous edema and coliclike abdominal pain negatively affect quality of life (QoL). Laryngeal edema is rare, but life-threatening if untreated. C1-INH is currently approved for prophylaxis to routinely prevent attacks in patients aged ≥ 6 (EU) and ≥ 12 years (US). Real life data in nine pediatric patients with HAE who received C1-INH concentrate for the routine prevention of angioedema attacks was documented and followed up. Methods: After giving informed consent the following data was collected and analyzed from patient's diaries and records 1 year before onset of and after introduction of prophylactic treatment: age at first manifestation and diagnosis, age at first treatment, frequency and location of attacks, prophylactic respectively on-demand therapy regimen. Initial standard prophylactic treatment (SP) consisted of 1000 U C1-INH, (bw > 40 kg) or 500 U C1-INH (bw < 40 kg) every 3-4 days i.v. and was intensified (individualized prophylaxis-IP) in case of > 2 breakthrough attacks per month. In 2 patients the prophylactic regimen had to be intensified to every 2 days regimen. Results: Six patients (3 male/3 female) aged 4.5-17.2 years with HAE-C1-INH type I were enrolled. Attacks before onset of prophylaxis occurred 3-11 times/month and affected mainly abdomen and extremities but also face; a history of laryngeal attacks was reported in four patients. SP resulted in zero break-through attacks in 4/6 patients during a prophylaxis period of 6 -41 months. Two patients still presented > 2 break-through attacks/month. Consecutive IP resulted in zero break-through attacks in these patients as well during 20-38 months.

Materials and methods:
We present the evolution and management of repeated angioedema attacks during pregnancy in a woman with HAE, with normal levels and function of C1-INH and a mis-sense mutation in F12 gene. She had been diagnosed in 2012, during her first pregnancy, due to a severe facial angioedema attack. She had previously suffered from several angioedema attacks after starting oral contraceptive hormone treatment. Results: Her second pregnancy was marked by recurrent episodes of facial angioedema. She was on sickness leave since the 7th week of pregnancy and was followed up in the high risk pregnancy consultation. During the first pregnancy trimester the patient was treated several times with intravenous plasma derived human C1-INH concentrate (pdhC1INH) (Berinert ® , CSL-Behring, Marburg, Germany) in the Emergency Room, sometimes needing two or three 1,500U doses to resolve the attack. pdhC1INH was discarded as LTP due to lack of efficacy in the treatment of acute angioedema attacks. The patient was evaluated by a haematologist before starting oral tranexamic acid (TXA), who recommended co-treatment with sodium bemiparin 7,500U daily and hematologic controls every few weeks. She was asymptomatic for 4 months immediately after starting oral TXA 500 mg every 8 h, having just 3 mild attacks in the last 3 months of pregnancy and treating 2 of them with 1,500U of pdhC1INH with acceptable response. A caesarean delivery was scheduled because of a prior caesarean and short term prophylaxis with IV pdhC1INH (1,000U) was administrated. She discontinued TXA the night before the delivery, which went through without incidences, and a healthy female baby was born. A tubal ligation was also performed. She was breastfeeding and had to continue the treatment with heparin for 6 weeks after the delivery. No new angioedema attacks were observed postdelivery. A F12 gene mutation was discarded in the newborn. Conclusions: In our patient, a successful management of the angioedema attacks during pregnancy was carried out with TXA and anticoagulant treatment. No side effects were observed. Background: Type I hereditary angioedema (type I HAE) is a rare genetic disease characterized by episodes of subcutaneous or mucosal edema, without urticaria or pruritus, that can be fatal due to laryngeal swelling. In Mexico the diagnosis is usually delayed due to lack of clinical suspicion in first-contact physicians. The most frequent previous diagnosis is chronic urticaria, whereby patients receive recurrent and prolonged treatment with antihistamines and corticosteroids. Metabolic syndrome (MS) is traditionally an adult disease, however its prevalence in pediatrics is increasing; is characterized by a combination of dyslipidemia, abnormal glucose regulation, central adiposity and hypertension. It has defined diagnostic criteria for children between 10 and 16 years (Table 1), in those under 10 years of age it is not possible to make the diagnosis due to lack of consensus. MS is associated with a higher risk of developing cardiovascular disease and type 2 diabetes (T2D). We present the case of 2 patients with type I HAE who met criteria for metabolic syndrome. The third patient had a diagnosis of Cushing syndrome (Table 2).

Case report:
We present the case of 3 patients with type I HAE who before diagnosis received multiple cycles of systemic corticosteroids as treatment for angioedema, emesis and abdominal pain. Two patients met obesity criteria by body mass index (BMI); within their diagnostic approach multiple metabolic disorders were evidenced: hypertriglyceridemia, low high density protein (HDL) cholesterol, increased abdominal circumference and hypertension for age, fulfilling criteria for metabolic syndrome. The third patient was obese, with full moon face, hirsutism, dorsal fat pad and total cholesterol level in 232 mg/dl, diagnosis of Cushing syndrome was made. Conclusion: Metabolic syndrome, obesity and cushing syndrome are serious complications of the excessive use of steroids in patients with type I HAE. As allergologist we must intervene quickly and aggressively seeking to avoid the increased in cardiovascular risk and type 2 diabetes in this group of patients. Consent to publish: Informed consent to publish has been obtained from this patients parents.   . FFP was effective in all cases, the edema and pain decreased within one hour and in 4-6 h the patients were transferred from intensive to a usual unit. Yet, after the FFP 2 patients developed rash and scleral icterus (probably due to not sufficient plasma purification) that went back to normal in 3-5 days of antiallergic and detoxication therapy. In Ukraine, FFP is also transfused upon a severe abdominal attack when a patient is in intensive care for an average of 3 days. The attacks of the peripherals are not treated because they are not life threatening. As shown in Table 1, during 2018 men and women had HAE attacks mainly of peripherals and abdominal parts. Men had twice more facial and upper airway attacks. When compared with others, the patients that suffer HAE from their childhood have more severe and frequent attacks.  Rationale: Dental hygiene behaviors and practices in HAE subjects, (i.e., the frequency of routine dental care visits and use of dental hygiene products) may be influenced by severe life-threatening episodes triggered by routine professional dental procedures. We utilized a questionnaire to analyze perceptions by HAE subjects about personal dental care practices compared to non-HAE (control) populations.

P06 Hereditary angioedema with C1-inhibitor deficiency (HAE-C1-INH) in childhood and adolescence
Methods: A self-reported questionnaire linked to REDCap ® server was distributed to gather information on differences in dental care perceptions and behaviors in HAE (n = 250) and non-HAE populations (n = 256) matched by age, gender, race, and ethnicity. Chi square analyses and a generalized linear model (SAS) were used to determine the significance of association between several parameters related to dental care beliefs and utilization of dental care products, using the questionnaire responses from both groups. Results: He frequency of routine dentist visits did not differ significantly between groups, but among the HAE group it was significantly less in subjects with previous post-procedure angioedema (AE) attacks. Interestingly, antibacterial toothpaste usage was higher among HAE subjects (9.6% vs. 4.3%, p = 0.02). The odds of using antibacterial toothpaste was significantly higher among HAE subjects concerned about AE attacks and actually experiencing attacks than those not concerned or experiencing such attacks (OR: 3.3 [1.1, 9.7], p = 0.03). Conclusion: Experiencing angioedema attacks after prior dental procedures was the most significant determinant in HAE subjects resulting in less frequent routine dentist visits and preference for using anti-bacterial toothpaste. Background: Prodromes of Hereditary Angioedema (HAE) are frequently reported in close association with the swelling attacks. Since attacks usually follow prodromes in a close proximity, patients may not be able to tell the difference between the two events. For practical purposes, especially self-administration and timing of treatments, it is important to distinguish prodromes from attacks. We sought to investigate the differences and correlations between prodromes and attacks, by using a new validated PRO instrument.

P09 The relationship between disease activity and quality of lifea first-time survey in hereditary angioedema
Methods: We designed and tested a questionnaire-based PRO instrument for the evaluation of HAE prodromes and attacks. The high internal content validity and reliability (Cronbach's α = .70 to .96) render it suitable for studying clinical expressions of HAE. A cohort of 66 HAE patients completed a questionnaire, developed specifically to address their most recent experience with prodromes and attacks. It incorporates five 'clusters' of body systems: limbs, abdomen, face, laryngeal, genitalia. This instrument was powered to evaluate if they could distinguish between five dimensions of prodromes and subsequent attacks. Items included: location, pain, intensity, impairment and dysfunction.
Patients were asked to grade their experience in both events on a Visual Analog Scale (Likert) of 0-10 cm. Results: One-way MANOVA with repeated measurements, on all dimensions, showed significant differences between the clinical dimensions of prodromes and attacks, in all body clusters [F (4, 56) = 45.7, P < .001, Eta 2 = .77]. Patients could distinguish between the two and consider them separately, but associated. Additionally, oneway ANOVA for each dimension demonstrated very high differences. . Therefore, we could demonstrate that higher intensity of a prodrome was followed by higher intensity of an attack. Collectively, the intensity, severity, impairment and loss Introduction: Hereditary angioedema (HAE) is a rare disease characterized by recurrent attacks involving hand-arm-leg, face, bowels, genitals and upper airways. Although symptoms usually begin in the first 10 years of life, the frequency and severity of attacks increase in adolescence. In this study we analyzed that how the sexual life quality is affected by HAE attacks' severity and frequency, attacks after sexual intercourse and anxiety and depression in HAE. Material and method: Forty-eight patients who have been followed at Ege University Medical Faculty Internal Medicine HAE special clinic were enrolled in this study. Socio-demographic characteristics of the patients, disease onset age, attack localization and frequency, gender-specific sexual life questions were assessed. Hospital Anxiety and Depression Scale (HAD) and new sexual satisfaction scale (NSSS) were also applied.
The adaptation and reliability studies of HAD for the Turkish population showed that 7 were cut-off scores for depression and 10 were cut-off scores for anxiety. Higher values than these cut-off points were defined as depression risk and anxiety disorder risk. Results: Of the 48 patients with the average age 39.89 ± 13.68; 26 (54.2%) were female. In females, the mean score of NSSS was 65 ± 14.24 and the mean anxiety score 8.38 ± 3.16 and the mean depression score was 6.1 ± 3.85; whereas mean scores of males were 72.95 ± 17.71, 7.4 ± 3.69 and 5.36 ± 3.27, respectively. The mean NSSS score of the patients which had attacks depending on sexual intercourse (n = 10; 63.8 ± 25.02) was lower than the patients which did not have attacks (n = 32; 71 ± 12.96) (t = 0.87, p = 0.402).

Discussion:
The sexual life of HAE patients with depression risk are affected negatively, therefore an intervention for this group should be planned. We believe that this study shed light on the related problem and will lead to further studies. We did not find any significant finding in women. Most probably female patients had not been able to answer the questions honestly due to the privacy of sexual satisfaction scale questions. Background: In the last decades several migrants with C1-inhibitor hereditary angioedema (C1-INH-HAE), a rare and potentially life-threatening disease, has moved to Denmark. HAE is known to impact quality of life (QoL) and patients often face a high disease burden, but there is a lack of data pertaining immigrants living with this rare disease. The objective of this study is therefore to investigate and improve our understanding of how patients of other ethnic backgrounds experience living with HAE in Denmark, and to gain deeper insight into these patients' understanding of disease, challenges and management of symptoms in their everyday life. We also explore their past and familial experiences from their countries of origin.

Materials and methods:
The study is designed as a qualitative study, based on semi-structured interviews, to ensure a deep and broad understanding of the patients' experiences. The participants are recruited from the group of adult immigrants that are treated at the national HAE center. In addition to the interviews, patients are asked to complete two quality of life questionnaires, EQ-5D and HAE-QoL. The anonymized data will be analyzed descriptively. Allergy Asthma Clin Immunol 2019, 15(Suppl 4):45 Results: 9 out of 13 adult immigrants with HAE in Denmark have chosen to participate in the study (age 21-60 years). Collection of data is ongoing until April 2019 and results of selected thematic areas will be presented. Preliminary results show that one main concern for several migrant patients is not receiving accurate treatment at emergency departments, when they present with severe attacks and emergency medication.
Conclusion: This study is expected to provide unique information about migrants experiences living with a rare disease in Denmark. Preliminary data highlights the challenges, but also importance of teaching migrant patients home therapy, as is also the case for ethnic Danish patients. Conclusion: This study highlights the importance of AE episodes in EDs or ICUs concerning patients under renin-angiotensin system inhibitors. No calls were made for known bradykinin mediated AE patients, as these patients are educated to the treatment of acute episodes. The absence of validated diagnostic criteria or tests to formally differentiate mast cell mediated AE in patients treated by an ACEi from an authentic ACEi induced BK-AE render the use of costly and restricted treatments unavoidable in urgent settings like the ER or ICUs. These patients should be addressed to specialists to avoid ulterior inappropriate treatment in case of recurrence. Between October 2017 and February 2019 patients attending HAE clinics were approached to complete the questionnaire and 24 agreed. All HAE patients in our clinics have access to a range of therapies. Some prefer to take traditional oral prophylactic therapies (attenuated androgens, tranexamic acid); others treat symptoms with icatibant or C1 esterase inhibitor concentrate (C1INH). C1INH (plasma-derived or recombinant) is available for short-term prophylaxis (pre-surgery, dental) or longer term (school/college exams) according to the UK HAE consensus document [1].

Results:
The questionnaire comprises 25 questions reflecting the previous 6 months. The answers are graded out of 5 or 6 with higher score reflecting 'not a problem' and lower score 'extremely' . Answers are captured into 7 dimensions: physical functioning and health, disease related stigma, emotional role and social functioning, concern about offspring, perceived control over illness, mental health, and treatment difficulties. The results are presented here by gender and age ranges for each dimension. Note: no female patients in this cohort fell into the age range 35 -50 years. Conclusion: High scores across all dimensions (mean and median scores) suggest this group of patients has reasonably good quality of life apart from one outlier, a female aged 50 + . However lower scores for perceived control over illness highlight the unpredictable nature of HAE attacks even if few patients experience treatment difficulties. The author intends to repeat this study when new 'pipeline' prophylactic medications become available for UK patients. Acknowledgements: Alex Symons, MSc Student Archaeological Science, University of Oxford for help with data presentation. Hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) is characterized by recurring and spontaneously resolving edematous attacks with not fully understood pathomechanism. Previously many studies published on the activation of plasma enzyme systems during edematous attacks, nevertheless kinetic follow-up has never been performed. For the first time, we aimed to study the kinetics of parameters in the coagulation and fibrinolytic systems in a spontaneously resolved edematous attack of a C1-INH-HAE patient.
In a 56-year-old female with C1-INH-HAE we monitored the severity of the symptoms during the observation period and altogether twelve blood samples were obtained. Blood samples collected from a healthy control volunteer at 5 different times during a 24-hour period. We measured Factors XI and XII activities (FXIa, FXIIa), prothrombin time (PT) and activated partial thromboplastin time (aPTT) as well as concentration of Factor V, VII and X (FV, FVII and FX respectively), prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin (TAT)-complex, D-dimer, fibrinogen. After a 24-hour symptom-free period and another 19-hour prodromal period (characterized by erythema marginatum), the patient had a 29-hour-long edematous attack in multiple skin locations, and was followed up for another day. During prodromal stage-the levels of D-dimer, F1 + 2 and TAT-complex were as constantly low as those levels measured in the healthy control, whereas fibrinogen level increased. Levels of F1 + 2 and TAT-complex were significantly elevated at the onset of edematous symptoms whereas level of D-dimer was elevated after 6 h. Levels of all three parameters reached maximum 12 h after reaching the maximum severity score of symptoms. FXIIa and FXIa as well as the levels of FV, FVII and FX did not show unidirectional changes during the observation period. PT and aPTT did not shorten before or during the edema. Real-time monitoring of F1 + 2 and TAT complex suggest that thrombin may contribute to edema formation. Whereas the generation of thrombin probably not related to the activation of neither the intrinsic nor the extrinsic pathway of coagulation but related to other factors such as MASP-1 or MASP-2. We confirmed that D-dimer is a prominent biomarker of an ongoing edematous attack while fibrinogen is could be a biomarker of prodromal period. This study was a part of a project aimed to better understandthe mechanisms leading to the onset and to the resolution of edematous attack. This study was supported by OTKA 112110 and the ÚNKP-16-3 New National Excellence Program of the Ministry of Human Capacities". Consent to publish: Written, informed consent for publication was obtained from the patient and control person. Sixty-six of the attacks were severe, 71 moderate and seven mild. One hundred and twelve attacks were treated with subcutaneous injection of Icatibant and four with additional plasma-derived C1-INH. Ten patients were on prophylactic therapy.

Conclusions:
A prospective long-term registry is a critical tool in building a broad and comprehensive knowledge base. By continuing to introduce valid data from as many patients as possible,useful information can be obtained for the better knowledge of thisrare disease.

P20
Hereditary Conclusion: To achieve an optimal control of symptoms, a precise treatment adapted to the severity of the disease is needed. According to this questionnaire, patients had an impaired QoL most prominent in the fatigue/Mood dimension. Surprisingly, no significant differences in QoL were found between patients requiring LTP, more severe cases, and patients in "on demand" treatment. The long interval between the onset of symptoms and the confirmation of the diagnosis was notorious in both groups.

Rationale:
In 2016, the French Educational Program "EDUCREAK" was assessed by the French Health Care Agencies (ARS) and further approved for an additional 4 years. This pilot program was initially developed in cooperation with staff from four sites in France. After the program's implementation and success in four years, our new objectives are to scale up the program on a national level and streamline best practices among HAE healthcare professionals (HCP). Methods: To reach these objectives, meetings and workshops were held to interactively share the different experiences and methods used by HCP. From these sessions we reflected and drew conclusions on the optimal way to cater to both adult and children HAE patients. We weighed costs and grants required to deliver adequate outputs. In a participatory approach, patients and HCP were asked to work together to attain common objectives, guided by a step-by-step explanatory sheet. Training kit components were then tested by HAE advocate patients and HCP in the last five months to ensure satisfaction.
An evaluation system has been established to keep measuring the kit's efficacy. Indicators are not only based on autonomous and safe patient skills but also on quality of life (HAE-QoL and AE-QoL scores) Results: According to the above criteria, an educational training kit was designed and delivered to assist HCP in providing skills for quality care for HAE patients. It has now been streamlined in 12 sites across the country (an additional 8 compared to the previous 4). We thank the French Ministry of Health for their financial support to the National Reference Centre for Angioedema "CREAK".

Conclusions:
We are pleased to present a valuable training kit for HAE patients and their HCP. In May, the training kit will be launched in Paris. Next steps include ensuring the training of HCP on using the training kit and systematically evaluating the 10 different sites where they will be used.
In about 5% of C1-INH-HAE cases no mutation in the coding region of SERPING1 can be detected. Bearing in mind that non-coding variants can potentially have deleterious effects on a transcript through the regulation of splicing or transcription, defects located in an intronic or an untranslated region of the gene have been considered responsible for modifying C1-INH expression in these cases. However, until today no such alteration has been described. Here, we present a deep intronic SERPING1 variant associated with type I

P26
The silo effect in the annotation of SERPING1

LMWH* Tranexamic acid
consequence of the permeability increasing effect of the elevated bradykinin (BK) level. Because of this key role of ECs in the edema formation, the question emerges: can ECs somehow downregulate the permeability increasing effect of BK? Although C1-INH production of endothelial cells was reported, the data are not consistent and sometimes are controversial. Since different tissues behave quite diversely during edematous attacks, we aimed to map the C1-INH producing capabilities of various ECs. We studied the regulation of C1-INH production by several potential factors -known to trigger edematous attacks-on endothelial cells. We measured the C1-INH mRNA production of primary ECs, such as human umbilical vein and arterial ECs (HUVECs and HUAECs), human dermal microvascular ECs (HDMECs) and human glomerular ECs (GECs), as well as of EC line, human brain microvascular ECs (HCMEC-D3), and of HepG2 cell line as a positive control. After this we used different stimuli: thrombin (TR), BK, TGF-beta, interferon gamma (IFNg), and TR and BK together, and measured the change of mRNA and protein levels of C1-INH after 24 and 48 h. We used qPCR to measure mRNA levels, and an in-house ELISA to detect C1-INH protein production.
We found that all investigated ECs can produce C1-INH at mRNA level. The concentrations measured with AgELISA in type II patients and in the controls were similar; however, activity levels were lower in the patients. In type I HAE, the activity/concentration ratio was not different from that seen in controls; however, it was the lowest in type II C1-INH-HAE. C1-INH levels were similar between samples obtained during attacks or during symptom-free periods. Kinetic monitoring of an edematous attack revealed that the activity/concentration ratio was the lowest (56%) at the onset of edematous symptoms, owing to the reduced activity measured at this time (0.018 g/L). We showed for the first time that absolute activity and activity/concentration ratio of C1-INH touches a bottom at the onset, but some improvement occurs at the peak of the symptoms. In contrast with kinetic monitoring, C1-INH levels measured during symptom-free periods or during attacks were not different in the cross-sectional study of the patients. This may be explained by the variability among individuals and edematous attacks, as well as by the differences in time between symptom onset and blood sampling. Supported by: OTKA 112110. Background: We recently investigated the pathways of immunoreactive bradykinin (iBK) formation in fresh blood of normal volunteers and of patients with hereditary angioedema due to C1-esterase inhibitor deficiency (HAE-1/-2) [1]. Since we did not detect iBK formation following platelet or neutrophil activation in whole blood, we adapted the techniques to small volumes (200 μl) of previously frozen plasma and further analyzed the mechanisms of iBK formation with additional biotechnological inhibitors. Materials and methods: Each experimental point was obtained using 200 μl of thawed citrated plasma transferred to a 1.5 ml conical test tube; activators or inhibitors were added to test various pathways of kinin generation. All tubes contained enalaprilat to protect BK from rapid inactivation. The tubes were incubated under rotary agitation in a pre-equilibrated (37 °C) Thermomixer apparatus. The ethanol extraction, sample evaporation and enzyme immunoassay were then performed as described [1]. Results: iBK formation was observed under stimulation with tissue kallikrein (KLK-1, 10 nM), the particulate material Kontact-APTT (concentration reduced to 2% v/v) or recombinant tissue plasminogen activator (tPA, 169 nM), with little background in unstimulated plasma incubated for up to 2 h. Plasma samples from HAE-1/-2 patients responded earlier to tPA than those from controls, as previously reported with whole blood. Lanadelumab inhibited iBK formation induced by Kontact-APTT and tPA. A highly specific plasmin inhibitor, DX-1000, abolished tPA-induced iBK formation in plasma but had no effect against Kontact-APTT, confirming the role of fibrinolysis in tPAinduced kinin formation. The anti-lanadelumab neutralizing antibody M293-D02 reversed the inhibitory effects of lanadelumab. Conclusions: Frozen plasma is a suitable material for measuring iBK formation kinetics, with possible applications such as investigating the effect of rare disease states on the kallikrein-kinin system and monitoring the effect of HAE prophylactic treatments. The instability of the kallikrein-kinin system in HAE-1/-2 may reside in the upstream fibrinolytic system. Introduction: Early treatment of acute attacks in HAE is associated with improved clinical outcomes. These clinical benefits are attributed to the reduction of plasma kallikrein mediated high molecular weight kininogen (HK) cleavage and bradykinin action. The effects of PKa inhibition on contact system activation has received relatively little attention. This study examines the effects of KVD900, a rapidly acting oral PKa inhibitor with high clinical exposure, on plasma prekallikrein cleavage and PKa activity during contact system activation. Methods: Single ascending doses of KVD900, a potent and selective small molecule plasma kallikrein inhibitor, were administered orally using a powder-in capsule formulation to healthy adult males. Pharmacodynamic measurements were determined in dextran sulphate (DXS) stimulated whole plasma using a fluorogenic enzyme assay to measure PKa catalytic activity. A capillary based immunoassay was used to measure plasma prekallikrein and HK cleavage following DXS stimulated contact system activation.

P34 Increased fibrinolysis-induced bradykinin formation in hereditary angioedema confirmed using stored plasma and biotechnological inhibitors
Results: Kinetic enzyme assays on whole plasma demonstrated that the orally administered 600 mg capsules of KVD900 achieved > 98% inhibition of DXS-stimulated PKa activity between 90 min and 3 h and provided > 90% inhibition of PKa catalytic activity between 30 min and 6 h post-dose. Moreover, the time for detectable DXS-stimulated PKa activity (lag time) was prolonged > 5 fold in plasma samples at 30 min post-dose, suggesting that KVD900 rapidly prevented the generation of PKa from plasma prekallikrein. Immunoassay analysis of plasma prekallikrein confirmed that KVD900 reduced DXS-induced plasma prekallikrein activation from 60.5% in pre-dose to < 20% at 1 h and 6 h post dose. Reduced plasma prekallikrein activation correlates with protection of HK from cleavage. The tablet formulation to be used in upcoming clinical studies achieves effective concentrations in less than 30 min, rapidly reaching complete PKa inhibition, and maintains > 85% PKa inhibition for up to 10 h. Conclusions: Orally administered 600 mg KVD900 achieves rapid plasma exposure sufficient to inhibit the formation of active PKa from plasma prekallikrein during contact system activation. These results suggest a mechanism to halt HAE attacks following early administration of KVD900.

P36
The On 39 occasions, the symptoms failed to improve or to resolve after the administration of a single dose. A second dose was administered in 23/39 instances, and this eliminated the symptoms in 20/23. The angioedema attack recurred in 9.3% of the instances (n = 51). We did not find any significant difference in time to injection between icatibant-responsive and non-recurrent vs. rebound attacks. However, the latter occurred in 16.32% of instances when the time to injection was 30 min or less, and in 7.71% when it was longer than 30 min. Thirty-three patients experienced a skin reaction at the injection site. On average, satisfaction with the treatment was 88.65 on a 100-mm VAS, and a mean score of 9.05 was assigned on a scale of 1 to 10. Conclusion: Icatibant is an effective and safe medicine with a rapid onset of action in C1-INH-HAE. We can conclude that early treatment resulted in quicker resolution of the symptoms, however 30 min or less administration time showed higher percent of rebound attacks. Local skin reactions were common, but possibly drug-related systemic adverse effects did not occur. This study was supported by OTKA K124557.