Passive blood anaphylaxis: subcutaneous immunoglobulins are a cause of ongoing passive anaphylactic reaction

Table 5 Difference between immunoglobulins (ScIg, IVIg) and typical drugs

Feature	Drug/medicine	Immunoglobulin
Source	Chemical (for example catalytic, enzymatic) reaction “IN VITRO”	Plasma obtained from blood donors^a “IN VIVO”
Chemical composition, dose	Known (standardization following pharmacopeia) Dose [g] describe active compound content	Not precisely defined Protein (in reality proteins complex) Dose [g] describe total protein content
Clinical pharmacology
Mechanism of action	Defined (by strict receptors)	Multifactorial (depends on antigenic specificity)
Elimination and half-life (T½)	Renal intestinal etc. after easy diffusion from tissue compartment Strictly defined T½	Not known Serum T½ does not reflect immunoglobulin elimination, but FcR opsonization^b
Unpredictable adrs
Immunogenicity	Usually low (in general haptenic formula)	Pathological anti—IgA^c
Immunoreactivity (immune reaction to pharmaceutical product)	Rare, but ever probable (e.g. benzylpenicillin allergy)	Physiological tolerance or antiidiotypic immune response^d

Immunoglobulins are a pharmaceutical product with unique technology, contrary to bio-synthetic drugs
^aImmunoglobulin preparation is plasma fractionation: plasma is obtained in accordance with WHO guidelines from at least 1000 donors
^bAfter immunoglobulin distribution to tissue compartment FcR opsonization occurs (see Figs. 2a, 3). It blocks inverse diffusion to serum
^cIn clinical practice immunoglobulins are used as replacement therapy in patients with primary and secondary immunodeficiencies. Lack of active immune response after antigenic stimulation (e.g. vaccination) in such patients is one crucial mechanism of low immunogenicity. Contrary to CVID, patients with selective IgA deficiency may produce IgG that reacts with IgA in immunoglobulins (product characteristic of many immunoglobulins as well as Subcuvia^® does not contain essential contraindication—selective IgA deficiency)
^dWhen immunoglobulin is used in immunomodulatory therapy (autoimmune disease) the immune response to immunoglobulins and hyperreactivity may be observed. For example Rheumatoid factor from patients with autoimmune disease and IgG from pharmaceutical product

ISSN: 1710-1492