Selective Iga Deficiency
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Contents |
Etiology
- pharmaceutical agents reported to cause IgA deficiency
Epidemiology
- most common immunoglobulin deficiency
- found in approximately 1/600 healthy subjects
Pathology
- frequently associated with IgG subclass IgG2 & IgG4 deficiency (may be risk factor for severe infection)
- most patients have normal levels of circulating B-cells which fail to differentiate into plasma cells secreting IgA
- pulmonary disease is common & often severe
- infections are most frequently caused by encapsulated organisms
- decreased antibody response to carbohydrate antigens such as pneumococcal vaccine
- bronchiectasis & obstructive airway disease occur in 40% of patients
- patients may make IgE anti- IgA
Genetics
- associated with defects in TNFRSF13B (type2), also seen with common variable immunodeficiency
Clinical-manifestations
- most patients are asymptomatic or minimally symptomatic
- recurrent sinopulmonary & gastrointestinal infections ( giardiasis) may occur
- autoimmune disease may also occur [2]
Laboratory
Complications
- greater prevalence of:
- allergy, especially food allergy
- autoimmune diseases
- maligancies
Management
- not an indication for intravenous immunoglobulin, except for patients who are also deficient in IgG2 or IgG4 (monitor closely)
- anaphylactoid reactions have occurred when IgA-deficient patients are given blood transfusions or IgG preparations containing small amounts of IgA ( IgE anti- IgA)
More General Terms
Additional Terms
Internet Database
OMIM: 609529
References
- Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 747
- Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, American College of Physicians, Philadelphia 1998, 2006, 2009
