Blood transfusion reaction in a patient with immunoglobulin A deficiency.

Selective deficiency of serum IgA is the most common immunodeficiency in humans; when immunodeficient individuals receive blood transfusions a severe anaphylactoid reaction can develop. The present report describes such a patient. After the transfusion reaction a hemagglutination inhibition assay revealed that her blood contained less than 1.0 micrograms/ml of IgA and an anti-IgA antibody that reacted with the 2 IgA proteins, isotypes IgA1 and IgA2. Immediately after the reaction the patient's serum anti-IgA antibody titer was 1:16,384, and when reevaluated 5 weeks later it was 1:8000. All 3 of her children were shown to be IgA deficient, and 2 of them had antibodies against IgA2. This type of anaphylactoid reaction can be avoided by transfusing blood from IgA-deficient donors, frozen deglycerolized red cells, or red cells that have been washed several times to extract all IgA proteins.