Abstract
IgA is best known in transfusion practice for its deficiency when anti-IgA antibodies cause severe anaphylactic reactions. Following the realization that IgA deficient products were needed on demand, blood donors were routinely screened, initially by latex agglutination inhibition and subsequently by hemagglutination inhibition using an Olympus PK-7200™ blood grouping machine. IgA deficiency (<.0016 g/L) was found in 357 (with anti-IgA in 28%) of 301,310 donors, an incidence of 1 in 844. By screening new donors and directed call-up, group O, D-red blood cell (RBC) units are always in stock. During 1 year, the center supplied 79 units of RBCs and 64 units of fresh frozen plasma to a variety of patients with IgA deficiency, including three undergoing liver transplantation. The center also provides a reference service for IgA/anti-IgA status. The technique used (hemagglutination inhibition) has a sensitivity well below the threshold of standard quantitation methods. Samples were most commonly referred from departments investigating possible immunodeficiency and suspected transfusion reactions. Of 247 patients investigated, 122 had IgA deficiency, 43 with anti-IgA (of whom 5 had suffered a transfusion reaction). Donors and patients with anti-IgA were issued blood group cards warning that they should only receive IgA deficient products.