Selective IgA deficiency in blood donors.

The frequency of selective IgA deficiency was determined in a healthy population of 6,240 blood donors. Screening for IgA deficiency was performed by double-diffusion analysis in agarose gel. Confirmation testing was performed with the more sensitive passive hemagglutination inhibition assay. Prevalence of IgA deficiency, characterized by a serum level of below 50 mg/L, was 0.30% (1 in 328), which is the highest prevalence of selective IgA deficiency reported in a healthy population. Antibodies to IgA were detected in sera of 36.8% of the blood donors with selective IgA deficiency, which also is the highest prevalence of anti-IgA antibodies reported in any previous study. The literature on IgA deficiency in healthy populations is reviewed. Current concepts in treatment of IgA-deficient patients requiring blood products are described.