Immunoglobulin A deficiency: genetic studies.

Immunoglobulin A (IgA) deficiency (less than 0.01 mg/ml) was demonstrated in 155 of 72,296 blood donors. Studies of families of 60 donors revealed IgA deficiency in other members of 12 families. No consistent pattern of inheritance of IgA deficiency was found. HLA typing of 62 unrelated IgA deficient blood donors showed a significant increase in the prevalence of HLA-B8 (p less than 0.005).