HLA-A, B, C and DR typing was performed in healthy IgA deficient donors and in IgA deficient patients with recurrent respiratory tract infections. In healthy donors, a strong association with HLA B8 and DR3 was observed. In the patient group however, no statistically significant association with these antigens could be found. In contrast, an increased frequency of HLA B40 was noted. The preference for HLA B8/DR3 in healthy donors could not be attributed to higher levels of serum immunoglobulins since no major differences in the concentrations of IgM, IgG or the IgG subclasses were seen between the two groups.