B lymphocyte determinants in immunoglobulin A nephropathy.

Because of our prior demonstration of a strong association betwen a specific B lymphocyte determinant and the occurrence of chronic membranoproliferative glomerulonephritis and the demonstration by others of the frequent concurrence of an IgA deposit disease, anaphylactoid purpura nephritis,with HLA-BW35, we conducted an investigation of the association among Minnesota Caucasians of the HLA markers BW35, DW1 and B lymphocyte determinants identified by three alloantisera with IgA nephropathy and the syndrome of recurrent macroscopic hematuria. The highly significant association between HLA-BW35, DW1, and B cell antigens identified by alloantisera L, B, and F, present in 50 normal Minnesota Caucasians, was not observed in 18 Minnesota patients with IgA nephropathy. The frequency of HLA-DW1 was the same among controls and patients, whereas the relative risk of developing IgA nephropathy was demonstrated to be increased 4- to 5-fold in the presence of the B cell antigens identified by alloantisera L and B. These sera appear to identify determinants on B lymphocytes associated with the disease state and possibly not intimately related to the HLA-D region. These findings emphasize the possible informativeness of defining B cell alloantisera on disease panels.