HLA-DR compatibility in couples with recurrent spontaneous abortions.

HLA antigens and antibodies of A,B and DR loci were investigated in order to study the relationship between early recurrent spontaneous abortions of unknown etiology and the HLA system, which is in a close relationship with the immune response. The frequencies of 8 HLA-A antigens, 21 HLA-B antigens and 10 HLA-DR antigens were determined in 26 patient couples, 45 control fertile couples without a history of abortion and 206 healthy adult controls (DR antigens in 106 controls). Sera from the wives in patient couples were tested for HLA-A, B, C and DR antibodies against their husbands' T and B lymphocytes and also against 2 panels of 29 typed T and B lymphocytes. Results obtained were as follows: 1) A significantly higher frequency of HLA-All antigen was found in the wives in patient couples as compared with the controls (corrected p less than 0.008). 2) A significantly higher frequency of one or two common HLA-DR antigens was shared by patient couples (84.6%, X2 = 21.66, p less than 0.001) as compared with control couples (24.4%). 3) Furthermore, a significantly higher frequency about HLA-DR locus without major incompatibility was found in patient couples (26.9%, X2 = 7.77, p less than 0.01) as compared with control couples (2.2%). 4) HLA-DR antibodies were not detected in the wives in patient couples at all. These results indicated that the compatibility of HLA-DR antigens or DR genes might possess some adverse influence on the maintenance of pregnancy.