Association of human leukocyte antigens B7 and BW35 with sperm antibodies.

One hundred three infertile couples and 50 fertile couples were tested for the presence of sperm antibodies by passive hemagglutination and cytotoxicity assays and typed for human leukocyte antigens (HLAs) of the A and B loci. Fifty-four percent of the males and 43% of the females with sperm antibodies were found to have the HLA-B7 antigen, in contrast to 19% of a general population (P less than 0.0001). HLA-BW35 (a Workshop antigen of the B locus) was also present at a significantly increased antigenic frequency (P less than 0.00001) in those females with sperm antibodies. Of the 73 infertile couples with sperm antibodies, 79% shared the B7, B8, and/or BW35 alleles. Two of 12 infertile couples and 10 of 50 fertile couples without sperm antibodies shared these alleles. The significant association of HLA-B7 and BW35 alleles with sperm antibodies in infertile subjects suggests a selective disadvantage of these antigens in human reproduction.