Sperm antibodies and human leukocyte antigens in couples with early spontaneous abortions.

Twenty-six couples with two or more early spontaneous abortions and 53 couples with recently proven fertility (control group) were typed for human leukocyte antigens (HLA) of A and B loci and screened for the presence of cytotoxic and hemagglutinating antibodies to sperm. Eighteen other couples with two or more abortions were tested for sperm antibodies alone. Both partners in 24 of 44 (54%) aborting couples were positive (titers of greater than or equal to 32), whereas the control group had sperm antibodies in the negative range (titers of 0 to 16; P less than .0001). Thirty-one husbands (70%) and 24 wives (54%) were positive for sperm antibodies in the study group. Sharing of HLA-A and/or -B antigens between partners was similar in the control and study groups. Fourteen of 26 (54%) couples with two or more abortions did not share HLA-A and/or -B antigens, in contrast to 14 of 53 (26%) in the control fertile group (P less than .02). Antigenic frequencies of HLA-B7 singly and in combination with HLA-B35 were increased in females in the aborting but not in the fertile control group (P less than .001). The combined incidence of HLA-B7, -B8, and -B35 in both partners was significantly higher in the aborting couples as contrasted with the control group. It is suggested that the presence of sperm antibodies is associated with early pregnancy wastage. Histocompatibility antigens B7 and B35 may play a role through their association with sperm antibodies and early spontaneous abortions.