HLA class I, class II, and class III antigen sharing is not found in couples with unexplained infertility.

OBJECTIVE

To find the degree of HLA antigen sharing in couples with infertility of unknown etiology and compare it with that in couples with infertility of known etiology as well as couples with normal fertility.

SUBJECTS: Eleven couples with infertility of unknown etiology, 26 with infertility of known etiology, and 31 fertile couples were tested for HLA class I (A, B, C), class II (DR, MLC), and class III (Bf) antigens and GLO alleles. HLA lymphocytotoxic antibodies and anti-sperm antibodies in both partners were also searched.

RESULTS

Gene frequencies and the number of HLA antigens shared between the two members of the couple were similar in all groups. When "intra-couple" MLC reactivity was measured, no quantitative differences were found in the infertile group with unknown etiology, as compared to the group of known etiology: spouses in couples of either group usually reacted in both ways as expected for unrelated individuals" lymphocytes. Lymphocytotoxic antibody frequency did not differ between the nonfertile groups, and anti-sperm antibodies, found in ten patients in the group of known etiology, were not associated with any HLA antigen. In spite of that, GLO and all the HLA antigen classes described (I, II and III) were analyzed.

CONCLUSIONS

Although the results are negative, these and others' (negative) results concerning couples with infertility of unknown etiology do not disprove that HLA has a role in fertilization, because HLA-related factors still unknown may exist. Exhaustive HLA available marker typing in international cooperative efforts may be needed to reach a significant number of carefully selected couples fully HLA typed to elucidate this problem.