Maternal-paternal histocompatibility: lack of association with habitual abortions.

Class I human leukocyte antigens (HLA-A, -B) and class II (HLA-DR) antigens were determined in 60 and 30 carefully selected couples with multiple abortions, respectively. The study group was compared with fertile couples with no history of abortion and with a control group consisting of randomly matched women and men from our laboratory cell panel. No significant deviation from the calculated control mating frequencies was observed in the group with habitual abortions. When the study and control couples were grouped by ethnic origin into Ashkenazim and non-Ashkenazim, the frequencies of shared HLA-A, -B, and -DR antigens were similar in both groups. These results do not confirm the observations of greater HLA compatibility between partners of aborting couples reported by other laboratories. Moreover, the results of an informative family in which the woman, after three consecutive spontaneous abortions, conceived and bore a healthy male infant genotypically HLA-identical to his mother are presented. Taken together, these results challenge the concept that compatibility in determinants of the major histocompatibility complex have a major role in habitual abortions.