PARENTAL MHC ANTIGEN SHARING AND PREGNANCY WASTAGE IN CAPTIVE PIGTAILED MACAQUES

Among some human populations, immunogenetic similarity between mates i s associated with increased risk of pregnancy loss. To investigate the relationship between histocompatibility and reproductive performance in non human primates, 128 pigtailed macaque couples were classified a s 'reproductively successful' or 'unsuccessful' according to previous breeding performance. These couples were arranged into 64 triads compo sed of individual females, and a 'successful' and 'unsuccessful' mate. Individuals were typed for class I MHC antigens using a microcytotoxi city technique and species-specific alloantisera. Matched-pair analysi s revealed that significantly more 'unsuccessful' couples shared MnLA- A antigens than did the matched 'successful' couples. Conditional matc hed-pair logistic regression analysis further revealed that parental s haring of MnLA-A antigens is an even more significant predictor of pre gnancy wastage than is advanced maternal age. In our study population, sharing oi MnLA-A antigens predicted 72% of pregnancy loss among 'uns uccessful' couples (P < 0.009). Identification of histocompatibility-a ssociated factors influencing pregnancy success could have profound cl inical implications for chronic spontaneous abortion, intra-uterine gr owth retardation and birth defects in humans. Among captive primates, identification of MHC or MHC-linked genes affecting reproductive outco me could lead to more efficient colony management strategies as well a s development of a model for understanding human immunologically-media ted reproductive failure.