Sensitized T-lymphocytes against paternal histocompatibility antigens cause intrauterine fetal death and growth retardation.

The influence on pregnancy of sensitized T lymphocytes against male histocompatibility antigens was investigated using inbred strain mice. Number of abortion, litter size, fetal weight and placental weight were studied on 18th day of pregnancy in the mice which were administered intravenously with T lymphocyte enriched fraction of sensitized spleen cells against allogeneic male histocompatibility antigens. The incidence of abortion in the experimental mice was higher than that in control mice. Mean fetal weight in the experimental mice was less than that in the control mice although mean placental weight in the experimental mice was unaffected. Those results show that immunologic interruption of pregnancy due to histoincompatibility between mother and fetus can occur and that the immunologic interruption of pregnancy is caused by sensitized T lymphocytes against paternal inherited histocompatibility antigens. Possible process of the immunologic interruption of pregnancy is discussed.