Immunity and pregnancy.

The existence of the maternal immune response to various paternally derived antigens on the fetus and placenta is apparently paradoxical, since the immune response is generally associated with host defense. In this context, the immune response to the fetal and placental antigens may have either physiological function or be advantitious. In either event, it appears to be closely associated with the existence of the polymorphisms of the cell surface antigens, particularly those controlled by the genes in the major histocompatibility complex. The major thrust of this review will be to examine the nature of the humoral and cellular immune response to the fetus and placenta and the genetic factors influencing it. A second portion of the review will address the genetic factors influencing development, including those involved in spontaneous abortion and in the genetic control of developmental abnormalities.