Maternal-fetal immunity: Presence of specific cellular hyporesponsiveness and humoral suppressor activity in normal pregnancy and their absence in preeclampsia
The hypothesis that aberrant maternal-fetal immunity might lead to the development of preeclampsia was examined using mixed lymphocyte culture reactions (MLC) as an in vitro analogue of maternal-fetal immunity. Maternal lymphocytes and serum from five normal pregnant women differed significantly from lymphocytes and serum from five preeclamptics. Maternal cells from normal pregnancy responded appropriately to unrelated control cells, but demonstrated selective hyporesponsiveness to fetal cells in the MLC. Serum from normal pregnancy suppressed MLCs when maternal cells were responder cells (RC) and maternal cells or fetal cells were stimulator cells (SC), and did not inhibit MLCs where maternal cells were RC and control cells were SC. Maternal lymphocytes and serum from preeclamptics did not demonstrate cellular hyporesponsiveness or humoral suppressor activity. Our findings support the notion that specific cellular hyporesponsiveness and humoral suppressor activity is responsible for normal pregnancy; absence of such adaptive immunity might lead to the development of preeclampsia.