STUDIES OF NATURAL-KILLER-CELLS IN PREGNANCY-INDUCED HYPERTENSION

The number and activity of natural killer (NK) cells were studied in 2 0 patients with pregnancy-induced hypertension (PIH), 15 uncomplicated pregnant women and 16 healthy non-pregnant women, All the pregnant wo men were primigravidae and were evaluated during the third trimester o f gestation. Peripheral blood NK cells were detected with monoclonal a ntibodies by indirect immunofluorescence and cytotoxic activity was me asured using a single-cell assay against K562 target cells. Hypertensi ve pregnant women had an increased number of circulating NK cells asso ciated with a significant decrease of NK activity, The cytotoxic activ ity was significantly lower in normal pregnant and PIH women when comp ared with non-pregnant controls. The onset of immature NK cells in per ipheral blood and the impairment of their cytotoxic activity in PIH pa tients may be associated with hormones and immunosuppressive substance s produced by tissues occurring at the maternal-fetal interface.