Maternal peripheral blood leukocytes in normal and pre-eclamptic pregnancies

Objective To analyse activation of maternal peripheral blood leukocytes by flow cytometric measurements of intracellular free-ionised calcium of lymph ocytes, granulocytes and monocytes, separately. Design Case-control study. Setting High risk pregnancy service in a regional centre. Material Samples from 10 women with pre-eclampsia, 10 appropriately-matched women with normal pregnancy, nine multigravid normal women at mid-gestatio n selected as being least likely to demonstrate any tendencies towards pre- eclampsia, and 11 healthy nonpregnant women of reproductive age were studie d. Methods Using flow cytometry, intracellular free ionised calcium ([Ca2+](i) ) was estimated by loading the cells with Fluo-3 and measuring the changes in fluorescence, intensity induced by free ionised calcium. After the basal levels were measured, the response of phagocytes to stimulation with n-for myl-methionyl-leucyl-phenylalanine (fMLP) was determined. Main outcome measures Basal [Ca2+](i) of peripheral blood leukocytes. Results Median basal [Ca2+](i) was significantly increased in all three sub sets of leukocytes-lymphocytes, granulocytes and monocytes in pre-eclampsia -compared with the three control groups. Samples from both groups of women with normal pregnancy did not differ from those from nonpregnant women. The peak responses of monocytes to stimulation with 10 nmol fMLP were greater in samples from pre-eclamptic women, giving evidence of priming. Conclusions Peripheral blood leukocytes are activated in pre-eclampsia in t erms of basal changes in the intracellular second messenger-free ionised ca lcium. Peripheral blood monocytes are primed to give greater responses afte r stimulation with fMLP.