Leukocyte-platelet interaction in pregnancies complicated with preeclampsia

Objective. Pregnancy is characterized by haemostasis activation, and in preeclampsia endothelial dysfunction, platelet and leukocyte activation are further characteristic features. The aim of this study was to investigate to which extent platelets from normotensive pregnant women or those with preeclampsia are circulating as microparticles or platelet-platelet aggregates. We also investigated if platelet-leukocyte multiconjugates were differently present in nonpregnant and pregnant women. Study design. Using flow cytometry we investigated these parameters in basal samples and after in vitro stimulation with adenosine diphosphate (ADP) or thrombin receptor activation peptide. This was done in samples from 20 matched preeclamptic and normotensive pregnant women and in a group of 12 nonpregnant women. Results. In the basal state we found that women with preeclampsia had a smaller portion of microparticles circulating than the normotensive pregnant women, Upon ADP stimulation both pregnancy groups showed a higher percentage of monocytes and granulocytes with platelets attached and also a higher number of platelets attached to each monocyte and granulocyte than in the group of nonpregnant individuals. Conclusion. This article presents further evidence that changes from the nonpregnant to the pregnant state are associated with hemostasis activation as an integrated part of an inflammatory reaction that is even more pronounced when pregnancy is complicated with preeclampsia.