Lymphocyte subset distribution and cytokine secretion in third trimester decidua in normal pregnancy and preeclampsia

BACKGROUND: Excessive Th1 activity in peripheral blood plays a probable role in the pathogenesis of preeclampsia. The aim of the study was to investigate whether disturbed local immune reactions are also present in decidua. METHODS: Flow cytometric analysis of CD3, CD19, CD56/CD16, CD4, CD8, CD4/CD29, CD4/CD45RA, CD4/CD45RO, CD8/CD28, CD3/CD69 lymphocyte subsets isolated from third trimester decidua of pregnants with preeclampsia (n=21) and pregnant controls (n=11) subjected to elective caesarean sections. Spontaneous and phytohemaglutynine stimulated "in vitro" secretion of IL-2, IL-4, IL-6, IL-10, IL-12, IFN-gamma and TGF-beta by decidual lymphocytes was studied by ELISA. For the statistical significance of differences between the groups the U Mann-Whitney test was performed (confidence interval P<0.05). RESULTS: Preeclamptic patients were characterized with an increased percentage of the CD3-/CD56+CD16+, CD8+/CD28+ and decreased percentage of CD3+, CD19+, CD4+/CD45RA+ lymphocytes. The profile of secreted cytokines shifts in favor of Th1 activity (extremely high IFN-gamma and low IL-6 and IL-10 secretion). Decidual IL-12 secretion in preeclamptic patients is decreased compared to controls. CONCLUSION: Changes in NK and T lymphocyte subsets followed with Th1 cytokine IFN-gamma over-activity, could affect local immunoregulatory mechanisms in third trimester decidua of preeclamptic patients.