Distribution of Th1 and Th2 cell populations in human peripheral and decidual T cells from normal and anembryonic pregnancies

Objective: To examine whether maternal immune responses during normal pregn ancy are Th2 biased and whether there are specific changes when anembryonic pregnancy occurs. Design: Prospective study. Setting: Department of Obstetrics and Gynecology at a university hospital. Patient(s): We studied 32 pregnant women receiving elective abortions of no rmal pregnancies and 35 women with anembryonic pregnancies between 6 weeks and 10 weeks of gestational age. Intervention(s): Using the multilabeling capability of three-color flow cyt ometry, it is possible to measure intracellular cytokines and cell surface markers simultaneously to determine which cells are the cytokine-producing cells. Main Outcome Measure(s): We examined the extent and proportion of mononucle ar cells expressing specific T-cell surface markers and cytokines, interfer on gamma, and interleukin 4 in the peripheral blood and deciduae. Secreted cytokines in the supernatants after 24-hour culture were also compared. Result(s): During the unstimulated status, the proportion of IL-4-secreting cells significantly exceeded that of IFN-gamma -secreting cells in the per ipheral blood and decidua in normal pregnancies and was significantly decre ased when anembryonic pregnancies occurred. Consequently, the Th1/Th2 ratio s were increased during anembryonic pregnancies. However, after 24-hour cul ture, only another Th2-type cytokine, IL-10, was markedly increased and exc eeded IFN-gamma secretion in cultures from both the peripheral blood and de cidua in normal pregnancies. Conclusion(s): The decidual T lymphocytes are Th2 predominant. When anembry onic pregnancy occurs, this Th2 predominance disappears. (Fertil Steril(R) 2001;76:797-803. (C) 2001 by American Society for Reproductive Medicine.).