Cytokine production by maternal lymphocytes during normal human pregnancy and in unexplained recurrent spontaneous abortion

It has been proposed that successful pregnancy is a T helper 2-type phenome non, and that T helper (Th)1-type reactivity is deleterious to pregnancy. T he objective of this study was to compare the concentrations of Th1 and Th2 cytokines produced by peripheral blood mononuclear cells from women underg oing unexplained recurrent spontaneous abortion (RSA) with those produced d uring normal pregnancy at a similar gestational stage. The control group co nsisted of 24 women with a history of successful pregnancies and the aborti on group comprised of 23 women with a history of unexplained RSA. Blood fro m the control group was obtained at the end of the first trimester as gesta tional age controls for the abortion group from whom blood was collected at the time of abortion. Phytohaemagglutinin-stimulated peripheral blood cell culture supernatants were analysed for concentrations of cytokines. Signif icantly higher concentrations of Th2 cytokines were produced by the first t rimester normal group than by the RSA group, while significantly higher con centrations of Th1 cytokines were produced by the abortion group as compare d to first trimester normal pregnancy, indicating a distinct Th2-bias in no rmal pregnancy and a Th1-bias in unexplained RSA.