Maternal Th1-and Th2-type reactivity to placental antigens in normal humanpregnancy and unexplained recurrent spontaneous abortions

Spontaneous abortion is the mast common complication of pregnancy, but the etiology of a significant proportion of abortions is still unknown. We have examined the production of Th1- and Th2-type cytokines by women with unexp lained recurrent spontaneous abortion (RSA) since it appears that successfu l murine pregnancy occurs in a Th2-dominant situation and that Th1-type imm unity is associated with pregnancy failure. We have compared maternal react ivity toward placental antigens in women with a history of successful pregn ancy with that in women with a history of RSA This was done by coculturing maternal peripheral blood mononuclear cells (PBMC) with autologous placenta l cells and also by stimulating maternal PBMC with antigens from a chorioca rcinoma cell line of trophoblastic origin. We detected significantly greate r levels of the Th2 cytokines IL-6 and IL-10 in normal pregnancy compared t o unexplained RSA and significantly higher levels of the Th1 cytokine IFN-g amma in RSA compared to normal pregnancy. These results suggest that women with normal pregnancy have a higher Th2 bias, while women with a history of RSA evince a bias toward Th1-type reactivity. (C) 1999 Academic Press.