‘In vitro’ Cytokine Secretion by Peripheral Blood and Decidual Lymphocytes during the Third Trimester of Normal Pregnancy

If the 'Th2 phenomenon' is dependent on trophoblastic antigens and cytokines, the profile of cytokines secreted by decidual lymphocytes (DL) should indicate stronger Th2 shift than that of peripheral blood lymphocytes (PBL). We studied spontaneous and mitogen-stimulated 'in vitro' cytokine secretion of cultured lymphocytes isolated from peripheral blood (n = 21) and decidua (n = 11) of third trimester healthy pregnant women not being in labor. The ELISA method was used for estimation of IL-2, IL-4, IL-6, IL-10, IL-12, IFN-gamma and TGF-beta. The results (given in pg/ml) were found to be statistically significant in the Mann-Whitney U-test (p < 0.05). Compared to PBL, DL produced spontaneously decreased concentrations of IL-12, IL-6, IFN-gamma and TGF-beta and upon mitogen stimulation increased quantities of IL-2, IL-4 and IL-10. It demonstrates that DL play an active role in local Th2-like immunoregulation and that their cytokine secretion pattern estimated in 'in vitro' conditions is biased towards Th2 activity more than that of PBL.