Cytokine patterns in maternal blood after premature rupture of membranes

OBJECTIVE: To compare two types of cytokines, type 1, which activate cell-mediated reactions and are important in cytotoxic and delayed-type hypersensitivity reactions, and type 2, which encourage vigorous antibody production and are commonly found in association with humoral immune responses, in blood of women with premature rupture of membranes (PROM). METHODS: Forty-four women with histories of at least three successful pregnancies and who currently delivered normally served as controls. The PROM group consisted of 30 women with spontaneous rupture of fetal membranes at term. Peripheral blood mononuclear cells were stimulated separately with a mitogen, placental cells, and a trophoblast antigen extract, and the supernatants examined for type 1 and type 2 cytokines. RESULTS: Mitogen-stimulated blood cells produced significantly higher levels of type 1 cytokines in PROM women than in normal controls. Higher levels of the type 1 cytokine interferon-γ were produced by PROM samples stimulated with autologous placental cells and with trophoblast antigens. Ratios of type 1 to type 2 cytokines were higher in PROM compared with normal pregnancy, and in some cases as much as 25-fold higher. CONCLUSION: Women in the PROM group had a stronger type 1 reactivity whereas normal women were more predisposed to type 2 immunity; thus, PROM appears to be associated with a maternal type 1 bias.