IL-17 blood levels increase in healthy pregnancy but not in spontaneous abortion.

Cytokines are essential to maintain and coordinate the correct activity of immune cells during human pregnancy. IL-17 is a pro-inflammatory cytokine that induces the expression of many inflammatory mediators. The aim of this study was to compare the levels of Th1, Th2 and Th17 cytokines of women ongoing normal pregnancy with those found in women who suffered spontaneous abortion. IL-2, IL-4, IL-6, IL-10, IL-17, TNF-α, and IFN-γ peripheral blood levels were measured in women who suffered spontaneous abortion (n = 13, blood collected up to 24 h after abortion), and were compared with healthy successful pregnancies (n = 16). Cytokine levels were measured using a cytometric bead array (CBA analysis). Similar cytokine levels were observed between spontaneous abortion and healthy pregnant women excepted to IL-17, which levels were increased in the healthy pregnant women (p = 0.0232). Our results show high IL-17 levels in the peripheral blood of women at late stages of healthy pregnancy, although low IL-17 levels were detected in the peripheral blood of women just after spontaneous abortion. In line with recent studies, this finding highlights IL-17 as a regulatory cytokine essential to the maintenance of a successful pregnancy.