A sustained decrease in serum CD83 in pregnant women.

Maternal immunity regulates tolerance to the semi-allogeneic fetus during pregnancy via modulation of immune regulatory factors. The serum factor CD83 is known to undergo changes during gestation in mice. Here we characterize serum levels of CD83 in women for the first time, revealing a consistent decline as pregnancy progresses and recovery to non-pregnant levels in miscarriage. Serum CD83 levels correlated negatively with rising progesterone (Pearson coefficient r = -0.489, ****p < 0.0001) and estradiol (r = -0.419, ***p = 0.0003). This result suggests that the regulation of soluble CD83 levels possibly depend on pregnancy hormones and on other yet unknown factors.