Levels of antibodies against protein C and protein S in pregnancy and in preeclampsia

Abstract OBJECTIVES: The clinical relevance of antibodies anti-protein C and anti-protein S in pregnancy remains controversial. We evaluate whether, in the absence of thrombophilic diseases, maternal plasma levels of antibodies (IgM and IgG) change during pregnancy and in preeclampsia (PE), with and without superimposed fetal growth restriction (FGR). METHODS: A retrospective cohort of 50 women with PE (n = 30) and PE + FGR (n = 20) and 70 controls [first trimester (n = 20); second trimester (n = 20); third trimester (n = 30)] were enrolled in the study. RESULTS: In healthy pregnant women, plasma levels of anti-protein C antibodies decreased from first to third trimester and were below the range of positivity. IgM anti-protein-C and anti-protein-S were significantly higher (P < 0.001) in both PE (23.88 +/- 10.65 MoM and 43.90 +/- 20.45 MoM, respectively) and PE + FGR group (15.95 +/- 12.62 MoM and 36.02 +/- 27.43 MoM, respectively) than in control group (2.23 +/- 3.23 MoM and 1.68 +/- 4.075 MoM, respectively), in the presence of unchanged levels of IgG isotype. CONCLUSIONS: In this study, we first found that the production of anti-protein C and anti-protein S antibodies decreases throughout healthy pregnancies, while they circulate in high levels in women with PE and PE/FGR.