Correlations between complement system's activation factors and anti-angiogenesis factors in plasma of patients with early/late-onset severe preeclampsia

Objective: To investigate the expression of complement system's activation factors in plasma of patients with severe preeclampsia and their correlations with anti-angiogenesis factors.Methods: A case-control study was performed. The study group consisted of 30 cases of early-onset severe preeclampsia (EOSPE) and 30 cases of late-onset severe preeclampsia (LOSPE). Thirty cases were selected as the early-onset control group (E-control) and 30 as the late-onset control group (L-control), with the weeks of gestation matched. Enzyme-linked immunosorbent assay (ELISA) was used to test C3a, C5a, MAC, sEng, and sflt-1 in the maternal peripheral circulation.Results: The complement system's activation factors C3a, C5a, and MAC were increased significantly in EOSPE and LOSPE (all P < 0.01) compared with E/L-control. Plasma levels of C3a correlated inversely with plasma sEng (r = -0.454, P < 0.001) and sflt-1 (r = -0.326, P = 0.011) in preeclampsia patients, while MAC correlated with soluble endoglin (sEng; r = 0.343, P = 0.007) and soluble fms-like tyrosine kinase-1 (sflt-1; r = 0.318, P = 0.013). There were no significant correlations between complement system's activation-related factors and the anti-angiogenesis factors in healthy control group.Conclusions: Abnormal activation of the complement system exists in the maternal circulation of patients with E/L-onset severe preeclampsia. There were correlations between the abnormal activation of the complement system and the abnormal expression of anti-angiogenesis factors in patients with severe preeclampsia, but the correlation was not strong.