Membrane attack complex of complement in pregnancy complicated by preeclampsia

Background: Recent studies have established a link between the development of preeclampsia (PE) and excessive activation or dysregulation of complement system. Investigating this system’s role may aid in the developing therapeutic strategies for treating PE.
Aims: To evaluate the levels of membrane attack complex (MAC) in blood serum during PE development in patients with chronic kidney disease (CKD) and the general population.
Materials and methods: The prospective observational study included 44 patients with PE: 17 women with a prior diagnosis of CKD and 27 women from the general population without a complicating somatic history. Soluble MAC levels was measured using an enzyme-linked immunoassay (HycultBiotech, Human Terminal Complement Complex Elisa Kit, HK32801).
Results: The incidence of mild and severe PE was similar between the groups. Among CKD patients, 29% (n=5) had mild PE and 71% (n=12) had severe PE, compared to 40% (n=11) and 60% (n=16), respectively. MAC levels were comparable between CKD and general population groups for mild PE (3933 [24676537] μU/ml vs 3202 [28134279] μU/ml [p=0.692]) and severe PE (4139 [38744458] μU/ml vs 4805 [32809594] μU/ml [p=0.378]), respectively. MAC levels did not differ significantly between mild and severe PE. In the general population, severe PE showed a trend toward higher MAC levels (4805 [32809594] μU/mL vs 3202 [28134279] μU/mL [p=0.054]). Severe PE was complicated by trombotiс microangiopathy (TMA) in 6 of 27 patients compared to 1 patient in the CKD group. Among patients with severe PE and TMA (7/44), MAC levels were significantly higher than in those without TMA (5345 [348713169] μU/ml vs 3933 [30574747] μU/ml [p=0.048]).
Conclusions: in PE patients, regardless of the development stage, severity or the presence CKD, MAC levels are elevated indicating hyperactivation of the complement system in this pregnancy complication. The highest MAC levels were observed in patients with TMA manifestations.

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