Increased Systemic Activation of Neutrophils but Not Complement in Preeclampsia

In Brief Objective To investigate whether neutrophils and systemic complement are activated in pregnancies complicated by preeclampsia more than in normal pregnancies. Methods We measured native complement components and activation products in plasma by enzyme immunoassays in 19 women with uncomplicated pregnancies, 15 with preeclampsia before cesarean deliveries, and 16 nonpregnant women. Neutrophil activation was measured by specific enzyme immunoassays for myeloperoxidase and lactoferrin. Results Myeloperoxidase was significantly higher in women with preeclampsia (197 μg/L, 95% confidence interval [CI] 94, 646) than in women with uncomplicated pregnancies (124 μg/L, 95% CI 70, 289; P = .009), whereas lactoferrin did not differ between groups. C4 was decreased in preeclamptic women (0.16 g/L, 95% CI 0.07, 0.48) compared with women with uncomplicated pregnancies (0.21, 95% CI 0.10, 0.30, P < .001). There were no differences for the other native complement components. There was a significant decrease in C1rs-C1 inhibitor, 13 AU/mL (95% CI 9, 34) versus 19 (95% CI 13, 38) (P ≤ .001) in normal pregnant women compared with nonpregnant women. There also was an increase in C3, C4, C9 (data not shown), C4bp, 132% (95% CI 94%, 161%) versus 91% (95% CI 57%, 128%); C3bc (7.4 AU/mL, 95% CI 4.2, 10.7) versus 4.8 AU/mL (95% CI 3.2, 7.3) and C4bc (8.6 AU/mL, 95% CI 5.7, 14.0) versus 3.5 AU/mL (95% CI 2.2, 6.7) in normal pregnant women compared with nonpregnant women (P ≤ .001). Conclusion Neutrophil activation in preeclampsia was shown by systemic increases in myeloperoxidase. Except for a decrease in C4, systemic complement activation could not be detected in preeclampsia. Neutrophils are activated in preeclampsia, but systemic complement activation is not enhanced more than that in normal pregnancies.