Soluble concentrations of the terminal complement complex C5b-9 correlate with end-organ injury in preeclampsia.

OBJECTIVE: We sought to determine if soluble levels of C5b-9, the terminal complement complex, correlate with end-organ injury in preeclampsia. STUDY DESIGN: Project COPA (Complement and Preeclampsia in the Americas), a multi-center observational study in Colombia from 2015 to 2016, enrolled hypertensive pregnant women into four groups: chronic hypertension, gestational hypertension, preeclampsia, and preeclampsia with severe features. Trained coordinators collected clinical data, blood and urine. End-organ injury was defined by serum creatinine ≥ 1.0 mg/dl, aspartate transaminase ≥ 70U/L, platelet count < 150,000/µl, or lactate dehydrogenase ≥ 500 U/L. Data were analyzed by χ2 or Fisher's exact test with significance at P < 0.05. MAIN OUTCOME MEASURE: C5b-9 concentrations in plasma and urine, using enzyme linked immunosorbent assays. RESULTS: In total, 298 hypertensive participants were enrolled. Plasma and urine C5b-9 levels were measured in all participants and stratified by quartile (Q1-4), from lowest to highest C5b-9 concentration. Participants with low plasma C5b-9 levels (Q1) were more likely to have end-organ injury compared to those with higher levels (Q2-Q4) [platelet count < 150,000/µl (20.8% vs. 8.4%, P = 0.01); elevated serum creatinine ≥ 1.0 mg/dl (14.9% vs. 4.5%, P = 0.009)]. In contrast, participants with high urinary C5b-9 levels (Q4) were more likely to have end-organ injury compared to those with lower levels (Q1-Q3) [platelet count < 150,000/µl (19.7% vs. 7.4%, P = 0.003); elevated serum creatinine ≥ 1.0 mg/dl (12.3% vs. 4.4%, P = 0.025)]. CONCLUSION: We identified a pattern of increased urine and low plasma C5b-9 levels in patients with preeclampsia and end-organ injury. Soluble C5b-9 levels may be used to identify complement-mediated end-organ injury in preeclampsia.

Plasma CD59 concentrations are increased in preeclampsia with severe features and correlate with laboratory measures of end-organ injury.

OBJECTIVES: Dysregulation of CD59 may lead to increased complement-mediated end-organ injury in preeclampsia. We sought to determine if soluble CD59 concentrations are altered in preeclampsia with severe features. STUDY DESIGN: Observational case-control study, which enrolled subjects prospectively from six centers in Colombia from 2015 to 2016. Cases had preeclampsia with severe features and controls were either healthy or had chronic hypertension, gestational hypertension, or preeclampsia without severe features. Trained coordinators collected clinical data, blood and urine. Analyses were by test of medians and Spearman's correlation. MAIN OUTCOME MEASURES: Soluble CD59 concentration in plasma and urine, using enzyme linked immunosorbent assays. RESULTS: In total, 352 subjects were enrolled (104 cases; 248 controls). Compared to healthy women or those with other hypertensive disorders of pregnancy, women with preeclampsia with severe features had increased concentration of CD59 in plasma (P < 0.001) and decreased CD59 in urine (P = 0.01). In sub-group analyses, plasma CD59 concentrations were increased in preeclampsia with severe features compared to healthy controls (P < 0.001) or controls with either chronic hypertension (P = 0.002) or gestational hypertension (P = 0.02). Increased plasma CD59 concentrations correlated with decreased platelet count and increased lactate dehydrogenase, creatinine, aspartate transaminase, urine protein/creatinine ratio, systolic blood pressure and diastolic blood pressure (P < 0.01, all correlations). CONCLUSION: In women with preeclampsia with severe features, soluble CD59 concentrations were increased in plasma and decreased in urine, and plasma levels correlated with increased blood pressure and end-organ injury. Soluble CD59 concentrations may help identify a subset of women with preeclampsia that have altered regulation of terminal complement proteins.

Terminal Complement Activation in Preeclampsia.

OBJECTIVE: To evaluate whether C5b-9 concentrations in blood and urine are increased in preeclampsia with severe features. METHODS: The Complement and Preeclampsia in the Americas study is a prospective, multicenter case-control study performed at six centers in Colombia from November 2015 to July 2016. The case group included women with preeclampsia with severe features, and the control group included women who were healthy or had chronic hypertension, gestational hypertension, or preeclampsia without severe features. We enrolled two women in the control group for every woman in the case group. Soluble C5b-9 concentrations were measured by enzyme-linked immunosorbent assays in blood and urine. The primary outcome was C5b-9 concentrations in women in the case group compared with all women in the control group, and the secondary outcome was C5b-9 levels in women in the case group compared with individual control subgroups. Differences were assessed by test of medians, and associations were further evaluated by receiver operating characteristic curve analysis and logistic regression with α=0.05. RESULTS: Three hundred fifty-two patients were enrolled. Plasma C5b-9 concentrations did not differ significantly between women in the case group and those in the control group, but urine C5b-9 concentrations were higher in women in the case group (median [interquartile range] 9.9 [1.6-43.7] vs 1.8 [0.54-4.1] ng/mL, P<.001). In subgroup analysis, plasma C5b-9 concentrations were increased in women in the case group compared with healthy women in the control group (median [interquartile range] 2,778 [1,633-4,230] vs 1,374 [1,064-2,332] ng/mL, P<.001), and urine C5b-9 concentrations were increased in women in the case group compared with all control subgroups (P<.001). Using receiver operating characteristic analysis, urine C5b-9 concentrations differentiated preeclampsia with severe features from hypertensive women in the control group (area under the receiver operating characteristic curve 0.74, 95% CI 0.68-0.80). Urine C5b-9 22 ng/mL or greater (range 0-158.4 ng/mL) was the optimal cut point for diagnosis of preeclampsia with severe features with adjusted odds ratio of 10.0 (95% CI 3.5-28.8, P<.001). CONCLUSION: Urinary excretion of terminal complement effector C5b-9 is higher in women with preeclampsia with severe features compared with women with other hypertensive disorders of pregnancy and women without hypertension.