Clinical application evaluation of serum C1q and other complement factors in the diagnosis and prediction of preeclampsia

Abstract

Objective To observe the levels of serum complement C1q, C3, C4 and factor B in different phases during normal pregnancy; To evaluate the diagnostic value and the predictive value of serum complement C1q, C3, C4 and factor B in preeclampsia (PE). Methods Three groups of subjectes were enrolled from January 2017 to March 2018 in Department of Obstetrics and Gynecology, Peking University Third Hospital. (1) 30 pregnant women in each group at 8-14 weeks, 20-26 weeks and 28-36 weeks were retrospectively selected, and the serum levels of complement C1q, C3, C4 and B factors were measured and compared. (2)Selecting 17 cases of early-onset mild PE, 47 cases of early-onset severe PE, 24 cases of late-onset mild PE, 27 cases of late-onset severe PE, and 30 normal pregnant cases of the same gestational stage as early-onset / late-onset controls, through ANOVA analysis and comparison between two groups, this study evaluated the diagnostic value of serum complement C1q, C3, C4 and factor B in PE. (3)To evaluate the predictive effect in PE, it analyzed serum C1q and factor B levels of pregnant women at 20-26 gestation weeks through prospective nested case-control study of 214 cases. Results The levels of serum C1q remained stable in the whole pregnancy. The levels of C3 and factor B increased at the early stage of pregnancy and remained stable after the middle stage. C4 increased early in pregnancy and then remained stable. Compared with the control group, the levels of serum C1q in all four types of PE patients were significantly decreased (median: 169 mg/L, 161 mg/L, 165 mg/L, 163 mg/L; early-onset, late-onset control group: 187 mg/L, 194 mg/L; U=130.500, 426.500, 159.500, 130.500, all P 0.05). 33 (15.4%) cases developed PE out of 214 pregnant women with PE risk factors. Compared to those who didn′t develop PE, it showed no statistical difference of serum C1q, C3, C4, and factor B levels at 20-26 gestational weeks of the women who subsequently developed PE (C1q: 175 mg/L vs. 184 mg/L; C3: 1 523 mg/L vs. 1 467 mg/L; C4: 230 mg/L vs. 229 mg/L; FB: 344 mg/L vs. 320 mg/L; U=2 090.000, 1 575.000, 2 058.500, 1 362.000, all P>0.05). Compared to those of the healthy pregnant controls, it showed no statistical difference of serum C1q, C3 and C4 levels of 20-26 gestational weeks of the women who subsequently developed PE (C1q: 175 mg/L vs. 190 mg/L; C3: 1 523 mg/L vs. 1 428 mg/L; C4: 230 mg/L vs. 227 mg/L; U=353.000, 395.000, 493.500, all P>0.05), while it showed statistical difference (344 mg/L vs. 306 mg/L; U= 233.500, P=0.007) for factor B. Conclusions Serum C1q level of PE patients significantly decreased, which can be used as potential indicators of PE diagnosis, but serum C1q, C3, C4 level of 20-26 gestational weeks cannot predict risk of PE. Factor B cannot serve as serum index of PE diagnosis, but its serum levels at 20-26 gestational weeks werer higher than those of normal pregnant controls, factor B may be a potential predictor, but need further verification. (Chin J Lab Med, 2018, 41: 934-942) Key words: Preeclampsia; Complement; C1q; C3; C4; factor B