Table 2.

Quantification, functionality, and genetics of factors in complement alternative pathway in patients with severe phenotype preeclampsia compared to matched normotensive controls

Complement ComponentReference IntervalsMedian (range)P ValuePE Patients with Genetic Variants (n=25), % (n)aAllele Frequency in General Population, (%)b
PE (n=25)Control (n=25)
Factor B, mg/dl15.2–42.332 (20–56)36 (24–48)0.720 (5)1.107–3.885
Bb, μg/mlc≤1.61.24 (0.5–4.3)0.6 (0.5–0.97)<0.001d
Factor I (genetics only)No variants8 (2)0.072–0.839
Factor H, mg/dl18.5–40.830.6 (24.1–47.5)31.5 (24.4–35.9)0.712 (3)1.0
CFHR1 (genetics only)4 (1)0.849
CFHR2 (genetics only)8 (2)0.397–0.770
CFHR4 (genetics only)4 (1)0.288
CFHR5 (genetics only)4 (1)1.621–1.777
MCP (CD46) (genetics only)No variants4 (1)1.532
THBD (genetics only)No variants8 (2)0.762
C3 concentration, mg/dl75–175140 (101–234)143 (106–233)0.412 (3)0.001–0.336
C3AR1 (genetics only)4 (1)2.019
CR2 (genetics only)8 (2)0.000
CR1L (genetics only)16 (4)0.184–4.89
C5 concentration, mg/dl10.6–26.328 (18–33)24.1 (15–34)0.03d4 (1)0.000
sMAC, ng/ml≤250371 (167–761)184 (112–249)<0.001d
  • PE, severe phenotype preeclampsia; CFHR, complement factor H related; MCP, membrane cofactor protein; THBD, thrombomodulin; C3AR1, C3a receptor 1; CR2, C3 receptor 2; CR1L, Complement C3b/C4b Receptor 1 Like; sMAC, soluble membrane attack complex.

  • a Encompasses all variants detected (including benign and likely benign).

  • b Population allele frequency as reported in Exome Aggregation Consortium (ExAC; and Genome Aggregation Database (gnomAD;; accessed January 19, 2018. See Supplemental Table 1 for individual variants and allele frequencies.

  • c Bb is the activation fragment of complement factor B, an activator of the complement alternative pathway.

  • d P<0.05.