title: Fragment Bb: evidence for activation of the alternative pathway of the complement system in pregnant women with acute pyelonephritis.
abstract: OBJECTIVE
  Pyelonephritis during pregnancy is associated with a more severe course than in the non-pregnant state. This has been attributed to an increased susceptibility of pregnant women to microbial products. The complement system is part of innate immunity and its alternative pathway is activated mainly by microorganisms. The purpose of this study was to determine if activation of the alternative pathway of the complement system (determined by maternal fragment Bb concentrations) occurs in pregnant women with acute pyelonephritis.
  
  
  METHODS
  This cross-sectional study included the following groups: (1) normal pregnant women (n=62) and (2) pregnant women with pyelonephritis (n=38). Maternal plasma fragment Bb concentrations were determined by ELISA. Non-parametric statistics were used for analyses.
  
  
  RESULTS
  (1) Pregnant women with pyelonephritis had a higher median plasma concentration of fragment Bb than those with a normal pregnancy (1.3 μg/ml, IQR: 1.1-1.9 vs. 0.8 μg/ml, IQR: 0.7-0.9; p<0.001); (2) No significant differences were observed in the median maternal plasma concentration of fragment Bb between pregnant women with pyelonephritis who had a positive blood culture and those with a negative blood culture (1.4 μg/ml, IQR: 1.1-3.5 vs. 1.3 μg/ml, IQR: 1.1-1.9; p=0.2).
  
  
  CONCLUSIONS
  Pregnant women with acute pyelonephritis have evidence of activation of the alternative pathway of the complement system, regardless of the presence or absence of a positive blood culture.
authors.affiliation: Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, USA.
authors.forename: Eleazar
authors.initials: E
authors.lastname: Soto
authors.forename: Roberto
authors.initials: R
authors.lastname: Romero
authors.forename: Edi
authors.initials: E
authors.lastname: Vaisbuch
authors.forename: Offer
authors.initials: O
authors.lastname: Erez
authors.forename: Shali
authors.initials: S
authors.lastname: Mazaki-Tovi
authors.forename: Juan Pedro
authors.initials: JP
authors.lastname: Kusanovic
authors.forename: Zhong
authors.initials: Z
authors.lastname: Dong
authors.forename: Tinnakorn
authors.initials: T
authors.lastname: Chaiworapongsa
authors.forename: Lami
authors.initials: L
authors.lastname: Yeo
authors.forename: Pooja
authors.initials: P
authors.lastname: Mittal
authors.forename: Sonia S
authors.initials: SS
authors.lastname: Hassan
mesh_terms: D000328:Adult; D011415:Complement Factor B / Q000032:analysis / Q000276:immunology*; D003170:Complement Pathway, Alternative / Q000276:immunology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000097:blood / Q000276:immunology*; D011704:Pyelonephritis / Q000097:blood / Q000150:complications / Q000276:immunology*; D055815:Young Adult
chemical_list: D011415:Complement Factor B