title: Complement depletion deteriorates clinical outcomes of severe abdominal sepsis: a conspirator of infection and coagulopathy in crime?
abstract: BACKGROUND
  The complement depletion commonly occurred during sepsis, but it was often underestimated compared with severe infection or coagulation dysfunction.
  
  
  OBJECTIVE
  This study was designed to investigate the alteration of complement system in patients with severe abdominal sepsis and evaluate the role of complement depletion in prognosis of such patients. The relationship between complement depletion and infection or coagulopathy was also explored.
  
  
  METHODS
  Forty-five patients with severe abdominal sepsis were prospectively conducted among individuals referral to SICU. Currently recommended treatments, such as early goal-directed resuscitation, source control and antibiotics therapy, were performed. Acute physiology and chronic health evaluation II (APACHE II) and sepsis related organ failure assessment (SOFA) scores were employed to evaluate severity. Plasma levels of C3, C4, CRP, PCT, D-dimer and other parameters were detected within eight times of observation. The 28-day mortality, length of stay, and postoperative complications were compared between complement depletion and non-complement depletion groups.
  
  
  RESULTS
  Within the study period, eight (17.8%) patients died, five of them suffering from complement depletion. The overall incidence of complement depletion was 64.4%. At admission, mean complement C3 and C4 levels were 0.70 and 0.13 mg/mL, respectively. Using ROC analysis for mortality prediction, the area under the curve of C3 was 0.926 (95% CI, 0.845-0.998, P<0.001), with optimal cutpoint value of 0.578 mg/mL. Complement C3 depletion was shown to be no correlation to severity scores, however, strongly correlated with elevated D-dimer, PCT concentrations and increased postoperative complications.
  
  
  CONCLUSIONS
  Complement C3 depletion was found to be connected to poor prognosis in severe abdominal sepsis. This depletion seems to be associated with coagulopathy and aggravated infection during sepsis, which should be paid close attention in critical care.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT01568853.
authors.affiliation: Department of Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, P.R. China. JiananR@gmail.com
authors.forename: Jianan
authors.initials: J
authors.lastname: Ren
authors.forename: Yunzhao
authors.initials: Y
authors.lastname: Zhao
authors.forename: Yujie
authors.initials: Y
authors.lastname: Yuan
authors.forename: Gang
authors.initials: G
authors.lastname: Han
authors.forename: Weiqin
authors.initials: W
authors.lastname: Li
authors.forename: Qian
authors.initials: Q
authors.lastname: Huang
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Tong
authors.forename: Jieshou
authors.initials: J
authors.lastname: Li
mesh_terms: D000328:Adult; D001777:Blood Coagulation; D001778:Blood Coagulation Disorders / Q000097:blood / Q000209:etiology; D003176:Complement C3 / Q000276:immunology; D003165:Complement System Proteins / Q000378:metabolism*; D005260:Female; D005402:Fistula / Q000150:complications; D006801:Humans; D059413:Intraabdominal Infections / Q000150:complications; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D018805:Sepsis / Q000097:blood* / Q000209:etiology / Q000401:mortality*; D012720:Severity of Illness Index
chemical_list: D003176:Complement C3; D003165:Complement System Proteins