title: Complement activation in Puumala hantavirus infection correlates with disease severity.
abstract: BACKGROUND
  Hantaviruses are important human pathogens that cause clinical diseases characterized by renal and cardiopulmonary manifestations. Their pathogenesis is currently poorly understood. We have studied the role of the complement system in the pathogenesis of Puumala (PUUV) hantavirus infection.
  
  
  METHODS
  We studied the activation of complement by measuring the terminal complement complex SC5b-9 and complement component C3 and C4 levels in patients with acute PUUV infection. Several laboratory parameters and clinical findings reflecting the severity of PUUV-HFRS were evaluated with regard to complement activation.
  
  
  RESULTS
  The levels of SC5b-9 were significantly increased and C3 decreased in the acute stage as compared to the levels at full recovery (P < 0.001). We found that SC5b-9 levels were higher in patients with chest X-ray abnormalities than in patients with a normal X-ray during the acute stage (P = 0.028). Furthermore, SC5b-9 and C3 levels showed significant correlation with several clinical and laboratory parameters that reflect the severity of the acute PUUV infection.
  
  
  CONCLUSIONS
  We showed that the complement system becomes activated via the alternative pathway in the acute stage of PUUV infection and the level of activation correlates with disease severity. The results further suggest that complement activation may contribute to the pathogenesis of acute PUUV infection.
authors.affiliation: Infection Biology Research Program, Department of Virology, Haartman Institute, University of Helsinki, Finland. jussi.sane@helsinki.fi
authors.forename: Jussi
authors.initials: J
authors.lastname: Sane
authors.forename: Outi
authors.initials: O
authors.lastname: Laine
authors.forename: Satu
authors.initials: S
authors.lastname: Mäkelä
authors.forename: Antti
authors.initials: A
authors.lastname: Paakkala
authors.forename: Hanna
authors.initials: H
authors.lastname: Jarva
authors.forename: Jukka
authors.initials: J
authors.lastname: Mustonen
authors.forename: Olli
authors.initials: O
authors.lastname: Vapalahti
authors.forename: Seppo
authors.initials: S
authors.lastname: Meri
authors.forename: Antti
authors.initials: A
authors.lastname: Vaheri
mesh_terms: D000328:Adult; D000368:Aged; D003167:Complement Activation; D003176:Complement C3 / Q000502:physiology; D003181:Complement C4 / Q000502:physiology; D015938:Complement Membrane Attack Complex / Q000502:physiology; D005260:Female; D006480:Hemorrhagic Fever with Renal Syndrome / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D029262:Puumala virus; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D003176:Complement C3; D003181:Complement C4; D015938:Complement Membrane Attack Complex; C047610:SC5b-9 protein complex