title: Immunoglobulin G anticardiolipin antibodies and progression to Q fever endocarditis.
abstract: BACKGROUND
  Immunoglobulin G (IgG) anticardiolipin (aCL) antibodies are associated with valvulopathy and endocarditis in patients with lupus and other diseases. During acute Q fever, high IgG aCL prevalence has been reported, but the clinical significance remains unknown.
  
  
  METHODS
  To test if increased IgG aCL at acute Q fever diagnosis is associated with an increased risk of progression to endocarditis, all patients diagnosed in the French National Referral Center for Q fever from January 2007 to December 2011 were included and followed regularly until January 2013 in a 5-year prospective cohort study. Q fever endocarditis was defined according to recently updated criteria.
  
  
  RESULTS
  Seventy-two patients were followed for a median time of 31 months (interquartile range, 18-47 months). Of these, 13 patients with valvulopathy without antibiotic prophylaxis progressed to endocarditis. IgG aCL levels were highly prevalent (57%) and significantly higher in the presence of a valvulopathy (P = .005). Using Cox regression analysis, highly increased levels of IgG aCL (adjusted hazard ratio [AHR], 12.95; 95% confidence interval, 2.85-58.95; P = .001) and high levels of phase II immunoglobulin M (IgM; AHR, 6.59; 95% CI, 1.37-31.62; P = .018) were the only independent predictors of progression to endocarditis.
  
  
  CONCLUSIONS
  Rapid progression from acute Q fever to endocarditis is associated with high levels of IgG aCL and high levels of phase II IgM, findings that should be critical in the prevention of endocarditis.
authors.affiliation: Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Faculté de Médecine, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7278, Institut de Recherche pour le développement 198, Aix-Marseille Université, Marseille, France.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Million
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Walter
authors.forename: Nathalie
authors.initials: N
authors.lastname: Bardin
authors.forename: Laurence
authors.initials: L
authors.lastname: Camoin
authors.forename: Roch
authors.initials: R
authors.lastname: Giorgi
authors.forename: Pierre
authors.initials: P
authors.lastname: Bongrand
authors.forename: Frédérique
authors.initials: F
authors.lastname: Gouriet
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Casalta
authors.forename: Franck
authors.initials: F
authors.lastname: Thuny
authors.forename: Gilbert
authors.initials: G
authors.lastname: Habib
authors.forename: Didier
authors.initials: D
authors.lastname: Raoult
mesh_terms: D000328:Adult; D000368:Aged; D017153:Antibodies, Anticardiolipin / Q000097:blood*; D004696:Endocarditis / Q000175:diagnosis / Q000276:immunology* / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D007075:Immunoglobulin M / Q000097:blood; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011778:Q Fever / Q000150:complications* / Q000276:immunology / Q000473:pathology
chemical_list: D017153:Antibodies, Anticardiolipin; D007074:Immunoglobulin G; D007075:Immunoglobulin M
keywords: Coxiella burnetii; Q fever; anticardiolipin; antiphospholipid; endocarditis