title: Longitudinal study of Stenotrophomonas maltophilia antibody levels and outcomes in cystic fibrosis patients.
abstract: Previous studies have shown an association between higher Stenotrophomonas maltophilia antibody levels and decreased lung function in patients with cystic fibrosis (CF). The purpose of this study was to assess the serologic response to S. maltophilia over time and to determine whether changes in antibody levels could predict clinical outcomes.
  
  
  
  Changes in S. maltophilia antibody levels in adult and pediatric patients with CF from 2008 to 2014 were assessed between groups of infection patterns. Regression models accounting for repeated measures were used to assess whether antibody levels could predict subsequent S. maltophilia microbiological status, and whether they are associated with lung function and subsequent pulmonary exacerbation.
  
  
  
  A total of 409 S. maltophilia antibody samples from 135 CF patients showed that antibody levels did not change significantly between study visits, regardless of infection group. Higher antibody levels were independently associated with future culture positivity (OR 1.62; 95% CI 1.09, 2.41; p=0.02). While higher antibody levels were not independently associated with decreases in FEV1% predicted, they were associated with an increased hazard ratio for subsequent pulmonary exacerbation (HR 1.3; 95% CI 1.1, 1.6; p<0.001).
  
  
  
  S. maltophilia antibody levels may be helpful to identify individuals at risk of exacerbation who may benefit from earlier antimicrobial treatment.
authors.affiliation: Division of Infectious Diseases, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, Canada M5G 1X8. Electronic address: 12jw73@queensu.ca.
authors.forename: Jillian
authors.initials: J
authors.lastname: Wettlaufer
authors.affiliation: Division of Respiratory Medicine, Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto. Electronic address: Michelle.Klingel@sickkids.ca.
authors.forename: Michelle
authors.initials: M
authors.lastname: Klingel
authors.affiliation: Division of Microbiology, Department of Pediatric Laboratory Medicine, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto M5G 1X8, Canada. Electronic address: Yvonne.Yau@sickkids.ca.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Yau
authors.affiliation: Division of Respiratory Medicine, Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto. Electronic address: Sanja.Stanojevic@sickkids.ca.
authors.forename: Sanja
authors.initials: S
authors.lastname: Stanojevic
authors.affiliation: Division of Respirology and Keenan Research Centre of Li Ka Shing Knowledge Institute, Department of Medicine, St. Michael's Hospital, University of Toronto, 30 Bond Street, Toronto, Canada M5B 1W8. Electronic address: Tullise@smh.ca.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Tullis
authors.affiliation: Division of Respiratory Medicine, Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto. Electronic address: Felix.Ratjen@sickkids.ca.
authors.forename: Felix
authors.initials: F
authors.lastname: Ratjen
authors.affiliation: Division of Infectious Diseases, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, Canada M5G 1X8. Electronic address: Valerie.Waters@sickkids.ca.
authors.forename: Valerie
authors.initials: V
authors.lastname: Waters
mesh_terms: D000293:Adolescent; D000328:Adult; D000906:Antibodies / Q000097:blood; D002170:Canada / Q000453:epidemiology; D002648:Child; D003550:Cystic Fibrosis / Q000097:blood / Q000453:epidemiology / Q000382:microbiology / Q000503:physiopathology; D018450:Disease Progression; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012129:Respiratory Function Tests / Q000379:methods; D012698:Serologic Tests / Q000379:methods; D020615:Stenotrophomonas maltophilia / Q000276:immunology / Q000302:isolation & purification
chemical_list: D000906:Antibodies
keywords: Antibodies; Cystic fibrosis; Pulmonary exacerbation; Stenotrophomonas maltophilia