title: Reduced rhinovirus-specific antibodies are associated with acute exacerbations of chronic obstructive pulmonary disease requiring hospitalisation.
abstract: BACKGROUND
  Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are often linked to respiratory infections. However, it is unknown if COPD patients who experience frequent exacerbations have impaired humoral immunity. The aim of this study was to determine if antibodies specific for common respiratory pathogens are associated with AECOPD.
  
  
  METHODS
  Plasma was obtained from COPD patients when clinically stable. AECOPD requiring hospitalisation were recorded. IgG1 antibodies to H. Influenzae outer membrane protein 6 (P6), pneumococcal surface protein C (PspC) and the VP1 viral capsid protein of rhinovirus were measured.
  
  
  RESULTS
  COPD patients who had an AECOPD (n = 32) had significantly lower anti-VP1 IgG1 antibody levels when stable compared to COPD patients who did not have an AECOPD (n = 28, p = 0.024). Furthermore, the number of hospitalisations was inversely proportional to anti-VP1 antibody levels (r = -0.331, p = 0.011). In contrast, antibodies specific for P6 and PspC were present at similar concentrations between groups. Plasma IL-21, a cytokine important for B-cell development and antibody synthesis, was also lower in COPD patients who had an AECOPD, than in stable COPD patients (p = 0.046).
  
  
  CONCLUSIONS
  Deficient humoral immunity specific for rhinoviruses is associated with AECOPD requiring hospitalisation, and may partly explain why some COPD patients have an increased exacerbation risk following respiratory viral infections.
authors: School of Medicine, The University of Queensland, Brisbane, Australia.
authors: Stephanie T
authors: ST
authors: Yerkovich
authors: Belinda J
authors: BJ
authors: Hales
authors: Melanie L
authors: ML
authors: Carroll
authors: Julie G
authors: JG
authors: Burel
authors: Michelle A
authors: MA
authors: Towers
authors: Daniel J
authors: DJ
authors: Smith
authors: Wayne R
authors: WR
authors: Thomas
authors: John W
authors: JW
authors: Upham
mesh_terms: D000368:Aged; D000914:Antibodies, Viral / Q000097:blood*; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D018450:Disease Progression; D005260:Female; D018073:Haemophilus Vaccines / Q000276:immunology; D006760:Hospitalization; D006801:Humans; D056724:Immunity, Humoral / Q000502:physiology*; D007074:Immunoglobulin G / Q000097:blood; D007378:Interleukins / Q000097:blood; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000276:immunology* / Q000503:physiopathology; D012141:Respiratory Tract Infections / Q000150:complications; D012229:Rhinovirus / Q000276:immunology*; D012720:Severity of Illness Index; D014764:Viral Proteins / Q000276:immunology; D000098546:Interleukin-21
chemical_list: D000914:Antibodies, Viral; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D015415:Biomarkers; D018073:Haemophilus Vaccines; D007074:Immunoglobulin G; D007378:Interleukins; C069990:P6 outer membrane protein, Haemophilus; C110344:SpsA protein, Streptococcus pneumoniae; D014764:Viral Proteins; C074995:viral protein 1, rhinovirus; D002097:C-Reactive Protein; D000098546:Interleukin-21