title: The H antigen at epithelial surfaces is associated with susceptibility to asthma exacerbation.
abstract: BACKGROUND
  Acute asthma exacerbations, precipitated by viral infections, are a significant cause of morbidity, but not all patients with asthma are equally susceptible.
  
  
  OBJECTIVE
  To explore susceptibility factors for asthma exacerbations, we considered a role for histoblood group antigens because they are implicated in mechanisms of gastrointestinal viral infection, specifically the O-secretor mucin glycan phenotype. We investigated if this phenotype is associated with susceptibility to asthma exacerbation.
  
  
  METHODS
  We performed two consecutive case-control studies in subjects with asthma who were either prone or resistant to asthma exacerbations. Exacerbation-prone cases had frequent use of prednisone for an asthma exacerbation and frequent asthma-related healthcare utilization, whereas exacerbation-resistant control subjects had rarely reported asthma exacerbations. The frequency of different mucin glycan phenotypes, defined by the presence or absence of H (O), A, B, or AB antigens, was compared in cases and control subjects.
  
  
  RESULTS
  In an initial study consisting of 49 subjects with asthma (23 cases and 26 control subjects), we found that having the O-secretor phenotype was associated with a 5.8-fold increase in the odds of being a case (95% confidence interval, 1.7-21.0; P = 0.006). In a replication study consisting of 204 subjects with asthma (101 cases and 103 control subjects), we found that having the O-secretor phenotype was associated with a 2.3-fold increased odds of being a case (95% confidence interval, 1.2-4.4; P = 0.02).
  
  
  CONCLUSIONS
  The O-secretor mucin glycan phenotype is associated with susceptibility to asthma exacerbation. Clinical trial registered at www.clinicaltrials.gov (NCT00201266).
authors: The Cardiovascular Research Institute, University of California, San Francisco, California, USA.
authors: Anh L
authors: AL
authors: Innes
authors: Kelly Wong
authors: KW
authors: McGrath
authors: Ryan H
authors: RH
authors: Dougherty
authors: Charles E
authors: CE
authors: McCulloch
authors: Prescott G
authors: PG
authors: Woodruff
authors: Max A
authors: MA
authors: Seibold
authors: Kimberly S
authors: KS
authors: Okamoto
authors: Kelsey J
authors: KJ
authors: Ingmundson
authors: Margaret C
authors: MC
authors: Solon
authors: Stephen D
authors: SD
authors: Carrington
authors: John V
authors: JV
authors: Fahy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000942:Antigens, Bacterial / Q000097:blood*; D001249:Asthma / Q000097:blood / Q000276:immunology*; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D004198:Disease Susceptibility / Q000097:blood / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D020545:Respiratory Mucosa / Q000276:immunology* / Q000378:metabolism; D012307:Risk Factors; D012463:Saliva / Q000378:metabolism; D055815:Young Adult
chemical_list: D000942:Antigens, Bacterial; D015415:Biomarkers; C022863:H antigen