The H antigen at epithelial surfaces is associated with susceptibility to asthma exacerbation.
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).
Innes
Anh L
AL
The Cardiovascular Research Institute, University of California, San Francisco, California, USA.
McGrath
Kelly Wong
KW
Dougherty
Ryan H
RH
McCulloch
Charles E
CE
Woodruff
Prescott G
PG
Seibold
Max A
MA
Okamoto
Kimberly S
KS
Ingmundson
Kelsey J
KJ
Solon
Margaret C
MC
Carrington
Stephen D
SD
Fahy
John V
JV
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
D000942:Antigens, Bacterial; D015415:Biomarkers; C022863:H antigen