The H antigen at epithelial surfaces is associated with susceptibility to asthma exacerbation.

Rationale: Acute asthma exacerbations, precipitated by viral infections, are a significant cause of morbidity, but not all patients with asthma are equally susceptible.

Objectives: 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.