Type O secretors have between a 2.3 and 5.8 fold increase in the odds of having exacerbated asthma attacks. - GreenMedInfo Summary

RATIONALE: Acute asthma exacerbations, precipitated by viral infections, are a significant cause of morbidity, but not all asthmatics 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. METHODS: We performed two consecutive case-control studies in asthmatic subjects 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 controls 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 controls. Measurements&MAIN RESULTS: In an initial study consisting of 49 asthmatic subjects (23 cases and 26 controls), we found that having the O-secretor phenotype was associated with a 5.8 fold increase in the odds of being a case (CI 1.7â 21.0, p=0.006). In a replication study consisting of 204 asthmatic subjects (101 cases and 103 controls), we found that having the O-secretor phenotype was associated with a 2.3 fold increased odds of being a case (CI 1.2 â 4.4; p=0.02). CONCLUSIONS: The O-secretor mucin glycan phenotype is associated with susceptibility to asthma exacerbation. www.clinicaltrials.gov NCT00201266.