Exploration of IgE Specific to Staphylococcal Serine Protease-Like Protein A as a Phenotypic Marker in Late-Onset Asthma.

PURPOSE: Staphylococcus aureus (SA) secretes pro-allergic molecules, including staphylococcal enterotoxins (SEs) and serine protease-like proteins (Spls). While IgE sensitization to SE has been relatively well documented in relation to severe eosinophilic late-onset asthma, the clinical implications of IgE sensitization to Spls remain unclear. We explored the clinical relevance of Spl-IgE in late-onset asthmatics.

METHODS

Adults with late-onset asthma (onset age ≥ 40 years) were prospectively enrolled. Demographic and clinical characteristics were assessed, and serum levels of total IgE, SE-IgE, and SplA-IgE were measured. Nasal swabs were obtained to assess SA colonization.

RESULTS

Among 109 participants, SplA-IgE levels were significantly associated with blood eosinophilia, total IgE, SE-IgE sensitization, and male sex, but not with SA colonization, asthma severity, or lung function.

CONCLUSION

Sensitization to SplA-IgE may indicate a type 2 inflammatory phenotype, but its role in asthma warrants further investigation.