Staphylococcal Sensitization: A Correlate of Type 2-High Inflammation in Children With Severe Asthma.

Background: Sensitization to Staphylococcus aureus enterotoxin (SE) has been identified to be a risk factor for asthma, but its determinants remain unclear.

Objective: To determine the significance of SE sensitization in children with moderate to severe asthma.

Methods: This was an observational cross-sectional analysis performed from 2011 to 2015 including children from the prospective Severe Asthma Molecular Phenotype cohort: school-age children with severe and moderate asthma or preschool-age children with severe and moderate recurrent wheeze. We evaluated sensitization to four SEs (Staphylococcus enterotoxin A, Staphylococcus enterotoxin B, Staphylococcus enterotoxin C, and toxic shock staphylococcic toxin).

Results: We analyzed data from 377 children: 233 of preschool age and 144 of school age. Among them, 26 (11.2%) and 59 (41.0%) children, respectively, had sensitization to at least one SE. The burden of sensitization was higher in older children in terms of both specific IgE levels and the number of sensitizations. In multivariable analysis, SE sensitization was associated with elevated total IgE in both populations (odds ratio [OR] = 9.35, P = .01; and OR = 8.06, P < .01), and with bronchoalveolar lavage eosinophilia in both preschool and school-age children (OR = 3.95, P = .03; and OR = 4.11, P = .03, respectively). Classification and regression trees showed an association of SE sensitization with age and with total IgE in the entire population, and with total IgE, bronchoalveolar lavage eosinophilia, and blood eosinophilia in school-age children.

Conclusions: Staphylococcal enterotoxin sensitization was correlated with type 2-high inflammation (eosinophilic inflammation and elevated total IgE count) in this population of moderate to severe asthmatic children.