The Prevalence of Serum Specific IgE to Superantigens in Asthma and Allergic Rhinitis Patients

Staphylococcus aureus is the most common bacterium present in upper respiratory tract, and the toxins it produced are involved in allergic inflammation pathogenesis. In this study, we investigated the clinical significance of IgE in association with staphylococcal superantigens in allergic asthma with rhinitis (BAwAR) and allergic rhinitis alone (AR). We recruited 100 patients with BAwAR (group I), 100 patients with AR (group II), and 88 healthy controls (group III). Patients were clinically diagnosed by physicians, and were sensitized to house dust mites. Specific IgE antibodies to staphylococcal superantigen A (SEA), B (SEB), and toxic shock syndrome toxin-1 (TSST-1) were measured using the ImmunoCAP system. Other clinical parameters were retrospectively analyzed. All specific IgE antibodies to SEA, SEB, and TSST-1 were detected most frequently in group I (22%, 21%, and 27%), followed by group II (11%, 14%, and 21%) and group III (4.5%, 3.4%, and 2.3%). Absolute values of serum specific IgE to SEA, SEB, and TSST-1 were also significantly higher in group I (0.300±1.533 kU/L, 0.663±2.933 kU/L, and 0.581±1.931 kU/L) and group II (0.502±2.011 kU/L, 0.695±3.337 kU/L, and 1.067±4.688 kU/L) compared to those in group III (0.03±0.133 kU/L, 0.03±0.14 kU/L, and 0.028±0.112 kU/L). The prevalence of serum specific IgE to SEA was significantly higher in group I compared to group II (P=0.025). Blood eosinophil counts were significantly higher in patients with specific IgE to SEA or SEB, and higher serum levels of specific IgE to house dust mites were noted in patients with specific IgE to TSST-1. In conclusion, the present study suggested that IgE responses to staphylococcal superantigens are prevalent in the sera of both BAwAR and AR patients. This may contribute to an augmented IgE response to indoor allergens and eosinophilic inflammation.