Clinical significance of immunoglobulin E responses to staphylococcal superantigens in patients with aspirin-exacerbated respiratory disease.

BACKGROUND Previous studies have reported a higher prevalence of immunoglobulin E (IgE) specific for staphylococcal superantigens (SAg) in the nasal mucosa of patients with aspirin-exacerbated respiratory disease (AERD), associated with eosinophilic inflammation and leukotriene production. However, the role of SAg-specific IgE in the pathogenesis of AERD is not well understood. We evaluated the clinical significance of serum IgE specific for three types of SAg, namely staphylococcal enterotoxins A and B (SEA and SEB) and toxic shock syndrome toxin-1 (TSST-1) in AERD. METHODS We enrolled 147 patients with AERD confirmed by a lysine-acetyl salicylic acid bronchoprovocative test and compared them with 147 patients with aspirin-tolerant asthma (ATA) and 141 healthy controls (NC). The levels of serum total IgE and SAg-specific IgE were measured using an ImmunoCAP system. Other clinical parameters were analyzed retrospectively. RESULTS The prevalences of SEA-, SEB- and TSST-1-specific IgE in the AERD and ATA groups were significantly higher than those in the NC group (p < 0.05, respectively). The total IgE level was significantly higher in patients with AERD with high levels of SEA-specific IgE than in those with lower levels (p < 0.05), with significant positive correlations between total and SAE-specific IgE levels (p < 0.05). The PC20 methacholine level was significantly lower in patients with AERD with high levels of SEA-specific IgE, while a significantly higher eosinophil count was noted in patients with AERD with high levels of SEB-specific IgE (p < 0.05, respectively). CONCLUSIONS Specific IgE responses to SAg may increase the serum total IgE level, airway hyperresponsiveness and eosinophil activation, leading to more severe clinical symptoms in AERD.