A possible link between sinusitis and lower airway hypersensitivity: the role of Staphylococcal enterotoxin B

BACKGROUND AND AIMS: The prevalence of asthma has been keeping arising with unknown etiology. The cumulative evidence indicates that chronic rhinosinusitis (CRS) closely relates to asthma, but the detailed mechanisms remain unclear. The present study aimed to take insight into the role of Staphylococcus enterotoxin B (SEB) in a possible association between CRS and asthma. METHODS: 38 patients with both CRS and asthma underwent functional endoscopic sinus surgery. Serum specific IgE and cytokines, clinical symptoms of CRS and asthma were evaluated before and after the surgery. Peripheral blood mononuclear cells (PBMCs) were separated from the patients and cultured. Th2 response of the cultured PBMCs in the presence or absence of specific antigens and SEB was evaluated. RESULTS: Besides the improvement of CRS symptoms, amelioration of asthma was also observed in the patients with both CRS and asthma after the sinus surgery. The preoperatively elevated Th2 cytokines, IL-4 and IL-5, normalized postoperatively. Th2 response was generated with separated PBMCs in the presence of specific antigens. SEB was required for maintaining Th2 response in these separated PBMCs. CONCLUSION: The present results indicate that a possible link exists between CRS and lower airway hypersensitivity. Sinusitis derived SEB may play a role in sustaining Th2 responses in the low airway hypersensitivity related to sinusitis.