Superantigens and chronic rhinosinusitis: detection of staphylococcal exotoxins in nasal polyps

The role of infectious agents in the etiology of chronic rhinosinusitis with nasal polyposis (CRSwNP) remains unclear. Recent studies have provided indirect evidence of exposure to staphylococcal exotoxins in the blood and polyp tissue of patients with CRSwNP. These exotoxins have the capacity to act as superantigens, bypassing normal antigen processing and directly stimulating a massive inflammatory response. The objective of the study was to analyze mucus and polyp tissue samples from patients with CRSwNP for the presence of staphylococcal exotoxins.

Prospective study.

Tissue and mucus samples were obtained from 42 patients undergoing endoscopic sinus surgery for chronic rhinosinusitis and 11 normal control patients. Twenty-nine of 42 patients had chronic rhinosinusitis with bilateral nasal polyposis, 2 had antrochoanal polyps, and 11 had chronic rhinosinusitis without nasal polyps. Eleven patients without chronic rhinosinusitis or polyps served as normal control patients. Specimens were analyzed for the presence of five staphylococcal exotoxins (SEA, SEB, SEC, SED, and toxic shock syndrome toxin type 1 [TSST-1]) using enzyme-linked immunosorbent assay (ELISA). Histological analysis of specimens and mean eosinophil counts were correlated with the presence of toxin.

At least one toxin was detected in 14 of 29 patients with bilateral nasal polyposis. Nine of the 14 patients also had positive findings for additional toxins. The dominant histological pattern in the CRSwNP patient group was polypoid mucosa with edema, which was found in both ELISA-positive and ELISA-negative patients. Mean eosinophil counts tended to be higher in ELISA-positive patients with polyps compared with patients without toxin detection. No toxin was detected in the 11 specimens taken from normal control patients. Only 1 of the 13 patients with CRS without polyps had positive ELISA results for toxin.

The current study demonstrates the presence of superantigen toxins in 14 of 29 patients with CRSwNP, with SEB and TSST-1 being the most common. Further studies are necessary to correlate the presence of toxin with the pathological changes present in polyp tissue.