Superantigen hypothesis for the early development of chronic hyperplastic sinusitis with massive nasal polyposis.

PURPOSE OF REVIEW

The pathogenesis, pathophysiology, and immunobiology of chronic hyperplastic sinusitis with massive nasal polyposis are starting to become unraveled. Allergy, viral infection, bacterial infection, fungal infection, and environmental pollution have all been suggested as possible initial triggers that may upregulate inflammation of the lateral wall of the nose to develop nasal polyposis. The purpose of this review is to present data from our laboratory that suggest that one of the possible early events in the development of inflammation of the lateral wall of the nose in chronic hyperplastic sinusitis with massive nasal polyposis is the production of exotoxins from Staphylococcus aureus. The exotoxins may act as superantigens and cause activation and clonal expansion of lymphocytes with specific Vbeta regions, resulting in massive cytokine production.

RECENT FINDINGS

Recent published studies suggest that S. aureus is the most common organism isolated from the mucus adjacent to massive nasal polyposis. Staphylococci produce exotoxins. These exotoxins, sometimes known as enterotoxins, include SEA, SEB, and TSST-1. These exotoxins are capable of acting as superantigens and therefore, reacting with T lymphocytes with specific Vbetas in the lateral wall of the nose. Thereafter, it is possible that these lymphocytes are stimulated to produce both TH1 and TH2 cytokines, which have also been demonstrated in the nasal polyp. The consequence of these findings may be the upregulation and increased survival of eosinophils in the nasal polyp.

SUMMARY

Staphylococcus aureus is present in the mucin adjacent to nasal polyps in about 60 to 70% of cases of massive nasal polyposis. These organism, as studied up to the present, always produce exotoxins, which may act as superantigens, causing activation and clonal expansion of lymphocytes with specific Vbeta region in the lateral wall of the nose. The present review suggests that activation of these lymphocytes produce both TH1 and TH2 cytokines. The potential damage to the nasal mucosa from eosinophils is briefly discussed. Theoretically, topical antibiotics to suppress the colonization of S. aureus may be a logical approach to downregulate the production of superantigen in the lateral wall of the nose after appropriate endoscopic sinus surgery.