NASAL POLYPOSIS - IMMUNOHISTOCHEMISTRY AND BIOELECTRICAL FINDINGS (A HYPOTHESIS FOR THE DEVELOPMENT OF NASAL POLYPS)

Nasal polyps and turbinates were obtained from individuals undergoing surgery for symptomatic nasal obstruction caused by nonatopic rhinosin usitis or allergic rhinosinusitis. One part of the tissue from each pa tient was fixed in neutral buffered formalin and prepared for study by histochemical and immunohistochemical methods. Monoclonal antibodies were used to identify macrophages, lymphocytes, and plasma cells. In m ost cases (12 of 16, 75%) the remainder of the polyp and turbinate sam ples was treated with protease to achieve disaggregation of the epithe lial cells. Those cells were cultured on permeable collagen matrix sup ports. Transepithelial potential difference and resistance were measur ed daily. At the time of maximal transepithelial potential difference, the epithelial cells were mounted in modified Ussing chambers and exp osed to a sodium-positive channel blocker (amiloride hydrochloride) an d to selected chloride-negative channel agonists (isoproterenol bitart rate and adenosine triphosphate). Middle turbinates and polyps were fo und to have more macrophages, lymphocytes, plasma cells, HLA-DR-positi ve cells, and eosinophils than the inferior turbinates. Epithelial cel ls obtained from polyps exhibited higher transepithelial potential dif ferences and equivalent short-circuit currents than turbinate cell cul tures. The responses to amiloride, isoproterenol, and adenosine tripho sphate were also greater for polyp than for turbinate cultures. A theo ry for the pathogenesis of nasal polyps is proposed. Local release of inflammatory mediators could cause sodium absorption and chloride perm eability to be higher in polyps than in turbinate epithelia. Increased sodium absorption is consistent with the hypothesis that epithelial f luid absorption contributes to the development of nasal polyps and is a result of the increased recruitment of inflammatory cells, which are present in nasal polyps.