Distribution of eosinophil granule proteins in nasal mucosa of atopic patients with nasal polyposis.

Nasal polyposis is characterized by heavy eosinophilic infiltration into nasal polyp tissue. Nasal polyps have a predilection for the anteroinferior aspect of the middle turbinate and middle meatal area. To elucidate the pathogenesis of nasal polyps, the authors investigated the distribution of eosinophil infiltrating into nasal polyp tissue, especially at its pedicle, in comparison with the apparently normal nasal mucosa of the middle and inferior turbinates of the same patients. Tissue samples were taken from 12 allergic rhinitis patients with nasal polyps during endoscopic sinus surgery. Three kinds of monoclonal antibodies, EG1, EG2 and BMK-13, were used for immunohistochemical staining. The average number per high-power field of EG1+ cells was 6.33 at the pedicle of polyps and 4.68 and 4.36 at the middle and inferior turbinates, respectively; for EG2+ cells, it was 6.16 at the polyp pedicle and 2.06 and 2.47 at the middle and inferior turbinates, and for BMK-13+ cells, 4.20 at the polyp pedicle and 5.17 and 4.81 at the middle and inferior turbinates. There were no significant differences in the distribution of EG1+ and BMK-13+ cells, but a relatively larger number of activated eosinophils (EG2+ cells) was noted at the pedicle of polyps compared with the other sites (p < 0.025). In addition, the EG2+ cell/EG1+ cell ratio was significantly higher at the pedicle of polyps compared with the other sites (p < 0.01). The results of this study suggest that the activation of eosinophils is significant in the pathogenesis of nasal polyps in atopic patients rather than the number of eosinophils.