Abstract
The low-dose and long-term macrolide therapy (the macrolide therapy) has been introduced for chronic sinusitis. The mechanism of the therapy has not been apparent yet. We have recently known that this therapy is very effective for a majority of patients with chronic sinusitis (effective group) but not for some (non-effective group). In this paper, we examined the histology of nasal polyp from both the effective group and the non-effective group by immunohistochemical technique. Eosinophil infiltration was seen in both group, but number of eosinophils in the noneffective group was more than that in the effective group. Eosinophils in the non-effective group were positive for both EG 1 and EG 2 antibody, whereas eosinophils in the effective group showed week staining for EG 2 antibody. Nasal polyp contained a lot of vessels that were identified by anti-von Willebrand factor antibody. In the noneffective group, many vessels in the nasal polyp were positive for anti-VCAM-1 antibody but negative for anti-ICAM-1 antibody. In the case of the effective group, vessels in the nasal polyp expressed ICAM-1 more than VCAM-1. Therefore, histological characteristics of the non-effective group compared with the effective group were massive infiltration of activated eosinophils and expression of VCAM-1 on the vessels. These results indicate that some feature of inflammation of the non-effective group are different from that of the effective group. These difference may be due to altered cytokine network activation and contribute diverse effects of the macrolide therapy.
