Low-dose and long-term administration of 14-lactone-ring
macrolides (
macrolide therapy) has been reported to be very effective in the treatment of chronic
sinusitis, including the sinobronchial syndrome. However, the mechanism whereby the chronic
inflammation is down-regulated is unknown. The present study was carried out to immunohistochemically identify the
antigens expressed on the surfaces of inflammatory cells in the paranasal mucosa and
nasal polyps of patients who responded well to
macrolide therapy and in control patients.
HLA-DR (a
class-II antigen) was detected on relatively large, irregularly shaped cells and on small, round cells in the submucosa. The former cells were considered to be macrophages because they were CD68-positive. Thus, in the paranasal mucosa macrophages act antigen-presenting cells. The numbers of
HLA-DR-positive cell and CD68-positive cells varied among the patients and did not differ significantly between the patients who had under gone
macrolide therapy and those who had not. There were significantly fewer CD4-positive T lymphocytes in the submucosa of patients who had under gone
macrolide therapy than in the control patients, but the number of CD8-positive T lymphocytes did not differ significantly between the two groups of patients. The mean ratio of the number of CD4-positive to the number of CD8-positive T lymphocytes (CD4/CD8) in the submucosa of the patients who had under gone
macrolide therapy, 0.77, was significantly lower than in the control patients, 1.92 (< 0.01).
HLA-DR expression induces differentiation of and
cytokine production by CD4-positive T lymphocytes in the presence of co-stimulators. The present results suggest that
macrolides may affect the manner of interaction between antigen-presenting cells such as macrophages and CD4-positive T lymphocytes.