Effects of low-dose, long-term macrolide therapy on neutrophil recruitment and IL-8 level in the nasal discharge in chronic sinusitis patients

Chronic sinusitis is characterized by purulent paranasal sinus effusion and nasal discharge with numerous emigrated neutrophils. Recent advances in sinusitis research have revealed that interleukin-8 (IL-8) largely participates in this phenomenon. In the present study, effects of 14-membered macrolide antibiotic on neutrophil recruitment and IL-8 level in the nasal discharge were studied in chronic sinusitis patients. Twelve non-allergic chronic sinusitis patients were orally given 150 mg roxithromycin per day without other treatments for 3 months. The number of neutrophils in the nasal smear was estimated in a grading scale, and the IL-8 concentration in the nasal discharge was measured by ELISA. The number of neutrophils was decreased in 7 cases out of 12 (58%) at 2 months and 6 cases out of 10 (60%) at 3 months. The IL-8 level in the nasal discharge was significantly lowered after 3-month-administration (14.3 ± 3.8 nM vs. 5.3 ± 1.7 nM, p < 0.005). Moreover, grading of neutrophils in the nasal smear was correlated with the IL-8 level in the nasal discharge. These findings suggest that roxithromycin inhibits positive feedback mechanism of neutrophil recruitment and IL-8 production by the recruited neutrophils. To investigate the mode of action of macrolide antibiotics may lead to the development of a cytokine therapy for chronic sinusitis.