Inhibitory effect of erythromycin on interleukin-8 secretion from exudative cells in the nasal discharge of patients with chronic sinusitis

Objectives: The mechanism of the efficacy of long term low-dose macrolide t herapy for chronic sinusitis is not fully understood. The authors studied t he inhibitory effect of erythromycin on interleukin-8 (IL-8) secretion from exudative cells in the nasal discharge of patients with chronic sinusitis. Study Design and Methods: Exudative cells in the nasal discharge were isol ated from six patients with nonallergic chronic sinusitis. The cells, more than 90% of which were neutrophils, were incubated with or without erythrom ycin in the presence of 10 mu g/mL of lipopolysaccharide. The IL-8 concentr ations in the culture supernatants were measured by enzyme-linked immunoass ay. Results: The amount of secreted IL-8 in the absence of erythromycin was 682 +/- 226 pg/10(6) cells/24 h. The IL-8 secretion was significantly redu ced to 66 +/- 15% and 46 +/- 13% of the control in the presence of 10(-6) a nd 10(-5) M of erythromycin, respectively. Conclusion: Erythromycin may act as a biologic modulator that inhibits IL-8 secretion from exudative cells and thereby blocks the vicious circle of neutrophil recruitment and IL-8 ge neration in the inflammatory site in chronic sinusitis.