The effects of erythromycin on human peripheral neutrophil apoptosis

Erythromycin is reported to have an anti-inflammatory action, which may account for its clinical effectiveness in treating chronic inflammatory diseases of the respiratory tract such as diffuse panbronchiolitis (DPB) and chronic sinusitis. The evaluate the anti-inflammatory action of erythromycin, we examined apoptosis of isolated neutrophils incubated with and without erythromycin. As a result, erythromycin augmented neutrophil apoptosis in a dose-dependent manner, with a maximal effect at 10 micrograms/ml and above. The percentage of neutrophil apoptosis at 12 h was 79.2 +/- 2.3% in medium with 10 micrograms/ml of erythromycin compared with 51.2 +/- 4.1% in control medium (p < 0.005). In a manner similar to that of erythromycin, another macrolide antibiotic, roxithromycin, also increased neutrophil apoptosis. However, there was no effect on apoptosis induced by treatment with josamycin (macrolide antibiotic), ampicillin (beta-lactam.) and cefazolin (cephalosporin antibiotic), or gentamycin (aminoglycoside). These findings suggest that erythromycin shortens neutrophil survival by accelerating neutrophil apoptosis.