Effects of clarithromycin on inflammatory cell mediator release and survival

Background: Clarithromycin exhibits anti-inflammatory as well as antimicrobial activity, leading to decreased symptoms of asthma and chronic sinusitis. The mode of anti-inflammatory effects of clarithromycin on inflammatory cells is not well understood. We hypothesized that clarithromycin inhibits inflammatory cell mediator release and survival. Methods: We investigated the effects of this drug on survival and mediator release from mast cells, eosinophils and neutrophils. Results: Human eosinophil and neutrophil respiratory burst was inhibited by up to 54% after 1-2 h pretreatment with 100 mu g/ml clarithromycin. Similar doses of erythromycin did not affect respiratory burst responses in these cells. Clarithromycin at doses of up to 100 mu g/ml had no effect on granule-derived mediators released from mast cells and neutrophils. However, we found that clarithromycin (100 mu g/ml) induced cell death in mast cells and eosinophils after 16-48 h incubation. Conclusion: Clarithromycin inhibited inflammatory cell mediator release and survival, which may enhance its ability to reduce the symptoms of chronic sinusitis and asthma. Copyright (C) 2005 S. Karger AG, Basel.