The effect of azithromycin and clarithromycin on ex vivo interleukin-8 (IL-8) release from whole blood and IL-8 production by human alveolar macrophages.

We investigated the effects of azithromycin and clarithromycin, two antibiotics that possess a broad spectrum of antimicrobial activity (including antimycobacterial activity), on interleukin-8 (IL-8) release from human whole blood leucocytes and lung macrophages. Ex vivo stimulation of leukocytes with either of the antibiotics (0.04-40 mg/L) significantly increased IL-8 secretion. Incubation of alveolar macrophages with different concentrations of azithromycin or clarithromycin modified IL-8 production: it increased at a drug concentration of 4 mg/L and decreased at concentration of 400 mg/L. Our findings suggest that azithromycin and clarithromycin may alter IL-8 production, thus enhancing the clinical effectiveness of these antibiotics.