Erythromycin suppresses interleukin 6 expression by human bronchial epithelial cells: a potential mechanism of its anti-inflammatory action.

We evaluated the effects of several antibiotics on IL-6 expression by human bronchial epithelial cells, potent sources of this proinflammatory cytokine important in airway inflammation. Among those tested, erythromycin (EM) and clarithromycin (CAM) uniquely suppressed mRNA levels as well as the release of IL-6 at the therapeutic and non-cytotoxic concentration (10(-6)M). Our findings suggested that these macrolide antibiotics had suppressive effect on cytokine expression in human cells, and this new mode of action may have relevance to their clinical effectiveness in airway inflammatory diseases.