Effects of ragweed and Th-2 cytokines on the secretion of IL-8 in human airway epithelial cells

Ragweed-induced asthma is a very common pulmonary disease. An important par t of asthma is a large increase in inflammatory cells, including neutrophil s and eosinophils, in ragweed-sensitilized subjects. In this study, we dete rmined if ragweed treatment could induce the release of interleukin-8 (IL-8 ) by human airway epithelial cells. We found that ragweed induces a substan tial increase of the secretion of IL-8 from A549 cells in a dose- and time- dependent manner. Th-2 cytokines, IL-4 and IL-13, Partially inhibited the r agweed-induced secretion of IL-8. Our results suggest that airway epithelia l cells may be one of the cell sources that provide IL-8 during ragweed-ind uced asthma.;The results also indicate that IL-4 and IL-13 may exert inhibi tory effects on IL-8 secretion by airway epithelium.