DETECTION OF GM-CSF IN ASTHMATIC BRONCHIAL EPITHELIUM AND DECREASE BYINHALED CORTICOSTEROIDS

The presence of granulocyte-macrophage colony-stimulating factor (GM-C SF) in airway epithelial cells in vivo was assessed in 15 asthmatic an d 9 normal subjects. GM-CSF was analyzed using immunohistochemistry wi th a polyclonal and a monoclonal antibody. Hue saturation intensity co lor image analysis was used to quantify staining. Asthmatic airway epi thelial cells stained significantly more with anti-GM-CSF than those f rom normal subjects (p = 0.0013 and p = 0.0003 for the polyclonal and monoclonal antibodies, respectively). Additionally, 8 asthmatic indivi duals inhaled 1,000 mug beclomethasone diproprionate per day for 8 wk and 6 asthmatic patients inhaled matching placebo. There was a signifi cant reduction of GM-CSF in the epithelium in the patients who were gi ven corticosteroids (p = 0.014), whereas the group of subjects who wer e given placebo showed no significant change in GM-CSF staining. There was a correlation between the percentage suppression of GM-CSF staini ng by inhaled corticosteroids and the percentage increase in FEV1 (r = 0.61, p < 0.05) and percentage decrease in carbachol responsiveness ( r = 0.80, p < 0.01). These findings suggest that GM-CSF may play a rol e in the inflammatory processes of bronchial asthma and that the epith elial cell may be a target cell for drug action.