ASM cells, in addition to proliferation and hypertrophy, also synthesize and release IL-6, GM-CSF, and other mediators of inflammation in response to IL-1β and tumor necrosis factor-α.23 Human bronchial smooth muscle cells treated with serum from patients with atopic asthma secrete IL-5, and treatment of these cells with IL-5 provoked an asthmatic constrictor response to acetylcholine. This evidence concerns the gene CSF2 and atopic asthma.