Since GM-CSF can stimulate leukotriene production by neutrophils and eosinophils[11] and changes in GM-CSF mediated signaling have been shown to occur in elderly human subjects in vitro[19,20], we examined GM-CSF production by peripheral blood mononuclear cells (PBMCs) in the older and young asthma subjects. The gene discussed is CSF2; the disease is asthma.