While the Th2-type cytokine IL-13 can induce AHR independently of eosinophilia (Grunig et al., 1998), ablation of eosinophils in a IL-5/eotaxin double knockout system abolishes AHR by reducing the ability of T cells to produce IL-13 (Mattes et al., 2002). The gene discussed is IL5; the disease is Increased total eosinophil count.