The Th2 effector response to helminth infections in the lungs is thus typified by the differentiation of antigen-specific CD4+ T cells to Th2, high levels of IL-4, IL-5, and IL-13, accompanied by eosinophilia, mucus production, and abundant IgE production, phenotypically similar to allergic airway disease (99). The gene discussed is CD4; the disease is helminthiasis.