The cytokines (IL-4, 5, 6, 10, and 13) produced by Th2 cells have been shown to play pivotal roles in the development of eosinophilic inflammation in asthma, while interleukin-2 and interferon-γ were produced by Th1 cells (Rankin et al., 1996). The gene discussed is IL4; the disease is asthma.