In the context of allergic reactions, Th1 polarization with priming of antigen-specific CD4+ T cells and CD8+ cells occurs in the background of Th1 cytokines including interleukin-2 (IL-2) and interferon-γ (IFN-γ), leading to recruitment and activation of eosinophils and monocytes/macrophages that together with the primed T lymphocytes, generate a T cell-mediated delayed immune hypersensitivity reaction [1]. The gene discussed is IL2; the disease is allergic disease.