Thus, patients with Tuberculoid leprosy (TL) are characterized by a relevant T cell immune response, including interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor (TNF), interferon-γ (IFN-γ), and interleukin-17 (IL-17) and lymphotoxin, manifested by few cutaneous or neural lesions with little or no bacilli. This evidence concerns the gene IL4 and tuberculoid leprosy.