T cells have receptors related to CD4 and CD8, they are αβ, which is the most common chain, and γ/δ, both of which recognize M. leprae lipids. Cytokines expressed by Th1 are responsible for the rapid elimination of bacilli in lepromatous lesions. Th17 is a third subset of helper T cells, express IL-17 and in leprosy present the transcription factor RORC and STAT3. The presence of Th17 expressing IL-17A in skin lesions correlates more with the tuberculoid form. Furthermore, Th17 may confer protection to individuals who fail to elicit Th1 and Th2 responses. This evidence concerns the gene CD4 and leprosy.