STAT3 and leprosy: 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.