IL-23 plays an ambiguous role in T helper type 1 (Th1) and Th17 profiles: alone, IL-23 is responsible for M. tuberculosis-induced IL-17 and IFN-γ expression in CD4<sup>+</sup> T cells from PPD<sup>+</sup> HD whereas, together with transforming growth factor (TGF-β), it promotes IL-17<sup>+</sup> IFN-γ<sup>-</sup> expansion in MDR-TB.