We evaluated the IFN-γ circuit by studying IFN-γ production after mycobacterial challenge as well as IL-12Rβ1 expression and STAT4 phosphorylation in response to IL-12p70 stimulation in whole blood of a 6-year-old Peruvian girl with disseminated recurrent mycobacterial infection diagnosed as multidrug-resistant tuberculosis.
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.