This may reflect chronicity of infection in MDR-TB and NTM infection, which is often treated sub-optimally; however, the contrast reported by the authors between elevated serum IL-10 levels in MDR-TB patients vs. elevated serum TGF-β levels in NTM-infected patients could also suggest different subsets of Tregs or different suppressive effector pathways to be involved in MDR-TB vs. NTM (113). Here, TGFB1 is linked to multidrug-resistant tuberculosis.