Shu CC, et al. - Researchers herein intended to gain insight into host vulnerability to Mycobacterium avium complex (MAC)-related immune responses, and in particular the interleukin (IL)-23/IL-17 axis in MAC-lung disease (LD). They noted that in patients with MAC-LD vs controls, MAC induced a similar expression of IL-23 from macrophages but a lower expression of IL-17 from lymphocytes, which may be through an increased expression of programmed death (PD)-1. The macrophage response of IL-12 p40 was stronger than that of IL-12 p70, and higher in the controls during MAC disease, which may suggest another kind of MAC-related immune evasion.