IL17A and Recurrent lower respiratory tract infections: Th17 lineage cytokines (IL-17A, IL-17F, and IL-22) and chemokines (CXCL1, CXCL2, CXCL5, and CXCL8) are known to control chronic lung infection caused by mycobacteria (Busman-Sahay et al., 2015; Lombard et al., 2016; Shu et al., 2018).