CXCL9 and pulmonary tuberculosis: Therefore, Th1 (pro-inflammatory) cytokines, such as IFN-γ, IL-2, and TNF-α; Th2 (anti-inflammatory) cytokines, including IL-4 and IL-10; and IFN-γ-induced chemokines, such as CXCL-9 and CXCL-10, were selected to investigate the gene expression in blood cells stimulated with MTB antigens and compare it with that of unstimulated control blood cells obtained from individuals categorized under four different groups of participants (healthy, latently infected, and smear-positive pulmonary tuberculosis (PTB) and EPTB).