The observation of significantly higher CXCL10 production in response to ESAT-6 in spouses (S2) and TB patients compared with spouses showing negative IFN-γ responses to ESAT-6 (S1) in this study supports the previous findings that CXCL10 may be an adjunct marker for detecting infection alongside with IFN-γ although in this cohort, it could not differentiate TB contacts from TB patients. Here, IFNG is linked to infection.