CXCL10 and tuberculosis: HIV co-infection rate is significantly higher in participants with indeterminate results of CXCL10 mRNA release assay and T-SPOT.TB test (33.3%, 3/9) than that in participants with valid results of CXCL10 mRNA release assay and T-SPOT.TB test (2.22%, 11/496) (p = 0.0013).