Tuberculosis Antigen Stimulated CXCR3 Ligand Assay for the Diagnosis of Tuberculous Lymphadenitis

<b>Background and Aim:</b> The diagnosis of Tuberculous lymphadenitis (TB-LAP) is challenging and often need invasive diagnostic procedures. The ligands for CXC chemokine receptor 3 (CXCR3) displayed good diagnostic performance in diagnosis of active pulmonary tuberculosis and we investigated their competence in the diagnosis of TB-LAP. <b>Methods:</b> 65 patients suspected to have TB-LAP were enrolled. 53 were confirmed to have TB-LAP and 12 had otherwise diagnosis. Age matched control group (86 had negative interferon- γ release assay (IGRA) results and 27 had positive IGRA positive results) were also recruited. After incubation, plasma IFN- γ levels and monokine induced by IFN- γ, (MIG, CXCL9), and IFN-inducible T-cell α–chemoattractant (I-TAC, CXCL11) were measured by enzyme-linked immunosorbent assay. Receiver operating characteristic (ROC) analysis was performed. <b>Results:</b> The TB antigen stimulated levels of IFN- γ, I-TAC and MIG were significantly increased in TB-LAP. From ROC analysis, MIG and I-TAC displayed superior diagnostic performance compared to IFN- γ for detecting TB-LAP. The areas under the curve (AUC; 95% confidence interval) for differentiating TB-LAP from all other group 0.956, 0.950 and 0.944, respectively for I-TAC, MIG and IFN- γ. The sensitivity and specificity were 88.8% and 93.6%, respectively, for I-TAC; 96.2% and 86.4% for MIG; 94.3% and 84% for IFN- γ. <b>Conclusion:</b> TB antigen stimulated assays of I-TAC and MIG may be useful surrogate markers in the diagnosis of tuberculous lymphadenopathy