Evaluation of a whole-blood chemiluminescent immunoassay of IFN-γ, IP-10, and MCP-1 for diagnosis of active pulmonary tuberculosis and tuberculous pleurisy patients.

The study explored the use of IP-10, MCP-1, and IFN-γ as biomarkers to improve the diagnoses of active pulmonary tuberculosis and tuberculous pleurisy. We enrolled 267 individuals, including 134 TB patients, 93 patients with non-tuberculous pulmonary diseases, and 40 healthy controls. Whole bloods were stimulated in vitro with rCFP-10/ESAT-6 protein antigen of Mycobacterium tuberculosis. The levels of IFN-γ, IP-10, and MCP-1 in cultured supernatants of whole bloods were detected by a chemiluminescence immunoassay. A receiver operating characteristic (ROC) curve was drawn to determine the cutoff value for diagnosing TB and to evaluate the diagnostic efficacies of the IFN-γ, IP-10, and MCP-1 for TB. The antigen-specific release of each cytokine, IFN-γ, IP-10, and MCP-1, was significantly higher in the TB groups than in either the non-tuberculous pulmonary disease group (p < 0.001) or the healthy control group (p < 0.001). The ROC curves indicated cutoff values for IFN-γ, IP-10, and MCP-1 at 147.8, 160.4, and 496.4 pg/mL, respectively. The sensitivity, specificity, PPV, NPV, and diagnostic efficiency for IFN-γ were 85.8%, 70.7%, 74.7%, 83.2%, and 78.3%, respectively; for IP-10 were 72.4%, 75.9%, 75.2%, 73.2%, and 74.2%, respectively; and for MCP-1 were 90.3%, 97.0%, 96.8%, 90.8%, and 93.6%, respectively. IFN-γ combined MCP-1 improved the sensitivity to 97.8% compared with IFN-γ (p < 0.001). Our findings indicate high sensitivity and specificity of MCP-1 as novel biomarkers for the diagnosis of active pulmonary tuberculosis and tuberculous pleurisy.