Diagnostic utility of interferon-γ–induced protein of 10 kDa (IP-10) in tuberculous pleurisy

Tuberculous pleuritis (TP) is characterized by predominant Th1 immune response. We observed significantly high levels of interferon γ (IFN-γ) and chemokines such as IP-10, monokine induced by IFN-γ (MIG), interleukin 8 (IL-8), monocyte chemotactic protein (MCP)-1, and macrophage inflammatory protein (MIP)-1α in tuberculous pleural effusions. In the current study, we evaluated the diagnostic utility of IFN-γ–dependent chemokine especially IP-10. The receiver operating characteristics (ROC) curve analyses based on cytometric bead array values depicted high sensitivity only for IP-10 (76.3%) followed by IFN-γ (73.7%). The ELISA test further confirmed the significantly high levels of IFN-γ and IP-10 in TP. The ROC curve analysis again demonstrated high area under the curve (AUC) for IP-10 (0.966) than the referred diagnostic marker IFN-γ (0.930). The better sensitivity (84.2% for IFN-γ and 89.2% for IP-10) and equal specificity (95.7%) of IP-10 assay compared with IFN-γ suggest that IP-10 is a potential diagnostic marker for evaluating TP.