Host biomarkers other than interferon gamma in QFT-TB supernatants for identifying active tuberculosis

Interferon gamma release assays (IGRAs) for tuberculosis (TB) remain limited in their ability to discriminate between active TB (ATB) and latent TB infection (LTBI). The objective of our study was to evaluate the value of additional cytokines/chemokines other than interferon gamma (IFN-γ) as biomarkers to identify different TB infection status. A total of 128 subjects were enrolled to detect the quantification of IL-2, IP-10, MCP-1 and RANTES in the supernatants of QuantiFERON®-TB (QFT-TB). Area under the curve (AUC) was used to evaluate the diagnostic efficiency. Notably, Mycobacterium tuberculosis (Mtb) induced cytokines/chemokines of ATB patients were significantly higher than those of the LTBI, other lung related diseases (ORD) and healthy controls (HC). Moreover, ROC analysis indicated that all cytokine/chemokine parameters detected were more capable of distinguishing ATB from LTBI than IFN-γ, especially IL-2. The diagnostic model including TB specific IL-2 and RANTES improved the performance in distinguishing ATB from LTBI, which was superior to single cytokines/chemokines in QFT-TB supernatants. Our results suggest that the combination of Mtb specific cytokines/chemokines has great prospects in the diagnosis of ATB, and the diagnostic model based on IL-2 and RANTES can be used as an alternative to distinguish ATB from LTBI.