Clinical evaluation of several biomarkers including IFN-γ for the diagnosis of tuberculosis infection

Abstract

Purpose: There are no other biomarkers availabe that improve the clinical performance of immunodiagnostic methods for tuberculosis (TB) diagnosis except two IGRAs (QFT and T-SPOT.TB) in Japan. We evaluated the clinical potential of new biomarkers such as IP-10, MIG, IL-2, TNF-α, MCP-1, MIP-1β including IFN-γ for the diagnosis of TB disease. Materials and Methods: The subjects consisted of 31 patients with active TB disease, 35 patients with pulmonary NTM disease, and 19 patients with other pulmonary diseases. We measured IFN-γ using QFT-IT, and IP-10, MIG, IL-2, TNF-α, MCP-1, MIP-1β using the supernatant from whole blood stimulated with MTB (Mycobacterium tuberculosis)-specific antigens in all patients. Results: In the TB group, While the positive response rate of IFN-γ was 74%, that of IP-10 was 87%, MIG was 84%, IL-2 was 61%, TNF-α was 71%, MCP-1 was 81%, and MIP-1β was 81%. In the non-TB group excluding the patienets with a past history of healed TB or pulmonary NTM disease due to Mycobacterium kansasii, while the positive response rate of IFN-γ was 7%, that of IP-10 was 9%, MIG was13%, IL-2 was 29%, TNF-α was 26%, MCP-1 was20%, MIP-1β was 17%. The combination of the diagnostic methods, such as IFN-γ, IP-10 and MIG increased the positive response rate in 94%. Conclusions: Several biomarkers, apart from IL-2, showed similar results compared to IFN-γ and , especially, IP-10 was most excellent biomarker.