Comparative Diagnostic Utility of Neopterin and IFN-γ/IL-2 in Extrapulmonary Tuberculosis

Abstract

Resurgence of TB has emphasized the need for newer methods of diagnosis. Extrapulmonary tuberculosis (EPTB), being paucibacillary, is a diagnostic dilemma. The aim of the present study was to correlate IFN-γ/IL-2 with neopterin in diagnosis of EPTB. Extrapulmonary specimens from 69 clinically diagnosed cases were stained by Ziehl-Neelsen and cultured on Lowenstein-Jensen medium for . ELISA was used to assess serum IFN-γ, IL-2 and neopterin levels. Median serum levels of IFN-γ/IL-2 and neopterin were 3.22 and 21.6 nmol/L in clinically diagnosed EPTB cases and 0.52 and 4.20 nmol/L in healthy controls respectively ( < 0.001). Both IFN-γ/IL-2 and neopterin were significantly higher in culture positive (14.64 and 49.8 nmol/L) than culture negative cases (3.01 and 17.5 nmol/L) respectively ( < 0.05). IFN-γ/IL-2 was significantly higher in AFB smear positive cases (8.63) than smear negative cases (3.04) ( = 0.003), whereas no significant difference in neopterin levels was seen ( = 0.307). A positive correlation between IFN-γ/IL-2 and neopterin was seen in EPTB cases (spearman's rho = 0.453, < 0.001), whereas in healthy controls no such correlation existed (spearman's rho = 0.018, = 0.884). An urgent need for research in the field of biomarkers exists to utilize them as point of care test in the diagnosis of EPTB.

QuantiFERON-TB Gold Plus Assay in Patients With Latent vs. Active Tuberculosis in a Low Incidence Setting: Level of IFN-γ, CD4/CD8 Responses, and Release of IL-2, IP-10, and MIG

“…The poor secretion of MIG and IP-10 that are Th1-related cytokines induced by IFN-γ may reflect the impairment of the T cell response against TB (Collins and Kaufmann, 2001). These results were in line with previous studies highlighting that IL-2/IFN-γ secretion and a relative IL-2 toward IFN-γ production were determined in ATB compared to LTBI (Suter-Riniker et al, 2011;Jeong et al, 2015;Goyal et al, 2017;Suzukawa et al, 2020). Low secretion of IL-2 compared to IFN-γ production and high frequency of single positive tumor necrosis factor alpha (TNF-α) Mtb-specific CD4 + T cells have been associated with the defect in TB infection (Sargentini et al, 2009;Harari et al, 2011;Jenum et al, 2014).…”