Diagnostic Value of Polyfunctional Flow Cytometry Analysis of CD4+ T Cells for Latent Tuberculosis Status

Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), is a major global health concern.Approximately one-third of individuals globally harbors latent TB infection (LTBI), posing a significant challenge as 5%-10% of those infected may develop active TB, especially in individuals with compromised immune systems.Rapid diagnostic tools and targeted LTBI treatments are essential to control TB.This study aimed to investigate the cytokine profiles of CD4+ T cells, particularly polyfunctional CD4+ T cells, as potential diagnostic markers of LTBI.Using a diluted whole-blood intracellular cytokine staining assay, the production of interferon-gamma (IFN-), tumor necrosis factor-alpha (TNF-), and interleukin-2 (IL-2) by CD4+ T cells in 25 participants were measured.The LTBI group exhibited significantly higher frequencies of CD4+ T cells producing IFN-, TNF-, and IL-2 compared to the healthy controls (P = 0.0023, P = 0.0002, P = 0.0473).Polyfunctional CD4+ T cells co-producing IFN-, TNF-, and IL-2 were more prevalent in the LTBI group (P < 0.0001).Receiver operating characteristic curve analysis demonstrated that these cytokine-producing CD4+ T cells are potential biomarkers for LTBI, with polyfunctional CD4+ T cells achieving a sensitivity and specificity of 92.31% and 100.00%, respectively.Polyfunctional CD4+ T cells are potential biomarkers for LTBI diagnosis.