Expression and clinical significance of peripheral blood NK cell surface co-signaling molecules in active pulmonary tuberculosis patients

Objective The aim of this study is to elucidate the expression of co-signaling molecules on NK cells following tuberculosis (TB) infection. Methods We analyzed peripheral blood mononuclear cells (PBMCs) from healthy controls (HC), individuals with latent tuberculosis infection (LTBI), and patients with active pulmonary tuberculosis (PTB). Using full-spectrum multi-parametric flow cytometry, we assessed the distribution of co-signaling molecules on the surface of NK cells, both without and with stimulation with tuberculosis-specific antigens ESAT6 and CFP10. 7 inhibitory receptors, and 6 co-stimulatory receptors were analyzed. Results The proportion of NK cells was significantly higher in the LTBI individuals compared to HC (P = 0.0199) and TB patients (P = 0.0027). In the absence of tuberculosis-specific antigen stimulation, the expression of TIGIT and TIM-3 were higher in the LTBI group compared to the TB group (P = 0.0128, P = 0.0340). The expression of CD160 in the TB group was significantly lower than in the HC and LTBI individuals (P = 0.0042, P = 0.0124). Upon stimulation with tuberculosis-specific antigens, the expression of OX40 was markedly elevated in LTBI and TB compared to HC (LTBI vs. HC, P = 0.0031; TB vs. HC, P = 0.0493), and the expression of CRTAM in the TB group was obviously higher than in HC (P = 0.0192). Conclusion Expression of co-signaling molecules on NK cells, including TIGIT, TIM-3, CD160, OX40, and CRTAM, was altered following TB infection. Our findings may provide potential targets for host-directed immunotherapy and novel vaccine development for TB. Clinical trial Not applicable.