[Analysis of the numbers and subsets of MTB-HAg specific TNF-α+ γδ T cells in peripheral blood of patients with active pulmonary tuberculosis].

Objective To investigate the differences of proportions of tumor necrosis factor α (TNF-α)-producing cells in peripheral blood γδ T cells stimulated with Mycobacterium tuberculosis heat resistant antigen (MTB-HAg) among patients with pulmonary tuberculosis (PTB), latent tuberculosis infection (LTBI) and healthy subjects (HC). Methods The peripheral blood specimens were collected from 15 normal adults, which were divided into HC group (n=9) and LTBI group (n=6), by enzyme-linked immunospot (ELISPOT) kit for diagnosis of Mycobacterium tuberculosis infection, and 12 patients with active PTB. The peripheral blood mononuclear cells (PBMCs) were separated by density gradient centrifugation and simulated with MTB-HAg for 20 hours. Then the cells were collected, and the proportions of TNF-α-producing cells in TCRαβ+ T cells, TCRγδ+ T cells, CD4+αβ T cells, CD8+αβ T cells, and TCR-Vδ2+ T cells were measured with flow cytometry. Results The proportion of TNF-α-producing cells in γδ T cells in patients with PTB was obviously lower than that in LTBI group and HC group; the proportion of TNF-α-producing cells in Vδ2 T cells in PTB patients was apparently lower than that in LTBI and HC; the proportion of Vδ2 T cells in TNF-α+γδ T cells in the peripheral blood of PTB patients was remarkably lower than that in LTBI and HC groups. The proportions of TNF-α-producing cells in peripheral αβ T cells, CD4+ and CD8+αβ T cells were dramatically lower than those in γδ T cells of the three according groups. Moreover, there were no statistical differences in regard with the proportions of TNF-α-producing cells in αβ T cells, and CD4+ and CD8+αβ T cells among the three groups. Conclusion The TNF-α production capacity of MTB-HAg specific γδ T cells and Vδ2 T cell subsets in patients with tuberculosis is obviously lower than that of LTBI and HC.