Application of γδ T cells with different memory phenotypes in clinical diagnosis of active pulmonary tuberculosis

To investigate the application and clinical significance of different memory phenotypes of γδ T-cell subsets in the clinical diagnosis of pulmonary tuberculosis.

In total, 42 patients with tuberculosis (TB) according to the diagnostic criteria for tuberculosis (WS288-2017) who were treated at the Infectious Diseases Hospital affiliated with Soochow University from February 2023 to July 2023 were enrolled. Additionally, 16 patients with latent TB infection (LTBI) and 20 healthy controls (HCs) were included. Flow cytometry was used to measure the expression levels of γδ T cells, Vδ1 T-cell subsets/Vδ2 T-cell subsets, naive (CD45RA + CD27⁺) cells, central memory (CD45RA-CD27⁺) cells, effector memory (CD45RA-CD27^-) cells, and terminally differentiated (CD45RA + CD27^-) cells in the peripheral blood. The expression levels at different stages of TB infection were compared.

There were no significant differences in peripheral blood γδ T cells or Vδ1 T cells among the HC, LTBI and TB groups. The proportion of CD45RA-CD27+Vδ2 T cells in TB patients was significantly lower than that in HCs and LTBI patients, but the proportion of CD45RA + CD27-Vδ2 T cells was greater. ROC curve analysis revealed that CD45RA-CD27+Vδ2 T cells (AUC), CD45RA + CD27-Vδ2 T cells (AUC), and the combination of both (AUC) were effective in differentiating TB patients from LTBI patients.

The proportions of CD45RA-CD27+Vδ2 T cells and CD45RA + CD27-Vδ2 T cells are potential biomarkers for the diagnosis of active TB infection and are helpful for distinguishing active TB infection from LTBI.