Increased long-term central memory T cells in patients with retreatment pulmonary tuberculosis

T cells are crucial in controlling Mycobacterium tuberculosis infection and disease progression. Nevertheless, the specific functions and changes of T lymphocyte subsets in retreatment tuberculosis remain poorly understand. The study aims to identify the changes in T lymphocyte subsets and the immunoprotective effect of T_CM in retreatment tuberculosis.

We collected venous blood from the participants and assessed using flow cytometry. Univariate analysis and regression model were used to evaluate the changes of T lymphocyte subsets and key subsets in retreatment tuberculosis.

In the study, while the frequencies of CD4 and CD8 T cells were similar between primary and retreatment patients, retreatment patients exhibited a significant increase in T_CM (P < 0.05), which may represent a protective factor for retreatment (adjusted OR=0.926, 95%CI: 0.860-0.996, P < 0.05) (adjusted OR=0.951, 95%CI: 0.912-0.992, P<0.05). Furthermore, T_CM significantly increased in retreatment patients who achieved cure (P < 0.05), though were similar between the cure and no-cure for primary patients; The potentially protective effect of T_CM in patients with repeated infection may possibly contribute by improving the efficacy of retreatment chemotherapy (adjusted OR=0.803, 95%CI: 0.677-0.953, P < 0.05) (adjusted OR=0.890, 95% CI: 0.812-0.976, P<0.05), particularly in those with lung injury (adjusted OR=0.780, 95% CI: 0.635-0.957, P< 0.05) (adjusted OR=0.805, 95% CI: 0.660-0.983, P<0.05).

Development of adjunct immunotherapies for increasing T_CM responses may improve the efficacy of retreatment tuberculosis with existing and with novel chemotherapies.