Changes of Peripheral Blood Lymphocyte Subsets in 212 Active Tuberculosis Patients: A Uni-centered Descriptive Study

  Objective  To explore the characteristics and their significance of peripheral blood lymphocyte subsets in patients with active tuberculosis(ATB), based on a relatively large sample.

  Methods  Clinical data were retrospectively collected from patients with ATB hospitalized in Peking Union Medical College Hospital (June 2012-January 2022) and the healthy population matched with age and sex (March 2019-May 2022). The characteristics of changes in peripheral blood lymphocyte subsets in ATB patients were analyzed using the healthy population as controls, and group comparisons were made between ATB patients with different modes of diagnosis and sites of involvement.

  Results  A total of 212 ATB patients and 200 healthy participants were included. ATB patients consisted of 82 cases (38.7%) without etiological evidence and 130 cases(61.3%) with etiological evidence (77 with pulmonary tuberculosis, 21 with extrapulmonary tuberculosis, and 32 with pulmonary and extrapulmonary tuberculosis). Compared to healthy population, ATB patients had significantly lower counts and percentages of multiple peripheral blood lymphocyte subsets indicators, significantly higher percentage in T lymphocyte, CD8⁺T lymphocyte as well as higher memory CD4⁺T lymphocyte/CD4⁺T lymphocyte ratio and CD38⁺CD8⁺T lymphocyte/CD8⁺T lymphocyte ratio(all P < 0.05). Lymphocyte, B-cell, natural killer (NK) cell, T-lymphocyte, CD4⁺T-lymphocyte, and CD8⁺T-lymphocyte counts were lower in patients with pathogenetically confirmed ATB than in those with clinically confirmed ATB (all P < 0.05). There were no significant differences in the counts of memory CD4⁺T lymphocytes, naïve CD4⁺T lymphocytes, CD28⁺T lymphocytes and activated CD8⁺T lymphocyte subpopulations and their percentages in patients with different tuberculosis infection sites (all P > 0.05). Compared to pulmonary tuberculosis alone, patients with pulmonary and extrapulmonary tuberculosis had lower B-cell counts23(10, 69)cells/μL vs. 73(25, 133)cells/μL, P=0.003 and patients with extrapulmonary tuberculosis alone had higher percentages of NK cells16.7%(10.8%, 23.6%) vs. 10.6% (5.3%, 17.4%), P=0.042.

  Conclusion  ATB patients manifested a reduction in peripheral blood lymphocyte subset, indicating remarkable dysfunction of immune system.