The role of CD_8~+ CD_(28)~- regulatory T lymphocytes in pulmonary tuberculosis

Objective To study the role of CD_8~+ CD_(28)regulatory T cells in tuberculosis.Methods The positive rates of CD_3~+ CD_8~-CD_(28)~-T cells,CD_3~+ T cells,CD_3~+ CD_8~+ T cells and CD~ CD2s T cells,and the content of IL-6 in CD_8~+ CD_8~-T cells in leukocytes of peripheral blood from 15 patients with pulmonary tuberculosis,15 patients with chronic bronchitis and 15 healthy controls were detected by flow cytometry. Results The positive expression rates of CD_3~+ T cells of tuberculosis group[(41±16)%]and bronchitis controls[(40±10)%]were significantly lower than those from healthy controls[(44±6)%] respectively,but no differences were found between tuberculosis group and bronchitis controls.The CD_3~+ CD_8~+ T cells in CD_3~+ T cells from the tuberculosis group[(47±16)%]and bronchitis controls[(44± 10)%]were significantly higher than those from the healthy controls[(41±12)%]respectively,but no differences were found between the tuberculosis group and bronchitis controls.The CD_8~+ CD_(28)~+ T cells in CD_3~+ T cells from tuberculosis group[(15±8)%]and bronchitis controls(20±7%)were significantly lower than those from healthy controls[(32±9)%]respectively,and those of the tuberculosis group were significantly lower than those from the bronchitis controls.CD_8~+ CD_(28)~+ T cells in CD_3~+ T cells from tuberculosis group[(27±9)%]and bronchitis controls[(22±9)%]were significantly higher than those from healthy controls[(10±4)%]respectively,and those of the tuberculosis group were significantly higher than those of the bronchitis controls.The level of IL-6 secreted by CD_8~+ CD_(28)~+ T cells from tuberculosis group[(32.4± 2.4)%]was significantly higher than bronchitis controls[(19.7±3.2)%]and healthy controls[(15.2± 2.7)%]and no differences were found between bronchitis controls and healthy controls.Conclusions The number of CD_8~+ CD_(28)~+ T cells and their production of IL-6 in the peripheral blood of tuberculosis patients are significantly increased as compared with the control groups,while the number of CD_8~+ CD_(28)~+ T cells(cytotoxie T cell)is significantly decreased.The results suggest that these cells and IL-6 may be involved in the pathogenesis of pulmonary tuberculosis.