Changes in lymphocyte subsets in the peripheral blood of patients with active pulmonary tuberculosis.

The aim of this study was to determine the percentage of lymphocyte subsets in peripheral blood in patients with active tuberculosis. A total of 21 patients with active tuberculosis and 15 healthy volunteers were included in the study. T-lymphocyte subsets, B-lymphocytes (CD19(+) cells), natural killer (NK) cells and cells positive for costimulatory molecules CD28 and CD152 were evaluated using flow cytometry. Patients with tuberculosis had a significantly decreased percentage of CD3(+) and CD3(+)CD4(+) cells, and a significantly decreased ratio of CD3(+)CD4(+) to CD3(+)CD8(+) cells compared with healthy controls. In contrast, the percentage of B-cells (CD19(+) cells), CD3(+)CD8(+) cells, CD28(+) cells, CD152(+) cells, and subpopulations of CD4(+)CD152(+), CD8(+)CD152(+) and CD8(+)CD28(+) T-cells were all significantly increased compared with healthy controls. There were no statistically significant differences in the percentages of NK cells or CD4(+)CD28(+) cells between patients and controls. These results indicate that patients with active tuberculosis have altered lymphocyte homeostasis.