Alterations of CD4＋CD8＋T cells in peripheral blood of patients with tuberculosis and its clinical sig-nificance

Objective To characterize CD4＋CD8＋double-positive T （ DPT） cells in PBMCs from patients with tuberculosis（TB）.Methods PBMCs were isolated from peripheral blood samples collected from patients with TB and healthy subjects.The subsets and percentages of CD4＋T, CD8＋T and DPT cells in PBMCs were determined by flow cytometry.Cell surface markers （ CD45RO, CCR7 and CD25 ） and intracellular cytokines （ IFN-γand TNF-α） were detected directly and after ESAT-6/PPD stimulation.Re-sults Patients with TB showed a significantly increased DPT cells as compared with the cured individuals and healthy subjects （P〈0.005）.The levels of DPT cells were gradually decreased down to normal upon the treatment of pharmacotherapy.DPT cells expressed higher levet of CD25 than CD4＋T and CD8＋T cells （ P〈0.005 ） . DPT cells could express more IFN-γand TNF-αupon the stimulation of ESAT-6/PPD （P〈0.005）.The analysis of memory phenotype indicated that DPT cells were memory T cells.Conclusion DPT cells in peripheral blood of the patients with tuberculosis played a critical role in protective immunity against tuberculosis.The alterations of DPT cells in PBMCs during the period of pharmacotherapy might be a potential indicator for the prognosis of pulmonary tuberculosis. Key words: Tuberculosis ;  Cellular immunity;  DPT cells