ABSTRACT
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.