Abstract: Objective To observe theclinical significance of CD4CD^high₂₅ T cells from peripheral blood in pulmonary tuberculosis (PTB) patients.  Methods From January 2008 to February 2010, 40 hospitalized PTB patients and 38 healthy controls from outpatient department for physical examination were enrolled. CD4, CD8 and CD4CD^high₂₅ T cells which were presented by their percentages in peripheral blood lymphocytes of the above subjects were assessed by flow cytometry.  Results The frequencies of CD4CD^high₂₅ T cells in PTB patients （1.9%±1.3%）were significantly higher than that in healthy controls （0.7%±1.0%）(t=5.237, P<0.01). The frequencies of CD4T cells in PTB patients （47.9%±11.2%）were significantly lower than that in healthy controls （56.0%±14.6%）(t=2.830, P<0.01). The frequencies of CD8T cells in PTB patients（26.2%±6.1%） were somewhat lower than that in healthy controls （33.0%±11.1%）, but there was not statistical difference（t=0.353, P>0.05）. After 2 months of anti-TB treatment, the frequencies of CD4CD^high₂₅ T cells in PTB patients （1.8%±0.8%）were decreased as compared with pre-treatment but without statistic significance (t=0.811, P>0.05), while the frequencies of CD4T cells and CD8T cells in PTB patients （51.6%±14.4%，33.7%±11.5%）were all increased as compared with pre-treatment but without statistic significance (t=1.496, 0.570, respectively, all P>0.05).  Conclusions CD4CD^high₂₅T cells are involved in cellular immune of PTB patients, inhibiting the activation and proliferation of CD4 and CD8T cells, affecting the clinical manifestations and prognosis of PTB.

Key words: tuberculosis,pulmonary/blood, T-lymphocytes, flow cytometry