ABSTRACT
Objective To study the expression of CD27 and CD28 in antigen-specific CD4~+T cells in patients with pulmonary tuberculosis and healthy people, and understand the role of differentiated stages of CD4~+T cells in the pathogenesis of tuberculosis. Methods The expression of CD27 and CD28 was analyzed by CD4, CD154, CD27 and CD28 staining and flow cytometry. The distributions of CD27 and CD28 in antigen-specific CD4~+T cells were compared between patients with pulmonary tuberculosis and healthy controls. Results In patients of pulmonary tuberculosis, the frequencies of CD27 + CD28 + (early differentiated stage), CD27~- CD28~+ and CD27~+ CD28~- (intermediate differentiated stage), CD27~- CD28~-(fully differentiated stage) T cell subsets in antigen specific CD4~+T cells were (49. 55 ±6. 15)%, (26. 85 ±3. 87)% ,(7. 2 ± 1.37)% and ( 16. 35 ±3.97)%, respectively. In healthy controls, the frequencies of the four subsets in antigen-specific CD4~+T cells were ( 51.81 ± 4. 94 ) %, ( 29. 83 ± 5.33 ) %, ( 12. 65 ±4. 48)% and (5.7±2)%, respectively. The early differentiated CD4~+T cell was the major subset both in patients and healthy people, however, which had significant difference compared with the fully differentiated subset ( t = 2. 26, P < 0. 05 ). Conclusion The population frequency of the fully differentiated CD4~+T cells in patients with pulmonary tuberculosis was significantly higher than that in healthy people. This suggested that the differentiation degree of the antigen-specific CD4~+T cell might be related with pulmonary tuberculosis.