T-lymphocyte subpopulations in tuberculosis

Background: Tuberculosis is associated with both qualitative and quantitative defects in the cell mediated immune response. The changes that occur in the lymphocyte profile in blood in children with tuberculosis are not well understood. Design: Prospective study. Setting: Referral hospitals. Methods: Lymphocyte subpopulations were determined by flow cytometry in 17 healthy tuberculin positive children, in 22 children with newly diagnosed pulmonary tuberculosis and in 8 of these children after antituberculosis therapy. Results: Absolute numbers and percentages of CD3+ and CD4+ T cells were reduced in children with tuberculosis, compared to controls. CD4+ counts increased significantly following antituberculosis treatment, compared to baseline values. In contrast, the proportion of T cells expressing the gdT cell receptor was similar in tuberculosis patients and controls. Conclusion: Children with tuberculosis have a systemic decrease in the proportion and number of CD3+ and CD4+ T cells which reverses during therapy