Peripheral blood T lymphocyte subpopulations in patients with tuberculosis and the effect of chemotherapy

Peripheral blood T lymphocytes and their subsets were determined in 30 patients with pulmonary tuberculosis (15 smear positive and 15 smear negative) and 11 healthy individuals. All patients were assessed clinically, radiologically, bacteriologically and by tuberculin testing, and their lymphocyte counts were repeated after completion of 3 months chemotherapy. The mean ratio of putative helper/suppressor T cell subsets (CD4/CD8) of healthy individuals was 1.8 (range 1.1-2.5). These ratios were independent of tuberculin reactivity and were unaffected by BCG vaccination. In both smear positive and smear negative patients there was a reduction in the total T cell and CD4 counts and an increase in the CD8 count, with a concomitant reduction in the CD4/CD8 ratio. Following successful chemotherapy, the mean CD4/CD8 ratios reverted from 0.82 to 1.57 in smear positive patients and 0.88 to 1.52 in smear negative patients, these being near normal values.