[Studies on the significance of CD4+ T lymphocytes in the development of tuberculosis]

Numerous studies on the natural history of HIV-infection have revealed that the number of CD4+ T lymphocytes in peripheral blood was the most important determining factor for the occurrence of various opportunistic infections and the most reliable prognosis indicator for the progression of HIV-infection to AIDS. It is also generally accepted that CD4+ T lymphocytes are the key cells in protective immunity in tuberculosis. Basing on these knowledges, we tried to analyze the significance of the number of CD4+ T lymphocyte in the development of clinical tuberculosis from latent infection with tubercle bacilli. Of 84 tuberculosis patients, younger than 70 years old, who had been analyzed lymphocyte subsets by flow cytometry (FACS), six patients (one female, five males) had remarkably reduced number of CD4+ T lymphocytes (< or = 250 cells/mm3) by their first FACS analysis after diagnosis. Any obvious risk behavior and/or habit was noticed in none of the six patients, three of whom were in the twenties. FACS analyses of these six cases revealed that: 1) The proportion of total lymphocytes to total leukocytes was remarkably lower than that of tuberculosis patients as a whole as well as than that of healthy control group. 2) The numbers of total lymphocytes, T lymphocytes and CD4+ T lymphocytes were all far below the normal range. (mean +/- 2 x SD of the control group). 3) The proportion of CD8+ T lymphocytes to total lymphocytes was higher in five of these six cases, but the number of CD8+ T lymphocytes was lower in all six than the respective mean value of the control group.(ABSTRACT TRUNCATED AT 250 WORDS)