[Memory T lymphocytes during infection and tuberculosis infection and disease]

To examine the role of naive and memory T cells (as determined by CD45 isoforms) in recent tuberculosis infection and in pulmonary and pleural forms to the disease. To relate such subpopulations to serum levels of soluble IL-2 receptor (sIL-2R) and interleukin-6 (IL-6).

T cell subpopulations (CD3, CD4, CD8), naive (CD45RA), memory (CD45RO) and activated CD24+ T cells (IL-2 receptor) were measured in the peripheral blood and pleura of patients with recent tuberculosis infection (n = 7), pulmonary tuberculosis (n = 22) and tuberculosis pleurisy (n = 12). Serum levels of sIL-2 and IL-6 were determined in 13 patients with pleural or pulmonary tuberculosis and their relation to CD45RA and CD45RO subsets was analyzed.

T lymphocytosis involving all the subpopulations studied, including naive and memory T cells, was detected, although the RA:RO ratio did not change in relation to control levels. Marked increases in memory T cells and CD24+ T cells were found for patients with tuberculous pleurisy. sIL-2 and IL-6 levels were unrelated to naive and memory T cell subpopulations.

T lymphocytosis involving all T cell subsets can be observed in recent tuberculosis infection; both naive and memory T cells are implicated, although neither one predominates over the other. In tuberculous pleurisy there is compartmentalization of memory and activated T cells, which presumably play important roles in the local immune response to Mycobacterium tuberculosis.