Cooperation between accessory cells and T lymphocytes in patients with tuberculous pleurisy

We studied interleukin 1 (IL-1) activity of pleural fluid macrophages and peripheral blood monocytes obtained from ten patients with tuberculous pleurisy and ten patients with malignant pleurisy, using purified protein derivative (PPD) as a stimulating agent. Tuberculous pleural fluid macrophages and peripheral blood monocytes tended to produce higher IL-1 activity than malignant pleural fluid macrophages and blood monocytes and showed significantly more IL-1 activity than healthy control monocytes. However, no significant difference in IL-1 activity was observed between tuberculous pleural macrophages and blood monocytes. With the cooperation of these accessory cells, pleural fluid T lymphocytes in patients with tuberculous pleurisy showed a significant level of interleukin 2 (IL-2) activity in the presence of PPD. Tuberculous pleural fluid macrophages promoted greater IL-2 production than blood monocytes from either tuberculous pleural fluid or blood T lymphocytes despite relative equivalence in measured IL-1 production. Combination of tuberculous pleural fluid macrophages and pleural fluid T lymphocytes was the most effective for increasing IL-2 activity when compared with other combinations. These results suggest that tuberculous pleural fluid macrophages and T lymphocytes may contribute to the immunopathogenesis of tuberculosis at a local site of disease.