Inverse relationship between spontaneous interleukin-1 production and mitogen-driven proliferation in patients with pulmonary tuberculosis

The blastogenic response to mitogens of peripheral blood mononuclear cells (PBMC) obtained from healthy volunteers and patients with chronic or acute tuberculosis (TB) was evaluated. Cells derived from TB patients showed a reduced proliferative capacity compared to that of healthy individuals. Three possible causes of such an impairment were investigated, namely: 1) a change in the proportion of lymphocyte subpopulations; 2) an altered ratio between monocytes and lymphocytes and 3) a reduction in the state of monocyte-macrophage activation, with an impaired production of interleukin-1 (IL-1). We observed no significant modification of lymphocyte subsets from TB patients and normal individuals. However, the relative number of monocytes in the patients was always higher than the controls. Furthermore, circulating monocytes from the patients with TB exhibited a decreased phagocytosis of latex beads, a normal expression of DR antigens, and an increased spontaneous production of IL-1. The possibility that the hyperactivation of macrophages may be responsible for the observed low blastogenic response is discussed.