Elevated chemokine levels in bronchoalveolar lavage fluid of tuberculosis patients

In pulmonary tuberculosis, the proportion of lymphocytes, particularly that of CD4+ T lymphocytes, was increased in bronchoalveolar lavage fluid (BALF), reflecting their protective role against mycobacterial infections. In order to elucidate the mechanisms of lymphocyte accumulation in lungs, we measured the levels of chemokines with potent lymphocyte chemotactic activities, including interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), and, regulated on activation, normal T-cell expressed and secreted (RANTES) present in BALF from patients with pulmonary tuberculosis in acute (n = 10) and convalescent phases (n = 6), as well as normal subjects (n = 10). During the acute phase of the disease, the proportions of lymphocytes and neutrophils were increased, as reported in previous studies. The levels of IL-8, MCP-1, and RANTES in the acute phase of pulmonary tuberculosis were also markedly elevated as compared with those of normal subjects. MCP-1 and RANTES, but not IL-8 levels present in BALF, decreased in the convalescent phase. Moreover, the concentration of RANTES correlated significantly with the absolute number of CD4+ cells in BALF. These data suggest that chemotactic cytokines are differentially produced and participate in the host response to Mycobacterium tuberculosis infection.