LOCAL IMMUNE-RESPONSES CORRELATE WITH PRESENTATION AND OUTCOME IN TUBERCULOSIS

Local cellular immune responses may affect presentation and outcome in tuberculosis (TB). To investigate this hypothesis, we performed bronc hoalveolar lavage (BAL) on 30 patients with untreated pulmonary tuberc ulosis and assessed the type of cellular inflammatory response and cyt okine production. We then correlated BAL findings and cytokine product ion with clinical findings. We also performed BAL on a subset of patie nts to examine changes in cytokine production by BAL cells over time. We found that at presentation patients with less clinically and radiog raphically advanced TB (smear-negative, noncavitary disease) had a loc al immune response characterized by a predominance of lymphocytes. Fur thermore, BAL cells from these patients secreted interferon (IFN gamma ), and not Interleukin-4, suggesting a Th 1-type lymphocytic response. In patients with smear-positive and/or cavitary disease, macrophages or polymorphonuclear leukocytes were the predominant BAL cell type, bu t with treatment and clinical improvement these patients went on to re cruit IFN gamma producing cells to the lung. We conclude that the type of cellular immune response that occurs locally in the lung may affec t presentation and outcome in pulmonary TB, and an understanding of th e development of this response may lead to insights into pathogenesis and novel therapies for TB.