Factors influencing the cellular response in bronchoalveolar lavage and peripheral blood of patients with pulmonary tuberculosis

Abstract

Subsegmental bronchoalveolar lavage was performed in 30 patients with active pulmonary tuberculosis and six control subjects. Total leucocyte count, absolute lymphocyte count, count of polymorphonuclear leucocytes, T and B lymphocytes were determined in peripheral venous blood. These parameters and macrophage counts were also determined in bronchoalveolar lavage fluid. Variations in the cellular responses were correlated with patients' age, sex, nutritional status and duration of symptoms as well as radiological severity of disease. Patients of both sexes (seven female) showed similar responses. Decreased cell counts in peripheral blood were observed in patients aged 31 to 40 years. Well-nourished patients (n=19) had higher counts of lymphocytes in peripheral blood and polymorphonuclear leucocytes in bronchoalveolar lavage fluid. The duration of symptoms had a significant influence on cellular responses. In blood, lymphocyte counts were increased in those with symptoms of shorter duration but reduced in those symptomatic for more than 6 months. In bronchoalveolar lavage fluid also all cellular elements were increased in those symptomatic for less than 6 months but a decline followed in those with symptoms for longer duration. Patients with minimal disease radiologically showed higher total leucocyte counts in blood, whereas those with moderately advanced lesions had elevated absolute lymphocyte counts. T cell lymphopenia was observed in blood of patients with far advanced disease. The inflammatory response in bronchoalveolar lavage fluid, however, increased in parallel with the severity of disease. Patients with far advanced lesions showed marked inflammation irrespective of duration of symptoms. Thus, the pattern of inflammation in bronchoalveolar lavage fluid was not similar to that in peripheral blood, particularly in patients with far advanced lesions.