Source of Support: None, Conflict of Interest: None
Bronchoalveolar lavage (BAL) studies were carried out in 27 sputum smear negative but radiographic probable pulmonary tuberculosis patients to characterize the inflammatory and immune effector cells in the lower respiratory tract and in 17 normal subjects. The diagnosis of active pulmonary tuberculosis was confirmed by isolation of Mycobacterium tuberculosis in culture from sputum and/or lavage specimens. BAL was done first from radiologically normal lobe and then from radiologically abnormal lobe prior to treatment and the BAL fluids were analyzed separately. Two groups were identified based on lavage results. One group (macrophage predominant) had significantly elevated total cells and alveolar macrophages in both radiologically normal (p<0.01) and abnormal lobes (p<0.001) compared to normal controls. The other group (lymphocyte predominant) had expanded numbers of total cells (p<0.01), lymphocytes (p<0.01), neutrophils (p<0.05) and eosinophils (p<0.01) in radiologically abnormal lobe. The cell profile in radiologically normal lobe in lymphocyte predominant group was within normal limits. These results suggest that two distinct cell profiles, In one group an increase in alveolar macrophages and in the other an increase in lymphocytes can occur in the lower respiratory tract of patients with sputum smear negative, but radiographic probable pulmonary tuberculosis.