Differential Cell Analysis and Lymphocyte Subset Analysis in Bronchoalveolar Lavage Fluid from Patients with Miliary Tuberculosis

Background: Bronchoalveolar lavage (BAL) is a useful technique to recover lower airway fluid and cells involved in many respiratory diseases. Miliary tuberculosis is potentially lethal, but the clinical manifestations are nonspecific and typical radiologic findings may not be seen until late in the course of disease. In addition, invasive procedures are often needed to confirm disease diagnosis. This study analyzed the cells and the T-lymphocyte subset in BAL fluid from patients with miliary tuberculosis to determine specific characteristics of BAL fluid that may help in the diagnosis of miliary tuberculosis, using a less invasive procedure. Methods: On a retrospective basis, we enrolled 20 miliary tuberculosis patients; 12 patients were male and the mean patient age was 40.5 +/- 16.2 years. We analyzed differential cell counts of BAL fluid and the T-lymphocyte subset of BAL fluid. Results: Total cells and lymphocytes were increased in number in the BAL fluid. The percentage of CD4+ T-lymphocytes and the CD4/CD8 ratio in BAL fluid were significantly decreased and the percentage of CD8+ T-lymphocytes was relatively higher. These findings were more prominent in patients infected with the human immunodeficiency virus (HIV). In the HIV-infected patients, the proportion of lymphocytes was significantly higher in BAL fluid than in peripheral blood. There were no significant differences between the BAL fluid and the peripheral blood T-lymphocytes subpopulation. Conclusion: BAL fluid in patients with miliary tuberculosis demonstrated lymphocytosis, a lower percentage of CD4+ T-lymphocytes, a higher percentage of CD8+ T-lymphocytes, and a decreased CD4/CD8 ratio. These findings were more significant in HIV-infected subjects.