Miliary tuberculosis is often potentially lethal form of tuberculosis. But it's clinical manifestations are non-specific and typical chest radiographic findings may not be seen until late in the course of the disease. In addition, invasive procedures are frequently needed to confirm the disease. Bronchoalveolar lavage(BAL) is relatively easy to perform and a useful technique recovering lower airway fluid and cells that are involved in the immunopathogenesis and inflammatory injury of many respiratory diseases. We analyzed the differential cells and T cell subset of BAL fluid in patients with miliary tuberculosis.
From January 2000 to June 2006, 17 miliary tuberculosis patients were studied retrospectively. Male were 11 and mean age of patients was 38 ± 12.1 yrs. Number of patients who reveal positive in Human immunideficiency virus (HIV) test were seven. Differential cell counts and T cell subset of BAL fluid were analyzed. And we compared whether there were difference in parameters of BAL fluid between HIV positive and negative group.
Total cells and lymphocytes were increased in number in BAL fluid of miliary tuberculosis. The percentage of CD4+ T cells (22.59 ± 17.41%) and the CD4/CD8 ratio in BAL fluid were significantly decreased (1.04 ± 1.11) and the percentage of CD8+ T cells was relatively higher in miliary tuberculosis (34.73 ± 27.04%). These findings were more prominent in HIV infected group.
Compare to other study which showed the CD4/CD8 ratio in BAL fluid in pulmonary tuberculosis was increased, this study indicates that BAL fluid in miliary tuberculosis shows prominent lymphocytosis, lower percentage of CD4+ T cells, higher percentage of CD8+ T cells and decreased CD4/CD8 ratio. These findings are more significant in HIV infection group.
The BAL fluid analysis is helpful for diagnosis of miliary tuberculosis without invasive procedure when combined to other diagnostic tools. Further studies will be needed to investigate the functional characteristics of CD8+ T cells and the cause of decreased CD4/CD8 ratio of BAL fluid in human miliary tuberculosis.
Yun Seong KIM, No Financial Disclosure Information; No Product/Research Disclosure Information