Immunophenotype of lung granulomas in HIV and non-HIV associated tuberculosis

OBJECTIVE: To describe the immunophenotype of pulmonary TB granulomas from autopsied patients with tuberculosis (TB group) and from HIV patients with tuberculosis (TB/HIV group), and to identify the Mycobacterium species using polymerase chain reaction (PCR) technique. METHODS: Lung samples of 15 TB group patients and 23 TB/HIV group patients were selected. Histopathologic analyses and immunohistochemistry tests were performed to describe the granulomas and to detect the infectious agent (anti-BCG). CD4, CD8, CD20 and CD68 were evaluated to characterize the immnophenotype of the granulomas. Polymerase Chain Reaction was performed to identify the mycobacterium species. RESULTS: CD4 þ T lymphocytes were the cells with highest density in the TB group, whereas CD68 cells exhibited the highest density in the TB/HIV group. Comparison between groups showed that the CD4 þ T density was significantly higher in the TB patients; whereas, CD68 density was significantly higher in the TB/HIV patients. M. tuberculosiswas identified in 8 cases of each group;M. aviumwas only found in one case of the TB/HIV group. CONCLUSION:With the advent of AIDS, the immunological profile of TB has changed. This may be associated with the depletion of CD4 þ T lymphocytes in lung granulomas.M. tuberculosiswas themajor etiological agent of TB in both groups.