Mesothelial cells in tuberculous pleural effusions of HIV-infected patients

The scarcity of mesothelial cells is a well-known characteristic of tuberculous pleural effusions. We report three HIV-infected patients with tuberculous pleural effusions, in which mesothelial cells were found in significant numbers in the pleural fluid. Clinicians should be aware that the altered immune responses that occur in HIV-infected patients may affect the cytologic profile of tuberculous pleural effusions, and they should be cautious not to exclude this diagnosis based solely on the presence of mesothelial cells in the fluid.