Detection of mycobacterial antigen responses in lung but not blood in HIV-tuberculosis co-infected subjects

Forty-seven HIV-infected adults had broncho-alveolar lavage stimulated with purified protein derivate of Mycobacterium tuberculosis. Eighteen of 19 (95%) with tuberculosis co-infection had interferon-gamma synthetic CD4 lymphocyte responses > 1% versus three of 28 (11%) without (P < 0.0001). Lung response was unrelated to blood CD4 cell count. BAL HIV tuberculosis responses were similar in 25 HIV-uninfected tuberculosis patients. Responses in matched blood samples were often undetectable. Therefore, immunological tuberculosis assays seem less affected by HIV co-infection when lung-based.