Surrogate Marker of Preclinical Tuberculosis in Human Immunodeficiency Virus Infection: Antibodies to an 88‐kDa Secreted Antigen ofMycobacterium tuberculosis

Antibodies to purified, size-fractionated secreted proteins of Mycobacterium tuberculosis in sera from patients with human immunodeficiency virus (HIV) infection and active tuberculosis (HIV/TB patients), and in stored sera obtained from the same patients prior to clinical manifestation of TB, were evaluated by ELISA, and the repertoire of antigens recognized was analyzed by immunoblotting. Compared with non-HIV/TB patients, HIV/TB patients had lower levels of anti-mycobacterial antibodies, and these were directed toward a restricted set of antigens. Antibodies to an 88-kDa secreted antigen were present in the sera of 74% of HIV/TB patients during the years (1.5-6) prior to manifestation of active, clinical tuberculosis, although only 66% were positive by the time tuberculosis was diagnosed. The presence of antibodies to the 88-kDa antigen can serve as a surrogate marker for identifying HIV-infected persons with active, subclinical disease who are at a high risk of developing clinical tuberculosis.