SEROLOGICAL MARKERS PREDICTING TUBERCULOSIS IN HUMAN IMMUNODEFICIENCYVIRUS-INFECTED PATIENTS

SETTING: Human immunodeficiency virus (HIV)-positive patients retrospe ctively identified at the Hospital of Bari, Italy, with diagnosis of t uberculosis (TB) (n = 30) or non-tuberculous pneumonia (n = 29). Serum samples drawn at the time of diagnosis and one year before. Anti-puri fied protein derivative (PPD) and antidiacyltrehalose (DAT) serum anti bodies quantified by ELISA assay. OBJECTIVE: Since TB patients with HI V infection may present with elevated serum antibodies against Mycobac terium tuberculosis, we hypothesized that TB-specific antibody markers might predict TB in these subjects. DESIGN: A retrospective study was designed to assess the presence of M. tuberculosis-specific antibodie s in HIV-positive patients developing TB. RESULTS: Of 30 HIV-positive TB patients, 24 (80%) had anti-PPD or anti-DAT antibodies at the time of TB diagnosis, and 20 (67%) one year before. In a subpopulation of 1 6 of the 30 HIV-positive subjects, positivity for anti-PPD or anti-DAT antibodies one year before TB diagnosis was higher (11/16, 69%) than for the PPD skin test (4/16, 25%, P < 0.01). Antibody tests were speci fic for TB since positivity rates were lower both in patients with non -tuberculous pneumonia (P < 0.01) and in those with M. avium infection (P < 0.05). CONCLUSION: Antibody markers may predict TB in HIV-positi ve subjects, including those with negative PPD skin test.