Detection of tuberculosis in HIV-infected children using an enzyme-linked immunospot assay.

Objective: To evaluate an enzyme-linked immunospot assay (ELISPOT) for the diagnosis of tuberculosis (TB) in HIV-infected children with suspected TB and to compare the performance of ELISPOT with the tuberculin skin test (TST). Methods: Interferon-gresponsestoMycobacteriumtuberculosis-specificantigenswere measured by ELISPOT in HIV-infected children with suspected TB. HIV-infected and HIV-uninfected children without TB were taken for comparison. Results: Results were available for 188 children, of whom 139 (74%) were HIVinfected. Of these, 22 were classified as having definite TB: 24 probable TB, 14 possible TB and 128 not having TB. The median (range) age of patients was 20 (10‐54.1) months. Median interferon-g responses to early-secreted antigenic target6 and culture filtrate protein-10 were higher in children with definite or probable TB compared with children without TB (P <0.002). In HIV-infected children with an interpretable ELISPOT result, the ELISPOT was positive in 14/21 (66%) with definite TB. A significantly higher proportion of HIV-infected children with definite or probable TB had a positive ELISPOT compared with a positive TST [25/39 (64%) vs. 10/34 (29%), P ¼0.005]. In contrast to TST, results from ELISPOT were not affected by young age or severe immunosuppression. In HIV-infected children without active TB disease, 27% had a positive ELISPOT, suggesting latent TB infection. Conclusion: ELISPOT is more sensitive than TST for the detection of active TB in HIVinfected children. However, the sensitivity of current ELISPOT assays is not sufficiently high to be used as a rule out test for TB. 2009WoltersKluwerHealth|LippincottWilliams&Wilkins AIDS 2009, 23:000‐000