Abstract
BackgroundAn accurate test for Mycobacterium tuberculosis infection is urgently needed in immunosuppressed populations. The aim of this study was to investigate the diagnostic power of enzyme-linked immunospot (ELISPOT)-based IFN-γ release assay in detecting active and latent tuberculosis in HIV-infected population in bacillus Calmette-Guerin (BCG)-vaccinated area. A total of 100 HIV-infected individuals including 32 active tuberculosis patients were recruited. An ELISPOT-based IFN-γ release assay, T-SPOT.TB, was used to evaluate the M. tuberculosis ESAT-6 and CFP-10 specific IFN-γ response. Tuberculin skin test (TST) was performed for all recruited subjects.ResultsThe subjects were divided into group HIV+ATB (HIV-infected individuals with active tuberculosis, n = 32), group HIV+LTB (HIV-infected individuals with positive results of T-SPOT.TB assay, n = 46) and group HIV only (HIV-infected individuals with negative results of T-SPOT.TB assay and without evidence of tuberculosis infection, n = 22). In group HIV+ATB and HIV+LTB, T-SPOT.TB positive rate in subjects with TST <5 mm were 50% (16/32) and 41.3% (19/46), respectively. Individuals in group HIV+ATB and HIV+LTB with CD4+ T cells <500/μl, T-SPOT.TB showed a higher sensitivity than TST (64.5% vs. 22.6% and 62.2% vs. 29.7%, respectively, both P < 0.0001). In addition, the sensitivity of T-SPOT.TB assay in group HIV+ATB increased to >85% in patients with TB treatment for less than 1 month and CD4+ T cells ≥200/μl, while for patients treated for more than 3 months and CD4+ T cells <200/μl, the sensitivity was decreased to only 33.3%. Furthermore, the results could be generated by T-SPOT.TB assay within 24 hours, which was more rapid than TST with 48–72 hours.ConclusionELISPOT-based IFN-γ release assay is more sensitive and rapid for the diagnosis of TB infection in Chinese HIV-infected individuals with history of BCG vaccination, and could be an effective tool for guiding preventive treatment with isoniazid in latently infected people and for TB control in China.
Highlights
An accurate test for Mycobacterium tuberculosis infection is urgently needed in immunosuppressed populations
Two commercial forms of the IFNGRA are licensed for use in the developed world: the T-SPOT.TB (Oxford Immunotec, Abingdon, UK), which has been developed based on the enzyme-linked immunospot (ELISPOT) assay [15]; and the whole blood-based QuantiFERON-TB Gold (QFT-G; Cellestis, Melbourne, Australia), which uses an enzyme-linked immunosorbent assay (ELISA) to detect IFN-γ released into culture supernatant [16]
The study subjects were categorized as HIV-infected individuals with active tuberculosis (HIV+active TB (ATB)), HIV-infected individuals with latent tuberculosis infection (HIV+latent TB (LTB)) and HIV-infected individuals without evidence of tuberculosis infection (HIV only)
Summary
An accurate test for Mycobacterium tuberculosis infection is urgently needed in immunosuppressed populations. The aim of this study was to investigate the diagnostic power of enzymelinked immunospot (ELISPOT)-based IFN-γ release assay in detecting active and latent tuberculosis in HIVinfected population in bacillus Calmette-Guerin (BCG)-vaccinated area. Compared with the TST, studies using IFNGRA demonstrate a high sensitivity for active tuberculosis [9,10,11] Positive scores in these assays have been shown in contact studies to equate well with a history of exposure to tuberculosis [12,13,14]. Two commercial forms of the IFNGRA are licensed for use in the developed world: the T-SPOT.TB (Oxford Immunotec, Abingdon, UK), which has been developed based on the enzyme-linked immunospot (ELISPOT) assay [15]; and the whole blood-based QuantiFERON-TB Gold (QFT-G; Cellestis, Melbourne, Australia), which uses an enzyme-linked immunosorbent assay (ELISA) to detect IFN-γ released into culture supernatant [16]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
