title: Tuberculosis treatment effect on T-cell interferon-gamma responses to Mycobacterium tuberculosis-specific antigens.
abstract: The hypothesis that T-cell interferon-gamma responses to Mycobacterium tuberculosis-specific antigens decline as disease activity diminishes with tuberculosis (TB) treatment has generated interest in the interferon-gamma release assays (IGRAs) as treatment-monitoring tools. We studied the effect of TB treatment on these responses as measured by the QuantiFERON-TB Gold In-tube (QFT-IT) and T-SPOT.TB assays. 275 sputum culture-positive, HIV-uninfected pulmonary TB patients were tested with QFT-IT and T-SPOT.TB at baseline, treatment completion and 6 months thereafter. The QFT-IT was also performed at the end of the intensive phase. The time-treatment effect on the qualitative and quantitative IGRA results was determined. There were significant declines in the positivity rates and quantitative results of both IGRAs with treatment. The QFT-IT positivity rate was significantly lower than the T-SPOT.TB. The test reversion rate was significantly different for the two assays (13.9% for T-SPOT.TB versus 39.2% for QFT-IT). 79% and 46% tested positive with T-SPOT.TB and QFT-IT respectively at 6 months post-treatment completion. The kinetics of the quantitative responses was not significantly different between subjects with and without risk factors for disease relapse. That a substantial proportion of patients remained test-positive after TB treatment would suggest a limited role of IGRAs as treatment monitoring tools.
authors.affiliation: Singapore Tuberculosis Control Unit, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. cynthia_chee@ttsh.com.sg
authors.forename: C B E
authors.initials: CB
authors.lastname: Chee
authors.forename: K W
authors.initials: KW
authors.lastname: KhinMar
authors.forename: S H
authors.initials: SH
authors.lastname: Gan
authors.forename: T M
authors.initials: TM
authors.lastname: Barkham
authors.forename: C K
authors.initials: CK
authors.lastname: Koh
authors.forename: L
authors.initials: L
authors.lastname: Shen
authors.forename: Y T
authors.initials: YT
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000942:Antigens, Bacterial / Q000276:immunology; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000097:blood* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000378:metabolism*; D015203:Reproducibility of Results; D013183:Sputum / Q000382:microbiology; D013601:T-Lymphocytes / Q000378:metabolism*; D014374:Tuberculin Test / Q000379:methods; D014376:Tuberculosis / Q000097:blood* / Q000382:microbiology*
chemical_list: D000942:Antigens, Bacterial; C072681:Mycobacterium tuberculosis antigens; D007371:Interferon-gamma