Tuberculosis treatment effect on T-cell interferon-γ responses to Mycobacterium tuberculosis-specific antigens

• Published in: The European respiratory journal Vol. 36; no. 2; pp. 355 - 361
• Main Authors: CHEE, C. B. E, KHINMAR, K. W, GAN, S. H, BARKHAM, T. M, KOH, C. K, SHEN, L, WANG, Y. T
• Format: Journal Article
• Language: English
• Published: Leeds Maney 01.08.2010
• Subjects: Adolescent; Adult; Aged; Antibiotics. Antiinfectious agents. Antiparasitic agents; Antigens, Bacterial - immunology; Antiviral agents; Bacterial diseases; Biological and medical sciences; Female; Human bacterial diseases; Humans; Infectious diseases; Interferon-gamma - blood; Interferon-gamma - immunology; Male; Medical sciences; Middle Aged; Mycobacterium tuberculosis - metabolism; Pharmacology. Drug treatments; Pneumology; Reproducibility of Results; Sputum - microbiology; T-Lymphocytes - metabolism; Tuberculin Test - methods; Tuberculosis - blood; Tuberculosis - microbiology; Tuberculosis and atypical mycobacterial infections; T-cell; Cellular immunity; Mycobacterial infection; Infection; Antigen; Treatment; Tuberculosis; Mycobacterium tuberculosis; Immunological investigation; Mycobacteriales; Interferon-γ; T-Lymphocyte; Bacteriosis; Mycobacteriaceae; Bacteria; Antiviral; Actinomycetes; Interferon; Pneumology
• ISSN: 0903-1936; 1399-3003
• DOI: 10.1183/09031936.00151309

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.