Transitional changes in T-cell responses to Mycobacterium tuberculosis -specific antigens during treatment

• Published in: The Journal of infection 2009-03, Vol.58 (3), p.197-204
• Main Authors: Kobashi, Yoshihiro, Mouri, Keiji, Yagi, Shinichi, Obase, Yasushi, Miyashita, Naoyuki, Oka, Mikio
• Format: Article
• Language: English
• Subjects: Active TB disease; Aged; Antigens, Bacterial - immunology; Antitubercular Agents - immunology; Antitubercular Agents - therapeutic use; Antituberculous treatment; Bacterial Proteins - immunology; Biological and medical sciences; Drug Monitoring - methods; Female; General aspects; Humans; IFN-γ assay; Infectious Disease; Interferon-gamma - secretion; Male; Medical sciences; Middle Aged; Mycobacterium; Mycobacterium tuberculosis - immunology; Sputum - microbiology; T-Lymphocytes - immunology; Tuberculosis - drug therapy; Tuberculosis - immunology
• ISSN: 0163-4453; 1532-2742
• DOI: 10.1016/j.jinf.2008.08.009

Summary Background Currently, there is no available test for monitoring the clinical effect of active tuberculosis (TB) disease treatment. Therefore, we studied the usefulness of two commercial IFN-γ assays (QuantiFERON TB-2G (QFT-2G) and T-SPOT.TB tests) for monitoring clinical efficacy. Methods The subjects were 40 patients with active TB disease. These two commercial IFN-γ assays were carried out every three months during active TB disease treatment. Results While the positive response rate of QFT-2G test significantly decreased from 83% at treatment initiation to 58% at treatment completion, that of T-SPOT.TB decreased from 90% at treatment initiation to 63% at treatment completion. Although there was a significant decrease in patients with TB infection showing positive responses for ESAT-6 only or CFP-10 only antigens on both IFN-γ assays, there was no significant decrease in patients showing positive responses for both ESAT-6 and CFP-10 antigens on both IFN-γ assays. On both QFT-2G test and T-SPOT.TB test, the mean values of the IFN-γ levels in the pre- and post-treatment responses showed significantly decreased responses to CFP-10. On the other hand, smear conversion results of clinical specimens were obtained in all patients at treatment completion. Conclusions Antituberculous treatment induced a significant decrease in T-cell responses to separate ESAT-6 and CFP-10 antigens as measured by both IFN-γ assays. Although IFN-γ assays might be later than smear conversion results of clinical specimens, the quantitative responses especially to CFP-10 may be one of the useful monitoring markers of clinical efficacy for active TB disease treatment.