title: Comparative analysis of whole-blood interferon-γ and flow cytometry assays for detecting post-treatment immune responses in patients with active tuberculosis.
abstract: BACKGROUND
  Intracellular cytokine flow cytometry (ICCFC) has been explored to detect tuberculosis (TB) infections; however, there are little data regarding its use to examine the dynamic responses of Mycobacterium tuberculosis (MTB)-specific T-cells after anti-tuberculous therapy. The aim of this study was to analyze both dynamic changes in functional MTB antigen-specific T-cell subsets and interferon-gamma (IFN-γ) levels using ICCFC and the QuantiFERON-TB Gold In-Tube (QFT-IT) test, respectively, following anti-tuberculous treatment in patients with active TB.
  
  
  METHODS
  Twenty-six patients with active TB were enrolled in the study, and QFT-IT and ICCFC were performed simultaneously both before and after treatment. IFN-γ levels (QFT-IT test) and the numbers of IFN-γ- or tumor necrosis factor-alpha (TNF-α)-expressing T-cells (ICCFC assay) were examined after stimulation with MTB antigen.
  
  
  RESULTS
  There was no significant reduction in the mean IFN-γ concentrations measured by the QFT-IT test after anti-tuberculous treatment (P = 0.314). ICCFC analysis showed that the numbers of IFN-γ(+) /CD4(-) T-cells, and CD4(+) T-cells producing TNF-α, either alone or in combination with IFN-γ, were significantly reduced after anti-tuberculous treatment. The IFN-γ(+) /TNF-α(+) /CD4(+) T-cell subset showed the greatest difference between untreated and treated patients with active TB (area under the curve = 0.734, P = 0.004).
  
  
  CONCLUSIONS
  Unlike the QFT-IT test, ICCFC provides diverse immunological information about dynamic changes in the number of MTB antigen-specific T-cells following anti-tuberculous therapy. Thus, analysis of MTB antigen-stimulated T-cell responses using ICCFC might have a role to play in monitoring treatment responses in patients with active TB.
authors: Department of Internal Medicine, Kyungpook National University, School of Medicine, Daegu, Republic of Korea.
authors: Chang Ho
authors: CH
authors: Kim
authors: Keum Ju
authors: KJ
authors: Choi
authors: Seung Soo
authors: SS
authors: Yoo
authors: Shin Yup
authors: SY
authors: Lee
authors: Dong Il
authors: DI
authors: Won
authors: Jeong Ok
authors: JO
authors: Lim
authors: Seung Ick
authors: SI
authors: Cha
authors: Jae Yong
authors: JY
authors: Park
authors: Jaehee
authors: J
authors: Lee
mesh_terms: D000995:Antitubercular Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D015496:CD4-Positive T-Lymphocytes / Q000473:pathology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007371:Interferon-gamma / Q000097:blood* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D014376:Tuberculosis / Q000188:drug therapy* / Q000276:immunology* / Q000382:microbiology / Q000473:pathology
chemical_list: D000995:Antitubercular Agents; D007371:Interferon-gamma
keywords: flow cytometry; interferon-gamma release assay; treatment monitoring; tuberculosis