title: Bifunctional T-cell-derived cytokines for the diagnosis of tuberculosis and treatment monitoring.
abstract: BACKGROUND
  Diagnosis and treatment monitoring of patients with tuberculosis remain challenging.
  
  
  OBJECTIVE
  We have evaluated whether Mycobacterium-specific interferon (IFN)-γ and interleukin (IL)-2 bifunctional cytokine immune response assays improve the diagnosis of and correlate to treatment response in pulmonary tuberculosis.
  
  
  METHODS
  Early secretory antigenic target (ESAT)6/culture filtrate protein 10 (CFP10), microsomal triglyceride transfer protein 65 (MTP65) and the purified protein derivative (PPD) tuberculin-specific immune profiles were investigated in peripheral blood mononuclear cells from 19 patients with culture-confirmed tuberculosis and 23 healthy community controls (HCCs; 82.6% with latent M. tuberculosis infection) using a novel fluorescence-based dual-colour enzyme-linked immunospot (EliSpot) technology (FluoroSpot).
  
  
  RESULTS
  The frequency of ESAT6/CFP10-induced IFN-γ+IL-2- producing cells was elevated (p < 0.001), whereas the percentages of specific IFN-γ-IL-2+ (p = 0.002) and IFN-γ+IL-2+ double producing cells (p = 0.037) were diminished in tuberculosis patients in comparison to HCCs. A 3-host marker model using a combination of those IFN-γ and IL-2 single-cell responses showed 93.8% sensitivity and 77.8% specificity for tuberculosis. During tuberculosis treatment, the PPD-induced immune responses shifted from an IFN-γ+IL-2- dominated profile towards a balance of IFN-γ-IL-2+ and IFN-γ+IL-2+ double producing cells (all p ≤ 0.05).
  
  
  CONCLUSIONS
  The addition of antigen-specific IL-2 production to IFN-γ responses by EliSpot in IFN-γ release assays increases diagnostic sensitivity for active tuberculosis.
authors.affiliation: DST/NRF Centre of Excellence for Biomedical Tuberculosis Research and MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa.
authors.forename: Paulin N
authors.initials: PN
authors.lastname: Essone
authors.forename: Barbara
authors.initials: B
authors.lastname: Kalsdorf
authors.forename: Novel N
authors.initials: NN
authors.lastname: Chegou
authors.forename: André G
authors.initials: AG
authors.lastname: Loxton
authors.forename: Magdalena
authors.initials: M
authors.lastname: Kriel
authors.forename: Rosemarie
authors.initials: R
authors.lastname: Preyer
authors.forename: Martin
authors.initials: M
authors.lastname: Ernst
authors.forename: Gerhard
authors.initials: G
authors.lastname: Walzl
authors.forename: Christoph
authors.initials: C
authors.lastname: Lange
mesh_terms: D000328:Adult; D000995:Antitubercular Agents / Q000627:therapeutic use; D002352:Carrier Proteins / Q000378:metabolism; D016022:Case-Control Studies; D016207:Cytokines / Q000378:metabolism; D058501:Enzyme-Linked Immunospot Assay; D005260:Female; D015200:Fluoroimmunoassay; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology; D007376:Interleukin-2 / Q000276:immunology; D055985:Latent Tuberculosis / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D016896:Treatment Outcome; D014373:Tuberculin / Q000378:metabolism; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology*; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents; D002352:Carrier Proteins; D016207:Cytokines; C505464:ESAT-6-CFP10 fusion protein; D007376:Interleukin-2; D011993:Recombinant Fusion Proteins; D014373:Tuberculin; C106092:microsomal triglyceride transfer protein; D007371:Interferon-gamma