title: Combined antigen-specific interferon-γ and interleukin-2 release assay (FluoroSpot) for the diagnosis of Mycobacterium tuberculosis infection.
abstract: BACKGROUND
  To evaluate interleukin (IL)-2 and interferon (IFN)-γ secreting T-cells in parallel for the differentiation of latent infection with Mycobacterium tuberculosis infection (LTBI) from active tuberculosis.
  
  
  METHODS
  Following ex-vivo stimulation of peripheral blood mononuclear cells (PBMC) with M. tuberculosis-specific antigens early secretory antigenic target (ESAT)-6 and culture filtrate protein (CFP)-10, immune responses were assessed by enzyme-linked immunospot IFN-γ release assay (EliSpot-IGRA) and a novel dual cytokine detecting fluorescence-linked immunospot (FluoroSpot) in 18 patients with pulmonary tuberculosis, 10 persons with previously cured tuberculosis, 25 individuals with LTBI and 16 healthy controls.
  
  
  RESULTS
  Correlation of IFN-γ+ spot-forming cells in EliSpot-IGRA and FluoroSpot were R2 = 0.67 for ESAT-6 and R2 = 0.73 for CFP-10. The number of IL-2- IFN-γ+ producing cells was higher in patients with tuberculosis compared with past tuberculosis (CFP-10-induced p = 0.0068) or individuals with LTBI (ESAT-6-induced p = 0.0136). A cutoff value of >16 CFP-10-induced IFN-γ+ secreting cells/200.000 PBMC in the EliSpot-IGRA discriminated with highest sensitivity and specificity (89% and 76%, respectively). However, overlap in cytokine responses precludes distinction between the cohorts on an individual basis.
  
  
  CONCLUSIONS
  Combined analysis of IFN-γ and IL-2 secretion by antigen specific T-cells does not allow a reliable differentiation between different states of M. tuberculosis infection in clinical practice.
authors.affiliation: Division of Pneumology and Allergology, State University of Medicine and Pharmacy "Nicolae Testemitanu", Chisinau, Republic of Moldova; Division of Clinical Infectious Diseases, Research Center Borstel, Borstel, Germany.
authors.forename: Dumitru
authors.initials: D
authors.lastname: Chesov
authors.affiliation: Division of Clinical Infectious Diseases, Research Center Borstel, Borstel, Germany; German Center for Infection Research, Tuberculosis Unit, Borstel, Germany; International Health/Infectious Diseases, University of Lübeck, Lübeck, Germany; Department of Medicine, Karolinska Institute, Stockholm, Sweden.
authors.forename: Christoph
authors.initials: C
authors.lastname: Lange
authors.affiliation: Division of Clinical Infectious Diseases, Research Center Borstel, Borstel, Germany; German Center for Infection Research, Tuberculosis Unit, Borstel, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Daduna
authors.affiliation: Laboratory of Microbiology and Morphology of Tuberculosis, Institute of Phthisiopneumology "Chiril Draganiuc", Chisinau, Republic of Moldova.
authors.forename: Valeriu
authors.initials: V
authors.lastname: Crudu
authors.affiliation: Autoimmun Diagnostika GmbH, Straßberg, Germany.
authors.forename: Rosemarie
authors.initials: R
authors.lastname: Preyer
authors.affiliation: Division of Immune Cell-Analytics, Research Center Borstel, Borstel, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Ernst
authors.affiliation: Division of Clinical Infectious Diseases, Research Center Borstel, Borstel, Germany; German Center for Infection Research, Tuberculosis Unit, Borstel, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Kalsdorf
mesh_terms: D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007371:Interferon-gamma / Q000276:immunology / Q000378:metabolism*; D007376:Interleukin-2 / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D014376:Tuberculosis / Q000175:diagnosis* / Q000276:immunology* / Q000382:microbiology
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C117940:CFP-10 protein, Mycobacterium tuberculosis; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D007376:Interleukin-2; D007371:Interferon-gamma