title: IP-10 is an accurate biomarker for the diagnosis of tuberculosis in children.
abstract: OBJECTIVE
  Performance of IFN-γ assays in children is compromised. Therefore, we investigated the utility of IP-10 for the detection of active tuberculosis (TB) and latent tuberculosis infection (LTBI) diagnosis in children; comparing its positivity with QuantiFERON-TB Gold In-Tube (QFN-G-IT) and T-SPOT.TB.
  
  
  METHODS
  We studied 230 children from three groups: active TB, screening (healthy children without known exposure to active TB patient screened at school or by their paediatrician) and contact-tracing studies. IFN-γ release was determined by QFN-G-IT and T-SPOT.TB. IP-10 was detected in QFN-G-IT supernatants by ELISA.
  
  
  RESULTS
  When combining QFN-G-IT and IP-10 assays, positive results improved significantly from 38.3% in QFN-G-IT and 33.9% in IP-10 to 41.3%. Age and type of contact were significant risk factors associated with positive QFN-G-IT and IP-10 results. IP-10 levels after antigen-specific stimulation were significantly higher in comparison to IFN-γ levels. Correlation between the three assays was good (κ = 0.717-0.783).
  
  
  CONCLUSIONS
  IP-10 cytokine is expressed in response to TB specific-antigens used in QFN-G-IT. In conclusion, the use of IFN-γ T-cell based assays in combination with an additional IP-10 assay detection could be useful for diagnosing active TB and LTBI in children.
authors: Servei de Microbiologia, Hospital Universitari Germans Trias i Pujol, Institut d'Investigació Germans Trias i Pujol, Badalona, Spain; Universitat Autònoma de Barcelona, Bellaterra, Spain; CIBER Enfermedades Respiratorias, Instituto de Salud Carlos III, Badalona, Spain.
authors: I
authors: I
authors: Latorre
authors: Servei de Microbiologia, Hospital Universitari Germans Trias i Pujol, Institut d'Investigació Germans Trias i Pujol, Badalona, Spain; Universitat Autònoma de Barcelona, Bellaterra, Spain; CIBER Enfermedades Respiratorias, Instituto de Salud Carlos III, Badalona, Spain.
authors: J
authors: J
authors: Díaz
authors: Unidad de Neumología Infantil, Hospital Clínico Universitario Valencia, Universidad de Valencia, Spain.
authors: I
authors: I
authors: Mialdea
authors: Servei de Microbiologia, Hospital Universitari Germans Trias i Pujol, Institut d'Investigació Germans Trias i Pujol, Badalona, Spain; Universitat Autònoma de Barcelona, Bellaterra, Spain; CIBER Enfermedades Respiratorias, Instituto de Salud Carlos III, Badalona, Spain.
authors: M
authors: M
authors: Serra-Vidal
authors: Unidad de Prevención y Control de la Tuberculosis de Barcelona, Spain; Universitat Autònoma de Barcelona, Bellaterra, Spain.
authors: N
authors: N
authors: Altet
authors: Servei de Microbiologia, Hospital Universitari Germans Trias i Pujol, Institut d'Investigació Germans Trias i Pujol, Badalona, Spain; Universitat Autònoma de Barcelona, Bellaterra, Spain; CIBER Enfermedades Respiratorias, Instituto de Salud Carlos III, Badalona, Spain.
authors: C
authors: C
authors: Prat
authors: Unidad de Neumología Infantil, Hospital Clínico Universitario Valencia, Universidad de Valencia, Spain.
authors: N
authors: N
authors: Díez
authors: Unidad de Neumología Infantil, Hospital Clínico Universitario Valencia, Universidad de Valencia, Spain.
authors: A
authors: A
authors: Escribano
authors: Servei de Medicina Preventiva, Hospital Universitari Germans Trias i Pujol, Institut d'Investigació Germans Trias i Pujol, Badalona, Spain; Universitat Autònoma de Barcelona, Bellaterra, Spain.
authors: I
authors: I
authors: Casas
authors: Universitat Autònoma de Barcelona, Bellaterra, Spain; Servei de Pediatria, Hospital Universitari Germans Trias I Pujol, Institut d'Investigació Germans Trias i Pujol, Badalona, Spain.
authors: C
authors: C
authors: Rodrigo
authors: Servei de Microbiologia, Hospital Universitari Germans Trias i Pujol, Institut d'Investigació Germans Trias i Pujol, Badalona, Spain; Universitat Autònoma de Barcelona, Bellaterra, Spain; CIBER Enfermedades Respiratorias, Instituto de Salud Carlos III, Badalona, Spain.
authors: V
authors: V
authors: Ausina
authors: Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark.
authors: M
authors: M
authors: Ruhwald
authors: Servei de Microbiologia, Hospital Universitari Germans Trias i Pujol, Institut d'Investigació Germans Trias i Pujol, Badalona, Spain; Universitat Autònoma de Barcelona, Bellaterra, Spain; CIBER Enfermedades Respiratorias, Instituto de Salud Carlos III, Badalona, Spain. Electronic address: jadomb@gmail.com.
authors: J
authors: J
authors: Domínguez
mesh_terms: D000293:Adolescent; D000942:Antigens, Bacterial / Q000097:blood / Q000276:immunology; D015415:Biomarkers / Q000097:blood*; D054357:Chemokine CXCL10 / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000097:blood* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007371:Interferon-gamma / Q000097:blood / Q000276:immunology; D055985:Latent Tuberculosis / Q000175:diagnosis*; D008297:Male; D012189:Retrospective Studies; D013601:T-Lymphocytes / Q000276:immunology; D014376:Tuberculosis / Q000175:diagnosis*
chemical_list: D000942:Antigens, Bacterial; D015415:Biomarkers; C114753:CXCL10 protein, human; D054357:Chemokine CXCL10; D016207:Cytokines; D007371:Interferon-gamma
keywords: Children; IFN-γ; IP-10; Tuberculosis