title: A comparative analysis of two interferon-γ releasing assays to detect past tuberculosis infections in Japanese rheumatoid arthritis patients.
abstract: OBJECTIVE
  To compare the utility of QuantiFERON-TB Gold in tube (QFT-GIT) and T-SPOT.TB assays to detect past tuberculosis infection in Japanese rheumatoid arthritis patients receiving methotrexate.
  
  
  METHODS
  We compared the sensitivities and specificities, the rates of indeterminate results, and the rates of positive results in patients with total and CD4-positive lymphocyte counts of both assays simultaneously performed on 68 rheumatoid arthritis patients receiving methotrexate, in whom 33 had evidence of past tuberculosis infection by chest computed tomography and the other had neither history of tuberculosis exposure nor abnormalities in chest computed tomography.
  
  
  RESULTS
  The sensitivities, specificities, and the rates of indeterminate results of QFT-GIT were 21.2%, 100%, and 4.4%, and those of T-SPOT.TB were 21.9%, 100%, and 1.5%, respectively. The overall agreement of both assays was good (κ = 0.68). In patients with past tuberculosis infection, there are significant positive linear trends in positive rates of both assays across ranges of larger numbers of total and CD4-positive lymphocyte counts.
  
  
  CONCLUSIONS
  Both assays were equally useful with high specificities, but may falsely identify past tuberculosis infection owing to low sensitivities. In patients with low total and CD4-positive lymphocyte counts, both assays might give higher rates of false negative results.
authors.affiliation: a Department of Internal Medicine, Division of Allergy, Respiratory Medicine and Immunology , Nagoya City University Graduate School of Medical Science , Nagoya City , Aichi , Japan , and.
authors.forename: Shiho
authors.initials: S
authors.lastname: Iwagaitsu
authors.affiliation: a Department of Internal Medicine, Division of Allergy, Respiratory Medicine and Immunology , Nagoya City University Graduate School of Medical Science , Nagoya City , Aichi , Japan , and.
authors.forename: Taio
authors.initials: T
authors.lastname: Naniwa
authors.affiliation: a Department of Internal Medicine, Division of Allergy, Respiratory Medicine and Immunology , Nagoya City University Graduate School of Medical Science , Nagoya City , Aichi , Japan , and.
authors.forename: Shinji
authors.initials: S
authors.lastname: Maeda
authors.affiliation: a Department of Internal Medicine, Division of Allergy, Respiratory Medicine and Immunology , Nagoya City University Graduate School of Medical Science , Nagoya City , Aichi , Japan , and.
authors.forename: Shinya
authors.initials: S
authors.lastname: Tamechika
authors.affiliation: b Department of Internal Medicine, Division of Rheumatology and Nephrology , Aichi Medical University School of Medicine , Nagakute City , Aichi , Japan.
authors.forename: Hironobu
authors.initials: H
authors.lastname: Nobata
authors.affiliation: b Department of Internal Medicine, Division of Rheumatology and Nephrology , Aichi Medical University School of Medicine , Nagakute City , Aichi , Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Imai
authors.affiliation: a Department of Internal Medicine, Division of Allergy, Respiratory Medicine and Immunology , Nagoya City University Graduate School of Medical Science , Nagoya City , Aichi , Japan , and.
authors.forename: Akio
authors.initials: A
authors.lastname: Niimi
authors.affiliation: b Department of Internal Medicine, Division of Rheumatology and Nephrology , Aichi Medical University School of Medicine , Nagakute City , Aichi , Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Banno
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000150:complications* / Q000188:drug therapy; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis*; D059425:Interferon-gamma Release Tests / Q000379:methods*; D008297:Male; D008727:Methotrexate / Q000627:therapeutic use; D008875:Middle Aged; D012680:Sensitivity and Specificity; D014374:Tuberculin Test; D014376:Tuberculosis / Q000150:complications / Q000175:diagnosis*
chemical_list: D007371:Interferon-gamma; D008727:Methotrexate
keywords: Interferon-gamma release assays; Latent tuberculosis infection; QuantiFERON-TB Gold in tube; Rheumatoid arthritis; T-SPOT.TB