title: Quantiferon TB Gold and tuberculin skin tests for the detection of latent tuberculosis infection in patients treated with tumour necrosis factor alpha blocking agents.
abstract: OBJECTIVE
  The risk of activation of latent tuberculosis infection (LTBI) is increased in patients treated with anti-TNF-α drugs. Tuberculin skin test (TST) and Quantiferon-TB Gold test (QFT) are used to detect LTBI before and during anti-TNF-α treatment. We describe here a relation of these tests at various timepoints and also longitudinal QFT data.
  
  
  METHODS
  Study group consisted of 305 patients with several rheumatic inflammatory diseases treated and/or scheduled for anti-TNF-α drugs. The QFT was performed in 303 patients during therapy and in 177 patients also during screening. The TST was used in 284 patients. Both tests simultaneously were utilised in 360 instances.
  
  
  RESULTS
  Twenty-two patients were QFT positive; 3.9% before and 5.9% during anti-TNF-α treatment. Two patients who became QFT positive developed active tuberculosis. The TST was positive in 42% and 38% of patients before and during treatment, respectively. There was poor agreement between the two tests. Patients on glucocorticoids had a negative TST more frequently. The IFN-γ response to mycobacterial antigens significantly increased after application of tuberculin, but never reached the positive threshold. There was a significant increase in mitogen-induced IFN-γ production after initiation of anti-TNF-α therapy.
  
  
  CONCLUSIONS
  Poor correlation between the QFT and TST renders the TST non-specific for LTBI. QFT is more specific to detect LTBI and conversion to a positive result may predict active TB. An increase in IFN-γ production in response to mycobacterial antigens is seen when the TST is performed before the QFT. Mitogen-induced IFN-γ production increases after initiation of anti-TNF-α therapy.
authors.affiliation: Institute of Rheumatology, Praha , Czech Republic. mklein@revma.cz
authors.forename: Martin
authors.initials: M
authors.lastname: Klein
authors.forename: Katerina
authors.initials: K
authors.lastname: Jarosová
authors.forename: Sárka
authors.initials: S
authors.lastname: Forejtová
authors.forename: Radim
authors.initials: R
authors.lastname: Bečvář
authors.forename: Liliana
authors.initials: L
authors.lastname: Sedová
authors.forename: Karel
authors.initials: K
authors.lastname: Pavelka
authors.forename: Gabriela
authors.initials: G
authors.lastname: Simková
authors.forename: Radka
authors.initials: R
authors.lastname: Svobodová
authors.forename: Katarína
authors.initials: K
authors.lastname: Hviscová
authors.forename: Herman
authors.initials: H
authors.lastname: Mann
authors.forename: Ivana
authors.initials: I
authors.lastname: Půtová
authors.forename: Jiri
authors.initials: J
authors.lastname: Vencovský
mesh_terms: D000328:Adult; D018501:Antirheumatic Agents / Q000009:adverse effects*; D001168:Arthritis / Q000175:diagnosis / Q000188:drug therapy* / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000097:blood*; D059425:Interferon-gamma Release Tests; D055985:Latent Tuberculosis / Q000097:blood / Q000139:chemically induced / Q000175:diagnosis* / Q000276:immunology / Q000382:microbiology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013997:Time Factors; D016896:Treatment Outcome; D014374:Tuberculin Test; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*
chemical_list: D018501:Antirheumatic Agents; D015415:Biomarkers; C573415:IFNG protein, human; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma