title: Comparison of interferon {gamma} release assays and conventional screening tests before tumour necrosis factor {alpha} blockade in patients with inflammatory arthritis.
abstract: OBJECTIVE
  To compare the performance of two interferon gamma release assays (IGRAs) and conventional screening tests in patients with inflammatory arthritis undergoing screening for latent tuberculosis infection (LTBI) before treatment with anti-tumour necrosis factor alpha (anti-TNFalpha) compounds.
  
  
  METHODS
  Successive patients were subjected to conventional LTBI screening, including a tuberculin skin test (TST). The T-SPOT.TB test was performed on all patients and the QuantiFERON-TB Gold test was performed on a large subset. The results of the IGRAs were compared with the results of conventional screening tests.
  
  
  RESULTS
  A total 150 patients were evaluated. The majority (57.9%) had rheumatoid arthritis. Previous vaccination with Bacille Calmette-Guerin was confirmed in 82% of patients. No patient had received prior anti-TB treatment. A total of 57 patients (38.0%) had at least one positive conventional risk factor. In contrast, an unequivocally positive T-SPOT.TB test was seen in only 14/143 (9.8%). There was 98.2% agreement between the two IGRAs. Statistically significant associations were found between each of the IGRAs and both TST and risk history, but not chest x-ray (CXR). A positive IGRA result was significantly associated with increased age. TB was not reactivated in any patient during the follow-up period.
  
  
  CONCLUSIONS
  This study suggests that IGRAs may be useful when screening for LTBI before anti-TNFalpha therapy in patients with immune-mediated inflammatory diseases. The observations reported here also highlight the inadequate performance of CXR as a marker of LTBI.
authors.affiliation: Departments of Rheumatology, Respiratory Medicine and Radiology, St Vincent's University Hospital, Dublin 4, Ireland.
authors.forename: J
authors.initials: J
authors.lastname: Martin
authors.forename: C
authors.initials: C
authors.lastname: Walsh
authors.forename: A
authors.initials: A
authors.lastname: Gibbs
authors.forename: T
authors.initials: T
authors.lastname: McDonnell
authors.forename: U
authors.initials: U
authors.lastname: Fearon
authors.forename: J
authors.initials: J
authors.lastname: Keane
authors.forename: M B
authors.initials: MB
authors.lastname: Codd
authors.forename: J
authors.initials: J
authors.lastname: Dodd
authors.forename: D
authors.initials: D
authors.lastname: Veale
authors.forename: O
authors.initials: O
authors.lastname: Fitzgerald
authors.forename: B
authors.initials: B
authors.lastname: Bresnihan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001168:Arthritis / Q000150:complications / Q000188:drug therapy / Q000276:immunology*; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000188:drug therapy / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis*; D055985:Latent Tuberculosis / Q000150:complications / Q000175:diagnosis* / Q000276:immunology; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D014374:Tuberculin Test; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*; D055815:Young Adult
chemical_list: D018501:Antirheumatic Agents; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma