title: Clinical applicability of Quantiferon-TB-Gold testing in psoriasis patients during long-term anti-TNF-alpha treatment: a prospective, observational study.
abstract: BACKGROUND
  Psoriasis patients who are treated with tumour necrosis factor (TNF)-alpha antagonists are at increased risk of reactivation of latent tuberculosis infection (LTBI) and should be adequately screened and monitored during active treatment.
  
  
  OBJECTIVE
  To evaluate in a prospective study, the performance of Quantiferon-TB-Gold in tube (QFT) in vitro assay compared to the conventional tuberculin skin test (TST) in detecting LTBI among a cohort of non-BCG-vaccinated patients with moderate-to-severe psoriasis during long-term treatment (12 months) with TNF-alpha antagonists.
  
  
  METHODS
  A total of 50 patients underwent QFT and TST testing at baseline and after 6 and 12 months of continuous anti-TNF-alpha treatment. Diagnosis of LTBI was made on the basis of a positive QFT result and negative chest-radiographic and microbiological assays. Patients with LTBI were subjected to standard isoniazid chemoprophylaxis and after 1 month, they resumed anti-TNF-alpha treatment with subsequent QFT and TST testing after 6 months. In all the cases, a follow-up period of 12 months was observed.
  
  
  RESULTS
  During the 12-month-study period, 14% of patients presented a QFT conversion. During active anti-TNF-alpha treatment, a QFT conversion was observed in 10% of patients (five cases). Agreement between QFT and TST was moderate (κ=0.408) at screening, good (κ=0.734) after 6 months and fair (κ=0.328) after 12 months of treatment. A total of 18% of patients presented a positive, discordant TST during the study period.
  
  
  CONCLUSIONS
  A single-test QFT-based screening strategy for LTBI in psoriasis patients receiving long-term anti-TNF-alpha treatment could reduce the incidence of false-positive LTBI cases, preventing unnecessary TB chemoprophylaxis.
authors.affiliation: Department of Internal Medicine and Specialist Sciences, Institute of Dermatology, A. Gemelli University Hospital, Catholic University of Sacred Heart, Rome, Italy. simgarko@yahoo.it
authors.forename: S
authors.initials: S
authors.lastname: Garcovich
authors.forename: A
authors.initials: A
authors.lastname: Ruggeri
authors.forename: M
authors.initials: M
authors.lastname: D'Agostino
authors.forename: F
authors.initials: F
authors.lastname: Ardito
authors.forename: C
authors.initials: C
authors.lastname: De Simone
authors.forename: G
authors.initials: G
authors.lastname: Delogu
authors.forename: G
authors.initials: G
authors.lastname: Fadda
mesh_terms: D000328:Adult; D000368:Aged; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D016174:Hepacivirus / Q000235:genetics; D006526:Hepatitis C / Q000150:complications / Q000453:epidemiology*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D011565:Psoriasis / Q000150:complications / Q000188:drug therapy*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*
chemical_list: D014409:Tumor Necrosis Factor-alpha