title: Effect of immunosuppressive therapy on interferon γ release assay for latent tuberculosis screening in patients with autoimmune diseases: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Interferon γ release assay (IGRA) is commonly used to diagnose latent TB infection (LTBI). Immunosuppressive therapy may affect its performance but data are conflicting. We aimed to determine the effect of immunosuppressive therapy on the performance of IGRA in patients with autoimmune diseases.
  
  
  METHODS
  We searched PubMed, MEDLINE, EMBASE and the Cochrane Library up to December 2014. We included studies that reported the IGRA results in patients with autoimmune disease with or without immunosuppressive therapy. The pooled effect of immunosuppressive therapy on IGRA was estimated using a Peto fixed-effects model.
  
  
  RESULTS
  We included 17 studies with 3197 participants in the meta-analysis. Among the subjects, 71.5% were taking immunosuppressive therapy and 56.7% had received Bacillus Calmette-Guérin vaccination. Compared with patients not on immunosuppressants, patients receiving immunosuppressive therapy were less likely to have a positive IGRA result (OR 0.66, 95% CI 0.53 to 0.83, I(2)=23%), especially patients receiving anti-tumour necrosis factor (anti-TNF) treatment (OR 0.50, 95% CI 0.29 to 0.88). The use of immunosuppressive therapy was also associated with a lower rate of positive tuberculin skin test result (OR 0.51, 95% CI 0.42 to 0.61).
  
  
  CONCLUSIONS
  Our meta-analysis showed that IGRA results are negatively affected by immunosuppressive therapy. IGRA alone may not be sufficiently sensitive to diagnose LTBI in patients on immunosuppressive therapy. Patients should preferably be screened for LTBI before initiation of immunosuppressive therapy, especially before anti-TNF therapy.
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong State Key Laboratory of Digestive Diseases, Institute of Digestive Disease, LKS Institute of Health Science, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Sunny H
authors.initials: SH
authors.lastname: Wong
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong Division of Gastroenterology and Hepatology, Ren-Ji Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai Institute of Digestive Disease, Shanghai 200240, China.
authors.forename: Qinyan
authors.initials: Q
authors.lastname: Gao
authors.affiliation: Faculty of Medicine, School of Public Health and Primary Care, Institute of Digestive Disease, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Kelvin K F
authors.initials: KK
authors.lastname: Tsoi
authors.affiliation: Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: William K K
authors.initials: WK
authors.lastname: Wu
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Lai-shan
authors.initials: LS
authors.lastname: Tam
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Nelson
authors.initials: N
authors.lastname: Lee
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong State Key Laboratory of Digestive Diseases, Institute of Digestive Disease, LKS Institute of Health Science, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Francis K L
authors.initials: FK
authors.lastname: Chan
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong State Key Laboratory of Digestive Diseases, Institute of Digestive Disease, LKS Institute of Health Science, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Justin C Y
authors.initials: JC
authors.lastname: Wu
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong State Key Laboratory of Digestive Diseases, Institute of Digestive Disease, LKS Institute of Health Science, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Joseph J Y
authors.initials: JJ
authors.lastname: Sung
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong State Key Laboratory of Digestive Diseases, Institute of Digestive Disease, LKS Institute of Health Science, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Siew C
authors.initials: SC
authors.lastname: Ng
mesh_terms: D001327:Autoimmune Diseases / Q000150:complications* / Q000188:drug therapy*; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D059425:Interferon-gamma Release Tests; D055985:Latent Tuberculosis / Q000175:diagnosis*
chemical_list: D007166:Immunosuppressive Agents
keywords: Infection Control; Tuberculosis