title: Do results of the T-SPOT.TB interferon-gamma release assay change after treatment of tuberculosis?
abstract: BACKGROUND
  Interferon-gamma (IFN-gamma) production by lymphocytes exposed to antigens specific of Mycobacterium tuberculosis has been shown to correlate with antigen load and disease activity.
  
  
  OBJECTIVE
  To determine whether treatment of tuberculosis (TB) led to a decrease and/or a reversion of results of a IFN-gamma release assay (T-SPOT.TB, Oxford Immunotec, UK) and thus if T-SPOT.TB could be used to monitor response to treatment.
  
  
  METHODS
  Qualitative and quantitative analysis (SFUs: spot-forming units) of T-SPOT.TB in HIV-negative patients with TB, during initial 2 weeks of treatment (T0), at end of treatment (TE) and 6 months later (TE+6).
  
  
  RESULTS
  Mean SFU (SD) was 75 (58; n=62) at T0, 46 (55; n=55) at TE, and 33 (46; n=41) at TE+6; positive rate was 98%, 93% and 98%, respectively. SFUs (paired samples, n=36) decreased significantly between T0 and TE; 2 reversions occurred between T0 and TE (6%), but none between TE and TE+6. Of 6 patients (17%) with an increase in SFUs between T0 and TE, 5 had a favourable outcome at TE and TE+6.
  
  
  CONCLUSIONS
  Decrease in SFUs under treatment suggests a relationship with antigen load; however, persisting high SFUs were not predictive of unfavourable outcome and test reversion was rare.
authors.affiliation: Division of Pulmonary Diseases, Geneva University Hospital, 1211 Geneva 14, Switzerland.
authors.forename: Valerie
authors.initials: V
authors.lastname: Bosshard
authors.forename: Pascale
authors.initials: P
authors.lastname: Roux-Lombard
authors.forename: Thomas
authors.initials: T
authors.lastname: Perneger
authors.forename: Marie
authors.initials: M
authors.lastname: Metzger
authors.forename: Regis
authors.initials: R
authors.lastname: Vivien
authors.forename: Thierry
authors.initials: T
authors.lastname: Rochat
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Janssens
mesh_terms: D000328:Adult; D000937:Antigen-Antibody Reactions; D000941:Antigens; D000942:Antigens, Bacterial; D000995:Antitubercular Agents / Q000627:therapeutic use; D001426:Bacterial Proteins; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis* / Q000378:metabolism; D008214:Lymphocytes / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D011446:Prospective Studies; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D013997:Time Factors; D016896:Treatment Outcome; D014376:Tuberculosis / Q000175:diagnosis* / Q000188:drug therapy*
chemical_list: D000941:Antigens; D000942:Antigens, Bacterial; D000995:Antitubercular Agents; D001426:Bacterial Proteins; C117940:CFP-10 protein, Mycobacterium tuberculosis; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D011933:Reagent Kits, Diagnostic; D007371:Interferon-gamma