title: Kinetics of anti-hepatitis B surface antigen titers after hepatitis B vaccination in patients with inflammatory bowel disease.
abstract: BACKGROUND
  Clinically significant hepatitis B (HB) virus infection has been documented among immunocompromised patients who do not maintain anti-hepatitis surface antigen (anti-HBs) concentrations ≥ 10 IU/L after an adequate response to the vaccine. The aims of the study were to understand the kinetics of anti-HBs titers over time in patients with inflammatory bowel disease (IBD) who initially responded to vaccination and to identify factors predictive of losing protective anti-HBs titers.
  
  
  METHODS
  Patients with IBD with a response (anti-HBs > 10 IU/L at 1-3 months) to HB virus vaccination were prospectively included. Anti-HBs titers were measured at 6 and 12 months. Anti-HBs titers were considered negative if they were <10 IU/L at any time during the follow-up. The kinetics of anti-HBs titers in the long term was estimated using Kaplan-Meier curves. Cox regression analysis was performed to identify the factors predictive of losing protective anti-HBs titers.
  
  
  RESULTS
  The sample comprised 100 patients (mean age, 42 years; 68% Crohn's disease; 49% on thiopurines; and 14% on anti-tumor necrosis factors during follow-up). The cumulative incidence of loss of anti-HBs titers was 2% after 6 months and 15% after 12 months. The incidence rate of loss of protective anti-HBs titers was 18% per patient-year. Baseline (after vaccination) anti-HBs titers were lower among patients whose titers became negative during the follow-up than among those who maintained them >10 IU/L (191 versus 515 IU/L; P < 0.001). Treatment with anti-TNFs was the only factor associated with a higher risk of loss of anti-HBs (hazard ratio = 3.1; 95% confidence interval = 1.1-8.8; P = 0.03).
  
  
  CONCLUSIONS
  A high proportion of patients with IBD with protective anti-HBs titers after vaccination lose them over time (18% per patient-year of follow-up). The risk of losing protective anti-HBs titers is 3-fold higher among patients on anti- tumor necrosis factors therapy.
authors: Department of Gastroenterology, Hospital Universitario de La Princesa, Instituto de Investigación Sanitaria Princesa, Madrid, Spain. gisbert@meditex.es
authors: Javier P
authors: JP
authors: Gisbert
authors: Jose Ramón
authors: JR
authors: Villagrasa
authors: Amelia
authors: A
authors: Rodríguez-Nogueiras
authors: María
authors: M
authors: Chaparro
mesh_terms: D000293:Adolescent; D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D003093:Colitis, Ulcerative / Q000150:complications / Q000188:drug therapy / Q000276:immunology*; D003424:Crohn Disease / Q000150:complications / Q000188:drug therapy / Q000276:immunology*; D005260:Female; D005500:Follow-Up Studies; D006509:Hepatitis B / Q000150:complications / Q000276:immunology / Q000517:prevention & control*; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D017325:Hepatitis B Vaccines / Q000276:immunology*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D015415:Biomarkers; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines