Multicenter, cross-sectional, observational study on Epstein-Barr viral infection status and thiopurine use by age group in patients with inflammatory bowel disease in Japan (EBISU study).

BACKGROUND

The Epstein-Barr virus (EBV) infection status in patients with inflammatory bowel disease (IBD), particularly those using thiopurines, may be associated with the risk of lymphoproliferative disorder and hemophagocytic lymphohistiocytosis. This was the first multicenter survey of EBV infection in Japanese patients with IBD. Factors related to the EBV infection status were also investigated.

METHODS

Five tertiary institutions in Japan participated in this study to examine pediatric and adult patients with IBD. Serum EBV anti-viral capsid antigen (VCA) IgG, EBV anti-VCA IgM, and anti-EBV nuclear antigen-antibody were measured in 495 patients with IBD. The patients' information was obtained from their medical records. Prior EBV infection was defined as anti-VCA IgM negativity and anti-VCA IgG positivity (UMIN000033004).

RESULTS

The patients' median age was 25 years (range 0-92 years). Of the 495 patients, nine were anti-VCA IgM-positive and 354 were anti-VCA IgG-positive (seroprevalence: 72.8%). The proportion of patients with prior EBV infection was 0% for those aged < 5 years, < 60% for those aged < 30 years, and > 90% for those aged > 30 years. The proportion of EBV-uninfected patients using thiopurines was 28.4% (52/183) for all patients and 51.8% (44/85) for pediatric patients. Age was significantly associated with anti-VCA IgG seropositivity (p < 0.01, odds ratio: 0.902, 95% confidence interval: 0.880-0.925). No cases of lymphoproliferative disorder, hemophagocytic lymphohistiocytosis, or chronic active EBV infection were reported.

CONCLUSIONS

Approximately 30% of Japanese patients with IBD were EBV-uninfected, including those using thiopurines. Age was a significant factor for anti-VCA IgG seropositivity.