Background: The risk of Hepatitis B virus (HBV) reactivation under immunosuppressant has been well known. Hepatitis B virus reactivation increase patient mortality and graft failure in renal transplant recipient. Especially, Rituximab® is identified as strong risk factors of HBV reactivation in recent studies. The purpose of this study is to identify the effect of antiviral agent and HBV reactivation in renal transplant recipient with rituximab usage.
Methods: Total 502 patients underwent renal transplantation with desensitization protocols for ABO incompatible or flowcytometry crossmatching(FCXM) positivity in our center from Jan 2009 to Dec 2016. Twenty-eight (5.8%) out of 502 recipients were HBsAg positive at the time of transplant. They were followed up at least 6 months with antiviral prophylaxis.
Results: At the time of transplant, serum HBV-DNA titers were less than 2.0x104/ml for all patients except one patient who performed simultaneous liver and kidney transplantation, in 23 patients HBV envelope antigen (HBeAg) was negative. Entecavir was used in 21 patients; Telbivudine was used in 3 patients.  Tenofovir was used in 2 and one patient stopped the antiviral agent after transplantation. During the follow up periods of median 1494 days (187-2572), there was no mortality or graft failure. During the follow up periods, mild ALT elevation was detected in 3 patients, without HBV reactivation. One patient experienced HBV reactivation 6 month after entecavir discontinuation due to economic reason. Resistant mutation emerged in 1 patient and one patient performed hepatectomy because of hepatocellular carcinoma at 6 months after renal transplantation.
Conclusion: For HBsAg positive renal transplant recipients, rituximab® can be used safely with antiviral prophylaxis, even though the use of Rituximab for desensitization can increase the risk of HBV reactivation. But, careful monitoring of liver function and HBV-DNA levels is mandatory for a long term outcome.