Myhre, Laura J.

AbstractLiver transplantation (LT) with hepatitis B core antibody (anti‐HBc) positive grafts to hepatitis B surface‐antigen (HBsAg) negative recipients is safe and has likely contributed to improvements in organ access over the years. The incidence of de novo hepatitis B infection (HBV) in these instances is low with appropriate prophylaxis and is affected by recipient immunologic status. There is debate as to whether hepatitis B surface antibody (anti‐HBs) positivity may safely inform prophylaxis discontinuation post‐LT. In this retrospective study of all hepatitis B surface antigen (HBsAg) negative recipients of anti‐HBc positive organs at three large academic centers between January 2014 and December 2019, nine LT recipients discontinued prophylaxis after developing anti‐HBs antibodies 1 year or later post‐LT. Three of the nine patients (33%) developed de novo HBV, defined by positive HBsAg or hepatitis B virus (HBV) DNA, during the study period. The remaining six patients had no evidence of HBV infection after a mean follow‐up of 37 months. The patients without de novo HBV had higher anti‐HBs titers at the time of prophylaxis discontinuation and were less likely to have negative anti‐HBs at the time of transplant or negative anti‐HBc at any time point. These results suggest that quantitative anti‐HBs titer thresholds rather than qualitative anti‐HBs positivity at 1 year or later after LT should be used to identify patients at decreased risk of de novo infection and help guide prophylaxis duration.

Introduction: Contemporary dosing strategies for rabbit anti-thymocyte globulin (rATG) in kidney transplantation aim to reduce cumulative exposure, minimizing long-term adverse events. The use of ideal body weight-based dosing has been trialed, however concern for increased rejection post-transplant exists due to lower doses of rATG. Research Questions: The primary aim of this study was to compare rejection rates between rATG dosing protocols using actual body weight and ideal body weight and secondarily to evaluate cost savings following protocol implementation. Design: This was a retrospective study surrounding implementation of an ideal body weight-based dosing protocol for rATG. We compared 75 kidney transplant recipients in whom rATG was dosed based on actual body weight (pre-protocol group) to 64 in whom dosing was based on ideal body weight (post-protocol group), following a nine-month washout. Results: The mean cumulative rATG dose in the pre-protocol group was 6.3 mg/kg of actual body weight. When ideal body weight was used in the post-protocol group, the mean dose was 4.5 mg/kg of actual body weight. The rejection rate was 18.7% pre-protocol and 23.4% postprotocol, which did not represent a statistically significant difference (p = 0.491). The actual annual cost savings after protocol implementation exceeded $162,000, approximately $2,500 per patient. Conclusion: Results suggest ideal body weight-based dosing of rATG may reduce exposure and cost, without significantly impacting the risk of rejection in kidney transplant recipients. More studies are needed to confirm these findings.