Donor–recipient Hepatitis B serological patterns and post-transplant HBV events in pediatric living donor liver transplantation: a single-center retrospective cohort with a nested case series

Background The combined effects of donor hepatitis B core antibody (anti-HBc) status and recipient pre-transplant hepatitis B surface antibody (anti-HBs) levels on post-transplant HBV events remain unclear in pediatric living donor liver transplantation (LDLT). Methods We retrospectively analyzed pediatric LDLT recipients transplanted between May 2018 and June 2023. The primary outcome was the first post-transplant hepatitis B surface antigen (HBsAg)-positive result, with death treated as a competing event. Recipients were stratified by donor anti-HBc status and recipient anti-HBs level (≥100 vs <100 mIU/mL). Antiviral prophylaxis with entecavir (0.015 mg/kg once daily) was given only to recipients of anti-HBc-positive grafts, and hepatitis B immune globulin was not used. Cumulative incidence was compared using Gray’s test, and associated factors were evaluated using Fine–Gray regression. Results Among 229 recipients, 14 (6.1%) developed HBV events. Events occurred in 0 of 97 recipients with an anti-HBc-negative donor and anti-HBs ≥100 mIU/mL (G1), 3 of 67 with an anti-HBc-negative donor and anti-HBs <100 mIU/mL (G2), 2 of 29 with an anti-HBc-positive donor and anti-HBs ≥100 mIU/mL (G3), and 9 of 36 with an anti-HBc-positive donor and anti-HBs <100 mIU/mL (G4); the corresponding 5-year cumulative incidences were 0%, 4.5%, 6.9% and 25.0% (global Gray’s test, P<0.001). Donor anti-HBc positivity (sHR, 8.28; 95% CI, 2.27–30.28; P = 0.001) and recipient anti-HBs <100 mIU/mL (sHR, 6.02; 95% CI, 1.32–27.55; P = 0.021) were independently associated with HBV events, although the wide confidence intervals reflect the small number of events (n = 14) and the magnitude of these estimates should be interpreted with caution. Conclusions Donor anti-HBc positivity and low recipient pre-transplant anti-HBs were independently associated with post-transplant HBV events after pediatric LDLT. Combined donor–recipient serological stratification identified a clear risk gradient and may support risk-adapted HBV surveillance and prevention.