HBV Reactivation

Hepatitis B virus (HBV) reactivation is a serious complication after allogeneic haematopoietic stem cell transplantation (allo-HSCT), particularly in patients with resolved HBV infection (HBsAg-negative, anti-HBc-positive). The incidence ranges from 10% to 40%, and severe reactivation can lead to hepatitis flare, hepatic failure, and death. Several risk factors have been identified: low recipient anti-HBs titre, donor anti-HBs negativity, recipient age ≥50 years, chronic GVHD, and use of rituximab. However, no validated clinical prediction model exists for this specific population. The only available study (Zhang et al., BBMT 2020) performed risk factor analysis but did not develop a predictive nomogram, and the sample size was limited (only 16 reactivation events). Therefore, we aim to develop and externally validate a robust nomogram using a large multicentre retrospective cohort and then validate its performance in a prospective cohort