Revaccination Response and Lack of Hepatitis B Reactivation After HCT for Sickle Cell Disease

Sickle cell disease (SCD) can be cured by hematopoietic cell transplantation (HCT), but patients face increased risk of hepatitis B virus (HBV) reactivation due to immunosuppression. Understanding hepatitis B surface antibody (anti-HBs) kinetics is essential for optimizing HBV revaccination and posttransplant care. This post hoc analysis examined HBV immunity, reactivation, and revaccination response in 71 SCD patients who underwent HCT at the National Heart, Lung, and Blood Institute (2008-2021) using alemtuzumab and low-dose total body irradiation. At baseline, 55% showed HBV immunity (anti-HBs ≥ 12 mIU/mL). Most patients responded to revaccination regardless of baseline immunity. Post-HCT revaccination was given to 93%, with 89% completing full series (Heplisav-B or Engerix-B). Vaccinated patients had a 67.5% chance of increased anti-HBs titers between Years 1 and 2, though no significant difference was seen compared to unvaccinated patients (p = 0.12). No HBV reactivation occurred; two patients with baseline HBcAb and HBsAg positivity showed decreasing HBV DNA levels. Results indicate that HBV immunity can decline post-HCT, but most patients remain immune, and revaccination is effective. However, some non-responders-especially those treated with IVIG, rituximab, or prolonged immunosuppression-need further study. Prospective research is needed to optimize revaccination timing and immune monitoring in this high-risk group.