From the Guidelines
A person who is hepatitis B core (HBc) antibody positive can potentially be a stem cell donor, but additional testing is required to determine eligibility. The presence of hepatitis B core antibodies alone indicates past exposure to the hepatitis B virus, not necessarily active infection. According to the guidelines for preventing opportunistic infections among hematopoietic stem cell transplant recipients 1, donors should be screened for transmissible infections, including viral hepatitis. Donors who are HBc antibody positive should undergo further evaluation including testing for hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (HBsAb), and hepatitis B viral DNA (HBV DNA).
- Key considerations for donor eligibility include:
- HBsAg status: Donors who are HBsAg negative may be eligible to donate.
- HBV DNA status: Donors who are HBV DNA negative may be eligible to donate.
- Presence of protective HBsAb: Donors with protective HBsAb may be eligible to donate. If the donor is HBsAg negative and HBV DNA negative, they may be cleared to donate, especially if they have protective HBsAb. Recipients of stem cells from HBc antibody positive donors may require prophylactic antiviral therapy such as entecavir or tenofovir to prevent hepatitis B reactivation, typically for 6-12 months post-transplant. The transplant team will assess the overall risk-benefit ratio, considering factors such as the urgency of the transplant and availability of alternative donors. This approach is based on the understanding that while there is a theoretical risk of viral transmission, modern antiviral prophylaxis can effectively manage this risk in most cases.
From the Research
Eligibility of HBc Antibody Positive Persons as Stem Cell Donors
- The eligibility of a hepatitis B core (HBc) antibody positive person as a stem cell donor is a complex issue that requires careful consideration of the risks and benefits.
- According to a study published in the Journal of Viral Hepatitis 2, the risk of reactivation of a resolved HBV infection is close to 100% in allogeneic stem cell recipients, and vaccination of the donor does not always warrant reliable protection.
- Another study published in Blood 3 found that the use of HBsAg-positive marrow for transplant was associated with a high incidence of HBV-related hepatitis, and a high viral load in the donor appeared to predispose recipients to the development of HBV-related hepatitis posttransplant.
Risk of Viral Transmission
- A study published in the Journal of Hepatology 4 found that the prevalence of occult HBV infection among hematopoietic stem cell donors in a hepatitis B virus endemic area was high, and that anti-HBc and anti-HBs status had no significant correlation with the presence of occult HBV infection.
- However, a study published in Transplantation 5 found that the use of HBcAb+ donors represented a safe and effective therapeutic option to increase available organs for lung transplantation, with no patient in the HB group developing clinical liver disease due to viral hepatitis.
Adoptive Immunity Against HBV
- A study published in Infection 6 found that adoptive transfer of immunity against hepatitis B virus was possible by BMT with unknown duration and mechanism, and that donor lymphocyte infusion could enhance this adoptive immunity.
- This suggests that a HBc antibody positive person may be able to donate stem cells to a recipient who is at risk of HBV reactivation, as long as the recipient has been vaccinated against HBV and the donor has a low viral load.
Key Considerations
- The decision to use a HBc antibody positive person as a stem cell donor should be made on a case-by-case basis, taking into account the individual's viral load, the recipient's vaccination status, and the potential risks and benefits of the transplant.
- Further research is needed to fully understand the risks and benefits of using HBc antibody positive donors for stem cell transplantation, and to develop effective strategies for preventing HBV reactivation in recipients.