ABO incompatibility is no longer considered a challenge or contraindication for adult living donor liver transplantation. Nowadays, ABO-incompatible (ABO-i) liver transplantation, in which the donor and the recipient have different blood group types, is a reality. This has been made possible thanks to a clutch of strategies devised to overcome the ABO blood group hurdle and prevent immune rejection of the transplanted liver.

This approach has expanded the pool of potential donors for patients needing a liver transplant, as it facilitates transplantation across blood type obstacles.

What makes this approach work?

Preconditioning: Prior to the transplant, recipients must undergo a process of removing antibodies from their bloodstream to lessen the risk of rejection, called preconditioning.
Desensitization: To suppress their immune system further and prevent antibody-mediated rejection, the recipients are administered medications like rituximab and intravenous immunoglobulin (IVIG).
Plasmapheresis: For further reducing the risk of rejection, plasma exchange or plasmapheresis is often carried out to remove circulating antibodies from the recipient’s bloodstream to an acceptable limit.
Immunosuppression: After the transplantation procedure, recipients are given immunosuppressive medications to prevent rejection and promote acceptance of the donor liver.

ABO-i transplantation

How is a donor selected?

Well-suited: The donor’s and recipient’s blood types can differ. However, certain other factors must still be considered, including liver size, anatomy, and overall health to ensure a successful transplant. Also, the donor must be above 18 years of age and a blood relative.
Medical assessment: Potential donors must undergo an exhaustive medical workup to evaluate their suitability for donation, including liver function tests, imaging studies, and psychosocial assessments.

Pros and cons of ABO-i transplantation

Extended donor pool: ABO-i transplantation includes donors who would otherwise be considered incompatible, thus reducing wait times and improving access to transplantation.
Comparable long-term survival: Long-term survival after ABO-incompatible transplantation is comparable to that of compatible procedures. Advances in desensitization protocols, peri-operative care and immunosuppression have significantly improved outcomes, making survival rates nearly equivalent.
The challenges: Despite its benefits, ABO-i liver transplantation brings certain challenges including a higher risk of antibody-mediated rejection, the requirement for intensive immunosuppressive therapy and an increased risk of infection. Thus, selecting the right recipient is key to a positive outcome.

To sum up

For patients who don’t have access to a compatible donor, ABO-i transplantation has opened a new door to a fresh lease of life. By expanding the potential donor pool and offering a lifeline to patients in need of an urgent transplant procedure, ABO-incompatible transplantation presents exciting possibilities.

Continuous research, innovation and collaboration will further refine and enhance the procedure of ABO-i transplantation, allowing more patients to benefit.