ABO-incompatible heart transplantation

Abstract

Purpose ABO-incompatible (ABOi) heart transplantation (HTx) in young children has evolved from an experimental approach to a standard allocation option in many countries. Clinical and immunological research in ABOi transplantation has revealed insight into the immature immune system and its role in superior graft acceptance in childhood and antigen-specific tolerance. Recent Findings Multicenter experience has confirmed equal actuarial survival, freedom from rejection and graft vasculopathy comparing ABOi to ABO-compatible (ABOc) HTx. Observations of reduced antibody production and B-cell immunity towards the donor blood group have been confirmed in long-term follow-up. Mechanisms contributing to tolerance in this setting involve the interplay between B-cells and the complement system and the development of B-cell memory. Better characterization of the ABH polysaccharide antigens has improved diagnostic methods and clinical assessment of blood group antibodies. Boundaries regarding age, immune maturity and therapeutic interventions to extend the applicability of ABOi HTx have been explored and resulted in data that may be useful for HTx patients beyond infancy and ABOi transplantation of other organs. Tolerance of ABH antigens possibly extends to HLA response. Summary This review provides insight into the clinical evolution of ABOi HTx and associated immunologic discoveries. Current experiences and boundaries are discussed together with recent and potential future developments for utilization in other patient and age groups.

Risk stratification to determine the impact of induction therapy on survival, rejection and adverse events after pediatric heart transplant: A multi-institutional study

“…5 Overall, there was more frequent use of induction therapy in patients having a higher risk of mortality within the first year post-transplant. Surprisingly, although infants have been recognized as generally having a decreased incidence of rejection and a more forgiving immune system, 9 in our cohort these patients were more likely to have received ALA. This may reflect the preferred use of this drug in patients with CHD based on presumed higher risk of early immunologic complications and secondary organ failure.…”

Identification of Genetic Risk Factors for Neonatal Hyperbilirubinemia in Fujian Province, Southeastern China: A Case-Control Study

“…ABO compatibility was defined as an O blood type for mothers and either A or B blood type for children [ 21 ].…”

New Answers to Old Conundrums

“…Natural anti-A and anti-B antibodies are produced as a presumed immunologic cross-reaction to similar epitopes found on the gut flora. 7 The first protocol for intentional ABOi heart transplantation was developed 20 years ago by West’s group, 7 , 8 with the rationale that the ontogeny of natural isohemagglutinins begins after 4 to 6 months of age, providing a window of opportunity to transplant infants across the ABO barrier safely in the absence of preformed anti-A and anti-B antibodies. 9 Since then, multiple teams worldwide have confirmed that ABOi heart transplantation is a safe procedure in infants and young patients with absent or low circulating isohemagglutinins, saving thousands of lives in the last 2 decades by increasing the donor pool.…”