ABO Incompatible Liver Transplantation in Children: A 20 Year Experience from Centres in the TransplantChild European Reference Network

ABO Incompatible Living Donor Liver Transplantation in Children: A Single Centre Experience from India

Background

In recent years, paediatric ABO incompatible (ABOi) living donor liver transplant (LT) has shown promising outcomes and can potentially eliminate organ shortage. This study aims to report paediatric ABOi LT experience, including short- and long-term outcomes.

Methods

It is a single-centre retrospective study. Out of 108 LTs, 20 were done in children. We compared the outcomes between ABOi (n = 20) and non-ABOi (n = 220) paediatric living donor liver transplantation (LDLT) performed during the study period. All the children received pre-LT desensitization therapy comprising rituximab and plasmapheresis targeting pre-LT isohemagglutinin (IHA) titres of ≤1:16.

Results

Out of 239 paediatric LDLTs from 2017 to 2022, 19 children (11 females) underwent 20 ABOi LTs (including one retransplant with an ABOi domino allograft) at a median age of 12 (12, 51) months, with the majority being biliary atresia (60%). The median change in CD19 cell%, CD20 cell%, and IHA titres after rituximab from day -14 to day -1 (before LT) was satisfactory. In the first 3 months following LT, acute cellular rejection, culture-proven sepsis, and biliary and vascular complications were seen in 10%, 20%, 20%, and 15%, respectively. None of the ABOi LT recipients developed antibody-mediated rejection. ABOi LT recipients, as compared to non-ABOi LT recipients, had a higher incidence of bile leaks and prolonged hospital stay, with the rest of the complications, including biliary strictures and long-term outcomes, being comparable. At a median follow-up of 21 (14, 33) months, 4 children expired (21%).

Conclusion

ABOi LT in children shows excellent outcomes and can be performed safely with prior desensitization when a compatible liver is unavailable.

A Retrospective Study of Long-Term Outcomes in 16 ABO-Incompatible Deceased Donor Pediatric Liver Transplants from a National Transplant Center at Helsinki University Hospital, Finland, 1987-2022

BACKGROUND The use of ABO-incompatible liver transplants (ABO-ILTs) from deceased donors has become more common due to the shortage of available donor livers and increased transplant waiting times. This retrospective study from a national transplant center at Helsinki University Hospital, Finland, aimed to assess the long-term outcomes of ABO-incompatible deceased donor pediatric liver transplants between 1987 and 2022. MATERIAL AND METHODS Sixteen (9.5%) of the 169 pediatric liver transplantations were ABO-ILTs. The median age at transplantation was 5.0 (0.5-15.4) years. Reasons for ABO-ILTs were acute liver failure (18.75%), malignancy (12.5%), small body size and long waiting time (25%), and other reasons (43.75%). The median post-transplant follow-up time was 147 (0.72-353) months. Patient and graft survival and occurrence of surgical complications were compared to ABO-identical transplants, and anti-ABO antibody titers were analyzed. RESULTS The 1-, 3-, and 5-year patient survivals were comparable between the ABO-I and ABO-compatible groups, being 81.3%, 73.9%, and 73.9% (ABO-I) and 87.5%, 82.5%, 77.9% (ABO-compatible), respectively. Three patients with ABO-ILTs died of sepsis and multiorgan failure during the first 3 months after transplantation. The occurrence of biliary complications and early vascular thrombosis (<30 days after transplantation) did not differ significantly between recipients with an ABO-ILT vs ABO-compatible liver graft. CONCLUSIONS The findings from this study support findings from previous studies that outcomes after ABO-incompatible liver transplants in children were comparable to outcomes from ABO-identical liver transplants.

Strategies for ABO Incompatible Liver Transplantation

Liver transplantation (LT) is a definitive treatment for the decompensated liver cirrhosis and fulminant liver failure. With limited availability of cadaveric liver allograft, ABO incompatible (ABOi) living donor liver transplantation (LDLT) plays an important part in further expansion of donor pool. Over the years, with the introduction of Rituximab and improving desensitisation protocol, outcomes of ABOi LDLT are on par with ABO compatible LT. However, ABOi LDLT protocol varies markedly from centre to centre. Intravenous Rituximab followed by plasmapheresis or immunoadsorption effectively reduce ABO isoagglutinins titre before transplant, thereby reducing the risk of antibody mediated rejection in the post-transplant period. Local infusion therapy and splenectomy are not used routinely at most of the centres in Rituximab era. Post-transplant immunosuppression usually consists of standard triple drug regime, and tacrolimus trough levels are targeted at higher level compared to ABO compatible LT. Introduction of newer therapies like Belatacept and Obinutuzumab hold promise to further improve outcomes and reduce the risk of antibody mediated rejection related complications. ABOi LT in emergency situations like acute liver failure and deceased donor LT is challenging due to limited time period for desensitisation protocol before transplant, and available evidence are still limited but encouraging.

Outcomes after ABO incompatible pediatric liver transplantation are comparable to ABO identical/compatible transplant

Background

ABO incompatible (ABOi) liver transplantation (LT) was initially associated with a higher incidence of vascular, biliary, and rejection complications and a lower survival than ABO compatible (ABOc) LT. Various protocols have been proposed to manage anti-isohemagglutinin antibodies and hyperacute rejection. We present our experience with a simplified protocol using only plasmapheresis.

Methods

A retrospective review of all patients who received an ABOi LT at our institution was performed. Comparisons were made based on era (early: 1997-2008, modern: 2009-2020) and severity of disease (status 1 vs. exception PELD at transplant). A pair-matched comparison was done to patients who received an ABOc LT. p < 0.05 was considered significant.

Results

17 patients received 18 ABOi LT (3 retransplants). Median age at transplant was 7.4 months (1.1-28.9). 66.7% patients were listed as status 1. Hepatic artery thrombosis (HAT) occurred in one patient (5.6%), there were 2 cases of portal vein thrombosis (PVT) (11.1%), and 2 biliary strictures (11.1%). Patient and graft survival improved in the ABOi modern era, although not significantly. In the pair-matched comparison, complications (HAT p = 0.29; PVT p = 0.37; biliary complications p = 0.15) and survival rates were similar. Patient and graft survivals were 100% in the non-status 1 ABOi patients compared to 67% (p = 0.11) and 58% (p = 0.081) respectively for patients who were transplanted as status 1.

Conclusion

ABO incompatible liver transplants in infants with a high PELD score have excellent outcomes. Indications for ABO incompatible transplants should be liberalized to prevent deaths on the waiting list or deterioration of children with high PELD scores.