Human leukocyte antigen compatibility and incidence of donorspecific antibodies in pediatric liver transplant recipients

BACKGROUND Antibody-mediated rejection following liver transplantation(LT)has been increasingly recognized,particularly with respect to the emergence of de novo donor-specific antibodies(DSAs)and their impact on graft longevity.While substantial evidence for adult populations exists,research focusing on pediatric LT outcomes remains limited.AIM To investigate the prevalence of human leukocyte antigen(HLA)mismatches and DSA and evaluate their association with rejection episodes after pediatric LT.METHODS A cohort of pediatric LT recipients underwent HLA testing at Santa Casa de Porto Alegre,Brazil,between December 2013 and December 2023.Only patients who survived for>30 days after LT with at least one DSA analysis were included.DSA classes I and II and cross-matches were analyzed.The presence of de novo DSA(dnDSA)was evaluated at least 3 months after LT using the Luminex®single antigen bead method,with a positive reaction threshold set at 1000 MFI.Rejection episodes were confirmed by liver biopsy.RESULTS Overall,67 transplanted children were analyzed;61 received grafts from living donors,85%of whom were related to recipients.Pre-transplant DSA(class I or II)was detected in 28.3%of patients,and dnDSA was detected in 48.4%.The median time to DSA detection after LT was 19.7[interquartile range(IQR):4.3-35.6]months.Biopsyproven rejection occurred in 13 patients at follow-up,with C4d positivity observed in 5/13 Liver biopsies.The median time to rejection was 7.8(IQR:5.7-12.8)months.The presence of dnDSA was significantly associated with rejection(36%vs 3%,P<0.001).The rejection-free survival rates at 12 and 24 months were 76%vs 100%and 58%vs 95%for patients with dnDSA anti-DQ vs those without,respectively.CONCLUSION Our findings highlight the importance of incorporating DSA assessment into pre-and post-transplantation protocols for pediatric LT recipients.Future implications may include immunosuppression minimization strategies based on this analysis in pediatric LT recipients.

Biliary complications after pediatric liver transplantation: Risk factors, diagnosis and management

The expanded indications of partial grafts in pediatric liver transplantation have reduced waiting list mortality. However, a higher morbidity is observed, including an increased rate of biliary complications(BCs). Factors such as the type of graft, the preservation methods applied, the donor characteristics, the type of biliary reconstruction, and the number of bile ducts in the liver graft influences the occurrence of these complications. Bile leaks and strictures comprise the majority of posttransplant BCs. Biliary strictures require a high grade of suspicion, and because most children have a bileoenteric anastomosis, its diagnosis and management rely on percutaneous hepatic cholangiography and percutaneous biliary interventions(PBI). The success rates with PBI range from 70% to 90%. Surgery is reserved for patients who have failed PBI. BCs in children after liver transplantation have a prolonged treatment and are associated with a longer length of stay and higher hospital costs. However, with early diagnosis and aggressive treatment, patient and graft survival are not significantly compromised.