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.

Liver volumetric and anatomic assessment in living donor liver transplantation: The role of modern imaging and artificial intelligence

The shortage of deceased donor organs has prompted the development of alternative liver grafts for transplantation.Living-donor liver transplantation(LDLT)has emerged as a viable option,expanding the donor pool and enabling timely transplantation with favorable graft function and improved long-term outcomes.An accurate evaluation of the donor liver’s volumetry(LV)and anatomical study is crucial to ensure adequate future liver remnant,graft volume and precise liver resection.Thus,ensuring donor safety and an appropriate graftto-recipient weight ratio.Manual LV(MLV)using computed tomography has traditionally been considered the gold standard for assessing liver volume.However,the method has been limited by cost,subjectivity,and variability.Automated LV techniques employing advanced segmentation algorithms offer improved reproducibility,reduced variability,and enhanced efficiency compared to manual measurements.However,the accuracy of automated LV requires further investigation.The study provides a comprehensive review of traditional and emerging LV methods,including semi-automated image processing,automated LV techniques,and machine learning-based approaches.Additionally,the study discusses the respective strengths and weaknesses of each of the aforementioned techniques.The use of artificial intelligence(AI)technologies,including machine learning and deep learning,is expected to become a routine part of surgical planning in the near future.The implementation of AI is expected to enable faster and more accurate image study interpretations,improve workflow efficiency,and enhance the safety,speed,and cost-effectiveness of the procedures.Accurate preoperative assessment of the liver plays a crucial role in ensuring safe donor selection and improved outcomes in LDLT.MLV has inherent limitations that have led to the adoption of semi-automated and automated software solutions.Moreover,AI has tremendous potential for LV and segmentation;however,its widespread use is hindered by cost and availability.Therefore,the integration of multiple specialties is necessary to embrace technology and explore its possibilities,ranging from patient counseling to intraoperative decision-making through automation and AI.

Phase angle and non-alcoholic fatty liver disease before and after bariatric surgery

BACKGROUND Obesity is a global health problem that is continuing to increase in the young population.In Brazil,the frequency of obesity in 2018 was 19.8%.Several comorbidities are directly associated with obesity,such as non-alcoholic fatty liver disease(NAFLD),which is considered the most common liver disorder in Western countries and affects up to 46%of adults.Bariatric surgery is effective in treating obesity and can improve NAFLD;however,the effect of bariatric surgery on body composition,phase angle(PA),and improving NAFLD needs to be further studied.AIM To analyze the PA in the postoperative period of bariatric surgery and to correlate it with changes in body composition and liver disease.METHODS This study is a retrospective cohort study of the analysis of the medical records of patients undergoing bariatric surgery in a reference center of a teaching hospital in Porto Alegre over a 2-year period.Patients older than 18 years whose record contained all information relevant to the study were included.The data analyzed were body composition and PA through electrical bioimpedance and NAFLD through liver biopsy in the pre-and postoperative period.The level of significance adopted for the statistical analyses was 5%.RESULTS We evaluated 379 patients with preoperative data.Regarding PA,169 patients were analyzed,and 33 patients had liver biopsy pre-and postoperatively with NAFLD information.In total,79.4%were female,with a mean age of 39.1±10.6 years.The average body mass index(BMI)was 45.9±7.5 kg/m².The PA showed a mean of 5.8±0.62°in the preoperative period and a significant reduction in the postoperative period.A postoperative reduction in body composition data(skeletal muscle mass,fat percentage,fat mass,body cell mass,BMI and visceral fat area)was shown as well.Regarding liver disease,all patients presented a reduction in the degrees and stages of liver disease in the postoperative period,and some had no degree of liver disease at all.CONCLUSION PA decreased after bariatric surgery,with a direct correlation with weight loss and changes in body composition.The decrease in PA was not correlated with the improvement in NAFLD.