Epstein-Barr virus-associated post-transplant lymphoproliferative disorders in pediatric transplantation: A prospective multicenter study in the United States.

BACKGROUND: Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disorders (PTLD) is the most common malignancy in children after transplant; however, difficulties for early detection may worsen the prognosis. METHODS: The prospective, multicenter, study enrolled 944 children (≤21 years of age). Of these, 872 received liver, heart, kidney, intestinal, or multivisceral transplants in seven US centers between 2014 and 2019 (NCT02182986). In total, 34 pediatric EBV+ PTLD (3.9%) were identified by biopsy. Variables included sex, age, race, ethnicity, transplanted organ, EBV viral load, pre-transplant EBV serology, immunosuppression, response to chemotherapy and rituximab, and histopathological diagnosis. RESULTS: The uni-/multivariable competing risk analyses revealed the combination of EBV-seropositive donor and EBV-naïve recipient (D+R-) was a significant risk factor for PTLD development (sub-hazard ratio: 2.79 [1.34-5.78], p = .006) and EBV DNAemia (2.65 [1.72-4.09], p < .001). Patients with D+R- were significantly more associated with monomorphic/polymorphic PTLD than those with the other combinations (p = .02). Patients with monomorphic/polymorphic PTLD (n = 21) had significantly more EBV DNAemia than non-PTLD patients (p < .001) and an earlier clinical presentation of PTLD than patients with hyperplasias (p < .001), within 6-month post-transplant. Among non-liver transplant recipients, monomorphic/polymorphic PTLD were significantly more frequent than hyperplasias in patients ≥5 years of age at transplant (p = .01). CONCLUSIONS: D+R- is a risk factor for PTLD and EBV DNAemia and associated with the incidence of monomorphic/polymorphic PTLD. Intensive follow-up of EBV viral load within 6-month post-transplant, especially for patients with D+R- and/or non-liver transplant recipients ≥5 years of age at transplant, may help detect monomorphic/polymorphic PTLD early in pediatric transplant.

Intrahepatic Transcriptomics Differentiate Advanced Fibrosis and Clinical Outcomes in Adults With Fontan Circulation.

BACKGROUND: The molecular mechanisms underlying Fontan-associated liver disease (FALD) remain largely unknown. OBJECTIVES: This study aimed to assess intrahepatic transcriptomic differences among patients with FALD according to the degree of liver fibrosis and clinical outcomes. METHODS: This retrospective cohort study included adults with the Fontan circulation. Baseline clinical, laboratory, imaging, and hemodynamic data as well as a composite clinical outcome (CCO) were extracted from medical records. Patients were classified into early or advanced fibrosis. RNA was isolated from formalin-fixed paraffin-embedded liver biopsy samples; RNA libraries were constructed with the use of an rRNA depletion method and sequenced on an Illumina Novaseq 6000. Differential gene expression and gene ontology analyses were performed with the use of DESeq2 and Metascape. RESULTS: A total of 106 patients (48% male, median age 31 years [IQR: 11.3 years]) were included. Those with advanced fibrosis had higher B-type natriuretic peptide levels and Fontan, mean pulmonary artery, and capillary wedge pressures. The CCO was present in 23 patients (22%) and was not predicted by advanced liver fibrosis, right ventricular morphology, presence of aortopulmonary collaterals, or Fontan pressures on multivariable analysis. Samples with advanced fibrosis had 228 upregulated genes compared with early fibrosis. Samples with the CCO had 894 upregulated genes compared with those without the CCO. A total of 136 upregulated genes were identified in both comparisons and were enriched in cellular response to cytokine stimulus or oxidative stress, VEGFA-VEGFR2 signaling pathway, TGF-ß signaling pathway, and vasculature development. CONCLUSIONS: Patients with FALD and advanced fibrosis or the CCO exhibited upregulated genes related to inflammation, congestion, and angiogenesis.

Real-world experience of maralixibat in Alagille syndrome: Novel findings outside of clinical trials.

OBJECTIVE: Maralixibat, an ileal bile acid transporter inhibitor, is the first drug approved by the U.S. Food and Drug Administration for the treatment of cholestatic pruritus in patients aged ≥3 months with Alagille syndrome (ALGS). Approval was based on reductions in pruritus from the pivotal ICONIC trial, information from two additional trials (ITCH and IMAGO), and long-term extension studies. Although participants in these trials met strict inclusion and exclusion criteria, patients have received maralixibat under broader circumstances as part of an expanded access program or commercially. The expanded access and postapproval settings inform a real-world understanding of effectiveness and safety. The objective was to report on the use of maralixibat in the real-world setting in eight patients who otherwise would not have met entrance criteria for the clinical trials, providing unique insights into its effectiveness in the management of ALGS. METHODS: We reviewed records of patients with ALGS who received maralixibat but would have been excluded from trials due to surgical biliary diversion, reduction of antipruritic/cholestatic concomitant medications, administration of medication through a gastrostomy or nasogastric tube, or use in patients under consideration for transplantation. RESULTS: Maralixibat appeared to be effective with reductions in pruritus compared to baseline. Consistent with clinical trials, maralixibat was well tolerated without appreciable gastrointestinal complications. Liver enzyme elevations were observed but were interpreted as consistent with normal fluctuations observed in ALGS, with no increases in bilirubin. CONCLUSION: Maralixibat may be effective and well tolerated in patients with ALGS in broader clinical contexts than previously reported.

The Development of the International Intestinal Failure Registry and an Overview of its Results.

Pediatric intestinal failure (IF) is a rare disease that represents an evolving field in pediatric gastroenterology and surgery. With only a limited number of multicenter collaborations, much of the research in pediatric IF is often confined to single-center reports with small sample sizes. This has resulted in challenges in data interpretation and left many knowledge gaps unanswered. Over the past two decades, five large multicenter collaborations, primarily from North America and Europe, have published their findings. Apart from one ongoing European adult and pediatric registry, these relatively large-scale efforts have been concluded.In 2018, the International Intestinal Failure Registry (IIFR) was initiated by the International Intestinal Rehabilitation and Transplant Association to continue these efforts and answer some of the knowledge gaps in pediatric IF. The IIFR goals are to prospectively assess the natural history of children diagnosed with IF and creating a worldwide platform to facilitate benchmarking and evidence-based interventions in pediatric IF. A pilot phase involving 204 enrolled patients was initiated in 2018 to assess the feasibility of an international IF registry and refine the study protocol and data collection forms. Following the successful completion of this phase, the current phase of the IIFR was launched in 2021. As of May 2023, the registry includes 362 prospectively followed children from 26 centers worldwide. This review provides an overview of the development, structure, and challenges of the IIFR, as well as the main findings from both the pilot and current phase.

Endoscopic Surveillance of the Intestinal Allograft: Recommendations From the Intestinal Rehabilitation and Transplant Association Working Group.

Intestinal transplant (ITx) rejection lacks a reliable noninvasive biomarker and rejection surveillance relies on serial endoscopies and mucosal biopsies followed by histologic assessment. Endoscopic biopsies are also essential for identifying other ITx-related complications such as infectious, allergic, and inflammatory graft enteritis as well as post-transplant lymphoproliferative disease or graft versus host disease. In spite of its central role in ITx, published guidelines on endoscopy and biopsy are lacking and significant variability between centers in terms of timing and technical performance exists. Therefore, an international expert group convened and discussed several aspects related to the surveillance endoscopy after ITx with the aim to summarize and standardize its practice. This article summarizes these considerations on endoscopic ITx monitoring and highlights practices of surveillance and for-cause endoscopy, biopsy techniques, pathologic evaluation, potential risks and complications, outsourcing, and less-invasive monitoring techniques.

Outcome After Intestinal Transplantation From Living Versus Deceased Donors: A Propensity-matched Cohort Analysis of the International Intestinal Transplant Registry.

OBJECTIVE: To describe the worldwide experience with living donation (LD) in intestinal transplantation (ITx) and compare short-term and long-term outcomes to a propensity-matched cohort of deceased donors. BACKGROUND: ITx is a rare life-saving procedure for patients with complicated intestinal failure (IF). Living donation (LD)-ITx has been performed with success, but no direct comparison with deceased donation (DD) has been performed. The Intestinal Transplant Registry (ITR) was created in 1985 by the Intestinal Transplant Association to capture the worldwide activity and promote center's collaborations. METHODS: Based on the ITR, 4156 ITx were performed between January 1987 and April 2019, of which 76 (1.8%) were LD, including 5 combined liver-ITx, 7 ITx-colon, and 64 isolated ITx. They were matched with 186 DD-ITx for recipient age/sex, weight, region, IF-cause, retransplant, pretransplant status, ABO compatibility, immunosuppression, and transplant date. Primary endpoints were acute rejection and 1-/5-year patient/graft survival. RESULTS: Most LDs were performed in North America (61%), followed by Asia (29%). The mean recipient age was: 22 years; body mass index: 19kg/m²; and female/male ratio: 1/1.4. Volvulus (N=17) and ischemia (N=17) were the most frequent IF-causes. Fifty-two percent of patients were at home at the time of transplant. One-/5-year patient survival for LD and DD was 74.2/49.8% versus 80.3/48.1%, respectively ( P =0.826). One-/5-year graft survival was 60.3/40.6% versus 69.2/36.1%, respectively ( P =0.956). Acute rejection was diagnosed in 47% of LD versus 51% of DD ( P =0.723). CONCLUSION: Worldwide, LD-ITx has been rarely performed. This retrospective matched ITR analysis revealed no difference in rejection and in patient/graft survival between LD and DD-ITx.

Intrahepatic transcriptomics differentiate advanced fibrosis and clinical outcomes in adults with the Fontan circulation.

Background: The molecular mechanisms underlying Fontan associated liver disease (FALD) remain largely unknown. We aimed to assess intrahepatic transcriptomic differences among patients with FALD according to the degree of liver fibrosis and clinical outcomes. Methods: This retrospective cohort study included adults with the Fontan circulation at the Ahmanson/UCLA Adult Congenital Heart Disease Center. Clinical, laboratory, imaging and hemodynamic data prior to the liver biopsy were extracted from medical records. Patients were classified into early (F1-F2) or advanced fibrosis (F3-F4). RNA was isolated from formalin-fixed paraffin embedded liver biopsy samples; RNA libraries were constructed using rRNA depletion method and sequencing was performed on Illumina Novaseq 6000. Differential gene expression and gene ontology analyses were carried out using DESeq2 and Metascape. Medical records were comprehensively reviewed for a composite clinical outcome which included decompensated cirrhosis, hepatocellular carcinoma, liver transplantation, protein-losing enteropathy, chronic kidney disease stage 4 or higher, or death. Results: Patients with advanced fibrosis had higher serum BNP levels and Fontan, mean pulmonary artery and capillary wedge pressures. The composite clinical outcome was present in 23 patients (22%) and was predicted by age at Fontan, right ventricular morphology and presence of aortopulmonary collaterals on multivariable analysis. Samples with advanced fibrosis had 228 up-regulated genes compared to early fibrosis. Samples with the composite clinical outcome had 894 up-regulated genes compared to those without it. A total of 136 up-regulated genes were identified in both comparisons and these genes were enriched in cellular response to cytokine stimulus, response to oxidative stress, VEGFA-VEGFR2 signaling pathway, TGF-beta signaling pathway, and vasculature development. Conclusions: Patients with FALD and advanced liver fibrosis or the composite clinical outcome exhibit up-regulated genes including pathways related to inflammation, congestion, and angiogenesis. This adds further insight into FALD pathophysiology.

Childhood Cholestatic Liver Diseases that Persist Into Adulthood: Lessons for the Adult Gastroenterologist.

Children with cholestatic liver diseases are increasingly living into adulthood, thanks to innovations in medical and surgical therapies. The excellent outcomes observed in pediatric liver transplantation for diseases, such as biliary atresia, have transformed the life trajectory of children born with once-fatal liver diseases. The evolution of molecular genetic testing, has helped expedite the diagnosis of other cholestatic disorders, improving the clinical management, disease prognosis, and family planning for inherited disorders, such as progressive familial intrahepatic cholestasis and bile acid synthesis disorders. The expanding list of therapeutics, including bile acids and the newer ileal bile acid transport inhibitors, has also helped slow the progression of disease and improve the quality of life for certain diseases, like Alagille syndrome. More and more children with cholestatic disorders are expected to require care from adult providers familiar with the natural history and potential complications of these childhood diseases. The aim of this review is to bridge the gap between pediatric and adult care in children with cholestatic disorders. The present review addresses the epidemiology, clinical features, diagnostic testing, treatment, prognosis, and transplant outcomes of 4 hallmark childhood cholestatic liver diseases: biliary atresia, Alagille syndrome, progressive familial intrahepatic cholestasis, and bile acid synthesis disorders.

Mutations in latent membrane protein 1 of Epstein-Barr virus are associated with increased risk of posttransplant lymphoproliferative disorder in children.

Epstein-Barr virus (EBV)-positive posttransplant lymphoproliferative disorder (PTLD) results in significant morbidity and mortality in pediatric transplant recipients. Identifying individuals at an increased risk of EBV-positive PTLD could influence clinical management of immunosuppression and other therapies, improving posttransplant outcomes. A 7-center prospective, observational clinical trial of 872 pediatric transplant recipients evaluated the presence of mutations at positions 212 and 366 of EBV latent membrane protein 1 (LMP1) as an indicator of risk of EBV-positive PTLD (clinical trials: NCT02182986). DNA was isolated from peripheral blood of EBV-positive PTLD case patients and matched controls (1:2 nested case:control), and the cytoplasmic tail of LMP1 was sequenced. Thirty-four participants reached the primary endpoint of biopsy-proven EBV-positive PTLD. DNA was sequenced from 32 PTLD case patients and 62 matched controls. Both LMP1 mutations were present in 31 of 32 PTLD cases (96.9%) and in 45 of 62 matched controls (72.6%) (P = .005; OR = 11.7; 95% confidence interval, 1.5, 92.6). The presence of both G212S and S366T carries a nearly 12-fold increased risk of development of EBV-positive PTLD. Conversely, transplant recipients without both LMP1 mutations carry a very low risk of PTLD. Analysis of mutations at positions 212 and 366 of LMP1 can be informative in stratifying patients for risk of EBV-positive PTLD.

Deceased donor organ allocation in pediatric transplantation: A historical narrative.

BACKGROUND: Since the earliest clinical successes in solid organ transplantation, the proper method of organ allocation for children has been a contentious subject. Over the past 30-35 years, the medical and social establishments of various countries have favored some degree of preference for children on the respective waiting lists. However, the specific policies to accomplish this have varied widely and changed frequently between organ type and country. METHODS: Organ allocation policies over time were examined. This review traces the reasons behind and the measures/principles put in place to promote early deceased donor transplantation in children. RESULTS: Preferred allocation in children has been approached in a variety of ways and with varying degrees of commitment in different solid organ transplant disciplines and national medical systems. CONCLUSION: The success of policies to advantage children has varied significantly by both organ and medical system. Further work is needed to optimize allocation strategies for pediatric candidates.

Host microRNAs are decreased in pediatric solid-organ transplant recipients during EBV+ Post-transplant Lymphoproliferative Disorder.

Post-transplant lymphoproliferative disorder (PTLD) is a serious complication of solid organ transplantation. Predisposing factors include primary Epstein-Barr virus (EBV) infection, reactivation of EBV in recipient B cells, and decreased T cell immunity due to immunosuppression. In our previous studies EBV infection was demonstrated to markedly alter the expression of host B cell microRNA (miR). Specifically, miR-194 expression was uniquely suppressed in EBV+ B cell lines from PTLD patients and the 3'untranslated region of IL-10 was determined to be targeted by miR-194. Although EBV has been shown to regulate host miR expression in B cell lymphoma cell lines, the expression of miRs in the circulation of patients with EBV-associated PTLD has not been studied. The objective of this study was to determine if changes in miR expression are associated with EBV+ PTLD. In this study, we have shown that miR-194 is significantly decreased in EBV+PTLD tumors and that additional miRs, including miRs-17, 19 and 106a are also reduced in EBV+PTLD as compared to EBV-PTLD. We quantitated the levels of miRs-17, 19, 106a, 155, and 194 in the plasma and extracellular vesicles (EV; 50-70 nm as determined by nanoparticle tracking analysis) from pediatric recipients of solid organ transplants with EBV+ PTLD+ that were matched 1:2 with EBV+ PTLD- pediatric transplant recipients as part of the NIH-sponsored Clinical Trials in Organ Transplantation in Children, (CTOTC-06) study. Levels of miRs-17, 19, 106a, and 194 were reduced in the plasma and extracellular vesicles (EV) of EBV+ PTLD+ group compared to matched controls, with miRs-17 (p = 0.034; plasma), miRs-19 (p = 0.029; EV) and miR-106a (p = 0.007; plasma and EV) being significantly reduced. Similar levels of miR-155 were detected in the plasma and EV of all pediatric SOT recipients. Importantly, ~90% of the cell-free miR were contained within the EV supporting that EBV+ PTLD tumor miR are detected in the circulation and suggesting that EVs, containing miRs, may have the potential to target and regulate cells of the immune system. Further development of diagnostic, mechanistic and potential therapeutic uses of the miRs in PTLD is warranted.

Low post-transplant measles and varicella titers among pediatric liver transplant recipients: A 10-year single-center study.

BACKGROUND: Vaccine preventable illnesses are important sources of morbidity, mortality, and increased healthcare costs in pediatric LT recipients. Our aim was to measure the seroprevalence of antibodies to measles and VZV in this population. METHODS: We conducted a retrospective chart review of 44 patients who received LT before age 18 at UCLA Mattel Children's Hospital from January 2008 to December 2017. RESULTS: Median age at transplantation was 2.5 years (IQR 1.2-7.7). Post-transplant measles antibodies were present in 17 of 37 patients (46%); risk factors for seronegativity included younger age at transplant (p = .02) and greater time from transplant to testing (p = .04). Post-transplant VZV antibodies were present in 17 of 39 patients (44%); risk factors for seronegativity included greater time from transplant to testing (p = .04). 6 of 16 patients (38%) who tested positive for pre-transplant VZV antibodies tested negative after transplantation. Fourteen of 20 patients (70%) with at least 1 documented dose of the MMR vaccine tested positive for post-transplant measles antibodies. Ten of 20 of patients (50%) with at least 1 documented dose of the VZV vaccine tested positive for post-transplant VZV antibodies. We also describe 10 patients who received post-transplant measles and VZV vaccines without documented complications. CONCLUSIONS: Our study suggests that pediatric LT patients are at greater risk of contracting measles and VZV despite vaccination status, and that prevalence of measles and VZV antibodies decreases as time from transplantation increases. This should weigh into the institutional risk-benefit assessment when deciding whether or not to administer LAVs to these patients.

Free-breathing radial magnetic resonance elastography of the liver in children at 3 T: a pilot study.

BACKGROUND: Magnetic resonance (MR) elastography of the liver measures hepatic stiffness, which correlates with the histopathological staging of liver fibrosis. Conventional Cartesian gradient-echo (GRE) MR elastography requires breath-holding, which is challenging for children. Non-Cartesian radial free-breathing MR elastography is a potential solution to this problem. OBJECTIVE: To investigate radial free-breathing MR elastography for measuring hepatic stiffness in children. MATERIALS AND METHODS: In this prospective pilot study, 14 healthy children and 9 children with liver disease were scanned at 3 T using 2-D Cartesian GRE breath-hold MR elastography (22 s/slice) and 2-D radial GRE free-breathing MR elastography (163 s/slice). Each sequence was acquired twice. Agreement in the stiffness measurements was evaluated using Lin's concordance correlation coefficient (CCC) and within-subject mean difference. The repeatability was assessed using the within-subject coefficient of variation and intraclass correlation coefficient (ICC). RESULTS: Fourteen healthy children and seven children with liver disease completed the study. Median (±interquartile range) normalized measurable liver areas were 62.6% (±26.4%) and 44.1% (±39.6%) for scan 1, and 60.3% (±21.8%) and 43.9% (±44.2%) for scan 2, for Cartesian and radial techniques, respectively. Hepatic stiffness from the Cartesian and radial techniques had close agreement with CCC of 0.89 and 0.94, and mean difference of 0.03 kPa and -0.01 kPa, for scans 1 and 2. Cartesian and radial techniques achieved similar repeatability with within-subject coefficient of variation=1.9% and 3.4%, and ICC=0.93 and 0.92, respectively. CONCLUSION: In this pilot study, radial free-breathing MR elastography was repeatable and in agreement with Cartesian breath-hold MR elastography in children.

Operational tolerance is not always permanent: A 10-year prospective study in pediatric liver transplantation recipients.

Immunosuppression withdrawal can be safely performed in select liver transplantation recipients, but the long-term outcomes and sustainability of tolerance have not been well studied. We completed a 10-year prospective, observational study of 18 pediatric liver transplantation recipients with operational tolerance to (1) assess the sustainability of tolerance over time, (2) compare the clinical characteristics of patients who maintained versus lost tolerance, (3) characterize liver histopathology findings in surveillance liver biopsies; and (4) describe immunologic markers in patients with tolerance. Comparator patients from two clinical phenotype groups termed "stable" and "nontolerant" patients were used as controls. Of the 18 patients with operational tolerance, the majority of patients were males (n = 14, 78%) who were transplanted for cholestatic liver disease (n = 12, 67%). Median age at transplantation was 1.9 (range, 0.6-8) years. Median time after transplantation that immunosuppression had been discontinued was 13.1 (range, 2.9-22.1) years. As many as 11 (61%) maintained tolerance for a median of 10.4 (range, 1.9-22.1) years, whereas 7 (39%) lost tolerance after a median of 3.2 (range, 1.5-18.6) years. Populations of T regulatory cells (%CD4+ CD25hi CD127lo ) were significantly higher in patients with tolerance (p = 0.02). Our results emphasize that spontaneous operational tolerance is a dynamic and nonpermanent state. It is therefore essential for patients who are clinically stable off immunosuppression to undergo regular follow-up and laboratory monitoring, as well as surveillance biopsies to rule out subclinical rejection.

Current review on the role of ileostomy following intestinal transplantation.

PURPOSE OF REVIEW: This review describes the historical rationale for ostomy creation at the time of intestinal transplantation (ITx), examines the utility of endoscopy in graft monitoring, details the limitations and potential complications of endoscopy in this patient population, highlights preliminary reports of ITx without surveillance biopsy or stoma formation, and emphasizes the importance of novel biomarkers for graft monitoring. Data will be discussed from contemporary publications in the field, as well as the Intestinal Transplant Registry. RECENT FINDINGS: Significant improvements have been made in early outcomes following ITx, yet long-term survival remains challenged by rejection. Although endoscopy and biopsy are the gold-standard for graft monitoring, some centers have performed ITx recently without surveillance endoscopy or stoma formation with similar success. Others have touted the need for less-invasive, timely and accurate biomarkers as essential to help improve results. SUMMARY: The review provides a thorough overview of the emerging debate in the field of ITx regarding the importance of surveillance endoscopy and stoma formation in ITx recipients.

De novo lupus-like glomerulonephritis after pediatric non-kidney organ transplantation.

BACKGROUND: We propose a novel clinically significant finding, de novo lupus-like glomerulonephritis (DNLLGN), in patients with autoantibodies and kidney abnormalities in pediatric liver transplant (LT) and intestinal inclusive transplants (ITx). METHODS: We describe the clinical, serologic, and histopathologic presentation and kidney outcomes in eight patients from our center found to have DNLLGN on kidney biopsy. RESULTS: Pediatric recipients of non-kidney solid organ transplants developed an unusual de novo immune complex glomerulonephritis with morphologic similarity to lupus nephritis. Six had isolated LT (0.9% of all pediatric LT at our center) and two had ITx (2.1% of all ITx). Five (63%) presented with nephrotic syndrome. Five patients had autoantibodies. Patients underwent kidney biopsy at a mean of 11.5 years in LT and 2.8 years in ITx after the index transplant. Biopsies demonstrated changes similar to focal or diffuse active lupus. Follow-up eGFR at a mean of 6 years after biopsy showed a mean decrease of 30 ml/min/1.73 m2 in all patients (p = 0.11). CONCLUSIONS: DNLLGN has not been previously recognized in this clinical setting, yet 8 kidney biopsies from pediatric recipients of LT and ITx at our center in 25 years demonstrated this finding. DNLLGN appears to be an under-reported phenomenon of clinical significance. A higher resolution version of the Graphical abstract is available as Supplementary information.

Intestinal mucormycosis initially identified by next-generation sequencing of cell-free DNA.

Mucormycosis is a rare fungal infection that typically affects severely immunocompromised individuals, often resulting in significant morbidity and mortality. Although early and aggressive intervention is necessary to prevent poor outcomes, diagnosis of this infection remains difficult. We report the first case, to our knowledge, of invasive gastrointestinal mucormycosis initially identified by next-generation sequencing of cfDNA from the blood, and discuss the various benefits and challenges which come with new molecular diagnostic techniques.

REG3α is a novel biomarker that potentially correlates with acute allograft rejection after intestinal transplantation.

Monitoring of intestinal allograft function remains a challenge. While frequent endoscopies and biopsies are the gold standard, no single biomarker exists to screen for intestinal transplant rejection. The novel REG3α, an antimicrobial peptide secreted by intestinal enterocytes and Paneth cells, has been associated with inflammatory bowel disease as well as intestinal graft versus host disease. Our aim was to identify and describe a role of REG3α in monitoring or predicting acute allograft rejection after intestinal transplantation (ITx). Since 2019, we have incorporated REG3α into the standard monitoring of patients after ITx. We conducted a retrospective analysis of a prospectively maintained IRB-approved database and present, herein, the results of 2 adults with irreversible intestinal failure who underwent isolated ITx under this monitoring protocol. Increases in REG3α corresponded with acute allograft rejection in both cases and preceded acute allograft rejection by 1 week in one of the cases. We describe REG3α as a non-invasive marker of acute allograft rejection after adult isolated ITx which not only corresponded with acute allograft rejection but also preceded histopathological changes by 1 week.

Management of Biliary Stricture in Pediatric Liver Transplantation Patients: Long-Term Outcomes.

Postoperative biliary complications have been reported to occur in 10% to 33% of pediatric liver transplantation (LT) recipients. Percutaneous intervention has become the primary treatment method for these complications; however, the efficacy and outcomes of these patients have not been well studied. Institutional pediatric LT from 1998 to 2019 were retrospectively reviewed to determine the patients referred for percutaneous treatment of post-LT biliary strictures. Clinical parameters, percutaneous transhepatic cholangiograms (PTCs), biliary catheter placement, cholangioplasty, and long-term outcomes were analyzed. Of the 396 consecutive pediatric LT recipients during our study period, 50 (12.6%) were diagnosed with biliary strictures on PTC. LT biliary reconstructions were Roux-en-Y hepaticojejunostomy in 28 patients (56%), choledochojejunostomy in 11 patients (22%), and choledochocholedochostomy in 11 patients (22%). Median age at LT was 23.2 months (interquartile range [IQR], 10.9-90.6), and 14 patients (28%) developed hepatic artery thrombosis. A total of 44 patients (88%) were treated with internal/external biliary catheters, of whom 38 (76%) underwent balloon cholangioplasty. By 12 months, 84% of patients had complete stricture resolution and catheter removal. Median total duration of catheter drainage was 152 days (IQR, 76-308). A total of 8 patients required additional surgery (biliary reconstruction or repeat LT [re-LT]) or died with a drainage catheter in place from complications unrelated to PTC intervention. Among the 6 patients (12%) treated with unilateral external biliary drainage catheters, 2 had catheters removed for inadequate drainage but then had spontaneous biliary obstruction resolution, 1 underwent duct reconstruction, and 3 required long-term catheterization. Biliary strictures following pediatric LT can be successfully treated with internal/external biliary drainage catheters and cholangioplasty if the stricture can be crossed. However, patients with isolated strictured ducts may require long-term external catheter drainage until re-LT or percutaneous obliteration of isolated ducts.

Orthotopic Heart and Combined Heart Liver Transplantation: the Ultimate Treatment Option for Failing Fontan Physiology.

Purpose of the Review: This is a comprehensive update on failing Fontan physiology and the role of heart and combined heart and liver transplantation in the current era. Recent Findings: Single ventricle physiology encompasses a series of rare congenital cardiac abnormalities that are characterized by absence of or hypoplasia of one ventricle. This effectively results in a single ventricular pumping chamber. These abnormalities are rarely compatible with long-term survival if left without surgical palliation in the first few years of life. Surgical treatment of single ventricle physiology has evolved over the past 60 years and is characterized by numerous creative innovations. These include the development of arteriopulmonary shunts, the evolution of partial cavopulmonary connections, and the eventual development of the "Fontan" operation. Regardless of the type of Fontan modification, the long-term consequences of the Fontan operation are predominantly related to chronic central venous hypertension and the multi-organ consequences thereof. Atrial arrhythmias can further compromise this circulation.Patients with single ventricle physiology represent a special sub-segment of congenital cardiac transplants and are arguably the most challenging patients considered for transplantation. Summary: This review describes in detail the challenges and opportunities of heart and liver transplantation in Fontan patients, as viewed and managed by the experienced team at the Ahmanson/UCLA Adult Congenital Heart Center.