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Regulatory T cells (Tregs) are not terminally differentiated but can acquire effector properties. Here we report an increased expression of human endogenous retrovirus 1 (HERV1-env) proteins in Tregs of patients with de novo autoimmune hepatitis and autoimmune hepatitis, which induces endoplasmic reticulum (ER) stress. HERV1-env-triggered ER stress activates all three branches (IRE1, ATF6, and PERK) of the unfolded protein response (UPR). Our coimmunoprecipitation studies show an interaction between HERV1-env proteins and the ATF6 branch of the UPR. The activated form of ATF6α activates the expression of RORC and STAT3 by binding to promoter sequences and induces IL-17A production. Silencing of HERV1-env results in recovery of Treg suppressive function. These findings identify ER stress and UPR activation as key factors driving Treg plasticity (species: human).

This is a descriptive study to characterize rates of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in pediatric solid organ transplant (SOT) recipients during the early days of the pandemic. We hypothesized that asymptomatic infection may represent a large proportion of SARS-CoV-2 infection in pediatric SOT recipients.We queried Organ Transplant Tracking Record (OTTR) for all pediatric SOT recipients followed at our center and reviewed medical records to identify patients tested for SARS-CoV-2 between March 15, 2020 and June 30, 2021. Patients were tested by polymerase chain reaction (PCR): prior to planned procedures or because of symptoms; OR: tested by measurement of IgG to spike protein with their routine labs q 2-monthly. A positive PCR was called acute infection. A positive IgG with negative PCR was called convalescence. For immunologic studies, blood was obtained when the PCR or IgG was positive. Statistical comparisons were made between (1) acute infection versus convalescence; (2) acute infection versus SOT recipients without infection (called healthy controls); (3) liver transplant (LT) versus small bowel (SB)/multivisceral transplant (MVT); (4) positive versus negative test result.Of 257 LT recipients, 99 were tested: 6 were PCR positive, 13 were antibody positive. Of 150 SB/MVT recipients, 55 were tested: 4 were PCR positive, 6 were antibody positive. Of 8 simultaneous liver, kidney transplant recipients, 3 were tested: 1 was PCR positive. Symptoms when present were mostly mild. Patients with a positive test result were younger (6.3 vs 10.0 years; P = 0.017). We observed a rapid decline in viral load within 96 hours without a change in immunosuppression. Antibody lasted8 months beyond the time it was monitored. Acute infection was associated with increased CD4 and CD8 T EM cell frequency ( P = 0.04, P = 0.03, respectively), decreased interferon (IFN)-γ production from T-cells (2.8% vs 11.3%; P = 0.006), and decreased CD8 TEMRA frequency (4.56% vs 11.70%; P = 0.006).Early in the pandemic, COVID-19 disease was mostly mild in pediatric SOT recipients with no rejection, patient death, or graft loss observed.

Surgical site infections (SSI) are a significant cause of morbidity in liver transplant recipients, and the current data in the pediatric population are limited. The goal of this study was to identify the incidence, classification, risk factors, and outcomes of SSIs among children undergoing liver transplantation (LT).A single-center, retrospective descriptive analysis was performed of patients age ≤18 years undergoing LT between September 2007 and April 2017. SSI identified within the first 30 days were analyzed. Primary endpoints included incidence, classification, risk factors, and outcomes associated with SSIs.We included 86 patients, eight patients (9.3%) developed SSIs. Among segmental grafts (SG) recipients, 7/61 (11.4%) developed SSI. Among whole grafts recipients, 1/25 (4%) developed SSI. SSIs were associated with the presence of biliary complications (35% vs. 3%, p.01; odds ratios 24, 95% CI: 3.41-487.37, p.01). There were no differences in long term graft or patient survival associated with SSI. Patients who developed SSI were more likely to undergo reoperation (50% vs. 16.7%, p = .045) and had an increased total number of hospital days in the first 60 days post-transplant (30.5 vs. 12.5 days, p = .001).SSIs after pediatric LT was less frequent than what has been previously reported in literature. SSIs were associated with the presence of biliary complications without an increase in mortality. SG had an increased rate of biliary complications without an association to SSIs but, considering its positive impact on organ shortage barriers, should not be a deterrent to the utilization of SGs.

Our knowledge of de novo anti-HLA donor-specific antibodies (dnDSA) in liver transplantation continues to be defined. We hypothesized that differences of HLA-DR/DQ mismatches can improve precision in alloimmune risk categorization and be applied to tailor immunosuppression.A retrospective chart review of 244 pediatric patients consecutively transplanted at our center between 2003 and 2019 was performed to identify patients tested for dnDSA. Records were queried for: demographics, pre-transplant diagnosis, biopsy-proven T-cell-mediated rejection (TCMR), radiology proven biliary complications, tacrolimus trough levels, dnDSA characteristics, and HLA typing. The eplet mismatch analyses were performed using HLAMatchmakerThere were 99 dnDSA-negative patients and 73 dnDSA-positive patients (n = 70 against class II and n = 3 against class I and II). ROC analysis identified optimal cutoff of eplet mismatch load for dnDSA and defined risk groups for an alloimmune outcome. Kaplan-Meier curves and log-rank tests showed high eplet mismatch load was associated with shorter dnDSA-free survival (log-rank p = .001). Multivariable Cox regression models showed that tacrolimus coefficient of variation and tacrolimus mean levels were significantly associated with dnDSA-free survival (p .001 and p = .036). Fisher's exact test showed that dnDSA was associated with an increased likelihood of TCMR (OR 14.94; 95% CI 3.65 - 61.19; p .001). Patients without TCMR were more likely to have dnDSA to HLA-DQ7 and less likely to have dnDSA to HLA-DQ2 (p = .03, p = .080).Mismatched epitope load predicts dnDSA-free survival in pediatric liver transplant, while dnDSA specificity may determine alloimmune outcome.

"Biliary atresia (BA) is a common cause of jaundice in infancy. There is increasing evidence that newborn screening with direct or conjugated bilirubin leads to earlier diagnosis. Although the Kasai portoenterostomy is the primary treatment, there are scientific advances in adjuvant therapies. As pediatric patients transition to adult care, multidisciplinary care is essential, given the complexity of this patient population."

Background Warm-antibody AIHA is known to complicate solid organ (SOT) and HSCT, the disease maybe refractory to standard therapy. Immunosuppressive therapies as well as IVIG, and rituximab have been the main stay of treatment. Over the past decade, B-lymphocyte targeted, anti-CD-20 antibody has been recognized in the treatment of autoimmune diseases and utilized in AIHA. Bortezomib, a proteasome inhibitor that causes apoptosis of plasma cells, is an appealing targeted therapy in secondary AIHA and has demonstrated efficacy in HSCT patients. From our experience, we advocate for early targeted therapy that combines B cell with plasma cell depletion. Case report We describe a 4-year-old-girl with stage III neuroblastoma, complicated with intestinal necrosis needing multivisceral transplant developed warm AIHA 1-year after transplantation, and following an adenovirus infection. She received immunoglobulin therapy, rituximab, sirolimus, plasmapheresis, and long-term prednisolone with no sustained benefit while developing spinal fractures related to the latter therapy. She received bortezomib for intractable AIHA in combination with rituximab with no appreciable adverse effects. Three years later the child remains in remission with normal reticulocyte and recovered B cells. In the interim, she required chelation therapy for iron overload related to blood transfusion requirement during the treatment of AIHA. Conclusion We propose early targeted anti-plasma cell therapy with steroid burst, IVIG, rituximab, and possible plasmapheresis may reduce morbidity in secondary refractory w-AIHA.

Objectives To identify the risk of developing acute rejection, allograft fibrosis, and antibody-mediated rejection, a retrospective review of pediatric patients who underwent liver transplant between July 31, 1998 and February 29, 2016 and had donor-specific antibodies measured at time of liver biopsy was undertaken. Materials and methods HLAMatchmaker Software (http://www.hlamatchmaker.net) was used to define epitope mismatches between donors and recipients and to predict de novo donor-specific antibody risk. Epitope mismatches were evaluated for their immunogenicity. Results In our group of 42 recipients, 20 (48%) had donor-specific antibodies. Having an antibody against HLA-DQB1*02 was associated with acute rejection (66.6% vs 36%; P = .024). We found that DQ epitope mismatch load was greater in recipients with class II donor-specific antibodies (9.7 vs 3.6; P = .001). HLA-DQ (7.4 vs 3.6; P = .04) and HLA-DR (8.8 vs 3.8; P = .04) epitope mismatch loads were higher in recipients with DQ + DR donor-specific antibodies. A high portal fibrosis score was associated with higher mismatch load at the DQ locus (P = .005) and DQ + DR loci (P = .03). Having > 5 or > 6 epitope mismatch loads at the DQ locus identified a threshold above which development of DQ donor-specific antibodies would occur (area under the curve = 0.878). Mismatches for eplet 4Q, 45GE, 52PQ, and 52PL, thought to be immunodominant epitopes, were observed for several recipients. Conclusions Knowledge of epitope mismatches between recipients and donors may aid transplant physicians in devising immunosuppression strategies.

Hepatobiliary disorders are common in patients with inflammatory bowel disease (IBD), and persistent abnormal liver function tests are found in approximately 20% to 30% of individuals with IBD. In most cases, the cause of these elevations will fall into 1 of 3 main categories. They can be as a result of extraintestinal manifestations of the disease process, related to medication toxicity, or the result of an underlying primary hepatic disorder unrelated to IBD. This latter possibility is beyond the scope of this review article, but does need to be considered in anyone with elevated liver function tests. This review is provided as a clinical summary of some of the major hepatic issues that may occur in patients with IBD.

Background Recent literature suggests that the Western diet's imbalance between high ω-6 (n–6) and low ω-3 (n–3) PUFA intake contributes to fatty liver disease in obese youth. Objectives We tested whether 12 wk of a low n–6:n–3 PUFA ratio (4:1) normocaloric diet mitigates fatty liver and whether the patatin-like containing domain phospholipase 3 (PNPLA3) rs738409 variant affects the response. Methods In a single-arm unblinded study, obese youth 9–19 y of age with nonalcoholic fatty liver disease were treated with a normocaloric low n–6:n–3 PUFA ratio diet for 12 wk. The primary outcome was change in hepatic fat fraction (HFF%), measured by abdominal MRI. Metabolic parameters included alanine aminotransferase (ALT), lipids, measures of insulin sensitivity, and plasma oxidized linoleic acid metabolites (OXLAMs). Outcomes were also analyzed by PNPLA3 rs738409 genotype. Wilcoxon's signed rank test, the Mann–Whitney U test, and covariance pattern modeling were used. Results Twenty obese adolescents (median age: 13.3 y; IQR: 10.5–16.4 y) were enrolled and 17 completed the study. After 12 wk of dietary intervention, HFF% decreased by 25.8% (P = 0.009) despite stable weight. We observed a 34.4% reduction in ALT (P = 0.001), 21.9% reduction in triglycerides (P = 0.046), 3.28% reduction in LDL cholesterol (P = 0.071), and a 26.3% improvement in whole body insulin sensitivity (P = 0.032). The OXLAMs 9-hydroxy-octadecandienoic acid (9-HODE) (P = 0.011), 13-HODE (P = 0.007), and 9-oxo-octadecadienoic acid (9-oxoODE) (P = 0.024) decreased after 12 wk. HFF% declined in both the not-at-risk (CC/CG) and at-risk (GG) PNPLA3 rs738409 genotype groups, with significant (P = 0.016) HFF% reduction in the GG group. Changes in 9-HODE (P = 0.023), 9-oxoODE (P = 0.009), and 13-oxoODE (P = 0.003) differed between the 2 genotype groups over time. Conclusions These data suggest that, independently of weight loss, a low n–6:n–3 PUFA diet ameliorates the metabolic phenotype of adolescents with fatty liver disease and that response to this diet is modulated by the PNPLA3 rs738409 genotype. This trial was registered at clinicaltrials.gov as NCT01556113.

Mother-to-infant transmission (MIT) is the leading cause of hepatitis B virus (HBV) infections globally. The aim of this international study was to assess the impediments to prevention of (MIT) of HBV.A cross-sectional survey was developed by the Federation of the International Societies for Pediatric Gastroenterology, Hepatology and Nutrition. (FISPGHAN) The survey was sent to HBV experts of the 5-member societies of FISPGHAN, and 63 of 91 countries/regions responded. Main outcome measures include percentage of countries having vaccine programs, timing of the first dose of HBV vaccine, availability of HBV vaccine for outborn neonates, payment of HBV vaccine and hepatitis B immune globulin, screening HBV markers during pregnancy, and antivirals to highly infectious pregnant mothers.Among the participating countries/regions, 11% did not implement infant HBV immunization programs. The first dose of vaccine was given24 hours in 36% of the total countries and 100% of African countries. The recommended birth dose was unavailable for outborn neonates in 45% of the total countries, including 92% of African and 50% of Latin American countries/regions. During pregnancy, 44% countries do not screen maternal viral markers, and 46% do not provide third trimester antiviral therapy for highly viremic pregnant mothers.Our study demonstrated multiple obstacles to achieving the goal of preventing MIT of HBV. Comprehensive public health programs to enhance vaccine coverage rate, supply HBV vaccine for out-born neonates, screening maternal HBV markers, treating highly viremic pregnant mothers are proposed to overcome these obstacles and achieve the goal of preventing MIT of HBV.

To understand factors contributing to liver graft loss and patient death, we queried a national database designed to follow pediatric patients transplanted between 1987 and 1995 till adulthood. A comparison was made to a cohort transplanted between 2000 and 2014. The 5-, 10-, 15-, 20-, and 25-year patient survival and graft survival were 95.5%, 93.7%, 89.1%, 80.8%, and 73.1%, and 92.5%, 86.7%, 77.6%, 68.7%, and 62.2%, respectively. The twenty-year patient/graft survival was significantly worse in those transplanted between 5 and 17 years of age compared to those transplanted at5 years of age (P 0.001). For the modern era cohort, the 3-year patient survival was significantly lower in children transplanted at 16-17 years of age compared to those transplanted at5 and 11-15 years of age (P ≤ 0.02). The 3-year graft survival was similarly lower in children transplanted at 16-17 years of age compared to those transplanted at5, 5-10, and 11-15 years of age (P ≤ 0.001). Infection as a cause of death occurred either early or15 years post-transplant. Chronic rejection remained the leading cause of graft loss in both cohorts and the commonest indication for retransplantation 20-25 years following primary transplant. Further research is required to identify modifiable factors contributing to development of chronic rejection.

Background: We describe the clinical presentation & immune response to COVID-19 infection in pediatric SOT. Method: Medical records of COVID-19 PCR+ & seropositive patients (SP) were reviewed for details of their disease course. Blood was obtained during PCR or seropositivity for immunophenotyping. Controls were pediatric solid organ transplant (SOT) patients with negative COVID-19 (NCs) status. As induction of immunological memory is central to anti-pathogen adaptive immunity induced by infection, immunohistochemistry of liver tissue for tissue resident memory cells (TRM) was performed. Results: 15 patients had COVID positive status (7 PCR+ & 8 SP) between March 2020 & January 2021. 4 symptomatic PCR+ patients were hospitalized for 24–72-hours & 1 symptomatic SP patient had a prolonged PICU stay. Infrequent TRM were seen in liver biopsies of PCR+ & SP patients vs. biopsies from same patients that pre-date a COVID-19+ status. Patients with COVID + status appeared to segregate into 2 groups: 1 group with activated CD4+ response, & the 2nd group lacking obvious activated CD4+ response, similar to NC patients (n=16). The PCR+ patients expressed significantly less CD4+ & CD8+ IFN-γ compared to the SP patients (p=0.009; p=0.01 respectively). Similarly, activated CD8 “EMRAs” was significantly lower in PCR+ patients compared to SP patients (p=0.01). Conclusion: COVID-19 infection in pediatric SOT patients is generally mild with notable increased frequency of CD8+ “EMRAs” & IFN-γ in SP patients, presumably a result of antigen-experienced cells.

A subset of human regulatory T cells (Tregs) can secrete IFN-γ or IL-17 and thus share features of TH1 or TH17 effector cells, and lose suppressive function. The main factors driving this differentiation of Tregs towards a pro-inflammatory phenotype include IL-12 for TH1-like and IL-6 for TH17-type Tregs. In this study we show that Tregs of patients with de novo autoimmune hepatitis (dAIH) display increased frequencies of pro-inflammatory IFN-γ and IL-17 cytokines. Irrespective of a fully demethylated FOXP3 locus, Tregs of subjects with de novo autoimmune hepatitis are functionally impaired. In line with the observed Treg phenotype, we detected the presence of two dominant cytokines (IL-12 and IL-6) clustering with CD68+ monocyte/macrophage cells in livers of subjects with de novo autoimmune hepatitis and isolated monocytes of subjects with de novo autoimmune hepatitis secrete high levels of pro-inflammatory IL-12 and IL-6 suggesting that this inflammatory milieu is key for functional impairment of Tregs. Importantly, the blockade of IFN-γ partially restores suppressive function of Tregs of subjects with de novo autoimmune hepatitis indicating that monocyte/macrophage derived triggers might play a central role in Treg dysfunction and pathogenesis of de novo autoimmune hepatitis.

Regulatory T cells are not terminally differentiated but can acquire effector properties. Here we report Human Endogenous Retrovirus 1 (HERV1-env) induction of endoplasmic reticulum (ER) stress with Unfolded Protein Response (UPR) activation, through its interaction with ATF6. UPR activation cleaves ATF6 to its α and β isoforms. ATF6α up-regulates RORC, STAT3 and TBX21 and induces IL-17A and INF-γ production in regulatory T cells by binding to promoter sequences. Silencing of HERV1-env results in partial recovery of regulatory T cell suppressive function and abrogation of apoptosis. These findings identify ER stress and UPR activation as key factors driving regulatory T cell plasticity.

The approach to elevated liver transaminases presented here includes an understanding of the biochemical testing, as well as a sequential pathway of investigations. In the pediatric patient who is not in acute liver failure, we discuss the differential diagnoses that should be considered, categorized in a systems-based approach. Infectious, autoimmune, genetic/metabolic, and cholestatic disease; drug-induced liver injury; and nonalcoholic fatty liver disease are among the categories that should be considered. Following a thorough history and physical examination, the patient should be referred to a pediatric specialist with expertise in the diagnosis and treatment of liver disease. Appropriate investigations by a pediatric gastroenterologist/hepatologist initially include blood tests and abdominal Doppler ultrasonography. This review contains 4 figures, 3 tables and 42 references Key words: acute liver failure, alanine aminotransferase, aspartate aminotransferase, cholestasis, chronic hepatitis, cirrhosis, elevated liver enzymes, end-stage liver disease, γ-glutamyl transaminase, portal hypertension

De novo autoimmune hepatitis (DAIH) is an important cause of late allograft dysfunction following liver transplantation, but its cause and underlying pathogenesis remains unclear. We sought to identify specific innate and adaptive immune mechanisms driving the pro-inflammatory cytokine secreting regulatory T cell (Treg) phenotype in DAIH and determine if modulation of these pathways could resolve the inflammatory milieu observed in the livers of patients with DAIH. Here, we demonstrate toll-like receptors (TLRs) 2- and 4-mediated inflammasome activation in CD14++ monocytes, a finding that is key to maintaining dysfunctional Tregs in patients with DAIH. Furthermore, silencing of TLR 2 and 4 in CD14++ monocytes prevented activation of the inflammasome and significantly decreased IFN-γ production by FOXP3+ Tregs. We also observed significantly increase in expression of tumor necrosis factor α-induced protein 3 (TNFAIP3), a negative regulator of the NLRP3 Inflammasome, in monocytes/macrophages of liver transplant subjects who have normal allograft function and do not have DAIH. TNFAIP3 expression was virtually absent in monocytes/macrophages of patients with DAIH. Our findings suggest that autoimmunity in DAIH is promoted by CD14++ monocytes predominantly through activation of inflammatory signaling pathways.

Autoimmune liver diseases (AILD) are rare diseases with a reported prevalence of less than 50 per 100 000 population. As the research landscape and our understanding of AILDs and liver transplantation evolves, there remain areas of unmet needs. One of these areas of unmet needs is prevention of disease recurrence after liver transplantation. Disease recurrence is not an insignificant event because allograft loss with the need for retransplantation can occur. Patients transplanted for AILD are more likely to experience acute rejection compared to those transplanted for non-AILD, and the reason(s) behind this observation is unclear. Tasks for the future include a better understanding of the pathogenesis of AILD, definition of the precise pathogenetic mechanisms of recurrent AILD, and development of strategies that can identify recipients at risk for disease recurrence. Importantly, the role of crosstalk between alloimmune responses and autoimmune responses in AILD is an important area that needs further study. This article reviews the relevant literature of de novo autoimmune hepatitis, recurrent autoimmune hepatitis, recurrent primary sclerosing cholangitis, and recurrent primary biliary cirrhosis in terms of the clinical entity, the scientific advancements, and future scientific goals to enhance our understanding of these diseases., A review of the relevant literature of de novo autoimmune hepatitis, recurrent autoimmune hepatitis, recurrent primary sclerosing cholangitis, and recurrent primary biliary cirrhosis in terms of the clinical entity, the scientific advancements and future scientific goals to enhance our understanding of these diseases.

The long-term course and outcome of DAIH is unknown. A retrospective multicenter study assessing associations and long-term consequences of DAIH developing in a transplanted allograft is presented. Children with DAIH were followed from diagnosis until death, re-LT, or transfer of care and for a minimum of 1 year. A total of 31 patients of 1833 (1.7%) LT were identified; 29 followed for a median of 7.1 years (range, 1.6-15); 52% had no rejection preceding diagnosis of DAIH. Transaminases fell following treatment with steroids and antimetabolites (ALT 108 vs 39 U/L (P=.002); AST 112 vs 52 U/L (P=.003); GGT 72 vs 36 U/L (P=.03), but this was not universally sustained. Transaminases >2X ULN observed in 38% of patients at last follow-up; commonly GGT, attributed to bile duct injury and ductopenia. Portal hypertension (PHT) was seen in four patients and associated with severe fibrosis and cirrhosis. Re-LT occurred in two patients for chronic rejection (CR) and uncontrolled PHT with gastrointestinal bleeding, respectively. No deaths from DAIH were reported. DAIH is an uncommon complication following pediatric LT requiring prolonged and augmented immunosuppression. It is associated with continued allograft dysfunction and may lead to bile duct injury, CR, and PHT necessitating re-LT.

Hepatocellular carcinoma (HCC) rarely occurs in childhood. We describe a patient with new onset of pruritus at 8 months of age who at 17 months of age was found to have a 2.5 cm HCC. To delineate the possible genetic basis of this tumour, we performed whole exome sequencing (WES) of the germline DNA and identified two novel predictably deleterious missense mutations in ABCB11, encoding bile salt export pump (BSEP), confirmed in the parental DNA as bi-allelic and inherited. Although inherited ABCB11 mutations have previously been linked to HCC in a small number of cases, the molecular mechanisms of hepatocellular carcinogenesis in ABCB11 disease are unknown. WES of the HCC tissue uncovered somatic driver mutations in the beta-catenin (CTNNB1) and nuclear-factor-erythroid-2-related-factor-2 (NFE2L2) genes. Moreover, clonality analysis predicted that the CTNNB1 mutation was clonal and occurred earlier during carcinogenesis, whereas the NFE2L2 mutation was acquired later. Interestingly, background liver parenchyma showed no inflammation or fibrosis and BSEP expression was preserved. This is the first study to identify somatic CTNNB1 and NFE2L2 mutations in early childhood arisen in the setting of inherited bi-allelic ABCB11 mutations. Rapid WES analysis expedited this child's diagnosis and treatment, and likely improved her prognosis.

Progressive familial intrahepatic cholestasis type 2 (PFIC2) results from recessive mutations in the adenosine triphosphate-binding cassette B11 gene, which encodes for bile salt export pump (BSEP). Liver transplantation (LT) is offered to PFIC2 patients with end-stage liver disease. Reports have described recurrent cholestasis in PFIC2 patients after transplantation, and this has been associated with immunoglobulin G antibodies to BSEP. High-titer anti-BSEP antibodies appear to correlate with episodes of cholestatic graft dysfunction. There is no established paradigm for treating antibody-mediated posttransplant BSEP disease. It appears to be refractory to changes in immunosuppressant medications that would typically be effective in treating allograft rejection. Taking what is known about its pathophysiology, we designed a treatment consisting of rituximab, a chimeric monoclonal anti-CD20 antibody, in combination with intravenous immunoglobulin and plasmapheresis. Using this approach, we report the successful management of 2 patients with antibody-mediated recurrence of PFIC2 after LT.

This review focuses on active clinical research in pediatric liver transplantation with special emphasis on areas that could benefit from studies utilizing the SPLIT infrastructure and data repository. Ideas were solicited by members of the SPLIT Research Committee and sections were drafted by members of the committee with expertise in those given areas. This review is intended to highlight priorities for clinical research that could successfully be conducted through the SPLIT collaborative and would have significant impact in pediatric liver transplantation.

Cholestatic jaundice in infancy affects approximately 1 in every 2500 term infants and is infrequently recognized by primary providers in the setting of physiologic jaundice. Cholestatic jaundice is always pathologic and indicates hepatobiliary dysfunction. Early detection by the primary care physician and timely referrals to the pediatric gastroenterologist/hepatologist are important contributors to optimal treatment and prognosis. The most common causes of cholestatic jaundice in the first months of life are biliary atresia (25%-40%) followed by an expanding list of monogenic disorders (25%), along with many unknown or multifactorial (eg, parenteral nutrition-related) causes, each of which may have time-sensitive and distinct treatment plans. Thus, these guidelines can have an essential role for the evaluation of neonatal cholestasis to optimize care. The recommendations from this clinical practice guideline are based upon review and analysis of published literature and the combined experience of the authors. The committee recommends that any infant noted to be jaundiced after 2 weeks of age be evaluated for cholestasis with measurement of total and direct serum bilirubin, and that an elevated serum direct bilirubin level (direct bilirubin levels >1.0 mg/dL or >17 μmol/L) warrants timely consideration for evaluation and referral to a pediatric gastroenterologist or hepatologist. Of note, current differential diagnostic plans now incorporate consideration of modern broad-based next-generation DNA sequencing technologies in the proper clinical context. These recommendations are a general guideline and are not intended as a substitute for clinical judgment or as a protocol for the care of all infants with cholestasis. Broad implementation of these recommendations is expected to reduce the time to the diagnosis of pediatric liver diseases, including biliary atresia, leading to improved outcomes.

Mevalonic aciduria because of mutations of the gene for mevalonate kinase causes limited synthesis of isoprenoids, the effects of which are widespread. The outcome for affected children is poor. A child with severe multisystem manifestations underwent orthotopic liver transplantation at age 50 months for the indication of end-stage liver disease. This procedure corrected liver function and eliminated portal hypertension, and the patient showed substantial improvement in neurological function. However, autoinflammatory episodes continued unabated until hematopoietic stem cell transplantation was performed at 80 months. Through this complex therapy, the patient now enjoys a high quality of life without significant disability.

Ekong UD, Mathew J, Melin-Aldana H, Wang D, Alonso EM. Successful resolution of inflammation and increased regulatory T cells in sirolimus-treated post-transplant allograft hepatitis. Pediatr Transplantation 2012: 16: 165–175. © 2012 John Wiley & Sons A/S. Abstract: This retrospective case series reviews our center’s experience with sirolimus and a CNI as alternative therapy for the treatment of PTAH. It also characterizes regulatory T cells (Tregs) in PTAH. LT recipients with PTAH who had received or were receiving treatment with sirolimus were retrospectively identified (n = 12). Liver enzymes, immunohistochemistry, and histology were compared in all 12 patients. Immunophenotyping for Tregs in peripheral blood mononuclear cells was performed on LT recipients with PTAH on conventional therapy with CNI, azathioprine ± prednisone (CT) (n = 11), recipients with PTAH on sirolimus, CNI ± prednisone (n = 8), recipients without PTAH (n = 25), and pre-transplant patients (n = 5). Severity of necro-inflammatory changes markedly improved with sirolimus. Treg frequency and number were significantly lower in recipients with PTAH on CT compared to (i) those on sirolimus (p = 0.002 and p = 0.01, respectively), and (ii) recipients without PTAH (p = 0.07 and p = 0.009, respectively). Treg frequency was significantly higher in recipients with PTAH on sirolimus compared to recipients without PTAH under CNI therapy (p = 0.027). Sirolimus in addition to a CNI is successful in reversing inflammation in LT recipients with PTAH. This is associated with significantly higher circulating Tregs.

This is an observational study with the primary objective to measure donor-specific immune responses by pediatric liver transplant (LT) recipients, using cell surface expression of lymphocyte activation markers and cytokine secretion in mixed lymphocyte reactions. The secondary objective was to demonstrate possible mechanism(s) involved in those who demonstrated donor-specific hyporesponsiveness. Study participants included 17 recipients, their respective parental donors, the non-donor parent, as well as unrelated third party individuals. Within the CD4(+) population, two distinct patterns of CD69 and CD71 expressions were observed: recipients who had a lower percentage of CD4(+)CD69(+) and CD4(+)CD71(+) cells after donor versus non-donor stimulation (therefore a donor/non-donor ratio1); and recipients who had a higher percentage of CD4(+)CD69(+) and CD4(+)CD71(+) cells after donor versus non-donor stimulation (therefore a donor/non-donor ratio ≥1). Eight recipients had the above defined ratio of1, with significantly decreased interferon-γ secretion after donor versus non-donor stimulation. CD4(+)CD25(hi.)CD127- regulatory T cells from these eight recipients suppressed donor and non-donor cell induced proliferation. Suppression of proliferation was partially abrogated by interleukin-2. In conclusion, CD69 and CD71 cell surface expression with interferon-γ secretion can be used to identify two distinct populations in pediatric LT recipients. Both active regulation and anergy underlie donor specific hyporesponsiveness.

Development of macrovesicular steatosis post-LT in patients with PFIC-1 is increasingly being observed, with the etiology not fully understood. We highlight successful and effective EBD for reversal of allograft steatosis in 2 patients with PFIC-1 disease and discuss our experience with internal biliary diversion in this patient population.

The factors that influence the long-term histological outcome of transplanted liver allografts in children are not yet fully understood, and the role of surveillance biopsies in patients with normal graft function remains controversial. The aims of this study were to describe the long-term graft histology of pediatric liver transplant recipients surviving at least 3 years and to analyze factors correlating with long-term histological outcome. Histological slides of 63 long-term liver transplant recipients were assessed for inflammation and fibrosis. The histological findings were correlated with clinical, biochemical, serological, and radiological findings. A significant proportion of biopsies from these patients showed some type of histological abnormalities, with fibrosis being observed in 61 (97%) patients. Duration of transplantation of >6 years and > or =grade 2 inflammation were significantly associated with advanced fibrosis. We could not identify any correlation between > or =stage 3 fibrosis and donor age, cold and warm ischemia time, history of de novo autoimmune hepatitis, hepatic artery thrombosis, chronic rejection, or alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transferase values. In conclusion, liver fibrosis appears to be a common finding in long-term pediatric liver transplant survivors. The cause of this fibrosis is uncertain, and normal alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transferase levels do not exclude the presence of significant fibrosis.

We describe longitudinal results in a cohort of pediatric liver transplant patients successfully minimized to once daily CNI monotherapy for longer than five yr and assess changes in liver biochemistries and liver histology. A retrospective chart review of all pediatric liver transplant patients at a single center was performed. Biopsies and serum biochemistries (AST, ALT, total bilirubin, direct bilirubin, INR, creatinine) are reported at time points: PM, five-yr, seven-yr, and nine-yr post-minimization. Biopsies were assessed for inflammation and fibrosis using Ishak and Batts grading systems. Successful minimization to daily CNI monotherapy was defined as normal liver enzymes with no episodes of rejection. Thirty-three patients have successfully remained on once daily CNI for >5 yr, and 19/33 of these patients have serial liver biopsies available for review. We report on the clinical and histological findings of these 19 patients. All 19 patients continue to have normal liver biochemistries. On post-minimization biopsies, fibrosis progressed by ≥2 stages in one patient (5.3%) despite normal liver biochemistries. Carefully selected patients can tolerate minimization to once daily CNI monotherapy as few have progression of fibrosis.

Acute liver failure in the newborn is relatively rare but often fatal. The broadest definition of acute liver failure is failure of the vital functions of the liver occurring within weeks or a few months of the onset of clinical liver disease. Therefore, by definition, any liver failure in the newborn can be construed to be acute liver failure. A second component of the general definition of acute liver failure is the lack of known preexisting liver disease. In the case of neonatal acute liver failure, preexisting disease would by definition be liver disease that affects the fetus. Almost nothing is known about fetal onset liver failure, and there is no literature addressing the subject. This review will address fetal liver disease that leads to liver failure in the fetus or newborn.

Posttransplant metabolic syndrome (PTMS)-obesity, hypertension, elevated triglycerides, low HDL and glucose intolerance-is a major contributor to morbidity after adult liver transplant. This analysis of the Withdrawal of Immunosuppression in Pediatric Liver Transplant Recipients (WISP-R) pilot trial is the first prospective study of PTMS after pediatric liver transplant. Twenty children were enrolled in WISP-R, at median age 8.5 years (IQR 6.4-10.8), and weaned from calcineurin-inhibitor monotherapy. The 12 children who tolerated complete immunosuppression withdrawal were compared to matched historical controls. At baseline, 45% of WISP-R subjects and 58% of controls had at least one component of PTMS. Calcineurin-inhibitor withdrawal in the WISP-R subjects did not impact the prevalence of PTMS components compared to controls. At 5 years, despite weaning off of immunosuppression, 92% of the 12 tolerant WISP-R subjects had at least one PTMS component and 58% had at least two; 33% were overweight or obese, 50% had dyslipidemia, 33% glucose intolerance and 42% systolic hypertension. Overweight/obesity increased the risk of hypertension in all children. Compared to controls, WISP-R tolerant subjects had similar GFR at baseline but did have higher GFR at 2, 3 and 4 years. Further study of PTMS and immunosuppression withdrawal after pediatric liver transplant is warranted.

Aim The significance of HLA antibody in liver transplantation has been unclear, although recent studies have described an increase in the diagnosis of antibody mediated damage in this population. Our specific aim is to correlate the development of de novo HLA antibody including C1q testing, and AT1R antibody levels with graft dysfunction to determine if there is a significant association of these antibodies with graft function. Methods 63 patients at our center from 7/31/1998 to 2/29/16 were included for analysis, of which 42 were screened for Anti-HLA DSA, C1q and AT1R. DSA >1000 mfi was considered positive and patients were evaluated retrospectively for ACR. Specificity of antibody locus as well as alleles were analyzed and correlated with liver dysfunction. Available biopsies were evaluated for rejection grade, mean fibrosis score as well as portal, central, and sinusoidal fibrosis. Patient characteristics were summarized using mean, standard deviation, median and range for continuous variable, frequency and percentage for categorical variable. Wilcoxon Rank Sum or Kruskal Wallace test was conducted to check differences of continuous variables. Two sided p value less than 0.05 was considered as statistically significant. Results Portal fibrosis scores were significantly lower in patients without Class II DQ DSA post transplant ( p p p p Conclusions There is significant development of Class II DSA in pediatric liver transplantation. These antibodies were associated with increases in fibrosis scoring and ACR. DQ2 mismatches in particular were shown to be more immunogenic, the significance of which is currently under study.

Current American Association for the Study of Liver Diseases (AASLD) liver transplant evaluation guidelines include both adult and pediatric patients. While pediatric liver transplants account for 7.8% of all liver transplants in the United States, sufficient differences between pediatric and adult patients seeking liver transplantation (LT) now require independent, yet complementary documents. This document will focus on pediatric issues at each level of the evaluation process. Disease categories suitable for referral to a pediatric LT program are similar to adults: acute liver failure, autoimmune, cholestasis, metabolic or genetic, oncologic, vascular, and infectious. However, specific etiologies and outcomes differ widely from adult patients, justifying independent pediatric guidelines. Data supporting our recommendations are based on a Medline search of the English language literature from 1997 to the present. Intended for use by physicians, these recommendations suggest preferred approaches to the diagnostic, therapeutic, and preventive aspects of care. They are intended to be flexible, in contrast to standards of care, which are inflexible policies to be followed in every case. Specific recommendations are based on relevant published information. To more fully characterize the available evidence supporting the recommendations, the AASLD Practice Guidelines Committee has adopted the classification used by the Grading of Recommendation Assessment, Development, and Evaluation (GRADE) workgroup with minor modifications (Table 1). The classifications and recommendations are based on three categories: the source of evidence in levels I through III; the Abbreviations: ALF, acute liver failure; GRADE, Grading of Recommendation Assessment, Development, and Evaluation; HB, hepatoblastoma; HCC, hepatocellular carcinoma; HPE, hepatoportoenterostomy; LT, liver transplantation; OTPN, Organ Procurement and Transplantation Network; PFIC, progressive familial intrahepatic cholestasis; TIPS, transjugular intrahepatic portosystemic shunt. From the Department of Pediatrics, University of Pittsburgh School of Medicine; Division of Pediatric Gastroenterology, Hepatology and Nutrition, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA; Department of Pediatrics, University of Toronto; Division of Pediatric Gastroenterology, Hepatology and Nutrition, SickKids Transplant and Regenerative Medicine Center, Hospital for Sick Children, Toronto, Canada; Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Emory University School of Medicine; Children’s Healthcare of Atlanta, Atlanta, GA; Department of Pediatrics, Division of Pediatric Gastroenterology and Hepatology, Yale School of Medicine, New Haven, CT; Department of Paediatrics, University of Melbourne; Department of Gastroenterology, Royal Children’s Hospital, Melbourne, Australia; Department of Surgery, Section of Transplantation and Immunology, Yale School of Medicine, New Haven, CT; Department of Surgery, University of Pittsburgh School of Medicine; Division of Pediatric Transplantation, Hillman Center for Pediatric Transplantation, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA. Financial support to develop this practice guideline was provided by the American Association for the Study of Liver Diseases. All AASLD Practice Guidelines are updated annually. If you are viewing a Practice Guideline that is more than 12 months old, please visit www.aasld.org for an update in the material. Received April 22, 2014; accepted April 22, 2014. Address reprint requests to: Robert H. Squires, M.D., Professor of Pediatrics, University of Pittsburgh, Children’s Hospital of Pittsburgh of UPMC, 4401 Penn Ave., Pittsburgh, PA 15224. E-mail: squiresr@upmc.edu Copyright VC 2014 by the American Association for the Study of Liver Diseases. View this article online at wileyonlinelibrary.com. DOI 10.1002/hep.27191 Potential conflict of interest: Dr. Romero received grants from Bristol-Myers Squibb.

This retrospective case series reviews our center's experience with sirolimus and a CNI as alternative therapy for the treatment of PTAH. It also characterizes regulatory T cells (Tregs) in PTAH. LT recipients with PTAH who had received or were receiving treatment with sirolimus were retrospectively identified (n = 12). Liver enzymes, immunohistochemistry, and histology were compared in all 12 patients. Immunophenotyping for Tregs in peripheral blood mononuclear cells was performed on LT recipients with PTAH on conventional therapy with CNI, azathioprine ± prednisone (CT) (n = 11), recipients with PTAH on sirolimus, CNI ± prednisone (n = 8), recipients without PTAH (n = 25), and pre-transplant patients (n = 5). Severity of necro-inflammatory changes markedly improved with sirolimus. Treg frequency and number were significantly lower in recipients with PTAH on CT compared to (i) those on sirolimus (p = 0.002 and p = 0.01, respectively), and (ii) recipients without PTAH (p = 0.07 and p = 0.009, respectively). Treg frequency was significantly higher in recipients with PTAH on sirolimus compared to recipients without PTAH under CNI therapy (p = 0.027). Sirolimus in addition to a CNI is successful in reversing inflammation in LT recipients with PTAH. This is associated with significantly higher circulating Tregs.

Context Although life-saving, liver transplantation burdens children with lifelong immunosuppression and substantial potential for morbidity and mortality. Objective To establish the feasibility of immunosuppression withdrawal in pediatric living donor liver transplant recipients. Design, Setting, and Patients Prospective, multicenter, open-label, single-group pilot trial conducted in 20 stable pediatric recipients (11 male; 55%) of parental living donor liver transplants for diseases other than viral hepatitis or an autoimmune disease who underwent immunosuppression withdrawal. Their median age was 6.9 months (interquartile range [IQR], 5.5-9.1 months) at transplant and 8 years 6 months (IQR, 6 years 5 months to 10 years 9 months) at study enrollment. Additional entry requirements included stable allograft function while taking a single immunosuppressive drug and no evidence of acute or chronic rejection or significant fibrosis on liver biopsy. Gradual immunosuppression withdrawal over a minimum of 36 weeks was instituted at 1 of 3 transplant centers between June 5, 2006, and November 18, 2009. Recipients were followed up for a median of 32.9 months (IQR, 1.0-49.9 months). Main Outcome Measures The primary end point was the proportion of operationally tolerant patients, defined as patients who remained off immunosuppression therapy for at least 1 year with normal graft function. Secondary clinical end points included the durability of operational tolerance, and the incidence, timing, severity, and reversibility of rejection. Results Of 20 pediatric patients, 12 (60%; 95% CI, 36.1%-80.9%) met the primary end point, maintaining normal allograft function for a median of 35.7 months (IQR, 28.1-39.7 months) after discontinuing immunosuppression therapy. Follow-up biopsies obtained more than 2 years after completing withdrawal showed no significant change compared with baseline biopsies. Eight patients did not meet the primary end point secondary to an exclusion criteria violation (n = 1), acute rejection (n = 2), or indeterminate rejection (n = 5). Seven patients were treated with increased or reinitiation of immunosuppression therapy; all returned to baseline allograft function. Patients with operational tolerance compared with patients without operational tolerance initiated immunosuppression withdrawal later after transplantation (median of 100.6 months [IQR, 71.8-123.5] vs 73.0 months [IQR, 57.6-74.9], respectively; P = .03), had less portal inflammation (91.7% [95% CI, 61.5%-99.8%] vs 42.9% [95% CI, 9.9%-81.6%] with no inflammation; P = .04), and had lower total C4d scores on the screening liver biopsy (median of 6.1 [IQR, 5.1-9.3] vs 12.5 [IQR, 9.3-16.8]; P = .03). Conclusion In this pilot study, 60% of pediatric recipients of parental living donor liver transplants remained off immunosuppression therapy for at least 1 year with normal graft function and stable allograft histology.

Purpose of review Histological abnormalities are commonly present in late posttransplant biopsies. Many of these changes are seen in recipients who are clinically well with good graft function. This review includes discussion of a small number of studies published within the past 18 months and details future directions in this area of research. Recent findings An analysis of protocol liver biopsies in adult liver allograft recipients revealed normal or near normal histology in less than one third of recipients. Idiopathic chronic hepatitis (not related to disease recurrence) was present in 33%. Interpreted in light of the calculated creatinine clearance, the histological findings led to a documented change in immunosuppression in 32% of the recipients studied. Another study that assessed the natural history of graft fibrosis after pediatric liver transplantation revealed that fibrosis was strongly related to transplant-related factors, and that by 10 years following liver transplantation, the severity had progressed in 25% of the studied recipients. Summary Current studies suggest protocol liver biopsies may provide important histological information about graft function that is not available from standard liver tests and may allow modification of immunosuppression to ensure long-term side-effects of drug therapy are minimized while graft function is maintained.

This report describes a group of pediatric liver transplant recipients who have undergone once daily calcineurin inhibitor (CNI) monotherapy at Children's Memorial Hospital, Chicago, between January 1, 2001 and November 30, 2008. We defined success as normal liver enzymes at 1 year after dose change, with normal enzymes throughout all follow-up. Patients who did not meet the set criteria or had lost an organ to chronic rejection were not considered for this therapeutic strategy. There were 147 patients in our organ transplant tracking record (OTTR) who wereor = 5 years post liver transplant. Of these, 56 underwent reduced dose, once daily CNI monotherapy. Patients who met the set criteria were placed on once daily calcineurin inhibitor at half their previous dose. Fifty patients successfully achieved this dose change, while six patients failed at a mean of 3.7 +/- 3.2 months following the dosing change. The mean interval from transplant was significantly longer in those patients who were successful compared to those who failed dose change (p0.05). Importantly, there have been no graft losses. Reduced dose, once daily CNI monotherapy is safe in carefully selected recipients, with a longer interval post liver transplantation increasing the likelihood of success.

With the success of solid organ transplantation has come the realization of the post-transplant morbidity and mortality related to the use of immunosuppressive medications (1–3). Induction of tolerance to the transplanted organ would likely prevent these complications, however, the use of tolerance induction protocols in solid organ transplantation will require assays that reflect the level of immune alloreactivity (allosensitization) of the recipient towards the donor. In order to understand the basis of in vitro assays of allosensitization, several concepts have to be considered. The dominant form of alloantigen is the non-self HLA molecule complexed with a variety of different peptides in its antigen binding groove. The frequency of precursor cells for an alloresponse is thought to be 100–1000 times as strong as the response to standard non-self antigens (4). Additionally, the alloresponse, unlike the response to most other antigens, is not dependent on previous exposure for an initial immune response (4). Any strategies to prevent allorecognition must take into account these cardinal observations. For the immune system to mount a response against a foreign antigen, it must be aware of the antigen’s presence. T cells recognize alloantigen via both direct and indirect pathways (Fig. 1) (5). In the direct pathway, recipient T cells recognize intact donor MHC alloantigens on the surface of donor-derived APC. Acute allograft rejection is thought to be mediated predominantly via this pathway (6). In the indirect pathway, allogeneic MHC molecules shed from the graft are processed by the recipient APC and then presented as peptides within the peptide binding sites of the recipient’s own MHC molecules. There is ample evidence that indirect allorecognition is an important driver of organ transplant rejection in humans (7–10). One of the challenges with measuring responses mediated by the indirect pathway is the low precursor frequency of indirectly primed T cells (6) compared to directly primed cells. Fig. 1 Two mechanisms for allorecognition. Direct allorecognition involves recognition of foreign HLA with a variety of potential peptides present in the antigen-presentation groove. In contrast, indirect allorecognition involves recognition of specific foreign ... This review will summarize in vitro assays of T cell reactivity that reflect alloantigen-specific responses. Humoral issues, proteomics, and genomics will not be covered in this review.