Unique Cholangiocyte-Targeted IgM Autoantibodies Correlate With Poor Outcome in Biliary Atresia.

BACKGROUND AND AIMS: The etiology of biliary atresia (BA) is not known and is likely multifactorial, including a genetic predisposition, a viral or environmental trigger, an aberrant autoimmune response targeting cholangiocytes, and unique susceptibilities of the neonatal bile ducts to injury. Damaged cholangiocytes may express neo self-antigens and elicit autoreactive T-cell-mediated inflammation and B-cell production of autoantibodies. The aim of this study was to discover autoantibodies in BA that correlated with outcomes. APPROACH AND RESULTS: An autoantigen microarray encompassing approximately 9,500 autoantigens was used to screen for serum immunoglobulin M (IgM) and immunoglobulin G (IgG) autoantibodies in patients with BA or other liver disease controls. Validation of candidate autoantibodies by enzyme-linked immunosorbent assay on a second cohort of subjects (6-12 months following Kasai portoenterostomy) and correlations of autoantibodies with outcomes were performed (serum bilirubin levels and need for liver transplant in first 2 years of life). Mean anti-chitinase 3-like 1 (CHI3L1), anti-delta-like ligand (DLL-4), and antisurfactant protein D (SFTPD) IgM autoantibodies in BA were significantly higher compared with controls, and IgM autoantibody levels positively correlated with worse outcomes. Immunofluorescence revealed cholangiocyte-predominant expression of CHI3L1, DLL-4, and SFTPD. The humoral autoantibody response was associated with C3d complement activation and T-cell autoimmunity, based on detection of cholangiocyte-predominant C3d co-staining and peripheral blood autoreactive T cells specific to CHI3L1, DLL-4 and SFTPD, respectively. CONCLUSIONS: BA is associated with cholangiocyte-predominant IgM autoantibodies in the first year after Kasai portoenterostomy. Anti-CHI3L1, anti-DLL-4, and anti-SFTPD IgM autoantibody correlations with worse outcomes and the detection of C3d on cholangioctyes and antigen-specific autoreactive T cells suggest that autoimmunity plays a role in the ongoing bile duct injury and progression of disease.

Subacute Liver Failure Following Gene Replacement Therapy for Spinal Muscular Atrophy Type 1.

Spinal muscular atrophy is a neurodegenerative disease resulting from irreversible loss of anterior horn cells owing to biallelic deletions/mutations in the survival motor neuron (SMN) 1 gene. Gene replacement therapy using an adeno-associated virus vector containing the SMN gene was approved by the US Food and Drug Administration in May 2019. We report 2 cases of transient, drug-induced liver failure after this therapy.

The Importance of Prioritizing Pre and Posttransplant Immunizations in an Era of Vaccine Refusal and Epidemic Outbreaks.

Vaccine-preventable infections are occurring at epidemic rates both nationally and internationally. At the same time, rates of vaccine hesitancy and refusal are increasing across the country leading to decreased herd immunity. For immunosuppressed transplant recipients, this situation poses great risk. Currently, 1 in 6 pediatric solid organ transplant recipients is hospitalized with a vaccine-preventable infection in the first 5 years posttransplant. For many recipients, these infections result in significant morbidity, mortality, and increased hospitalization costs. Surprisingly, despite this risk many transplant recipients are not up-to-date on age appropriate immunizations at the time of transplant and thereafter. As a transplant community, we must prioritize immunizations in both pre and posttransplant care. Research is needed to understand how to monitor immune response to vaccines in immunosuppressed patients and when to optimally immunize patients posttransplant. Finally, recommendations about administration of live vaccines posttransplant may need to be reevaluated in the setting of measles outbreaks and decreased herd immunity.

A Phase I/IIa Trial of Intravenous Immunoglobulin Following Portoenterostomy in Biliary Atresia.

OBJECTIVES: Biliary atresia (BA) is a progressive neonatal fibroinflammatory cholangiopathy. We hypothesized that intravenous immunoglobulin (IVIg) would be safe, feasible, acceptable, and efficacious for the treatment of BA. The primary objective of this study was to establish the feasibility, acceptability, and safety profile of IVIg administration after hepatoportoenterostomy (HPE) in BA. The secondary objective was to determine the treatment efficacy of IVIg based on good bile drainage and survival with the native liver. METHODS: A multicenter, prospective, open-labeled, phase I/IIA trial of IVIg was conducted, with 1 g/kg/dose of IVIg infused at 3-5, 30, and 60 days post-HPE, and subjects followed for 360 days post-HPE. Twenty-nine participants completed the study. RESULTS: Administration of IVIg infusions was feasible and acceptable in 79%. None of the serious adverse events (SAEs) were directly related to IVIg infusions; however, 90% of participants had an SAE. Compared with a historical placebo-arm group, there was no significant increase in the proportion of IVIg participants with a serum total bilirubin <1.5 mg/dL at 90, 180, or 360 days post-HPE. Survival with the native liver in the IVIg participants showed no significant benefit over the historical placebo arm, with a difference at 360 days of -11.9% (IVIg: 58.6%, placebo: 70.5%; 90% UCB: 2.1%; P > 0.05). CONCLUSIONS: Although IVIg infusions in infants with BA post-HPE were feasible, acceptable and safe, there was no trend to lower bilirubin levels or improved 360-day survival with the native liver. CLINICAL TRIAL: Safety Study of Intravenous Immunoglobulin Post-Portoenterostomy in Biliary Atresia; #NCT01854827.

Impact of Steroid Therapy on Early Growth in Infants with Biliary Atresia: The Multicenter Steroids in Biliary Atresia Randomized Trial.

OBJECTIVE: To investigate the impact of corticosteroid therapy on the growth of participants in the Steroids in Biliary Atresia Randomized Trial (START) conducted through the Childhood Liver Disease Research Network. The primary analysis in START indicated that steroids did not have a beneficial effect on drainage in a cohort of infants with biliary atresia. We hypothesized that steroids would have a detrimental effect on growth in these infants. STUDY DESIGN: A total of 140 infants were enrolled in START, with 70 randomized to each treatment arm: steroid and placebo. Length, weight, and head circumference were obtained at baseline and follow-up visits to 24 months of age. RESULTS: Patients treated with steroids had significantly lower length and head circumference z scores during the first 3 months post-hepatoportoenterostomy (HPE), and significantly lower weight until 12 months. Growth trajectories in the steroid and placebo arms differed significantly for length (P < .0001), weight (P = .009), and head circumference (P < .0001) with the largest impact noted for those with successful HPE. Growth trajectory for head circumference was significantly lower in patients treated with steroids irrespective of HPE status, but recovered during the second 6 months of life. CONCLUSIONS: Steroid therapy following HPE in patients with biliary atresia is associated with impaired length, weight, and head circumference growth trajectories for at least 6 months post-HPE, especially impacting infants with successful bile drainage. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00294684.

Cytokine-Producing B Cells Promote Immune-Mediated Bile Duct Injury in Murine Biliary Atresia.

Biliary atresia (BA) is a neonatal T cell-mediated, inflammatory, sclerosing cholangiopathy. In the rhesus rotavirus (RRV)-induced neonatal mouse model of BA (murine BA), mice lacking B cells do not develop BA, and the lack of B cells is associated with loss of T-cell and macrophage activation. The aim of this study was to determine the mechanism of B cell-mediated immune activation (antigen presentation versus cytokine production) in murine BA. Normal neonatal B cells in the liver are predominantly at pro-B and pre-B cellular development. However, BA mice exhibit a significant increase in the number and activation status of mature liver B cells. Adoptively transferred B cells into RRV-infected, B cell-deficient mice were able to reinstate T-cell and macrophage infiltration and biliary injury. Nonetheless, neonatal liver B cells were incompetent at antigen presentation to T cells. Moreover, 3-83 immunoglobulin transgenic mice, in which B cells only present an irrelevant antigen, developed BA, indicating a B-cell antigen-independent mechanism. B cells from BA mice produced a variety of innate and adaptive immune cytokines associated with immune activation. In vitro trans-well studies revealed that BA B cells secreted cytokines that activated T cells based on increased expression of T-cell activation marker cluster of differentiation 69. Conclusion: Neonatal liver B cells are highly activated in murine BA and contribute to immune activation through production of numerous cytokines involved in innate and adaptive immunity; this work provides increased knowledge on the capacity of neonatal B cells to contribute to an inflammatory disease through cytokine-mediated mechanisms, and future studies should focus on targeting B cells as a therapeutic intervention in human BA.

Outcomes in Pediatric Autoimmune Hepatitis and Significance of Azathioprine Metabolites.

OBJECTIVES: Autoimmune hepatitis (AIH) is a common pediatric liver disease and long-term remission is usually maintained with azathioprine (AZA). There is no consensus on the target range for AZA active metabolite 6-thioguanine (6-TGN) levels in pediatric AIH. The aim of the present study was to characterize the outcomes of pediatric patients with AIH and determine correlations between AZA dosing or 6-TGN metabolite levels and biochemical remission. METHODS: A retrospective chart review was performed and data on presentation, laboratories including AZA metabolite levels, medication use, and outcomes were collected. RESULTS: Between 2002 and 2013, 66 children with AIH were identified (mean age at diagnosis 9.6 ±â€Š5.1 years) with a mean follow-up period of 2.9 ±â€Š3.2 years. Common presenting symptoms included jaundice, fatigue, and abdominal pain. The majority of subjects received steroids for induction and AZA for maintenance of remission. Seventy-nine percent achieved biochemical remission (mean time to remission 6.2 ±â€Š9.2 months), 14% were in the induction phase of therapy, 6% required liver transplantation, and 18% were weaned off immunosuppression and remained in remission. 6-TGN levels ranging from 50 to 250 pmol/8 × 10 red blood cell count were associated with biochemical remission (alanine aminotransferase levels of ≤50 U/L). CONCLUSIONS: The vast majority of children with AIH maintain a sustained remission with AZA monotherapy. Biochemical remission was maintained with 6-TGN levels much lower than that recommended for inflammatory bowel disease. These findings suggest that patients should be maintained at the lowest AZA dose possible that is associated with biochemical remission.

Biliary atresia: Indications and timing of liver transplantation and optimization of pretransplant care.

Biliary atresia (BA) is a progressive, fibro-obliterative disorder of the intrahepatic and extrahepatic bile ducts in infancy. The majority of affected children will eventually develop end-stage liver disease and require liver transplantation (LT). Indications for LT in BA include failed Kasai portoenterostomy, significant and recalcitrant malnutrition, recurrent cholangitis, and the progressive manifestations of portal hypertension. Extrahepatic complications of this disease, such as hepatopulmonary syndrome and portopulmonary hypertension, are also indications for LT. Optimal pretransplant management of these potentially life-threatening complications and maximizing nutrition and growth require the expertise of a multidisciplinary team with experience caring for BA. The timing of transplant for BA requires careful consideration of the potential risk of transplant versus the survival benefit at any given stage of disease. Children with BA often experience long wait times for transplant unless exception points are granted to reflect severity of disease. Family preparedness for this arduous process is therefore critical. Liver Transplantation 23:96-109 2017 AASLD.

CD4+ and CD8+ T Cell Activation in Children with Hepatitis C.

OBJECTIVES: To assess if peripheral T cell populations in children with chronic hepatitis C virus (HCV) infection would show evidence of activation/exhaustion and an attenuated functional response. STUDY DESIGN: Compared with adults, children with HCV infection have a higher rate of spontaneous viral clearance. In adults, chronic HCV has been linked to T cell exhaustion. Little is known of the immune status of children with HCV. Peripheral blood mononuclear cells were isolated from 16 children with HCV (6 males, 10 females; mean age 8.6 years, range 2-17), 16 age- and sex-matched control children without HCV infection, and 20 adults with chronic HCV. Multiparameter flow cytometry was performed to characterize T cell differences across the 3 groups. RESULTS: Controls and children with HCV had similar levels of CD4(+), CD8(+), and γδ(+) T cells. Children with HCV demonstrated a decrease in naïve T cells compared with control children and increased activation/exhaustion marker expression on both CD8(+) and CD4(+) T cells. Transcription factor analysis suggested functional activation of T cells in children with HCV; however, only the CD4(+) subset had enhanced cytokine production (interferon gamma and interleukin-2) compared with control children. CONCLUSIONS: The HCV response in children is characterized by several changes in T cell phenotype. Many of these changes, such as increased T cell expression of programmed cell death-1, are similar to responses in adults. Of note, cytokine production by CD4(+) helper T cells is increased in children with HCV compared with age- and sex-matched control children, which may influence long-term prognosis in children with HCV.

Treatment of neonatal hemochromatosis with exchange transfusion and intravenous immunoglobulin.

OBJECTIVE: To determine if immunomodulatory treatment including intravenous immunoglobulin (IVIG) can favorably affect survival in neontatal hemochromatosis (NH) diagnosed postnatally because it can effectively prevent occurrence of NH when applied during gestations at risk. STUDY DESIGN: We treated 16 newborn infants with liver failure due to NH with high-dose IVIG, in combination with exchange transfusion in 13 (ET/IVIG), and compared the outcome with 131 historical controls treated conventionally. RESULTS: The severity of liver disease as estimated by prothrombin time was similar in the subjects receiving ET/IVIG and the historical controls, and the medical therapy was equivalent with the exception of the ET/IVIG therapy. Twelve subjects (75%) had good outcome, defined as survival without liver transplantation, whereas good outcome was achieved in only 17% (23/131) of historical control patients (P < .001). Four subjects died, 2 without and 2 after liver transplant. Survivors were discharged 6 to 90 days after receiving ET/IVIG therapy, and those followed for more than 1 year are within normal measures for growth, development, and liver function. CONCLUSIONS: Immune therapy with ET/IVIG appears to improve the outcome and reduce the need for liver transplantation in patients with NH.

Surgical restoration of portal flow corrects procoagulant and anticoagulant deficiencies associated with extrahepatic portal vein thrombosis.

Extrahepatic portal vein thrombosis (EHPVT) is associated with abnormal circulating procoagulants and anticoagulants. Eleven children with EHPVT and abnormal coagulation factors underwent a mesenterico-left portal vein bypass to restore portal flow. Coagulation factors had returned to normal by one year. The data suggest that portal venous flow is essential for maintaining normal coagulation.