Elaboration of tubules with active hedgehog drives parenchymal fibrogenesis in gestational alloimmune liver disease

Hunting for the elusive target antigen in gestational alloimmune liver disease (GALD)

The prevailing concept is that gestational alloimmune liver disease (GALD) is caused by maternal antibodies targeting a currently unknown antigen on the liver of the fetus. This leads to deposition of complement on the fetal hepatocytes and death of the fetal hepatocytes and extensive liver injury. In many cases, the newborn dies. In subsequent pregnancies early treatment of the woman with intravenous immunoglobulin can be instituted, and the prognosis for the fetus will be excellent. Without treatment the prognosis can be severe. Crucial improvements of diagnosis require identification of the target antigen. For this identification, this work was based on two hypotheses: 1. The GALD antigen is exclusively expressed in the fetal liver during normal fetal life in all pregnancies; 2. The GALD antigen is an alloantigen expressed in the fetal liver with the woman being homozygous for the minor allele and the father being, most frequently, homozygous for the major allele. We used three different experimental approaches to identify the liver target antigen of maternal antibodies from women who had given birth to a baby with the clinical GALD diagnosis: 1. Immunoprecipitation of antigens from either a human liver cell line or human fetal livers by immunoprecipitation with maternal antibodies followed by mass spectrometry analysis of captured antigens; 2. Construction of a cDNA expression library from human fetal liver mRNA and screening about 1.3 million recombinants in Escherichia coli using antibodies from mothers of babies diagnosed with GALD; 3. Exome/genome sequencing of DNA from 26 presumably unrelated women who had previously given birth to a child with GALD with husband controls and supplementary HLA typing. In conclusion, using the three experimental approaches we did not identify the GALD target antigen and the exome/genome sequencing results did not support the hypothesis that the GALD antigen is an alloantigen, but the results do not yield basis for excluding that the antigen is exclusively expressed during fetal life., which is the hypothesis we favor.

RNA-Sequencing Analysis Identifies Etiology Specific Transcriptional Signatures in Neonatal Acute Liver Failure

OBJECTIVE

To assess hepatic transcriptional signatures in infants with gestational alloimmune liver disease (GALD) compared with other etiologies of neonatal acute liver failure (ALF) and older pediatric patients with ALF.

STUDY DESIGN

Neonates with ALF (international normalized ratio ≥2 within 30 days of life) and deceased neonates without liver disease (<30 days of age) with available liver tissue between 2010 and 2021 were identified at Ann & Robert H. Lurie Children's Hospital of Chicago. Clinical information, liver histology, and data from RNA-sequencing analysis was compared between neonates with GALD, non-GALD etiologies of neonatal ALF, and nondiseased neonatal liver.

RESULTS

Quantification of trichrome staining showed an increase in fibrosis in patients with GALD vs those with non-GALD neonatal ALF (P = .012); however, quantification of α-cytokeratin 19-positive ductules did not differ between groups (P = .244). Gene set enrichment analysis of RNA-sequencing data identified the pathways of complement activation, fibrosis, and organogenesis to be upregulated in patients with GALD with ALF. In contrast, patients with non-GALD causes of neonatal ALF had increased gene expression for interferon-driven immune pathways. Individual genes upregulated in GALD included matrix metallopeptidase 7, hepatocyte growth factor, and chemokine ligand 14.

CONCLUSIONS

We have identified distinct pathways that are significantly upregulated in patients with GALD and potential disease-specific diagnostic biomarkers. Future studies will aim to validate these findings and help identify GALD-specific diagnostic biomarkers to improve diagnostic accuracy and reduce GALD-associated patient mortality.

Identification of signature of gene expression in biliary atresia using weighted gene co-expression network analysis

Biliary atresia (BA) is the most common cause of obstructive jaundice during the neonatal period. This study aimed to identify gene expression signature in BA. The datasets were obtained from the Gene Expression Omnibus database. Weighted gene co-expression network analysis identified a critical module associated with BA, whereas Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed the functions of the essential modules. The high-connectivity genes in the most relevant module constructed protein-protein interaction networks via the string website and Cytoscape software. Hub genes screened by lasso regression consisted of a disease classification model using the randomforest method. Receiver operating characteristic curves were used to assess models' sensitivity and specificity and the model was verified using the internal and external validation sets. Ten gene modules were constructed by WGCNA, of which the brown module had a strong positive correlation with BA, comprising 443 genes. Functional enrichment analysis revealed that module genes were mainly involved in biological processes, such as extracellular matrix organization, cell adhesion, inflammatory response, and the Notch pathway (P < .001), whereas these genes were involved in the metabolic pathways and cell adhesion molecules (P < .001). Thirty-nine high-connectivity genes in the brown module constructed protein-protein interaction networks. keratin 7 (KRT7) and C-X-C motif chemokine ligand 8 (CXCL8) were used to construct a diagnostic model that had an accuracy of 93.6% and the area under the receiver operating curves for the model was 0.93. The study provided insight into the signature of gene expression and possible pathogenesis of BA; furthermore, it identified that the combination of KRT7 and CXCL8 could be a potential diagnostic model for BA.

Liver Diseases in the Perinatal Period: Interactions Between Mother and Infant

Liver diseases affecting the mother and infant dyad may present in the perinatal period from 20 weeks of gestation to 28 days of life. This review will focus on the current approach to neonatal acute liver failure and the progress made in the diagnosis and management of gestational alloimmune liver disease. It will highlight mother-to-child transmission of viral hepatitis, both management and public health implications. Emerging concepts implicating maternal obesity and nutrition in the development of a rapidly progressive nonalcoholic steatohepatitis phenotype in the offspring will be discussed. Finally, the presentation and management of acute fatty liver of pregnancy and intrahepatic cholestasis of pregnancy, and their impact on the fetus, will be reviewed.

The Effects of Gestational Alloimmune Liver Disease on Fetal and Infant Morbidity and Mortality

OBJECTIVES

To evaluate pregnancy outcomes in pedigrees of neonatal hemochromatosis to determine the spectrum of gestational alloimmune liver disease (GALD) in a large cohort.

STUDY DESIGN

We prospectively collected data from women with a prior offspring with proven neonatal hemochromatosis between 1997 and 2015 and analyzed pregnancy outcomes.

RESULTS

The pedigrees from 150 women included 350 gestations with outcomes potentially related to GALD. There were 105 live-born infants without liver disease, 157 live-born infants with liver failure, and 88 fetal losses. Fetal loss occurred in 25% of total gestations. Ninety-seven pedigrees contained a single affected offspring, whereas 53 contained multiple affected offspring. Analysis of these 53 pedigrees yielded a per-pregnancy repeat occurrence rate of 95%. Notably, the first poor outcome occurred in the first pregnancy in 60% of pedigrees. Outcomes of the 157 live-born infants with liver failure were poor: 18% survived, 82% died. Of the 134 live-born infants with treatment data, 20 received intravenous immunoglobulin with or without double-volume exchange transfusion of which 9 (45%) survived; 14 infants (10%) received a liver transplant of which 6 (43%) survived.

CONCLUSIONS

GALD is a significant cause of both fetal loss and neonatal mortality with a high rate of disease recurrence in untreated pregnancies at risk. Poor outcomes related to GALD commonly occur in the first gestation, necessitating a high index of suspicion to diagnose this disorder at first presentation.

Neonatal acute liver failure

Neonatal acute liver failure (NALF) is a rare disease about which there is little published data; however, NALF is an extremely important condition as it is distinct from acute liver failure seen in older children and adults. First, unlike acute liver failure in older patients, NALF can be diagnosed in an infant with cirrhosis. This is due to the fetal-neonatal continuum of liver disease, or the principle that neonatal liver failure may be the result of a liver disease that began in utero. Further differences exist in the mechanism of disease, diagnostic principles, and the common etiologies of NALF when compared with pediatric and adult acute liver failure. This review will address many of the distinguishing features of NALF and focus on the most common etiologies of NALF, including gestational alloimmune liver disease (GALD), the most common cause of NALF. Additionally, this review will provide insight into the pathogenesis, diagnosis, and treatment of this rare condition. Liver Transplantation 22 677-685 2016 AASLD.