Diagnostic Approach to Acute Liver Failure in Children: A Position Paper by the SIGENP Liver Disease Working Group

Acute liver failure (ALF) is a clinical condition characterized by the abrupt onset of coagulopathy and biochemical evidence of hepatocellular injury, leading to rapid deterioration of liver cell function. In children, ALF has been characterized by raised transaminases, coagulopathy, and no known evidence of pre-existing chronic liver disease; unlike in adults, the presence of hepatic encephalopathy is not required to establish the diagnosis. Although rare, ALF has a high mortality rate without liver transplantation (LT). Etiology of ALF varies with age and geographical location, although it may remain indeterminate in a significant proportion of cases. However, identifying its etiology is crucial to undertake disease-specific management and evaluate indication to LT. In this position statement, the Liver Disease Working Group of the Italian Society of Gastroenterology, Hepatology and Nutrition (SIGENP) reviewed the most relevant studies on pediatric ALF to provide recommendations on etiology, clinical features and diagnostic work-up of neonates, infants and children presenting with ALF. Recommendations on medical management and transplant candidacy will be discussed in a following consensus conference.

Prevention of perinatal hepatitis B virus transmission: are we missing something?

Background

The prevention of perinatal Hepatitis B virus (HBV) is crucial to reach the WHO's challenge to eliminate viral hepatitis as public health threat by 2030. After diagnosing 2 infants infected by vertical transmission, a retrospective analysis of policies and practices to prevent HBV congenital infection was conducted to assess any potential risk.

Methods

Paired maternal-infant medical records between 2017 and 2019 were reviewed at A.O.U Città della Salute e Scienza di Torino, the italian hospital with the highest number of deliveries. Data included maternal HBSAg and coinfection (HIV, HCV) status and the administration of prophylaxis in newborns at risk. Other serologic markers of HBV maternal infection were not available.

Results

132 (0,6%) newborns from HBsAg positive mothers were identified between 2017-2019 among 21143 newborns. In this group pre-natal HBSAg status was known in 127 (96,2%), the remaining were tested during the hospitalization. Regarding maternal coinfection 130 (98%) were tested for HIV (1 positive), only 60 (45.1%) for HCV (all negative). All newborns received immunoprophylaxis consisting in the administration of vaccination and immunoglobulin: 119 (89%) within 24 hours (63% within 12 hours), 12 (9%) between 24-36 hours and 2 (1,6%) after 36 hours. The 2 cases of vertical transmission, even if correctly vaccinated, show a vaccination failure of 1,5%.

Conclusions

Although most of the mothers were tested for HBSAg status and all newborns were given immunoprophylaxis, vaccination failure seems to explain the 2 cases of vertical transmission. Since the lack in early maternal serologic screening and the late vaccination time could increase the risk of HBV infection, to achieve WHO goal we suggest to implement a multidisciplinary pathway to identify HBV positive mothers, to treat in case of high viral load, to provide a timely immunoprophylaxis considering a early vaccination and to set up a structured postnatal serologic check for newborns at risk.

Key messages

Vaccination failure must be considered in the service organization, a structured postnatal serologic check for all newborns at risk should be implemented to detect potential vaccination failure. A multidisciplinary pathway to identify HBV positive mothers, with a full serological markers set, should be implemented to give a correct maternal therapy and newborn prophylaxis.

Liver transplantation in defects of cholesterol biosynthesis: the case of lathosterolosis

We report the outcome of liver transplantation (LT) in the only surviving patient with lathosterolosis, a defect of cholesterol biosynthesis characterized by high lathosterol levels associated with progressive cholestasis, multiple congenital anomalies and mental retardation. From her diagnosis at age 2 she had shown autistic behavior, was unable to walk unaided and her sight was impaired by cataracts. By age 7 she developed end-stage liver disease. After a soul-searching discussion within the transplantation team, she was treated with LT as this represented her only lifesaving option. At 1-year follow-up, her lathosterol levels had returned to normal (0.61 mg/dL from 13.04 ± 2.65) and her nutrition improved. She began exploring her environment and walking by holding onto an adult's hand and then independently. Her brain magnetic resonance imaging (MRI) had shown a normal picture at age 1, whereas a volume reduction of white matter with ex vacuo ventricular dilatation and defective myelinization were observed before transplant. At 5-year follow-up, a complete biochemical recovery, an arrest of mental deterioration and a stable MRI picture were achieved, with a return to her every day life albeit with limitations. Timely liver transplant in defects of cholesterol biosynthesis might arrest the progression of neurological damage.

Long-standing mild hypertransaminasaemia caused by congenital disorder of glycosylation (CDG) type IIx

A 32 year-old asymptomatic male came to our attention with a 21-year history, documented elsewhere, of puzzling increases in his serum transaminase level. At first, very low serum ceruloplasmin level suggested Wilson disease. Two liver biopsies showed mild portal inflammation, steatosis and mild fibrosis. Further investigation revealed low levels of the glycoproteins AT III and clotting factor XI, leading to a diagnosis of congenital disorder of glycosylation (CDG) type II. Further studies as to the cause of this 'apparently new' CDG, are ongoing. On the basis of our data and a literature review, we suggest that subjects with asymptomatic hypertransaminasaemia be screened for CDG.

Hepatitis C virus heteroduplex tracking assay : application to genotype determination, quasispecies analysis, and molecular evolution studies

The heteroduplex tracking assay (HTA) is a tool that can be used for determining genotype, quasispecies analysis, molecular evolution, and epidemiological studies (1-7). By hybridizing a labeled, single-stranded DNA probe to colinear, reverse transcriptase (RT) PCR products from a sample of interest, the probe will either form a homoduplex with identical molecules or a heteroduplex with nonidentical sequences. The hybridization products are separated on MDE or polyacrylamide gels and visualized. Delwart et al., the developers of the HTA technique (1,2,7), have previously shown that the migration of heteroduplexes relative to the homoduplex on gels are approximately proportional to the percent nucleotide divergence between two species, and therefore, the genetic distance between two species can be determined. Genetic rearrangements, deletions, and/or insertions can alter the migration of heteroduplexes in a manner that disturbs the direct relationship between relative migration and genetic distance. Typically, heteroduplexes of 0.176-1.8 kb containing >1.4-3% to ~30% nucleotide substitutions, which lack genetic alterations, can be identified as unique species on MDE gels (1,4,6). The number and distribution of unique bands indicates the genetic complexity of viral species in each sample.

Characterization of antimitochondrial antibodies in health adults

The detection of antimitochondrial antibodies (AMAs) is an important criterion for the diagnosis of primary biliary cirrhosis (PBC). During the last decade, the mitochondrial autoantigens have been cloned, sequenced, and identified as members of the 2-oxo-acid dehydrogenase pathway, including the E2 subunits of pyruvate dehydrogenase (PDC-E2), branched-chain 2-oxo-acid dehydrogenase (BCOADC-E2), and 2-oxo-glutarate dehydrogenase (OGDC-E2). We have developed a rapid and sensitive diagnostic test for use in PBC based on a triple hybrid recombinant molecule (r-MIT3) that contains the autoepitopes of PDC-E2, BCOADC-E2, and OGDC-E2. To help understand the frequency and antigen specificity of AMAs in an asymptomatic population and to identify patients with early disease, we investigated the prevalence of AMA, by enzyme-linked immunosorbent assay (ELISA), in a cohort of 1,530 people from northern Italy. Positive sera were further analyzed for immunoglobulin (Ig) isotypes, subclasses, and epitopes of AMA by a combination of ELISA and immunoblotting. In this cohort of 1,530 people, 9 (0.5%) reacted to r-MIT3 by ELISA. Of the 9 reactive sera, 2 recognized PDC-E2, 2 of 9 recognized BCOADC-E2, 1 of 9 recognized OGDC-E2, 2 of 9 recognized both PDC-E2 and BCOADC-E2, and 1 of 9 recognized PDC-E2 and OGDC-E2. AMA reactivity was primarily IgM and IgA. Epitope mapping revealed an AMA pattern of reactivity to PDC-E2 that differed from that found in patients with histologically proven PBC in most of the sera. However, 1 sera of a 72-year-old female with a normal alkaline phosphatase had an AMA profile identical to typical PBC. After a variable follow-up period (8-14 months), sera from 8 of 9 of these people were re-obtained for AMA and relative epitope mapping. Interestingly, the reactivity had a wider AMA pattern than before.

Hepatitis C virus heteroduplex tracking assay for genotype determination reveals diverging genotype 2 isolates in Italian hemodialysis patients

A heteroduplex tracking assay (HTA) was developed for genetic analyses of the hepatitis C virus (HCV) using single-stranded probes from the core (C)/E1 region. Nucleotide sequencing of reverse transcriptase (RT)-PCR products from 15 Italian dialysis patients confirmed the specificity and accuracy of the HTA genotyping method, which identified 5 of 15 (33.3%) 1b, 7 of 15 (46.7%) 3a, and 3 of 15 (20%) type 2 infections. The genotypes of an additional 12 HCV antibody-positive blood donors from different geographical locations were also in agreement with the genotypes determined by the Inno-LiPA HCV II kit (Innogenetics) and/or restriction fragment length polymorphism (RFLP). Isolates which had between 35 to 40% nucleotide divergence from control subtype 1a, 1b, 2a, 2b, or 3a standards could be typed. Surprisingly, HTA detected one 1b-2 coinfection which was missed by DNA sequencing. Three samples that were designated non-2a or 2b type 2 by HTA were found to be type 2a by both RFLP and direct nucleotide sequencing of the 5' untranslated region. The genetic distance between patient type 2 and control 2a, 2b, and 2c isolates indicated that a new subtype was present in the population being studied. Serotyping (RIBA serotyping strip immunoblot assay kit) of 23 dialysis patients showed that the genotype could be determined in 6 of 8 (75%) C/E1 RT-PCR-negative and 15 of 23 (65.2%) RT-PCR-positive samples, indicating that the two tests complement each other.

Hepatitis C virus infection and liver disease

Hepatitis C Virus (HCV) is a RNA virus that lacks the retroviral properties of surviving in infected hosts by integration into cellular DNA, nevertheless it is capable to cause chronic infection and disease in a considerable number of infected individuals (30-70% of cases). This results in a worldwide prevalence of chronic HCV carriers similar to those of hepatitis B virus carriers. We review and discuss here some of the peculiar aspects of chronic HCV infection and associated disease.

Quantitative analysis of wild-type and HBeAg minus hepatitis B viruses by a sequence-dependent primer extension assay

The ratio between wild-type hepatitis B virus (HBV) and HBV mutant, unable to secrete "e" antigen (HBeAg minus HBV) appears to be an important determinant of the outcome of chronic hepatitis B. Quantitative analysis of wild-type and HBeAg minus HBVs in the blood could be useful to monitor chronic hepatitis B patients. We developed a solid-phase minisequencing assay for both viruses using a primer-guided incorporation of a single labeled nucleotide on an affinity captured biotinylated amplified HBV-DNA template. A standard curve was constructed by mixing increasing quantities of wild type and mutant virus DNAs. The detection of wild-type and HBeAg minus sequences, ranging from 10% to 90% of overall viremia, was linear and reproducible till 0.1 pg/microliter of serum HBV-DNA. The assay yields numerical values and the ratio of incorporated nucleotides defines the relative proportions (%) of the two viral sequences with accuracy. We tested the sensitivity and accuracy of the minisequencing on mixed end point dilutions of wild-type and HBeAg minus reference sera and amplified products. The feasibility and reproducibility of the assay were tested in 35 sera from 21 HBsAg positive patients with chronic hepatitis B using both minisequencing and oligo-hybridization assays. A high correlation was found between the two assays (r = 0.957 P < 0.0001). In conclusion, the minisequencing assay provides a precise and reproducible quantitative analysis of wild-type and HBeAg minus HBVs in clinical specimens. It is proposed to study the relations between HBV heterogeneity and the course of hepatitis B and its response to therapy.

Hepatitis C virus infection and liver disease: peculiar epidemiological and clinicopathological features

Hepatitis C virus (HCV) infection is associated with a wide spectrum of liver disease ranging from asymptomatic carriage to severe forms of chronic hepatitis. HCV is not invariably pathogenic and genetic heterogeneity of HCV could be a major cause of such a variability. In clinical practice this means that presence and replication of the virus do not invariably imply a virus-induced liver damage. IgM antibodies that are the best diagnostic tools for the other forms of viral hepatitis are not sensitive and specific enough for hepatitis C, therefore we have to look for alternatives. Detection of anti-HCV does not help to distinguish past from present infections and only anti-HCV seroconversion in previously negative patients can indicate a recent HCV infection. However, the significant association between serum anti-C100-3 and HCV-RNA suggests that anti-HCV can be considered an indirect marker of HCV infectivity. In anti-HCV-negative infections and early acute hepatitis cases HCV-RNA detection will represent a valid diagnostic alternative. In patients undergoing antiviral therapy monitoring anti-HCV by immunoblotting assays and HCV-RNA by quantitative assays represent a valid tool to predict response that invariably has occurred in patients who had undetectable serum HCV-RNA and/or decreasing anti-HCV titres. Assays that detect multiple anti-HCV antibodies all together appear unsuitable for monitoring because they miss the disappearance of single antibodies. Anti-C22 appears the most frequent and earliest to be detected and usually it has the highest titre. Anti-C100 titres decrease earlier than anti-C33 and anti-C22 in patients with chronic HCV hepatitis who respond to antiviral therapy. The natural course of HCV infection appears to be characterized by three consecutive phases: disease, asymptomatic carrier and recovery. If transition from the first to the last occurs very slowly or the disease phase persists for years it may warrant in susceptible hosts severe forms of liver disease.

Hepatitis C virus markers in patients with long-term biochemical and histological remission of chronic hepatitis

We measured hepatitis C virus (HCV) RNA and antibodies against HCV recombinant proteins (C22/S1, E1/S2, E2/NS1, C33/NS3, C100/NS4, NS5) in serial serum samples from 22 interferon-treated patients with a long-term follow up (range: 36-44 months). Eleven of them showed persistently normal liver function tests and a significant histological amelioration or a complete resolution of chronic hepatitis (long-term responders, LTRs). In the remaining 11 patients (non-responders (NRs)) liver function tests normalized temporarily during therapy or remained unchanged. At the end of the follow up (3 years), viraemia was undetectable in six of 11 LTRs (54.6%). HCV-RNA was always detectable in the serum of NRs (p = 0.017). At admission, anti-C22/S1, anti-E1/S2, anti-E2/NS1, anti-C33/NS3, anti-C100/NS4 and anti-NS5 were detected in 95.4%, 40.9%, 77.3%, 95.4%, 72.7% and 77.3% of the patients, respectively. Three years after suspension of therapy, anti-C100/NS4 was undetectable in five of six (83.3%) LTRs who cleared HCV-RNA and in only one with ongoing viraemia (20%). Anti-E2/NS1 was undetectable in 54.5% of LTRs and in no NRs (p = 0.067). Anti-E1/S2 was detected more frequently in LTRs than in NRs (81.8% vs 45.5%). Serum levels of anti-C22/S1, C33/NS3 and NS5 did not change during therapy and the follow up in either group of patients. The clearance of viraemia in LTRs was associated with that of anti-C100/NS4 (p = 0.017). Serum HCV-RNA and anti-C100/NS4 appear suitable tools for monitoring patients who respond to therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Monitoring the natural course and response to therapy of chronic hepatitis B with an automated semi-quantitative assay for IgM anti-HBc

The clinical significance of a semi-quantitative microparticle enzyme immunoassay (IMx Core-M, Abbott) was evaluated for detection of IgM-class antibodies against the hepatitis B core antigen (IgM anti-HBc) in 136 hepatitis B surface antigen (HBsAg) positive individuals (96 chronic HBV carriers, 20 patients with chronic HBV-HDV infections and 20 patients with acute hepatitis B) and 50 HBV-negative controls. Baseline and follow-up sera (4-11 samples) were analysed from 79 carriers with chronic hepatitis B, 44 of whom were treated with interferon. IMx indexes above 3,000 were found in 95% of the acute hepatitis B patients and above 0.300 in 91.5% of patients with ongoing chronic hepatitis B. IMx indexes between 0.200 and 0.300 were observed in (a) patients with recent HBeAg to anti-HBe seronconversion (6-12 months) and normal serum ALT levels, (b) patients immuno-tolerant to HBV infection and without liver disease despite high levels of viremia, and (c) patients with anti-HBe-positive chronic hepatitis B during 7-13-month intervals of asymptomatic carriage between episodes of disease reactivation. IMx indexes below 0.200 were detected in all HBV-negative individuals and healthy HBV carriers, in 14 (70%) of 20 chronic hepatitis D patients and in all but 1 of 22 interferon-treated patients with histological remission of liver disease, 5-12 months after clearance of viremia and normalization of serum ALT levels. In contrast, IMx indexes remained above 0.200 in all patients with hepatitis B reactivation.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical significance of the antibody to the putative core protein of hepatitis C virus in patients with chronic liver disease

We evaluated the clinical significance of the antibody to hepatitis C core protein (anti-p22) analysing 147 sera from 99 patients; 45 of them had post-transfusion non A non B (NANB) hepatitis, 28 cryptogenic non A non B hepatitis, 12 chronic hepatitis B, 7 chronic hepatitis D, 6 other forms of liver disease (4 primary biliary cirrhosis, 2 autoimmune hepatitis) and 1 rheumatoid arthritis. All sera were tested by commercial 1st and 2nd-generation ELISAs and anti-p22 single antibody ELISA. We found a highly significant correspondence between anti-p22 and commercial assays (p = 0.0001). HCV-RNA was detected by reverse transcriptase polymerase chain reaction (RT-PCR) in sera showing positive or negative concordant results and in all sera (24) that showed discordant results by anti-p22 and commercial ELISAs. HCV-RNA was found in 14 of 17 (82%) anti-p22 positive sera that were negative by commercial ELISAs, in 1 of 7 (14.3%) anti-p22 negative sera that were positive by commercial ELISAs (p = 0.001) and in all control sera from patients with positive concordant results. It was undetectable in 7 sera from patients with autoimmune diseases (negative by all ELISAs). We studied follow-up sera from 16 patients treated with interferon: 8 long-term responders (with persistently normal ALT levels for at least 24 months after discontinuation of therapy and histological remission) and 8 non-responders. Sera were also tested by a 4-antigen recombinant immunoblotting assay (RIBA II).(ABSTRACT TRUNCATED AT 250 WORDS)

'e' antigen defective hepatitis B virus and course of chronic infection

We studied the relations between HBV heterogeneity and different phases of HBV infection and disease in 145 HBsAg-positive carriers followed-up for 28 months (range 24-60 months). Viraemia was characterized for the relative prevalence of wild-type and HBeAg minus HBVs after HBV-DNA amplification by PCR using an oligonucleotide hybridization assay. HBeAg minus HBV was detected in 27% of immunotolerant HBV carriers, in 67% of patients with chronic hepatitis B (immunoelimination phase) and in 17% of HBsAg carriers with latent infection. Serum HBV-DNA and IgM anti-HBc became undetectable and ALT levels normalized, either spontaneously or after interferon therapy in 12 (36.3%) of 33 patients with an exclusive wild-type viraemia, but only in two (5.7%) of 35 patients with homogeneous HBeAg minus HBV (p = 0.005). An HBeAg minus viraemia higher than 20% was associated, in both HBeAg- and anti-HBe-positive patients, with HBV-induced liver disease and an unfavourable outcome of hepatitis. These findings suggest that surgence of HBeAg defective HBV is a virus strategy to survive under peculiar conditions dictated by the interplay between HBV and the host's immune system. The HBeAg/anti-HBe serological status is determined not only by the extent of virus replication and integration of HBV-DNA into cellular DNA but also by heterogeneity of HBV. The study of HBV heterogeneity in baseline sera of patients undergoing antiviral therapy appears to have a predictive value of the outcome of HBV infection in the single patient.