Hepatitis C virus infection associated with liver-kidney microsomal antibody type 1 (LKM1) autoantibodies in children

Pathogens and autoimmune hepatitis

Autoimmune hepatitis (AIH) is a severe form of hepatitis resulting in the autoimmune-mediated destruction of the liver parenchyma. Whereas many of the immunopathogenic events have been elucidated and some of the drivers of the disease have been identified, little is known about the aetiology of the disease. There are certain risk factors, such as particular human leucocyte antigen (HLA) haplotypes, that enhance the susceptibility for AIH or influence the severity of the disease. However, as for many other autoimmune diseases, the mere presence of such risk factors does not warrant the occurrence of the disease. Not all individuals carrying risk factors develop AIH, and not all patients with AIH are carriers of high-risk alleles. Thus, additional environmental factors need to be considered as triggers for AIH. Environmental factors include diet, sunlight exposure, stress, medication and hygiene, as well as pathogen infections and vaccinations. This review discusses if pathogens should be considered as triggers for the initiation and/or propagation of AIH.

Hepatitis C Viral Infection in Children: Updated Review

Hepatitis C virus (HCV) infection is a major medical challenge affecting around 200 million people worldwide. The main site of HCV replication is the hepatocytes of the liver. HCV is a positive enveloped RNA virus from the flaviviridae family. Six major HCV genotypes are implicated in the human infection. In developed countries the children are infected mainly through vertical transmission during deliveries, while in developing countries it is still due to horizontal transmission from adults. Minimal nonspecific and brief symptoms are initially found in approximately 15% of children. Acute and chronic HCV infection is diagnosed through the recognition of HCV RNA. The main objective for treatment of chronic HCV is to convert detected HCV viremia to below the detection limit. Children with chronic HCV infection are usually asymptomatic and rarely develop severe liver damage. Therefore, the benefits from current therapies, pegylated-Interferon plus ribavirin, must be weighed against their adverse effects. This combined treatment offers a 50-90% chance of clearing HCV infection according to several studies and on different HCV genotype. Recent direct acting antiviral (DAA) drugs which are well established for adults have not yet been approved for children and young adults below 18 years. The most important field for the prevention of HCV infection in children would be the prevention of perinatal and parenteral transmission. There are areas of focus for new lines of research in pediatric HCV-related disease that can be addressed in the near future.

Vertically acquired hepatitis C virus infection: Correlates of transmission and disease progression

The worldwide prevalence of hepatitis C virus (HCV) infection in children is 0.05%-0.4% in developed countries and 2%-5% in resource-limited settings, where inadequately tested blood products or un-sterile medical injections still remain important routes of infection. After the screening of blood donors, mother-to-child transmission (MTCT) of HCV has become the leading cause of pediatric infection, at a rate of 5%. Maternal HIV co-infection is a significant risk factor for MTCT and anti-HIV therapy during pregnancy seemingly can reduce the transmission rate of both viruses. Conversely, a high maternal viral load is an important, but not preventable risk factor, because at present no anti-HCV treatment can be administered to pregnant women to block viral replication. Caution is needed in adopting obstetric procedures, such as amniocentesis or internal fetal monitoring, that can favor fetal exposure to HCV contaminated maternal blood, though evidence is lacking on the real risk of single obstetric practices. Mode of delivery and type of feeding do not represent significant risk factors for MTCT. Therefore, there is no reason to offer elective caesarean section or discourage breast-feeding to HCV infected parturients. Information on the natural history of vertical HCV infection is limited. The primary infection is asymptomatic in infants. At least one quarter of infected children shows a spontaneous viral clearance (SVC) that usually occurs within 6 years of life. IL-28B polymorphims and genotype 3 infection have been associated with greater chances of SVC. In general, HCV progression is mild or moderate in children with chronic infection who grow regularly, though cases with marked liver fibrosis or hepatic failure have been described. Non-organ specific autoantibodies and cryoglobulins are frequently found in children with chronic infection, but autoimmune diseases or HCV associated extrahepatic manifestations are rare.

Histopathology of hepatitis C in children, a systematic review: implications for treatment

Chronic hepatitis C in children is usually considered a clinically mild and slowly progressive disease. Few pediatric studies focused on histopathology of children with hepatitis C are available. Those available show, overall, a wide spectrum of findings ranging from normal liver to cirrhosis and hepatocellular carcinoma. The present systematic review provides a comprehensive overview of the studies that explored histopathology in children with hepatitis C. Factors affecting the presence and the degree of necroinflammation, fibrosis and steatosis and the risk of progression to advanced liver disease were extensively evaluated. Insights on the possible role of histopathology findings in the decision-making process of whether or not to treat children with hepatitis C are provided.

Pathogen infection as a possible cause for autoimmune hepatitis

Autoimmune disorders afflicting the liver comprise the bona fide autoimmune diseases, primary biliary cirrhosis, primary sclerosing cholangitis, and autoimmune hepatitis as well as drug-induced autoimmune-like diseases, such as halothane hepatitis. Whereas drug-induced forms of acute or chronic hepatitis often have a clear triggering factor, the etiology of classical autoimmune liver diseases is only poorly understood. Besides a genetic component present in disease susceptible individuals, environmental triggering factors are likely to play a role in the initiation and/or propagation of the disease. In this article, we will review on current evidence obtained from epidemiological associations, case studies, and findings in animal models for pathogens, to be involved in the etiology of autoimmune liver disease with a special focus on autoimmune hepatitis.

Autoantibodies and autoimmune disease during treatment of children with chronic hepatitis C

OBJECTIVES

Autoantibodies were studied in a well-characterized cohort of children with chronic hepatitis C during treatment with pegylated interferon and ribavirin to assess the relation with treatment and development of autoimmune disease.

METHODS

: A total of 114 children (5-17 years), screened for the presence of high-titer autoantibodies, were randomized to pegylated interferon with or without ribavirin. Anti-nuclear, anti-liver-kidney-microsomal, anti-thyroglobulin, anti-thyroid peroxidase, insulin, anti-glutamic acid decarboxylase (GAD) antibodies were measured after trial completion using frozen sera.

RESULTS

At baseline, 19% had autoantibodies: anti-nuclear antibodies (8%), anti-liver-kidney-microsomal antibodies (4%), and glutamic acid decarboxylase antibodies (4%). At 24 and 72 weeks (24 weeks after treatment completion), 23% and 26% had autoantibodies (P=0.50, 0.48 compared with baseline). One child developed diabetes and 2 hypothyroidism during treatment; none developed autoimmune hepatitis. At 24 weeks, the incidence of flu-like symptoms, gastrointestinal symptoms, and headaches was 42%, 8% and 19% in those with autoantibodies versus 52%, 17%, and 26% in those without (P=0.18, 0.36, and 0.20, respectively). In children with negative hepatitis C virus polymerase chain reaction at 24 weeks, there was no difference in the rate of early virologic response/sustained virologic response, respectively, in those with autoantibodies 76%/69% vs 58%/65% in those without (P=0.48).

CONCLUSIONS

Despite screening, we found autoantibodies commonly at baseline, during treatment for chronic hepatitis C and after. The presence of antibodies did not correlate with viral response, adverse effects, or autoimmune hepatitis. Neither screening nor archived samples assayed for thyroid and diabetes-related antibodies identified the 3 subjects who developed overt autoimmune disease, diabetes (1), and hypothyroidism (2).

Autoimmunity and extrahepatic manifestations in treatment-naïve children with chronic hepatitis C virus infection

Hepatitis C virus (HCV) infection has been associated with autoimmunity and extrahepatic manifestations in adults. Few data are available on these topics in children. Nonorgan specific auto-antibodies development is part of the natural course of chronic hepatitis C in children. Smooth muscle autoantibody is the most common autoantibody found, while liver-kidney microsomal type-1 antibody positivity is the most peculiar autoimmune feature of children with HCV infection. The clinical significance of non-organ specific autoantibodies in the course of paediatric chronic hepatitis C is still debated. Autoantibody positivity can be considered neutral for most patients, while it can be associated with negative connotations for others, especially those positive for liver-kidney microsomal type-1 autoantibody. Subclinical hypothyroidism but not autoimmune thyroiditis has been demonstrated in HCV infection in children, while only few cases of HCV-associated membranoproliferative glomerulonephritis have been described. Single reports are available in the literature reporting the anecdotal association between chronic hepatitis C and other extrahepatic manifestations such as myopathy and opsoclonus-myoclonus syndrome. Despite the low incidence of extrahepatic manifestations of chronic hepatitis C in children, overall, available data suggest a careful monitoring.

Management of chronic hepatitis C in childhood: the impact of therapy in the clinical practice during the first 2 decades

BACKGROUND AND AIM

Treatment of chronic hepatitis C in children is controversial and its role in the clinical practice is unknown. We retrospectively investigated the impact of treatment in a large cohort of children with chronic hepatitis C over the past 20 years.

METHODS

376 hepatitis C virus RNA positive children were recruited consecutively in five Italian centres since 1990 and followed for 1-17 years.

RESULTS

86 (23%) subjects were treated: 73 with recombinant interferon alone and 13 with pegylated-interferon and ribavirin. Sustained clearance of hepatitis C virus RNA was observed in 25% of the former, in 92% of the latter and in 9% of untreated cases (p < 0.001). Loss of viraemia was recorded in all children with genotype 2-3 and in 6 of 7 with hepatitis C virus genotype 1 treated with combination therapy. At last evaluation 45% of patients were young adults and 15% had cleared viraemia. Overall, 152 (40%) were putative candidates to therapy.

CONCLUSIONS

Few Italian children with chronic hepatitis C have been treated in the past 20 years. The poor propensity to spontaneous clearance of viraemia and the efficacy of combination therapy should encourage to consider treatment in attempt to shorten the duration of viral replication.

Chronic hepatitis C virus infection in children and adolescents: Epidemiology, natural history, and assessment of the safety and efficacy of combination therapy

Hepatitis C virus (HCV) is the most common cause of chronic liver disease of infectious etiology in children. Most of the children infected with HCV are asymptomatic, and only a few of them develop signs and symptoms of end-stage liver disease early in life. It is not possible to predict either in which patients HCV infection will have a bad outcome or the critical time in early adulthood when disease progression will accelerate. The experiences with therapy in children with chronic hepatitis C are based on earlier and continuing data from adult trials. The currently recommended treatment for chronic HCV infection in adults is the combination of peginterferon-á and ribavirin. The choice of this regimen is based on the results of randomized clinical trials that demonstrated the superiority of this combination treatment over standard interferon-á and ribavirin. Recently, results of pivotal, multicenter, interventional open-label studies on combined treatment with peginterferon-á and ribavirin in children have been published, and the US Food and Drug Administration and the European Medicines Agency have approved the combination therapy in those older than 3 years. The aim of this review is to evaluate critically the available data regarding the safety and efficacy of combination treatment with peginterferon-á and ribavirin in children.

Treatment of hepatitis C in children

Hepatitis C affects 4-10% of children born to infected mothers, and 80% of them develop chronic infection. Most patients with chronic hepatitis C virus infection are asymptomatic, with persistent or intermittent biochemical abnormalities. Severe liver disease may develop 10 years after onset of infection, with a less than 2% overall risk during the pediatric age. Available therapies have no contraindication in children if otherwise healthy. The US FDA and EMEA have recently approved combined pegylated-IFN-alpha 2b plus ribavirin treatment for children, who should be over 3 years of age in order to avoid severe side effects. Experiences in pilot trials and international studies indicate a response rate of 50% in genotype 1 patients, and more than 90% in genotype 2 or 3 patients, indicating resolution of chronic disease.

Long-term course of chronic hepatitis C in children: from viral clearance to end-stage liver disease

BACKGROUND & AIMS

The natural course of chronic hepatitis C (CHC) in children is not well understood. The aim of this study was to assess the long-term course of CHC in a large sample of otherwise healthy children.

METHODS

From 1990 to 2005, 504 consecutive antihepatitis C virus (HCV)-positive children were enrolled at 12 centers of a national observatory and were followed up retrospectively/prospectively.

RESULTS

Putative exposure was perinatal in 283 (56.2%) cases, parenteral in 158 (31.3%), and unknown in 63 (12.5%). At baseline, 477 (94.6%) cases were HCV RNA seropositive, 118 (24.7%) of which were treated with standard interferon alpha. Ten years after putative exposure, the outcome in 359 HCV RNA-positive, untreated patients was (1) undetectable viremia in 27 (7.5%) (by Cox regression analysis, spontaneous viral clearance was independently predicted by genotype 3 [hazard ratio 6.44; 95% confidence interval: 2.7-15.5]) and (2) persistent viremia in 332 (92%) cases. Six of these 332 cases (1.8%) progressed to decompensated cirrhosis (mean age, 9.6 years). This latter group included 5 Italian children perinatally infected with genotype 1a (4 of the mothers were drug users). Thirty-three (27.9%) treated patients achieved a sustained virologic response.

CONCLUSIONS

Over the course of a decade, few children with chronic HCV infection cleared viremia spontaneously, and those who did were more likely to have genotype 3. Persistent viral replication led to end-stage liver disease in a small subgroup characterized by perinatal exposure, maternal drug use, and infection with HCV genotype 1a. Children with such features should be considered for early treatment.

Efficacy and safety of peginterferon-alpha2b and ribavirin combination therapy in children with chronic hepatitis C infection

BACKGROUND

Interferon (IFN)-alpha2b plus ribavirin is approved for treatment of hepatitis C in children; however, little is known about efficacy and tolerability of pegylated IFN (PEG-IFN)-alpha2b in this population. The objective of this study was to test the efficacy and safety of PEG-IFN-alpha2b plus ribavirin in children with chronic hepatitis C.

METHODS

Thirty children 3-16 years of age who had detectable hepatitis C virus (HCV) RNA for >or=3 years after exposure and elevated alanine aminotransferase values received PEG-IFN-alpha2b 1.0 microg/kg/wk plus ribavirin 15 mg/kg/d for 24 weeks (genotype 2/3) or 48 weeks (genotype 1/4). The primary endpoint was sustained virologic response (SVR), defined as undetectable HCV RNA (<50 IU/mL) at week 24 of follow-up.

RESULTS

SVR was achieved in 50% of patients (3/3 genotype 3; 12/27 genotype 1/4). At week 12, 52% of patients were HCV RNA negative and 72% had a >2 log10 decrease in viral load, compared with baseline; 87% and 71% of these patients, respectively, attained an SVR. Therapy was discontinued in 3 patients as a result of adverse events. No patient required ribavirin dose reduction; PEG-IFN-alpha2b dose was reduced in 23% of patients to manage neutropenia.

CONCLUSIONS

Combination therapy with PEG-IFN-alpha2b and ribavirin treatment was effective in children with chronic hepatitis C. Virologic status at week 12 identified future responders and nonresponders. PEG-IFN-alpha2b and ribavirin were reasonably well tolerated, with no unexpected or permanent adverse effects. Further studies are needed to identify the optimum treatment regimen for this patient population.

Hepatitis C virus infection acquired in childhood

Hepatitis C virus (HCV) infection occurs less frequently in children than in adult patients, and the natural history, prognosis, and clinical significance of HCV infection in children are poorly defined. We report here a descriptive follow-up of the clinical course, biochemical data, and viral markers observed in 37 children with anti-HCV. Ten patients included in the study tested persistently negative for serum HCV-RNA (group 1) and 27 patients tested persistently positive (group 2). In group 1, serum alanine aminotransferase (ALT) was normal in all patients, while two patients had non-organ-specific autoantibodies. In group 2, serum ALT was elevated in 13 of 27 patients, and five patients had non-organ-specific autoantibodies. HCV genotype 1a and 1b were the most prevalent among HCV-RNA-positive patients. Twenty liver biopsies were carried out on 17 patients in our series (mean evolution time, 11.2 years; range, 3-21 years). The liver specimens showed mild necroinflammatory changes in most patients, and fibrosis was absent or low grade. Two HCV-RNA-positive patients became persistently HCV-RNA negative. Of the 26 children investigated, 7 (one in group 1, six in group 2) had a co-infection with hepatitis G virus. Conclusion Most children chronically infected with HCV were asymptomatic and presented only mild biochemical evidence of hepatic injury. Autoimmunity in the form of non-organ-specific autoantibodies was common. HCV in children induced mild changes in the liver with a low level of fibrosis and at a low rate of progression.

Thyroid function and anti-thyroid autoantibodies in untreated children with vertically acquired chronic hepatitis C virus infection

OBJECTIVE

The reported data on thyroid function and anti-thyroid autoantibodies in adults with untreated hepatitis C virus (HCV) infection are controversial. Data are scarce for HCV-infected children, and only in those treated with interferon-alpha (IFN-alpha). We investigated thyroid function and anti-thyroid autoantibodies in a cohort of untreated children with vertically acquired, chronic, HCV infection.

DESIGN AND PATIENTS

FT4 and TSH serum levels (measured by immunometric assays) and anti-thyroglobulin (TgA) and anti-thyroperoxidase (TPOA) antibodies (evaluated by fluorescence enzymatic immunoassays) were studied in 36 consecutive HCV-infected children and 150 age- and sex-matched controls. The prevalence of thyroid involvement was also related to family history of autoimmune disease, distribution of HCV genotypes, and duration and activity of HCV infection.

RESULTS

Four out of 36 (11.1%) HCV-infected children and 4/150 controls (2.7%) showed subclinical hypothyroidism [P = 0.04; relative risk (RR) 4.56, 95% confidence interval (CI) 1.08-19.21]. None of these had anti-thyroid autoantibodies. Two out of 36 (5.6%) HCV-infected children and 1/150 (0.7%) controls had increased TgA values with normal levels of TSH (P > 0.05). Subclinical hypothyroidism and anti-thyroid autoantibodies were not related to family history of autoimmune disease, duration of infection, HCV viral load, liver function or different HCV genotype distribution, but seemed to be related to the presence of active HCV infection.

CONCLUSIONS

Our data suggest a role for HCV infection in the development of nonautoimmune thyroid disease in untreated HCV-infected children, confirming previous studies in adults. Clinicians should be aware of thyroid dysfunction even in untreated children.

Clinical spectrum and histopathologic features of chronic hepatitis C infection in children

OBJECTIVE

To define the natural history and outcomes of children infected with hepatitis C virus (HCV) at birth or in early childhood.

STUDY DESIGN

This retrospective, prospective study identified 60 HCV-infected children through a transfusion look-back program (group 1) and by referrals (group 2). Perinatal/transfusion history, clinical course, and laboratory studies were correlated with findings from 42 liver biopsy specimens.

RESULTS

Mean age at infection was 7.1 months, and duration of infection 13.4 years. The sources of infection were blood transfusion (68%), perinatal transmission (13%), and both (7%). Most patients were asymptomatic; three referral patients had advanced liver disease at presentation. Mean alanine aminotransferase level was normal in 25%, 1 to 3 times normal in 62%, and greater than 3 times normal in 13%. Liver biopsy specimens showed minimal to mild inflammation in 71%, absent or minimal fibrosis in 88%, and bridging fibrosis in 12%. Age at infection and serum gamma-glutamyltranspeptidase correlated with fibrosis; serum alanine aminotransferase correlated with inflammation unless complicated by comorbidity. Repeat biopsies within 1 to 4 years in four patients showed no significant progression in three and cirrhosis in one. Two patients died after liver transplantation.

CONCLUSIONS

Children with chronic HCV infection are generally asymptomatic. By 13 years after infection, 12% of patients had significant fibrosis. Patients enrolled by referral had more severe liver disease than those identified through the look-back program, demonstrating the importance of selection bias in assessing the long-term outcome of HCV infection.

Evidence of a genetic basis for the different geographic occurrences of liver/kidney microsomal antibody type 1 in hepatitis C

Antibodies to liver/kidney microsome type 1 occur in Italian patients with hepatitis C, but rarely develop in North American patients. Our goals were to compare the frequencies of the HLA markers associated with autoimmune expression in Italian and North American patients with chronic hepatitis C and to determine genetic bases for regional differences in antibody production. HLA B8, DR3, DR4, DR7, DR11, DR13, DQ2, and the B8-DR3-DQ2 haplotype were determined by microlymphocytotoxicity and polymerase chain reaction in 105 Italian patients (50 with microsomal antibodies), 100 North American patients (none with microsomal antibodies), and Italian and North American healthy control subjects. Italian patients with microsomal antibodies differed from North American patients without these antibodies by having a higher frequency of HLA DR7 (54% vs. 27%, P=0.002). HLA DR7 occurred more frequently in seropositive Italian patients than in seronegative counterparts (54% vs. 11% P < 0.0001), Italian healthy control subjects (54% vs. 29%, P=0.0009), and North American healthy control subjects (54% vs. 19%, P < 0.0001). The frequency of HLA DR7 was similar in North American patients and controls (27% vs. 19%, P=0.2), but it was lower than in Italian controls (19% vs. 29%, P=0.059). Seropositive Italian patients had a lower frequency of HLA DR11 than seronegative Italian patients and Italian controls (18% vs. 34%, P=0.07, and 18% vs. 35%, P=0.02, respectively). In contrast to seropositive Italian patients, North American patients had HLA DR4 (30% vs. 12%, P=0.02), HLA DR13 (29% vs. 10%, P=0.01), and the B8-DR3-DQ2 haplotype (23% vs. 6%, P=0.01) more often. Similarly, HLA DR4 and the B8-DR3-DQ2 phenotype were more frequent in North American patients than in Italian controls (30% vs. 16%, P=0.005, and 23% vs. 7%, P=0.00002, respectively). HLA DR7 is associated with the development of microsomal antibodies in Italian patients with chronic hepatitis C. The lower frequency of HLA DR7 in North America could contribute to the rarity of these antibodies in this region. HLA DR11 may be protective against the development of microsomal antibodies in Italian patients, whereas HLA DR4, HLA DR13, and the B8-DR3-DQ2 haplotype may be protective in North American patients.

New horizon of MDR1 (P-glycoprotein) study

MDR1 (once P-glycoprotein, now referred to as ABCB1) plays a role as a blood-brain barrier, preventing drug absorption into the brain, and is known to confer multiple drug resistance in cancer chemotherapy. MDR1 is composed of two repeated fragments, and there are six transmembrane domains (TMD) on the N-terminal of each repeat and a nucleotide (ATP) binding domain (NBD) on the C-terminal. These two repeats are dependent but cooperate as one functional molecule, with one pocket for excreting drugs. The 12 TM domains form a funnel facing the outside of cells, and NBD is in cytosol as a dimer. One NBD is composed of the Walker A, Q-loop, ABC-signature and the Walker B for phosphate binding of nucleotide. This tertiary structure of MDR1 is suggested from the structure of the NBD of histidine permease (HisP), clarified by x-ray crystallography. On the model of HisP, the NBD positions described above make a functional domain, and the same NBD structure is found on many other ABC transporters. An experiment with MDR1 gene knockout mice showed the high plasma AUC of drugs in mdr null mice [mdr1a(-/-)] and a high level in the brain, indicating that MDR1 has an efflux function (prevention of absorption) in the intestinal lumen and acts as a barrier of drug uptake in the brain, as well as has the function of urinary and biliary excretion of drugs. The transcription of MDR1 is dependent on two sites; the promoter site (-105/-100)(-245/-141) and the enhancer site (-7864/-7817). Autoantibody from autoimmune hepatitis patients weakly reacted with the extracellular peptide (aa314-aa328 between TM5 and 6) of MDR1 on the outside of the cell membrane, and did not react with peptides in the NBD and in the membrane-spanning region in TM5. There is an ambiguity about the function of MDR1 as GlcCer translocase.

Chronic hepatitis C in childhood: an 18-year experience

BACKGROUND

The long-term outcome of chronic hepatitis C (CHC) has not been well studied, both for untreated and interferon-treated children. The aim of this study was to evaluate the long-term outcome of disease in a large series of children with CHC.

METHODS

Clinical, biochemical, virological, and histological features were evaluated in all children (age, 2-18 years) with CHC who did not have concomitant disease and who attended at our hospital's liver unit during the period of 1986-2004.

RESULTS

One hundred twenty-five children with CHC were studied. All patients remained free of symptoms throughout the period of observation. On the basis of transaminase levels during the first year of positivity for antibodies to hepatitis C virus (HCV), children were divided into 2 groups: patients with hypertransaminasemia (100 patients, all of whom had detectable HCV RNA), and those with normal transaminases (25 patients; 16 had viremia and 9 did not have viremia). Sustained clearance of viremia was achieved in 38% of the patients treated with interferon, compared with 12% of untreated children (P<.05). A sustained response to therapy was obtained in 64.7% of children infected with an HCV genotype other than genotype 1 and in 24.2% of those infected with HCV genotype 1 (P<.05). Histological lesions were mild in all 64 patients who underwent liver biopsy. No linear correlation was found between duration of disease and progression of fibrosis. Examination of a follow-up liver biopsy specimen revealed cirrhosis only in 1 (4.7%) of 21 children.

CONCLUSIONS

Children with CHC were symptom free and had a morphologically mild liver disease. Interferon therapy may be effective for patients infected with HCV genotypes other than genotype 1, whereas lower response rates are expected for HCV genotype 1-infected children. The real impact of therapy on long-term outcome remains to be established.

LKM1 autoantibodies in chronic hepatitis C infection: a case of molecular mimicry?

Anti-liver-kidney microsome type 1 (LKM1) autoantibodies directed against the cytochrome P450 2D6 (CYP2D6) are considered specific markers of type 2 autoimmune hepatitis, but are also found in 5% of sera from patients chronically infected by hepatitis C virus (HCV). Molecular mimicry between HCV proteins and CYP2D6 has been proposed to explain the emergence of these autoantibodies. Anti-LKM1 autoantibodies from hepatitis C-infected patients were affinity-purified against immobilized CYP2D6 protein and used to screen a phage display library. CYP2D6 conformational epitopes were identified using phage display analysis and the identification of statistically significant pairs (SSPs). Cross-reactivity between CYP2D6 and HCV protein candidates was tested by immunoprecipitation. Nineteen different clones were isolated, and their sequencing resulted in the mapping of a conformational epitope to the region of amino acids 254-288 of CYP2D6. Candidate HCV proteins for molecular mimicry included: core, E2, NS3 and NS5a. Affinity-purified autoantibodies from HCV+/LKM1+ patients immunoprecipitated either NS3, NS5a, or both, and these reactivities were specifically inhibited by immobilized CYP2D6. In conclusion, HCV+/LKM1+ sera recognize a specific conformational epitope on CYP2D6 between amino acids 254 to 288, the region that contains the major linear epitope in type 2 autoimmune hepatitis patients. Cross-reactivity due to molecular mimicry at the B-cell level was shown between the CYP2D6 and the HCV NS3 and NS5a proteins and could explain the presence of anti-LKM1 in patients chronically infected with HCV. Further investigation of the role played by this molecular mimicry in HCV-infected patients may lead to more specific strategies for diagnosis and treatment.

The management of HCV infected pregnant women and their children European paediatric HCV network

BACKGROUND/AIMS

As evidence accumulates relating to mother-to-child (vertical) transmission of hepatitis C virus (HCV), it is timely to draw up guidelines for the clinical management of HCV infected pregnant women and their children.

METHODS

A review of evidence from the European Paediatric HCV Network (EPHN) prospective study of HCV infected women and their children and other published studies. Meeting of EPHN clinical experts to reach a consensus on recommendations for management. Each recommendation was graded according to the level of evidence.

RESULTS/CONCLUSIONS

Although several risk factors for mother-to-child transmission have been identified, none are modifiable and there are currently no interventions available to prevent vertical transmission of HCV. Data on timing of loss of maternal antibodies and reliability of diagnostic tests inform the optimum follow-up schedule for confirmation or exclusion of infection in children born to HCV infected women. Based on the current evidence, routine antenatal screening for HCV should not be introduced and neither elective caesarean section nor avoidance of breastfeeding should be recommended to HCV infected women to prevent mother-to-child transmission of HCV. HCV/HIV co-infected women should follow existing HIV guidelines.

Autoantibodies against CYP2D6 and other drug-metabolizing enzymes in autoimmune hepatitis type 2

Autoimmune hepatitis (AIH) is a disease of unknown etiology, characterized by liver-related autoantibodies. Autoimmune hepatitis is subdivided into two major types: AIH type 1 is characterized by the detection of ANA, SMA, ANCA, anti-ASGP-R, and anti-SLA/LP. Autoimmune hepatitis type 2 is characterized to be mainly related with drug-metabolizing enzymes as autoantigens, such as anti-LKM (liver-kidney microsomal antigen)-1 against CYP2D6, anti-LKM-2 against CYP2C9-tienilic acid, anti-LKM-3 against UGT1A, and anti-LC1 (liver cytosol antigen)-1 and anti-APS (autoimmune polyglandular syndrome type-1) against CYP1A2, CYP2A6, and others. Anti-LKM-1 sera inhibited CYP2D6 activity in vitro but did not inhibit cellular drug metabolism in vivo. CYP2D6 is the major target autoantigen of LKM-1 and expressed on plasma membrane (PM) of hepatocytes, suggesting a pathogenic role for anti-LKM-1 in liver injury as a trigger. Anti-CYP1A2 was observed in dihydralazine-induced hepatitis, and radiolabeled CYP1A2 disappeared from the PM with a half-life of less than 30 min, whereas microsomal CYP1A2 was stably radiolabeled for several hours. Main antigenic epitopes on CYP2D6 are aa 193-212, aa 257-269, and aa 321-351; and D263 is essential. The third epitope is located on the surface of the protein CYP2D6 and displays a hydrophobic patch that is situated between an aromatic residue (W316) and histidine (H326). Some drugs such as anticonvulsants (phenobarbital, phenytoin, and carbamazepine) and halothane are suggested to induce hepatitis with anti-CYP3A and anti-CYP2E1, respectively. Autoantibodies against CYP11A1, CYP17, and/or CYP21 involved in the synthesis of steroid hormones are also detected in patients with adrenal failure, gonadal failure, and/or Addison disease.

Clinical impact of non-organ-specific autoantibodies on the response to combined antiviral treatment in patients with hepatitis C

BACKGROUND

Hepatitis C virus (HCV)-related chronic hepatitis is frequently associated with non-organ-specific autoantibodies (NOSAs), but available data about the relationship between NOSA positivity and the effect of antiviral therapy in persons with hepatitis C are few and controversial. Our aim was to evaluate the impact of NOSA positivity on the outcome of combined antiviral therapy in HCV-positive patients.

METHODS

A total of 143 consecutive adult patients with hepatitis C were studied. Antinuclear antibody (ANA), anti-smooth muscle antibody (SMA), and anti-liver/kidney microsomal antibody type 1 (LKM1) were detected by indirect immunofluorescence. All patients were treatment naive and received combined antiviral therapy (interferon [IFN]-ribavirin) after enrollment in the study. Patients were classified as nonresponders if HCV RNA was detectable after 6 months of therapy, as relapsers if abnormal transaminase levels and reactivation of HCV replication were observed after the end of treatment, and as long-term responders if transaminase levels were persistently normal and HCV RNA was undetectable 6 months after the end of treatment.

RESULTS

Thirty-seven patients (25%) were NOSA positive (SMA was detected in 19 patients, ANA in 10, ANA and SMA in 4, LKM1 in 3, and SMA and LKM1 in 1). The prevalence of long-term response was similar between NOSA-positive patients and NOSA-negative patients (48.6% vs. 56.6%; P=not significant). Compared with HCV genotype 1 (HCV-1), HCV genotypes other than 1 were more often associated with long-term response among NOSA-positive patients (93.3% vs. 30%; P=.0017). The overall rate of long-term response, irrespective of NOSA status, was 54.5%. Detection of HCV-1 and elevated gamma-glutamyl transpeptidase serum levels were independent negative prognostic factors of treatment response (P=.007 and P=.026, respectively).

CONCLUSIONS

Combined antiviral treatment (IFN-ribavirin) is safe and effective in NOSA-positive patients with hepatitis C, even if long-term response is less likely in those infected with HCV-1.

Hepatitis C virus-related extra-hepatic disease--aetiopathogenesis and management

Summary Hepatitis C virus infection is often associated with extra-hepatic manifestations, secondary to the elicitation of autoimmune reactions, generalized deposition of immune complexes and lymphoproliferative disorders. The most clearly established associations are those linking chronic hepatitis C with mixed cryoglobulinaemia (and the related glomerulonephritis and cutaneous vasculitis), as well as with the presence of autoantibodies. Less well-documented disorders include non-Hodgkin's lymphoma, thrombocytopenia, sialadenitis, thyroid disease, lichen planus, porphyria cutanea tarda, rheumatoid disorders and neurological disorders. Extra-hepatic manifestations are most frequent in patients of female sex, advanced age, long-lasting infection and cirrhosis. Optimal treatment strategies should be based on the predominant manifestation of the disease. In the case of autoimmune disorders not clearly attributable to the viral infection, corticosteroids may be the most effective option. Interferon-alpha alone or in combination with ribavirin may be indicated for those disorders related to immune complex deposition, such as mixed cryoglobulinaemia, although relapses of extra-hepatic signs often occur on discontinuation of treatment. In some cases, interferon-alpha may induce or exacerbate some extra-hepatic manifestations.

Non-organ-specific autoantibodies in children with chronic hepatitis C: clinical significance and impact on interferon treatment

We evaluated the prevalence and clinical significance of non-organ-specific autoantibodies (NOSAs) in 47 hepatitis C virus (HCV)-positive children with abnormal alanine transaminase levels and analyzed the association between NOSAs and virus level, genotype, human leukocyte antigen status, and interferon (IFN) response. Forty-two hepatitis B virus (HBV)-positive children and 25 age- and sex-matched healthy children served as control subjects. NOSAs were found in 34% of the HCV-positive children, 12% of the HBV-positive controls, and none of the healthy control subjects. Liver-kidney microsomal antibody type 1 (LKM1) was detected in 11% of the HCV-positive children but in none of the controls. The HCV load was significantly higher in NOSA-negative than in NOSA-positive children. HCV genotype distribution and human leukocyte antigen alleles were similar, irrespective of NOSA status. Long-term response to IFN therapy was achieved by 18% of the NOSA-positive and 55% of the NOSA-negative subjects. Two LKM1-positive children developed acute, self-limited hepatocellular necrosis while receiving IFN therapy. NOSAs are frequently present in children with hepatitis C, who are less likely to benefit from IFN therapy.