Chronic viral hepatitis in childhood

Hepatitis B and C

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections represent a major global public health and economic burden, with an estimated 257 million and 71 million people, respectively, having chronic infection worldwide. The natural history of HBV and HCV in children depends on age at time of infection, mode of acquisition, ethnicity, and genotype. Most children infected perinatally or vertically remain asymptomatic but are at uniquely higher risk of developing chronic viral hepatitis, progressing to liver cirrhosis and hepatocellular carcinoma (HCC), hence classifying HBV and HCV as oncoviruses. This article discusses the epidemiology, virology, immunobiology, prevention, clinical manifestations, evaluation, and the advances in treatment of hepatitis B and C in children.

Genetics of transfusion recipient alloimmunization: can clues from susceptibility to autoimmunity pave the way?

The search for genetic determinants of alloimmunization in sickle cell disease transfusion recipients was based on two premises: i) that polymorphisms responsible for stronger immune and/or inflammatory responses and hemoglobin β(S) mutation were co-selected by malaria; and ii) that stronger responder status contributes to development of lupus. We found a marker of alloimmunization in the gene encoding for Ro52 protein, also known as Sjögren syndrome antigen 1 (SSA1) and TRIM21. Surprisingly, the nature of the association was opposite of that with lupus; the same variant of a polymorphism (rs660) that was associated with lupus incidence was also associated with induction of tolerance to red blood cell antigens during early childhood. The dual function of Ro52 can explain this apparent contradiction. We propose that other lupus/autoimmunity susceptibility loci may reveal roles of additional molecules in various aspects of alloimmunization induced by transfusion as well as during pregnancy.

Hepatitis C virus infection in children

The prevalence of hepatitis C virus (HCV) infection is relatively low in childhood, with anti-HCV prevalence rates of 0.1-0.4% in the Western world. To date, blood transfusion has been the principal route of acquisition of HCV in children, but there is evidence that vertical transmission is overtaking it. The overall risk of vertical perinatal transmission of HCV is about 5%, although it increases with HIV co-infection and higher maternal viraemia. The mode of delivery and breastfeeding do not seem to affect the vertical transmission of HCV. Diagnosis of perinatal transmission relies on determination of ALT levels and the presence of HCV after the second month, while maternal anti-HCV antibodies may persist until 18 months of life. After infancy, a variable percentage of perinatally infected children are anti-HCV negative; thus, detection of HCV-RNA is necessary for accurate diagnosis. The natural history of HCV in childhood is not well understood and the outcome depends on host and viral factors. The rate of progression to chronicity is about 60-80% in both post-transfusion and vertically acquired HCV infection. Compared with adult patients, chronic hepatitis C in children is characterized by both low ALT levels and low viral load, as well as by the mildest histological and immunohistochemical forms of chronic hepatitis. The prognosis is usually worse in multitransfused, thalassaemic children and those who have had cancer. Experience of treatment of chronic hepatitis C in children is limited, with about 40% having a sustained response to the interferon therapy. It is necessary to perform long-term follow-up and multicentre treatment studies to improve knowledge of the natural history of HCV in children, as well as that of the efficacy of anti-viral therapy in childhood.

Interferon-alpha treatment of chronic hepatitis B in childhood: a consensus advice based on experience in European children

BACKGROUND

The efficacy of interferon (IFN) in children with chronic hepatitis B has been evaluated in randomized controlled trials over the past decade, but recommendations for treatment based on this experience have not been published yet. The purpose of this workshop, held in Madrid in October 1997, was to provide pediatricians with guidelines for practical use of IFN in hepatitis B.

METHODS

Eighteen European pediatricians and hepatologists agreed to report and discuss their experience on 1,122 treated children, 40% of whom were considered responders.

RESULTS

Agreement was obtained on the following main items: 1) rationale for treatment is to accelerate hepatitis B early antigen (HBeAg) clearance in a subgroup of patients; 2) candidates for treatment are children with HBeAg and HBV DNA positivity, with low-intermediate HBV DNA levels and abnormal alanine aminotransferase values, aged 2 years or more; 3) IFN is contraindicated in children with decompensated liver disease, cytopenia, severe renal or cardiac disorders, and autoimmune disease; 4) the standard treatment regimen is 5 mU/m2 thrice weekly for 6 months. Retreatment in nonresponders is not indicated.

CONCLUSIONS

A consensus was obtained on the use of IFN in children with hepatitis B, based on its short-term efficacy. The long-term clinical and virological effects of the drug, however, remain to be evaluated.