Management strategies for hepatitis C virus infection in children

Mechanisms of methods for hepatitis C virus inactivation

Virus inactivation by chemical disinfectants is an important instrument for infection control in medical settings, but the mechanisms involved are poorly understood. In this study, we systematically investigated the effects of several antiviral treatments on hepatitis C virus (HCV) particles as model for enveloped viruses. Studies were performed with authentic cell culture-derived viruses, and the influence of chemical disinfectants, heat, and UV treatment on HCV was analyzed by the determination of infectious particles in a limiting-dilution assay, by quantitative reverse transcription-PCR, by core enzyme-linked immunosorbent assay, and by proteolytic protection assay. All different inactivation methods resulted in a loss of HCV infectivity by targeting different parts of the virus particle. Alcohols such as ethanol and 2-propanol did not affect the viral RNA genome integrity but disrupted the viral envelope membrane in a capsid protection assay. Heat and UV treatment of HCV particles resulted in direct damage of the viral genome since transfection of viral particle-associated RNA into permissive cells did not initiate RNA replication. In addition, heat incubation at 80°C disrupted the HCV envelope, rendering the viral capsid susceptible to proteolytic digest. This study demonstrated the molecular processes of viral inactivation of an enveloped virus and should facilitate the development of effective disinfection strategies in infection control not only against HCV but also against other enveloped viruses.

Inactivation of hepatitis C virus infectivity by human breast milk

BACKGROUND

Hepatitis C virus (HCV) is spread through direct contact with blood, although alternative routes of transmission may contribute to the global burden. Perinatal infection occurs in up to 5% of HCV-infected mothers, and presence of HCV RNA in breast milk has been reported. We investigated the influence of breast milk on HCV infectiousness.

METHODS/RESULTS

Human breast milk reduced HCV infectivity in a dose-dependent manner. This effect was species-specific because milk from various animals did not inhibit HCV infection. Treatment of HCV with human breast milk did not compromise integrity of viral RNA or capsids but destroyed the lipid envelope. Fractionation of breast milk revealed that the antiviral activity is present in the cream fraction containing the fat. Proteolytic digestion of milk proteins had no influence on its antiviral activity, whereas prolonged storage at 4°C increased antiviral activity. Notably, pretreatment with a lipase inhibitor ablated the antiviral activity and specific free fatty acids of breast milk were antiviral.

CONCLUSIONS

The antiviral activity of breast milk is linked to endogenous lipase-dependent generation of free fatty acids, which destroy the viral lipid envelope. Therefore, nursing by HCV-positive mothers is unlikely to play a major role in vertical transmission.

Pegylated interferon alfa and ribavirin for children with chronic hepatitis C

AIM: To study current treatment options for pediatric hepatitis C infection and their associated success rates.

METHODS: We retrospectively reviewed charts of thirty children who had been treated with combination therapy of pegylated interferon alfa plus ribavirin for chronic hepatitis C infection. Patients had been treated with ribavirin (15 mg/kg per day) and either pegylated interferon alfa 2a (180 mg/m² once weekly) or pegylated interferon alfa 2b (1.5 mg/kg once weekly). Patients’ follow-up included subjective assessment of complaints, physical examination including weight and height, as well as laboratory evaluations for viral load [before treatment, at 12 wk, and 6 mo following treatment completion, as determined by sustained viral response (SVR)], complete blood count, liver enzymes, alkaline phosphatase, bilirubin, renal function tests, and thyroid function tests. For patients not achieving a two log decrease in viral load at treatment week 12, treatment was discontinued and the patient was considered a treatment non-responder.

RESULTS: Thirty children aged 3-18 years were included in the study. Twenty patients (11 males, 9 females) received pegylated interferon alfa 2b and ten patients (6 males, 4 females) received pegylated interferon alfa 2a. Twenty-three patients were infected with genotype 1, six patients were infected with genotype 3, and one patient was infected with genotype 2. Twenty patients (67%) achieved SVR. Treatment success rates were 90% with pegylated interferon alfa 2a vs 55% with pegylated interferon alfa 2b. Although a trend was noted for improved outcomes in the group receiving pegylated interferon alfa 2a, there were no statistically significant outcome differences between the two treatment groups (P = 0.1). Treatment success was 56.5% for patients infected with genotype 1 virus, compared to 100% for patients infected with other genotypes (P = 0.064). There was no difference in treatment response between males and females. A cut-off age of twelve years was used to dichotomize younger vs older participants; however, no difference in treatment response was observed between these groups. Using multivariate regression analysis, we could not determine predictors for achieving SVR from among the variables we examined (age, sex, and viral genotype). Although we noted a trend toward SVR with peginterferon alfa-2a, there was no statistical difference between the two peginterferons. A high incidence of adverse reactions to treatment was noted. Twenty-five patients (83%) suffered from at least one adverse reaction, but most experienced more than one adverse reaction. All patients except one became leukopenic (white blood cell count less than 5500 leukocytes/μL), six (20%) became anemic (hemoglobin less than 110 g/L), and one (3.3%) became thrombocytopenic (platelets less than 100 000/μL).

CONCLUSION: Combination therapy to treat hepatitis C in children is as effective as in adults. There may be a benefit for treatment with pegylated interferon alfa 2a.

Medical management of chronic liver diseases in children (part I): focus on curable or potentially curable diseases

The management of children with chronic liver disease (CLD) mandates a multidisciplinary approach. CLDs can be classified into 'potentially' curable, treatable non-curable, and end-stage diseases. Goals pertaining to the management of CLDs can be divided into prevention or minimization of progressive liver damage in curable CLD by treating the primary cause; prevention or control of complications in treatable CLD; and prediction of the outcome in end-stage CLD in order to deliver definitive therapy by surgical procedures, including liver transplantation. Curative, specific therapies aimed at the primary causes of CLDs are, if possible, best considered by a pediatric hepatologist. Medical management of CLDs in children will be reviewed in two parts, with part I (this article) specifically focusing on 'potentially' curable CLDs. Dietary modification is the cornerstone of management for galactosemia, hereditary fructose intolerance, and certain glycogen storage diseases, as well as non-alcoholic steatohepatitis. It is also essential in tyrosinemia, in addition to nitisinone [2-(nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione] therapy, as well as in Wilson disease along with copper-chelating agents such as D-penicillamine, triethylenetetramine dihydrochloride, and ammonium tetrathiomolybdate. Zinc and antioxidants are adjuvant drugs in Wilson disease. New advances in chronic viral hepatitis have been made with the advent of oral antivirals. In children, currently available drugs for the treatment of chronic hepatitis B virus infection are standard interferon (IFN)-α-2, pegylated IFN-α-2 (PG-IFN), and lamivudine. In adults, adefovir and entecavir have also been licensed, whereas telbivudine, emtricitabine, tenofovir disoproxil fumarate, clevudine, and thymosin α-1 are currently undergoing clinical testing. For chronic hepatitis C virus infection, the most accepted treatment is PG-IFN plus ribavirin. Corticosteroids, with or without azathioprine, remain the basic strategy for inducing remission in autoimmune hepatitis. Ciclosporin (cyclosporine) and other immune suppressants may be used for patients who do not achieve remission, or who have significant side effects, with corticosteroid/azathioprine therapy. The above therapies can prevent, or at least minimize, progression of liver damage, particularly if started early, leading to an almost normal quality of life in affected children.

Current therapies for chronic hepatitis C

Hepatitis C virus affects more than 180 million people worldwide and as many as 4 million people in the United States. Given that most patients are asymptomatic until late in the disease progression, diagnostic screening and evaluation should be performed in patients who display high-risk behaviors associated with acquisition of hepatitis C. Chronic hepatitis C is associated with cirrhosis, hepatic failure, and death; therefore, treatment is aimed at reducing these complications, as well as improving quality of life and minimizing adverse effects. The American Association for the Study of Liver Diseases Practice Guidelines on the Diagnosis, Management, and Treatment of Hepatitis C represent the gold standard for guidance on the management of hepatitis C. Standard treatment for hepatitis C is peginterferon alpha in combination with ribavirin. Currently, two pegylated interferon products are approved by the U.S. Food and Drug Administration for the treatment of hepatitis C. The duration of therapy with peginterferon and ribavirin is dictated by viral genotype and virologic response. Additional therapies are under investigation for treatment of chronic hepatitis C and show early promise of comparative efficacy and fewer adverse effects. Special considerations in certain populations, including patients coinfected with human immunodeficiency virus, those with end-stage renal disease, injection drug users, pregnant women, and pediatric patients, should guide treatment decisions.

Re-treatment of children with chronic hepatitis C who did not respond to interferon-alpha treatment

BACKGROUND

Many patients with chronic hepatitis C do not respond to antiviral treatment. In adult patients the re-treatment of these patients has been extensively investigated. Because the response to re-treatment in children is not well defined we evaluated the efficacy and safety of interferon (IFN)-alpha plus ribavirin in patients who have failed to respond to previous treatment.

PATIENTS AND METHODS

In an open-label, uncontrolled study, 18 chronically infected children were investigated. Fifteen children had been treated with IFN-alpha plus ribavirin and 3 patients with IFN-alpha alone. Fourteen patients were nonresponders; 4 experienced viral breakthrough during treatment and/or relapse after treatment. Patients received IFN-alpha 3 times per week subcutaneously plus ribavirin for 48 weeks. Sixteen patients were infected with hepatitis C virus (HCV) genotype 1, 2 with genotype 4, and 1 with genotype 3 and co-infection with hepatitis B.

RESULTS

Four patients showed early viral response to therapy and became HCV-RNA negative after 12 weeks. Sustained viral response (HCV-RNA negative 6 months after end of treatment) was documented in 2 of them. These 2 patients belonged to the group of 4 children who relapsed or experienced a viral breakthrough during previous treatment. None of the 14 patients with prior nonresponse had sustained viral response.

CONCLUSIONS

Re-treatment with IFN-alpha plus ribavirin may be useful in children who relapsed in a previous antiviral treatment but seems not to be useful in nonresponders. These results are in line with studies from adult patients and should be therefore encouraged to provide a second chance for healing in a subgroup of patients.

Managing HCV infection in pediatric age group: suggested recommendations

Hepatitis C virus (HCV) infection in children is different from the adult infection in many ways, like natural course of the disease; duration, therapeutic response and side effects profile of the drug therapy; and prognosis. Special considerations include consideration on what could be the appropriate time to investigate a suspected child, when to institute drug therapy and how to prevent vertical transmission. Although over the past one decade many landmark studies have greatly increased our insight on this subject, yet we are far from developing a consensus statement. In this article, a concise yet comprehensive review of HCV infection in children - diagnosis and treatment - is given, followed by suggested recommendations at the end. It is hoped that these recommendations will help develop local guidelines on this subject.