Chronic non-A, non-B hepatitis in pregnancy: outcome and possible transmission to the offspring

No. 96-The Reproductive Care of Women Living With Hepatitis C Infection

OBJECTIVE

hepatitis C virus (HCV) is an increasingly important public health problem worldwide. Health care workers providing care to women of childbearing age are uniquely placed in their practices to identify a significant proportion of at-risk patients and to provide appropriate screening and counselling. The primary objective of this guideline is to provide accurate, current information to those offering reproductive care to women living with HCV. This document is also intended to raise awareness of HCV in both the medical and general populations.

OPTIONS

the areas of clinical practice considered in formulating this guideline are disease prevention, targeted screening of individuals at risk of contracting HCV, management of identified patients in the context of reproductive care, and the appropriate referral of patients to those with particular expertise.

OUTCOMES

implementation of these guidelines should facilitate identification of infected individuals. It should also result in improved physical and mental well-being for patients and their families and reduction in transmission rates.

EVIDENCE

the literature between 1966 and 2000, including non- English language publications, was extensively searched utilizing Medline. A multidisciplinary group consisting of experts within the fields of obstetrics and gynaecology, infectious diseases, hepatology, and public health convened in Montreal in February 2000. The working group also included a patient and a representative from the Hepatitis C Society of Canada. The level of evidence for the recommendations has been determined using the criteria described by the Canadian Task Force on Periodic Health Examination.

BENEFITS, HARMS AND COSTS

the public health benefits of increased identification of at-risk individuals, diagnosis, treatment, implementation of risk reduction behaviours, and reduced transmission rates, both on an individual and at the community level, are significant. However, it must be remembered that the diagnosis of a chronic disease may have far reaching effects for the individual patient and her family.

RECOMMENDATIONS

VALIDATION: references were collected through Medline searches and comparison made to existing current guidelines for assessment of consistency. External reviewers expert in their field were also consulted.

Hepatitis C virus infection in pediatric patients

In contrast to our understanding of hepatitis C virus infection in adults, relatively little is known about the evolution and treatment of HCV infection in pediatric patients. Children at risk for HCV infection include recipients of multiple blood-product transfusions, organ transplantation and infants born to HCV-infected mothers. A proportion of HCV-infected pediatric patients do not have an identifiable risk factor. HCV infection is commonly detected in children previously presumed to have non-A, non-B hepatitis and cryptogenic liver disease. HCV infection usually leads to mild chronic liver disease in children but is also associated with chronic active hepatitis and cirrhosis. Interferon therapy is effective in a proportion of patients with chronic hepatitis C.

Liver transplantation for hepatitis C-associated cirrhosis in a single Australian centre: referral patterns and transplant outcomes

During the study period, 63 patients with hepatitis C virus (HCV) cirrhosis were referred to our unit for liver transplantation. All cases referred and transplanted were retrospectively examined. Eighty-six per cent of referred patients were male, 35% consumed alcohol in the harmful/hazardous range, 13% were infected with hepatitis B and 7% had hepatocellular carcinoma. Patients with sporadic infection were more likely to be born outside Australia and were an average of 10 years older than those with HCV acquired via intravenous drug use (P < 0.001). However, patients were an average of 12 years younger at referral if they consumed harmful amounts of alcohol than if they abstained (P = 0.002). We examined the impact of HCV on the outcome of 28 patients who underwent liver transplantation (mean follow up 25 months; range 3-76 months). The use of OKT3, HCV genotype and hepatitis B status were examined for their effect on HCV-related graft dysfunction. Three year survival was 84%, equivalent to a control group. Chronic HCV-related graft dysfunction occurred in 15 (56%) patients, of whom 10 had an asymptomatic elevation in serum amino transferase, two had cholestatic hepatitis and three had severe hepatitis C that progressed onto chronic rejection. Hepatitis C virus genotype 1b tended to be associated with HCV graft dysfunction (5/6 type 1b vs 10/16 in non-type 1b). In conclusion, HCV is an increasingly common indication for liver transplantation. Alcohol and hepatitis B were frequently occurring cofactors in the referral cohort. Most patients referred were male, although the reason why is not clear. Transplantation offers a good medium-term outcome, despite the high incidence of HCV-associated graft dysfunction.

Hepatitis C genotypes: current trends and future implications

OBJECTIVE

To review the geographic distribution and current understanding of hepatitis C virus (HCV) genotypes in regard to liver disease activity and response to treatment.

MATERIAL AND METHODS

We review the relevant medical literature and discuss our recent findings relative to chronic HCV infection and the importance of HCV genotypes.

RESULTS

HCV genotypes 1a and 1b are the most commonly found genotypes in patients with chronic HCV in the United States. Infection with HCV genotype 1b may be associated with more severe liver disease and may have a higher risk for the development of hepatocellular carcinoma. HCV genotype 2b seemed to be the most sensitive and HCV genotype 1b was the least sensitive to interferon therapy.

CONCLUSION

The identification of the infectious HCV genotype may be beneficial in clinical settings and may assist in the selection of patients who would benefit from interferon treatment.

Immune-mediated liver damage in chronic hepatitis C

Although the exact mechanisms inducing the hepatic injury in chronic hepatitis C infection are still not completely elucidated, the evidence of a direct cytopathic viral effect is sparse. The overall majority of experimental studies and clinical observations among patients instead favour immune-mediated hepatocellular damage. This does not exclude the possibility of direct cytopathic viral effects partly contributing to the cell injury. The immune reaction is not always harmful, however. Instead, an intact immune system is probably important for virus clearance in acute infection and after interferon treatment. The therapeutic possibilities are still not adequate, and attempts to understand the immunologic events and manipulate them could perhaps in the future give us more effective tools in the management of this disease.

Hepatitis C: progress and problems

The hepatitis C virus (HCV), a single-stranded RNA virus, is the major cause of posttransfusion hepatitis. HCV isolates differ in nucleotide and amino acid sequences. Nucleotide changes are concentrated in hypervariable regions and may be related to immune selection. In most immunocompetent persons, HCV infection is diagnosed serologically, using antigens from conserved regions. Amplification of RNA may be necessary to detect infection in immunosuppressed patients. Transmission by known parenteral routes is frequent; other means of spread are less common and may represent inapparent, percutaneous dissemination. Infection can lead to classical acute hepatitis, but most infected persons have no history of acute disease. Once infected, most individuals apparently remain carriers of the virus, with varying degrees of hepatocyte damage and fibrosis ensuing. Chronic hepatitis may lead to cirrhosis and hepatocellular carcinoma. However, disease progression varies widely, from less than 2 years to cirrhosis in some patients to more than 30 years with only chronic hepatitis in others. Determinants important in deciding outcome are unknown. Alpha interferon, which results in sustained remission in selected patients, is the only available therapy. Long-term benefits from such therapy have not been demonstrated. Prevention of HCV infection by vaccination is likely to be challenging if ongoing viral mutation results in escape from neutralization and clearance.

Lymphocyte subsets and beta 2-microglobulin expression in chronic hepatitis C/non-A, non-B. Effects of interferon-alpha treatment

Thirty-three patients with chronic hepatitis C/non-A, non-B were included in a randomized controlled study of interferon-alpha 2b (IFN-alpha 2b) treatment, 3 x 10(6) U three times weekly for 36 weeks. Using an immunoperoxidase technique, frozen liver biopsy specimens were examined with MoAbs for the presence of T helper cells (CD4), T suppressor/cytotoxic cells (CD8), total T cells (CD2) and B cells (CD22) before and after treatment. beta 2-microglobulin (beta 2-MG) expression on hepatocytes was semiquantified using a scoring system on sections from paraffin-embedded biopsy specimens. Serum levels of beta 2-MG were analysed with a radioimmunoassay technique. Intralobular T helper and T suppressor/cytotoxic cells declined significantly in the treated patients but not in the controls. The portal CD4/CD8 ratio did not change. Before treatment, serum beta 2-MG levels and hepatocyte beta 2-MG expression were significantly higher in patients with chronic active hepatitis compared to patients with chronic persistent hepatitis. Serum beta 2-MG levels increased significantly in responders during IFN treatment, with a maximum after 12 weeks. However, in the liver, the hepatocyte beta 2-MG expression was significantly decreased after treatment. Thus, IFN-alpha treatment does not seem to induce an increased HLA class I antigen hepatocyte expression in chronic non-A, non-B hepatitis, which favours the hypothesis that its anti-viral effects are more important in modulating the disease activity.

Hepatitis C: a sleeping giant?

In the United States, non-A, non-B hepatitis accounts for 20-40% of acute viral hepatitis. Although it has traditionally been considered a transfusion-associated disease, non-A, non-B hepatitis is more likely to occur outside the transfusion setting. Surveillance data from the Centers for Disease Control show that in 1988 6% of patients with non-A, non-B hepatitis reported a history of blood transfusion, 46% parenteral drug use, 10% household or sexual exposure to a contact who had had hepatitis or exposure to multiple sex partners, 2% medical or dental employment involving frequent blood contact, less than 1% hemodialysis, and 40% no known source. Antibody to hepatitis C virus (anti-HCV) is found in the majority of patients with non-A, non-B hepatitis independent of the source of infection; however, antibody may not appear for 6 to 9 months after exposure or onset of illness. Limited serologic studies of the prevalence of anti-HCV in various population groups have found high anti-HCV rates (50-80%) in parenteral drug users and hemophiliacs, intermediate rates among the sexually active (5-15%), and low rates among health care workers (1%). In persons with acute or chronic hepatitis C, the presence of anti-HCV appears to indicate infectivity. Persons with no history of hepatitis who are anti-HCV positive may or may not be infectious. More sensitive and specific markers for the detection of hepatitis C virus will be needed to resolve this question.

Mother to infant transmission of hepatitis C virus infection

Eight women with chronic hepatitis C virus (HCV) infection during pregnancy gave birth to 11 children. Five of these children had elevated ALT, but only two had increased levels in more than one sample. All children tested before 6 months of age were positive for anti-HCV at most up to 7 months of age and then became negative. One child with a maximum ALT level of 8.4 mukat/l however, regained anti-HCV positivity at 12 months of age, and a liver biopsy at 21 months of age showed resolving hepatitis. Passively acquired HCV antibodies are obviously found in newborns of anti-HCV-positive mothers with chronic hepatitis. In 1 of 11 children, active anti-HCV production and concomitant liver disease suggested mother to infant transmission of hepatitis C virus infection.