Selection of more pathogenic hepatitis C virus genotype II during long-term follow-up of interferon-treated patients

High doses of alpha-interferon are required in chronic hepatitis due to coinfection with hepatitis B virus and hepatitis C virus: long term results of a prospective randomized trial

OBJECTIVE

Coinfection with hepatitis B (HBV) and hepatitis C (HCV) viruses is associated with a more severe liver disease, increased frequency in the development of hepatocellular carcinoma, and resistance to interferon (IFN) therapy when performed with the standard dosages used in single infections. In the attempt to verify whether the outcome of IFN therapy in patients with hepatitis B and hepatitis C coinfection can be improved, we have planned a prospective, randomized trial with medium to high dosages of interferon three times a week for 6 months.

METHODS

Thirty patients with HBV-HCV coinfection, and chronic hepatitis were randomized to receive either 6 or 9 MU alpha-interferon three times a week for 6 months. Patients were HBsAg positive, anti-HBe positive, HBV DNA negative by dot blot (6/30 positive by polymerase chain reaction), and anti-HCV-positive, HCV RNA positive. Pretreatment and posttreatment liver biopsies were performed.

RESULTS

Five patients treated with 9 MU IFN consistently cleared HCV RNA and HBV DNA, whereas none of those treated with 6 MU reacted in a similar fashion (p = 0.045). Responders showed significant improvement of histological activity index in comparison with nonresponders (mean Ishak score pretreatment versus posttreatment p = 0.002). Long term follow-up showed that none of the patients treated with high doses developed cirrhosis whereas 4/14 treated with low doses did develop cirrhosis.

CONCLUSION

Even though the percentage was not very high, the sustained response, the striking histological improvement, and the lack of development of cirrhosis achieved in these patients, indicate that with HBV-HCV coinfection, a trial with high doses of interferon is strongly recommended.

Evaluation of two simplified methods for genotyping hepatitis C virus

A number of different approaches have been used for genotyping hepatitis C virus (HCV). Two simplified methods were evaluated, both of which used polymerase chain reaction (PCR) to amplify products from the 5' non-coding region of HCV: non-isotopic restriction fragment length polymorphism (RFLP) analysis and type-specific PCR. Sixty-four viraemic patients suffering from chronic HCV infection were studied using these two techniques; 25/64 samples were further tested with a commercial serotyping ELISA based on synthetic NS4 antigen (Murex, U.K.). The results of the three typing methods were generally in agreement with each other. When only the predominant genotype identified by each method was analysed, the 3 methods had 100% agreement. RFLP did not detect any mixed infections and it was unsuccessful in 16/64 (25%) samples. Both type-specific PCR and serotyping ELISA detected mixed infections. However, serotyping ELISA did not give typeable results in 7/25 (28%) samples, whereas type-specific PCR gave typeable results in all 64 samples. Type-specific PCR detected more mixed infections than serotyping ELISA. Direct sequencing of four PCR products with indeterminate RFLP confirmed changes in restriction enzyme recognition sites. The sequences also confirmed the validity of the predominant genotype in cases of apparent mixed infections. It is possible that some of these cases were artefacts as a result of quasispecies.