Update of research and management of hepatitis B

Abstract

and the mutation of precore and core promoter regions. 7,23 Most HBV carriers in Asian countries have resulted from maternal transmission of the infection during early childhood, and around 80% of the carriers show natural seroconversion from a hepatitis B e antigen (HBeAg)-positive state to an HBe antibody (HBeAb)-positive state before 25 years of age. Furthermore, HBeAg to HBeAb seroconversion frequently occurs in chronic hepatitis patients with a high serum alanine aminotransferase (ALT) level. Thus, it is important to clarify the natural course of HBV carriers before antiviral treatment. This article focuses on the recent advances in basic research of HBV and suggests a strategy of antiviral therapy for chronic hepatitis B patients. HBV genotypeThere are currently eight HBV subgroups based on genetic differences. HBV genotypes A, B, C, and D were first classified by an intergroup divergence of more than 8%. 1 HBV genotypes E and F were then identified, 2 followed by recent reports of genotypes G and H. 3,4 One cannot discriminate these genotypes by four serological subtypes (adw, adr, ayw, ayr) of HBV, which are classified by antigenic determinants of the hepatitis B surface antigen, but a there is a partial correlation between genotypes and serotypes (Table 1). There are also a few reports on a serological method for determining HBV genotypes using several monoclonal antibodies to preS2 and S proteins. 24,25 These HBV genotypes show a close relation to ethnicity (Table 1); more importantly, recent investigations have revealed associations between HBV genotypes and clinical features of the infection.Two major genotypes, HBV/B and HBV/C, prevail in East Asia including Japan. HBV genotype C was more prevalent than genotype B in cirrhotic patients in Japan, 5,26 China, 27 and Taiwan. 28 Another study from

Management of HBV infection in Japan

“…Most hepatitis B virus (HBV) infections are acquired perinatally or during early childhood, and HBV genotype C prevails in Japan. The response rate to antiviral therapy seems lower in Japanese compared with Caucasian patients, probably because of the differences in mode of transmission and genotype 1 …”

“…The response rate to antiviral therapy seems lower in Japanese compared with Caucasian patients, probably because of the differences in mode of transmission and genotype. 1 Approximately 80% of cases of vertical transmission naturally seroconvert from HBe antigen-positive to HBe antibody-positive by the age of 25-30 years. However, the remaining patients are refractory to therapy.…”

Interferon and nucleoside analog combination therapy for hepatitis B

“…HBV genotypes A and B are sensitive to interferon therapy compared with genotypes C and D, and vertical transmission cases are more refractory to horizontal transmission cases [9,10]. Thus, a low rate of response to interferon therapy would seem probable in Japan, where refractory HBV genotype C and vertical transmission cases prevail [11].…”

Drug resistance in antiviral treatment for infections with hepatitis B and C viruses

“…Specifi c antiviral drugs developed recently that inhibit hepatitis viral replication, for example, by inhibition of reverse transcriptase in HBV, have shown remarkable effi cacy. 3,4 However, these treatments have also turned out to be a double-edged sword because they have led to the emergence of strains resistant to these drugs. The emergence of antiviral drug-resistant strains of these viruses may hinder the development of treatments against them.…”