Caution is requires, as HBV genotype Bj and the 1896 mutation have been identified as independent risk factors for fulminant hepatitis.[60] HBV genotype Ba is a recombinant gene arrangement resembling in part HBV genotype C from the core promoter through to the core. HBV genotype Ba reportedly has a relatively KPT-330 clinical trial high HCC risk, though the characteristics differ significantly between subtypes. HBV genotype C has a high HCC risk (higher even than HBV genotype Ba) and poor prognosis.[61] HBV genotype C is resistant to conventional IFN treatment. HBV genotype D is normally found in Western countries. There are several localized pockets of infection and a number of subtypes in existence. R428 in vivo The most common

form is HBV genotype D1, which has been studied extensively and found to include a specific genetic mutation linked to disease phenotype.[62] Reports from Europe suggest

that HBV genotype D is more resistant to IFN treatment than HBV genotype A, with a poor overall prognosis.[63] Recommendations HBV genotype A has been linked to horizontal infection among young people in Japan, who often become carriers following the acute hepatitis phase. Among HBV genotype B, subtype Bj is found only in Japan. Most cases remain asymptomatic carriers indefinitely, with negligible risk of HCC. However infection with pre-core mutations can lead to fulminant hepatitis. HBV genotype C has a high HCC risk and is resistant to conventional IFN treatment. The prognosis is poor. HBV DNA quantification is for assessment of liver disease, evaluation of therapeutic effects, and diagnosis of breakthrough hepatitis via HBV mutation. It is also linked to prognosis, since high HBV DNA levels indicates a high risk of cancer.[34] Conventional techniques for measuring HBV DNA levels in the past included the Amplicor HBV Monitor test (Roche Diagnostics Systems, Branchburg, NJ, USA) and the HBV DNA TMA-HPA test (transcription-mediated amplification-hybridization Y-27632 mouse protection

assay, Chugai Diagnostics Science, Tokyo). Real-time detection PCR testing has become more popular in recent years, as it offers greater sensitivity and a wider measurement range. Real-time detection PCR installs primers and a probe on the well conserved S domain sequences on the HBV genome. The HBV probe is a short oligonucleotide for 5′-end fluorescence labeling and 3′-end quencher labeling. Real-time PCR HBV DNA quantification offers both high sensitivity and a broad dynamic range for detecting the quantity of PCR products based on PCR cycles once the fluorescence intensity reaches a given level. In addition to evaluation of antiviral therapeutic effects, improved sensitivity allows detection of viral breakthroughs, detection of HBV in HBeAg negative cases and latent HBV infections, as well as early prediction of exacerbation of hepatitis and HBV reactivation.