Genotyping of hepatitis D virus by restriction-fragment length polymorphism and relation to outcome of hepatitis D.

The outcome of hepatitis D virus (HDV) superinfection varies among patients and in different geographical areas. To find out whether HDV genotype affects outcome, we used a simple genotyping method based on restriction-fragment length polymorphism with enzymes XhoI and SacII for cleavage of PCR products of the HDV genome. Of samples from 88 patients studied, the genotypes of 61 were confirmed by two methods--analysis with both enzymes or by combined restriction-enzyme and direct sequencing analyses--with consistent results. No genotype III HDV was detected among these patients. The majority of patients with acute HDV infection (35/41 [85%]) had genotype II HDV. Among the 41 patients with acute infection, four of six with genotype I had fulminant disease compared with two of 35 with genotype II. Among patients in chronic stage, cirrhosis or hepatocellular carcinoma were found in 12 of 18 with genotype I HDV and eight of 29 with genotype II. Thus genotype II was the predominant HDV genotype in this study in Taiwan. Genotype II HDV was less frequently associated with fulminant hepatitis at the acute stage or with an unfavourable long-term clinical outcome at the chronic stage than was genotype I.