Genotype distribution of hepatitis C virus infection in Greece: correlation with different risk factors and response to interferon therapy.

The aim of this study was to investigate the prevalence of HCV genotypes among Greek patients with chronic hepatitis C and to assess the influence of genotypes and quasi-species populations on efficacy of interferon therapy. Genotypes were determined in 65 patients (18 patients after kidney transplantation, 16 with thalassemia and 31 with no known risk factor) with elevated ALT for more than 6 months and histologically proven chronic hepatitis, using the Inno-Lipa strip assay. The quasi-species were determined using the fluorescence single-strand conformational polymorphism method. Most patients were infected with genotype 3a, namely 61% of patients with kidney transplants (n = 18), 50% of patients with thalassemia (n = 16) and 48% of patients without known risk factors (n = 31). Other genotypes were found including coinfection with different genotypes. In all patients with mixed infection, genotype 3a was present. Thirty-six patients from the last two groups received interferon (3Mio U 3x week) for 1 year. Biochemical and/or virological and histological responses were found in 11/19 patients with genotype 3a (58%), 3/5 with mixed infection, 2/4 with genotype 1b, 2/5 with genotype 2a, 1/4 with genotype 1a and 1/1 with genotype 4. The virus found in non-responders with genotype 3a was genetically more heterogeneous than in responders. These data indicate that (1) the genotype 3a is prevalent in Greek patients (68% of all patients), (2) there is no significant difference regarding genotypes among patients with different risk factors and (3) although based on a small number of patients, the genotype 3a seems to respond better to interferon therapy. Finally, the number of quasi-species may be a factor predictive of response.