Molecular epidemiology of hepatitis B, C and D viruses in Turkish patients

Summary.

Different genotypes of the hepatitis viruses may influence the clinical outcome of the disease. The distribution of genotypes may vary according to geographical regions. The aim of this study was to evaluate hepatitis B virus (HBV), hepatitis C virus (HCV) and hepatitis D virus (HDV) genotypes in Turkish patients with chronic hepatitis in a large cohort of patients. Genotyping was performed in 41, 59 and 365 patients with chronic hepatitis B, D and C, respectively, and 36 hemodialysis patients with chronic hepatitis C. Genotypes were determined by direct sequencing in hepatitis B and by polymerase chain reaction-restriction fragment length polymorphism in hepatitis C and D patients. In addition, HBV subtyping by multiplex PCR and subtype specific ELISA were performed in 83 and 71 HBsAg (+) blood donors, respectively. All hepatitis B (100%) and hepatitis D (100%) patients had genotype D and type I, respectively. HBsAg subtyping by two methods yielded that 99% of the patients were subtype ayw. S gene amino acid sequence in the 41 patients included for HBV genotyping revealed the ayw2 subtype. Genotype distribution of 365 patients with chronic C hepatitis were as follows: 306 (84%) patients genotype 1b, 43 (11%) patients genotype 1a, 10 (3%) patients genotype 2, 3 (1%) patients genotype 3, 3 (1%) patients genotype 4. Among 36 patients receiving hemodialysis, 28 (78%) patients had genotype 1b and 8 (22%) patients had genotype 1a. The study indicates that Turkish patients with chronic viral hepatitis show very little genotypic heterogeneity. Subtype ayw and the genotype D of HBV DNA, and the type I of HDV RNA represent almost 100% of related infections. The genotype 1b of HCV RNA was found to be significantly dominant in Turkish patients.