Sequence variation of the HVR1 region of Hepatitis C virus in response to interferon-α and ribavirin treatment.

INTRODUCTION Hepatitis C virus (HCV), which is a major cause of liver diseases worldwide, undergoes genetic variation during the course of infection. The aim of this study was to examine sequence variations within the HVR1 region of HCV genotype 4 in infected Saudi patients treated with a combination therapy of interferon-α and ribavirin. METHODOLOGY cDNA of the HVR1 region of HVC-4 from one responder and one non-responder patients was generated, cloned and sequenced. Ten clones were randomly selected and analyzed for changes in nucleotide and amino acid sequences before the start of treatment, and subsequently three and six months after the start of the therapy course. RESULTS Based on nucleotide and amino acid sequence variations, the HVR1 region is highly sequence variable. In both the responder and the non-responder patients, amino acid sequence variations were observed and a clear distinction between patients was evident. The amino acid changes after the treatment course were different in the responder compared to the non-responder subject. Five amino acids (residues 364 to 367, 381 and 409) were unique in the non-responder patient. CONCLUSION Considerable amino acid variations were observed in the HVR1 region in both responder and non-responder patients. These findings could have implications for the development of an HCV vaccine as well as treatment protocols for HCV infections.