A high frequency of GBV-C/HGV coinfection in hepatitis C patients in Germany

AIM To detect infection rate of GBV-C/HGV inhepatitis C patients,to determine the methodsof higher sensitivity and the primers of higherefficiency for GBV-C/HGV RNA detection and tostudy the dominant subtype and mutation ofGBV-C/HGV.METHODS Quantitative RT-PCR for detectionpf HCV RNA concentration in serum samples,RT-nested PCR with two sets of primers fordetection of GBV-C RNA,RT-PCR ELISA with twosets of primers for detection of HGV RNA,nucleotide sequence and putative amino acidsequence analysis.RESULTS The positive rates of GBV-C RNA atthe 5’-NCR and NS3 region in 211 serums amplesfrom the patients with HCV infection were 31.8%and 22.8% respectively.The positive rates ofHGV RNA at the 5’-NCR and NS5 region in thesame samples were 47.9% and 31.8%respectively.The total positive rate of GBV-C/HGV RNA was as high as 55.5%.HCV copynumbers in the patients without GBV-C/ HGVcoinfection were statistically higher than that inthe patients with GBV-C/ HGV coinfection(P<0.01).Frequent mutation of nucleotideresidue was present in the amplificationproducts.Frameshift mutation was found in twosamples with GBV-C NS3 region nucleotidesequences.All nucleotide sequences fromamplification products showed higher homologyto HGV genome than to GBV-C genome even though part of the sequences were amplifiedwith GBV-C primers.CONCLUSION A high frequency of GBV-C/ HGV coinfection existed in the hepatitis C patients. RT-PCR ELISA was more sensitive than RT-nested PCR for detection of GBV-C/ HGV RNA. The primers derived from the 5 -NCR was more efficient than those derived from the NS3 and NS5 regions. A reverse relationship was found to exist between HCV RNA concentration and GBV-C/ HGV infection frequency. HGV was the dominant subtype of the virus in the local area. The major mutations of GBV-C/ HGV genomes were random mutation of nucleotide residue.