BACKGROUND: Although HCV and HBV are essentially hepatoptropic, severallines of evidence suggest that these viruses can infect other cells, also PBMC in most patients withchronic HCV. MATERIAL/METHODS: The presence of HBV DNA and HCV-RNA was determined by a polymerase chainreaction (multiplex PCR and RT-PCR - nested PCR) in a group of patients with chronic liver disease. HCV-RNAwas investigated in serum, plasma and peripheral blood mononuclear cells (PBMC) while HBV-DNA only inserum or plasma. RESULTS: Among 374 patients tested, HCV-RNA was detected in the venous blood of 208patients; HCV RNA alone was detected in 154 patients and 54 patients were co-infected by HCV and HBV.HBV-DNA was found in 128 of 374 patients, while infection by HBV only was found in 74 patients. It wasalso shown that in the presence of HBV the replication ability of HCV is lower (p=0.085, Goodman-KruskalGamma = 0.561 and YuleQ = 0.5610). CONCLUSIONS: Since coexistence of HBV and HCV is not a rare case,diagnostics of hepatitis cannot be limited to detection of one type of the virus only. Misinterpretationof the virus type that caused the infection may lead to serious complications, especially in those caseswhen interferone is used for treatment.

Keywords: Base Sequence, DNA Primers, Hepacivirus, Hepatitis B, Hepatitis C, Polymerase Chain Reaction, RNA, Viral, Research Support, Non-U.S. Gov, Sensitivity and Specificity, Virus Replication