Detection of Hepatitis C Virus RNA in Peripheral Blood Mononuclear Cells and in Saliva

The nested polymerase chain reaction (PCR) technique was applied to investigate hepatitis C virus (HCV) RNA in the peripheral blood mononuclear cells (PBMCs), saliva, and serum of patients with chronic type C hepatitis. The specificity of the amplified products was analyzed and confirmed by agarose gel electrophoresis, Southern blot hybridization, and restriction endonuclease pattern analysis. HCV RNA was detectable in the PBMCs of 24% (12/50) of the patients. The HCV RNA detected in PBMCs was not due to the contamination from plasma, since no viral sequences could be detected in the third washing of PBMCs. Of the 12 patients with HCV RNA in PBMCs, five were negative for HCV RNA sequences in the serum. Thus the presence of HCV RNA in PBMCs was not strictly correlated to the results for sera. Among 25 patients with HCV RNA in their saliva, 18 were negative for PBMCs. Among 25 patients without HCV RNA in their saliva, five had HCV RNA in PBMCs. In conclusion, PBMCs are an extrahepatic target for chronic HCV infection. However, we do not suggest that PBMCs act as a vehicle for carrying HCV to saliva, since the presence of HCV RNA in PBMCs and in saliva was not closely correlated.