Hepatitis C virus is detected in a monocyte/macrophage subpopulation of peripheral blood mononuclear cells of infected patients.

Hepatitis C virus (HCV) is the primary agent of posttransfusion non-A, non-B hepatitis. HCV RNA was detected in peripheral blood mononuclear cells (PBMC) by polymerase chain reaction in 17 of 24 HCV-infected patients with chronic hepatitis with or without cirrhosis. One of 5 patients whose PBMC contained HCV RNA also had negative-stranded HCV RNA in the PBMC. In 3 of 11 patients whose PBMC contained HCV RNA, flow cytometry with a murine monoclonal antibody to HCV core epitope revealed cytoplasmic staining of peripheral blood monocytes. The monocyte surface and the peripheral blood lymphocytes did not stain for HCV core epitopes. No correlation could be made between the presence of HCV RNA or antigen in PBMC and any serologic markers of HCV infection. These results indicate that monocyte uptake of HCV by either phagocytosis or infection may be part of the pathophysiology of this chronic disease.