Infection of Circulating and Liver Infiltrating T Cells by Hepatitis C Virus of Different Subtypes

Hepatitis C virus (HCV) infection display a very high rate of progression to chronicity and, like many other viruses causing persistent infections, it displays a tropism for the cells of the immune system. Peripheral blood mononuclear cells (PBMCs) from 21 HCV chronic carriers and long-term T cell clones derived from circulating or liver infiltrating T lymphocytes were tested by cDNA "nested" PCR for positive and negative strand HCV-RNA. The presence of HCV genomes in PBMCs is a frequent, although not constant, finding and can be accompanied by active viral replication, as suggested by the coexistence of negative strand HCV-RNA. Infected T cells are more represented in livers than in periphery, as indicated by comparing HCV-RNA detection in T cell clones isolated from both the compartments. Sequencing of viral genomes present in PBMCs and liver infiltrating lymphocytes showed that all the three major HCV genotypes present in our population of chronic carriers can infect lymphoid cells. Although each clonal population of T cells is infected by a single strain of HCV, in the same patient lymphoid cells can harbor different viral populations, different from those circulating at that moment in the serum.