CD45RA AND CD45RO ISOFORM EXPRESSION ON INTRAHEPATIC T-LYMPHOCYTES INCHRONIC HEPATITIS-C

A liver tissue recruitment of antigen-specific cytotoxic cells has bee n reported in chronic hepatitis C virus (HCV) infection, but whether t hey really play a role in viral clearance is still a matter of investi gation. To further evaluate T-cell involvement in HCV-induced hepatic disease, the authors analysed, in a cohort of chronic hepatitis C pati ents, the intrahepatic T-cell expression of CD45 isoforms by using spe cific monoclonal antibodies. Within hepatic specimens, CD45RA(+) (naiv e) cell frequency at the portal tract level was significantly higher t han that exhibited at lobular level. At the same time, a Targe number of CD45RO(+) (memory) cells was found at periportal sites in compariso n with the lobular counterpart. The evaluation of CD45RA and CD45RO is oform topographical distribution in relation to CD4(+) and CD8(+) lymp hocytes, as determined on serial sections, showed that CD45RA antigen expression was predominantly coexpressed with CD4(+) lymphocytes at th e portal tract level, and the CD45RO phenotype with CD8 structure at t he lobular and periportal sites. The levers of CD45 isoforms did not s how any correlation with biological and/or histological disease activi ties. The results suggest that a liver recruitment of both naive and m emory cells occurs during chronic HCV infection, even if their functio nal role needs to be further clarified.