NAIVE AND MEMORY T-CELL INFILTRATES IN CHRONIC HEPATITIS-C - PHENOTYPIC CHANGES WITH INTERFERON TREATMENT

The phenotypes of infiltrating lymphocytes in liver with chronic hepat itis C, including changes associated with interferon (IFN) treatment, were characterized. Specimens obtained from 22 patients treated with I FN were examined using avidin-biotin-peroxidase immunohistochemistry. In areas of lobular and periportal inflammation, most lymphocytes were CD8(+) T cells of the CD45RO(+) (memory) subset. The centres of lymph oid follicles were occupied by CD20(+) B cells and a few CD4(+) T cell s which were CD45RA(+) (naive subset). Follicular centres were surroun ded mainly with CD4(+) T cells. CD8(+) T cells, mostly CD45RO(+), were scattered through the mantle zones of follicles and extended around t hem. No significant changes in CD45RA(+) lobular infiltrates accompani ed IFN treatment. On the other hand, the number of CD45RO(+) lobular i nfiltrates decreased after IFN treatment in complete responders (P < 0 .01). Moreover, there were significant correlations between CD45RO(+) cell counts and serum alanine aminotransferase concentrations, CD45RO( +) cell counts and the liver histologic grade and CD45RO(+) cell count s and CD8(+) cell counts. These results suggest that CD8(+) memory T c ells participate in hepatocyte injury in chronic hepatitis C, and that a decrease of CD8(+) memory T cells correlates with the decreased liv er inflammation with IFN treatment.