T lymphocyte subsets implicated in cytotoxicity in autologous hepatocytes in chronic active hepatitis patients with active viral replication

A possible cytotoxicity inducer role of 5/9 positive lymphocytes infiltrating the liver in CAH patients

The presence, in chronic active hepatitis (CAH) patients, of an inflammatory infiltrate basically composed of T lymphocytes suggested the hypothesis that these lymphocytes could play a role in the pathogenesis of the disease. The aim of this study has been to characterize, in a group of carefully selected CAH patients, the liver-infiltrating T lymphocyte, utilizing commercial monoclonal antibody (anti-Leu 1, anti-Leu 2a, anti-Leu 3a) and 5/9 monoclonal antibody that recognizes a further lymphocyte subset within T4 cells. Our data show that both T4 positive subpopulation and T8 positive subpopulation are represented in the infiltrate in the same ratio; furthermore the distribution of 5/9 positive lymphocytes is prevalent where the infiltrate is mainly composed of T8 positive lymphocytes. Moreover, there is a positive correlation between 5/9 positive cells in the liver and GPT and the patients with high percentages of infiltrating 5/9 positive lymphocytes show a low T4/T8 ratio with respect to patients with low percentages of 5/9 positive cells. These data support the hypothesis that 5/9 positive lymphocytes may present an inducer role on cytotoxic cells.