Lymphocyte cytotoxicity to autologous hepatocytes in HBsAg positive chronic liver disease.

Abstract

Lymphocytes from 39 patients with HBsAg positive chronic liver disease were incubated with their own hepatocytes to investigate mechanisms of lymphocyte-mediated liver damage. Cytotoxicity was significantly increased in 46% overall, and in 73% of those with chronic active hepatitis. Unlike HBsAg negative chronic active hepatitis where only non-T cells were cytotoxic, HBsAg positive patients had both cytotoxic T and non-T cells. A purified liver membrane complex (LSP) and aggregated IgG both blocked non-T cytotoxicity without affecting T cell cytotoxicity; this suggests that the former is probably an antibody-dependent cell-mediated reaction against normal membrane components. This was confirmed in preliminary studies which demonstrated that preincubation of hepatocytes with the F(ab)2' fragment of an anti-human IgG reduced non-T lymphocyte cytotoxicity. T-cell cytotoxicity was restricted to HBeAg-positive patients, suggesting a relationship between T-cell cytotoxicity and viral replication. Purified HBsAg, however, blocked cytotoxicity in only three of 11 cases. Non-T lymphocytes reacting with normal membrane components may contribute to liver damage in both 'autoimmune' and virus-associated chronic liver disease, whereas cytotoxic T-cells, probably reacting with viral determinants, are exclusive to those with viral replication.