CLONOTYPIC ANALYSIS OF T-CELLS IN PATIENTS WITH AUTOIMMUNE AND VIRAL-HEPATITIS

The immunopathogenesis of autoimmune hepatitis (AIH), and the role of T cells in the onset and maintenance of this disease, are still unclea r, Since T cells expand clonally after stimulation by an antigen, it i s important to analyze the behavior of T cells at a clonal level, We h ave established recently a novel system, using reverse transcriptase-p olymerase chain reaction (RTPCR) and subsequent single-strand conforma tion poly morphism (SSCP) that allows the identification of clonal acc umulation of T cells in a lymphocyte population, Using this system, we demonstrated that oligoclonal T cells were accumulated in the liver o f patients with AIH, and that identical T-cell clonotypes were detecte d in two different regions of the liver, although these features were also observed in cases with viral hepatitis. Only in cases with AIH, h owever, nearly all identical T cells were found to belong to CD8(+) su bset and there were very few CD4(+) T cells in this population, Our re sults suggest that common antigens presented to CD8(+) T cells in the context of HLA class I molecule are distributed diffusely in the liver of AIH. These findings also suggest that antigens recognized by CD4() T cells may be relatively heterogeneous in the liver with AIH.