Limited T cell receptor Vβ-chain repertoire of liver-infiltrating T cells in autoimmune hepatitis

Background/Aims: To characterize the cellular immune reactions in autoimmune hepatitis, the T cell receptor repertoire of livre-infiltrating and circulating T cells was studied. Methods: Nucleic acids of liver-tissue and peripheral blood-derived T cells from 12 patients with untreated autoimmune hepatitis, four patients with chronic hepatitis C and three patients with toxic liver injury were extracted and analysed using a semiquantitative RT-PCR with a panel of T cell receptor Vβ family specific primers. After agarose gel electrophoresis, the distribution of T cell receptor (TCR) Vβ molecules was assessed by densitometry. Furthermore, results were compared to the TCR Vβ distribution of 10 healthy blood donors. Results: Four of 12 patients with untreated autoimmune hepatitis but no patients with chronic hepatitis C and toxic liver injury showed a significant overexpression of TCR Vβ3 (17.8%±2.6% vs. 9.3%±4.6%; p=0.01) and three an overexpression of Vβ13.1 (14.6%±2.3% vs. 6.6%±3.5%; p=0.02) molecules compared to the TCR Vβ-distribution in healthy blood donors. In addition, Vβ3+ T cells were found enriched in the liver tissue compared to autologous peripheral blood in three autoimmune hepatitis patients (15.3%±7.0% vs. 5.2%±3.1%; L/B ratio: 2.9), while Vβ13.1+ T cells were enriched in the liver tissue from one of three patients with overexpression. Conclusions: In autoimmune hepatitis a disease specific compartmentalisation of TCR Vβ3+ T cells was observed in the liver tissues. Although their specificity was unknown, this might indicate that these infiltration T cells could have relevance for abnormal immunoregulation.