• autoimmune hepatitis;
  • CD4+CD25+ regulatory T cells;
  • cytotoxic T-lymphocyte-associated antigen-4;
  • forkhead box P3;
  • interleukin-10

Aim:  Recently, forkhead box P3 (Foxp3), cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4), glucocorticoid-induced tumor necrosis factor receptor family-related gene (GITR), and CD28 were identified as the key molecules that control the development and activation of CD4+CD25+ regulatory T cells (T-reg). We investigated the expression pattern of these molecules on T-reg, and investigated the ability of T-reg to produce cytokines in patients with autoimmune hepatitis (AIH).

Methods:  Fifteen patients with AIH and nine healthy patients were included. To determine the frequency of T-reg, a two-color flow cytometry analysis was performed. T-reg were isolated using immunomagnetic beads, and the mRNA levels of Foxp3, CTLA-4, GITR, and CD28 were quantified by real-time polymerase chain reaction (PCR). The ability of T-reg to produce interferon-γ, interleukin (IL)-10, transforming growth factor-β, and tumor necrosis factor-α after stimulation by OKT3 was evaluated by measuring the levels of mRNA in T-reg by real-time PCR.

Results:  The frequency of T-reg was increased in AIH. The mRNA levels of Foxp3 and CTLA-4 were significantly lower in AIH. The ability of T-reg to produce IL-10 was impaired in AIH.

Conclusion:  We speculate that the inferiority of the Foxp3 and CTLA-4 gene expressions on T-reg results in the impaired suppressor function of T-reg, and eventually in the breakdown of self-tolerance.