Treg-specific IL-2 therapy can reestablish intrahepatic immune regulation in autoimmune hepatitis
Laura Elisa Buitrago‐Molina, Julia Pietrek, Fatih Noyan, Jérôme Schlué, Michael P. Manns, Heiner Wedemeyer, Matthias Hardtke‐Wolenski, Elmar Jaeckel
Abstract
Autoimmune hepatitis (AIH) is a chronic autoimmune inflammatory disease that usually requires life-long immunosuppression. Frequent relapses after discontinuation of therapy indicate that intrahepatic immune regulation is not restored by current therapies. As steroid therapy preferentially depletes intrahepatic regulatory T cell (Tregs), immune regulation might be re-established by increasing and functionally strengthening intrahepatic Tregs. In recent clinical trials with low dose IL-2, the Treg compartment was strengthened in autoimmune diseases. Therefore, we tested complexed IL-2/anti-IL-2 to increase the selectivity for Tregs. We used our model of experimental murine AIH (emAIH) and treated the mice with complexed IL-2/anti-Il-2 in the late course of the disease. The mice showed increased intrahepatic and systemic Treg numbers after treatment and a reduction in activated, intrahepatic effector T cells (Teffs). This resulted in a reduction in liver-specific ALT levels and a molecular pattern similar to that of healthy individuals. In conclusion, complexed IL-2/anti-IL-2 restored the balance between Tregs and Teffs within the liver, thereby improving the course of emAIH. Treg-specific IL-2 augmentation offers new hope for reestablishing immune tolerance in patients with AIH.