Cutaneous immuno-surveillance and regulation of inflammation by group 2 innate lymphoid cells (P6374)

Abstract

Abstract Type 2 immunity is critical for defense against cutaneous infections, but also underlies the development of allergic skin diseases. We report the identification in normal murine dermis of an abundant, phenotypically unique group 2 innate lymphoid cell (ILC2) subset that depends on IL-7 and constitutively produces IL-13. Intravital multiphoton microscopy revealed that dermal ILC2 specifically interact with mast cells, whose function is suppressed by IL-13. Treatment of Rag1−/− mice with IL-2 led to a marked expansion of activated, IL-5-producing dermal ILC2, resulting in the development of spontaneous dermatitis characterized by eosinophil infiltrate and activated mast cells. Our data uncover a novel interactive pathway between two innate immune cell populations implicated in type 2 immunity, and demonstrate that ILC2 exhibit both pro- and anti-inflammatory properties.