Innate lymphoid cells, mediators of tissue homeostasis, adaptation and disease tolerance.

Innate lymphoid cells (ILC) are a recently identified group of tissue-resident innate lymphocytes. Available data support the view that ILC or their progenitors are deposited and retained in tissues early during ontogeny. Thereby, ILC become an integral cellular component of tissues and organs. Here, we will review the intriguing relationships between ILC and basic developmental and homeostatic processes within tissues. Studying ILC has already led to the appreciation of the integral roles of immune cells in tissue homeostasis, morphogenesis, metabolism, regeneration, and growth. This area of immunology has not yet been studied in-depth but is likely to reveal important networks contributing to disease tolerance and may be harnessed for future therapeutic approaches.