Innate lymphoid cells — how did we miss them?

Abstract
Innate lymphoid cells (ILCs) are newly identified members of the lymphoid lineage that have emerging roles in mediating immune responses and in regulating tissue homeostasis and inflammation. Here, we review the developmental relationships between the various ILC lineages that have been identified to date and summarize their functions in protective immunity to infection and their pathological roles in allergic and autoimmune diseases.