Innate Lymphoid Cells: The Hidden Actors in Skin Disorders

Innate lymphoid cells (ILCs) is a collective term that defines a population of lymphoid cells that do not express the typical rearranged receptors, but depends on the common c-chain of IL-2 receptor. The innate lymphocytes includes NK cells and the non-NK ILC: ILC1, ILC2 and ILC3. ILCs groups are categorized based on certain transcription factors and the cytokine production, in an homologous fashion to T cells effector Th1, Th2 and Th17. ILCs play an important role in the lymphoid organogénesis, initiation of inflammation in response to infection and tissue remodelling. They participate in the transition from innate to adaptive immunity and ILCs are involved in the regulation of the chronic inflammation. The dysregulation of their function plays an important role in inflammatory skin diseases, allergies, autoimmunity and cancer. In the present manuscript, we outline the biology of ILCs and review their role in homeostasis and in skin diseases.