Immunophenotyping of Human Innate Lymphoid Cells.

In the last years, the family of innate lymphocytes has been growing following the discovery of innate lymphoid cells (ILCs). ILCs are lymphocytes able to rapidly produce a wide range of soluble mediators in an antigen-independent fashion. So far, three main subsets of ILCs have been discovered, ILC1, ILC2, and ILC3, expressing respectively the transcription factors T-bet, GATA3, and Rorγt and secreting distinct types of cytokines. After their discovery, several studies showed that different pathologies, such as allergic airway diseases and inflammatory disorders, are sustained by dysfunctional ILCs before adaptive immune sets in. In this regard, considerable efforts are currently performed to harmonize the identification and monitoring of ILCs in healthy and pathologic conditions to streamline a uniform immunophenotyping. Standardized ILC monitoring techniques will accelerate our understanding of these effector innate immune cells and ultimately facilitate their targeting in the context of infection, cancer, autoimmune disease, and transplantation.