<p class="first" id="d9037339e233">Innate lymphoid cells (ILCs) are lymphocytes that
do not express the type of diversified
antigen receptors expressed on T cells and B cells. ILCs are largely tissue-resident
cells and are deeply integrated into the fabric of tissues. The discovery and investigation
of ILCs over the past decade has changed our perception of immune regulation and how
the immune system contributes to the maintenance of tissue homeostasis. We now know
that cytokine-producing ILCs contribute to multiple immune pathways by, for example,
sustaining appropriate immune responses to commensals and pathogens at mucosal barriers,
potentiating adaptive immunity, and regulating tissue inflammation. Critically, the
biology of ILCs also extends beyond classical immunology to metabolic homeostasis,
tissue remodeling, and dialog with the nervous system. The last 10 years have also
contributed to our greater understanding of the transcriptional networks that regulate
lymphocyte commitment and delineation. This, in conjunction with the recent advances
in our understanding of the influence of local tissue microenvironments on the plasticity
and function of ILCs, has led to a re-evaluation of their existing categorization.
In this review, we distill the advances in ILC biology over the past decade to refine
the nomenclature of ILCs and highlight the importance of ILCs in tissue homeostasis,
morphogenesis, metabolism, repair, and regeneration.
</p>