The central nervous system (CNS) and its meningeal coverings accommodate a diverse myeloid compartment that includes parenchymal microglia and perivascular macrophages as well as choroid plexus and meningeal macrophages, dendritic cells, and granulocytes. These myeloid populations enjoy an intimate relationship with the CNS, playing an essential role in both health and disease. Although the importance of these cells is clearly recognized, their exact function in the CNS continues to be explored. Here we review the subsets of myeloid cells that inhabit the parenchyma, meninges, and choroid plexus, and discuss their roles in CNS homeostasis. We also discuss the role of these cells in various neurological pathologies, such as autoimmunity, mechanical injury, neurodegeneration, and infection. We highlight the neuroprotective nature of certain myeloid cells, emphasizing their therapeutic potential for the treatment of neurological conditions.

Immune responses to central nervous system (CNS) injuries are multifaceted, but their contributions are incompletely understood. Here, Gadani et al. describe type 2 innate lymphocytes as novel meningeal-resident cells, characterizing their transcriptional profile and response to CNS injury.