Preface to the special issue "Neuroimmunology".

This preface introduces the Special Issue on Neuroimmunology in the Journal of Neurochemistry. The basis of neuroimmunology is to understand functional interactions between cells of the immune system and the central nervous system (CNS). These cells communicate across systems because they share signaling molecules and corresponding receptors. Moreover, this cell signaling allows for dynamic bidirectional communication between the immune system and the brain both within the CNS proper as well as across peripheral organs. Because of this, Neuroimmunology intersects with many biological processes including immunity, behavior, endocrinology, metabolism, and pathology. Understanding neuroimmune interactions that influence CNS homeostasis is especially relevant in health and disease. This special issue comprises of 14 articles, representing 9 review articles and 5 original articles, covering the roles of neuroimmunology relevant to CNS injury, CNS & peripheral infections, cancer, Alzheimer's disease, and COVID-19. Thus, these articles highlight different aspects of neuroimmunology and signaling, and represent progress in understanding the consequences of inflammation on key communication pathways between the immune system and the brains.