Neuroimmunology and ageing – the state of the art

Excerpt

For decades, the central nervous system (CNS) was known as an immune-privileged site. This concept was formulated based on experimental studies that demonstrated that, unlike what was observed in peripheral organs, skin grafts were not rejected when transplanted into the brain parenchyma. The presence of the blood-brain barrier (BBB), capable of selectively regulating the entry of molecules and cells from the bloodstream into the brain parenchyma, and the absence of conventional lymphatic vessels contributed to reinforcing this concept [1]. However, meningeal lymphatic vessels in the dura mater and, more recently, glymphatic vessels have raised questions about the dogma of the CNS as an immune-privileged site [2, 3]. The CNS has thus adopted mechanisms that enable communication with the immune system, which is crucial for a healthy brain. …