Fig. 5

CD56^bright NK cells in multiple sclerosis (MS), Alzheimer’s disease (AD), Parkinson’s disease (PD) and amyotrophic lateral sclerosis (ALS). CD56^bright NK cells accumulate in periventricular areas of MS patients, where they can secrete granzyme K in close contact of T cells. They also express granzymes and migratory markers in higher levels compared to control donors, which could explain their propensity towards the brain [4, 5]. In PD, AD and ALS, more research is available on NK cells, without CD56^bright and CD56^dim distinction. Similarly as in MS, NK cells from PD patients release lower levels of IFN-γ compared to controls. In contrast, NK cells release a plethora of pro-inflammatory cytokines in AD and ALS, probably explaining their pathogenic potential in those diseases [6, 216, 230]