CD200 and nervous system disorder: To sum up, the results presented here show that the alterations in the CD200-CD200R1 system observed in PD, mainly increases in CD200R1 and CD200 expression, differ from those observed in Alzheimer’s disease20 and multiple sclerosis18,19, mainly decreases in CD200R1 and CD200 expression, suggesting that mechanisms associated with neuroinflammation differ among neurological disorders.