The results from immunohistochemical examination of postmortem brains revealed that CX3CL1-expressing neuronal numbers and levels were relatively reduced, and CX3CL1 expression in vascular endothelial cells was augmented, nigral microglial and CD4+ cells were relatively increased in MMD-LB and PD subjects displaying synucleinopathy. Here, CD4 is linked to synucleinopathy.