S100B and Parkinson disease: Besides the main pathological features of Lewy bodies (LBs) and neurites predominantly composed of α-Synuclein (α-Syn) protein (Marques and Outeiro, 2012; Wales et al., 2013) in the brain and gut of PD patients, neuroinflammatory markers such as reactive microglial expression of HLA-DR, CXCL2 and S100b in substantia nigra (SN), IgG in LBs, proinflammatory cytokines (IL-1β and TNF-α) in SN and striatum are additional neuropathological characteristics of PD (Gelders et al., 2018).