IL17A and Parkinson disease: In MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) treaded mouse and MPP+ (1-methyl-4-phenylpyridinium) treated rats (animal models of PD), the levels of IL-17A are upregulated in the substantia nigra, spleen, serum, and mesenteric lymph nodes.