LRRK2 and Parkinson disease: Several lines of evidence indicate strong immune involvement in PD pathogenesis, including neuroinflammation in PD postmortem brains shown by immunochemistry and PET imaging.5, 6, 7 Several of the mutations that give rise to PD are found in genes that are highly expressed by immune cells including the relatively common genetic mutations in LRRK2 and GBA and the meta‐GWAS hit HLA‐DQB1.