[Comment] Exploring immunomodulation with azathioprine in Parkinson's disease

Neuroinflammation has been recognised as a characteristic feature of Parkinson's disease for decades.1 Early observations of activated microglia in affected brain regions, most notably the substantia nigra, were initially viewed as a reaction to neurodegeneration rather than a contributor to Parkinson's disease pathogenesis. Interpretation of these neuropathological observations has since shifted due to mounting evidence implicating immune dysregulation in the disease process. This evidence includes in-vivo PET imaging studies showing microglial activation early in the disease course,2 and experimental models demonstrating microglial activation, which can be induced by α-synuclein, contributing to neuronal loss in the substantia nigra.