Does Parkinson's disease have an immunological basis? The evidence and itstherapeutic implications

Parkinson's disease (PD) is an age-related neurodegenerative movement disor der of unknown aetiology. Immune abnormalities have been described in PD in cluding the occurrence of autoantibodies against neuronal structures and hi gh numbers of microglia cells expressing the histocompatibility glycoprotei n human leucocyte antigen-DR in the substantia nigra. An infectious cause f or PD has been discussed for years. Disturbed cellular and humoral immune f unctions in peripheral blood of patients with PD have been also reported. A n elevated gamma delta (+) T cell population and increased immunoglobulin G immunity in CSF to heat shock proteins have been found in PD. Cytokines an d apoptosis-related proteins were elevated in the striatum in patients with PD. Activated glial cells may participate in neuronal cell death in PD by providing toxic substances. We may conclude that the immune system is invol ved in the pathogenesis of PD. However, we are not able to determine whethe r the disturbances described above constitute a primary or secondary phenom enon. Immunomodulatory agents may have important applications in the develo pment of new therapies for PD.