Degeneration process of Lewy bodies in the brains of patients with dementia with Lewy bodies using alpha-synuclein-immunohistochemistry

We investigated the degeneration process of Lewy bodies (LB) in the brains of dementia with Lewy bodies, using alpha-synuclein-immunohistochemistry. I ntracellular LB, LB-related neurites and some extracellular LB were positiv ely immunostained with anti-alpha-synuclein antibodies. Concentric LB-beari ng neurons had no microglial involvement, while degenerated neurons with il l-defined LB displayed intense microglial involvement. The late stage of ex tracellular LB were immunoelectron-microscopically composed of loose aggreg ates of filamentous components with lost alpha-synuclein-immunoreactivity a nd penetrated astroglial processes. These findings suggest that microglias are involved during the stages from degenerated LB-bearing neurons to extra cellular LB, while astroglias are involved during the stage of extracellula r LB, Some intracellular LB were positive for anti-C3d and -C4d antibodies, suggesting that the classical complement pathway is activated in degenerat ed LB-bearing neurons, inducing microglial activation and neuronal death. ( C) 2000 Published by Elsevier Science Ireland Ltd. All rights reserved.