Diffuse Lewy body disease (DLBD) is characterized by the presence of Lewy bodies 
(LB) in the neurons and neurites of cortical, subcortical, and brain stem 
structures. Recently, alpha-synuclein (alphaS) has been found to be a central 
constituent of LB. In DLBD, abnormal accumulation of alphaS has been reported in 
both neurons and glia, but studies on glial lesions in DLBD have been limited. 
We examined in detail the constituents and distribution of glial lesions in 
eight patients with DLBD and report the pathogenesis of the glial lesions. 
alphaS-positive neuronal cytoplasmic inclusions (NI), neuropil threads (NT), and 
coiled bodies (CB) showed similar immunostaining profiles. Without pretreatment, 
NI, NT, and CB were detected by all antibodies against alphaS. The 
immunostaining profile of star-like astrocytes (SLA) was quite different from 
those of NI, NT, and CB. A few SLA were stained by an antibody against the 
non-Abeta component portion of alphaS without pretreatment, but formic acid 
pretreatment dramatically enhanced SLA immunoreactivity. SLA and CB were found 
in all eight brains with DLBD. SLA were scarce in the brain stem, but there were 
hundreds of SLA per visual field at x100 magnification in the temporal cortex of 
most cases, while CB were found diffusely in both the cerebral cortex and brain 
stem, similar to NI. This suggests that the pathogenesis of SLA is different 
from those of NI and CB.