HSPB1 and cerebral amyloid angiopathy: However, in another study, a diffuse, rather than granular, HSP27 immunostaining was observed in a subpopulation of astrocytes and microglial cells associated with senile plaques and cerebral amyloid angiopathy, but this was not seen in neurofibrillary tangles in either the neocortex or hippocampus [27].