MICROGLIAL REACTION IN PICKS-DISEASE

Number and morphology of microglial cells (MC) were compared in 6 cases each of Pick's disease (PD), Alzheimer's disease (AD) and controls using immunohistochemistry with the monoclonal antibody Ki-MlP. The severely involved neocortex of both PD and AD, and in particular the white matter subjacent to spongy PD lesions showed a marked increase of MC density, whereas non-affected PD areas and AD white matter showed no MC changes. The PD hippocampus, particularly the dentate gyrus, showed reduction of MC density and processes. We conclude that (1) MC reaction represents a major element of PD histopathology. and (2) density, morphology and distribution of MC are different in AD and PD.