COMPARATIVE IMMUNOHISTOCHEMICAL CHARACTERISTICS OF HUMAN CHOROID-PLEXUS IN VASCULAR AND ALZHEIMERS DEMENTIA

Autoimmune alterations are indirectly supported in Alzheimer's disease by the demonstration of circulating antibodies directed to the epithe lial basement membrane (BM) of the choroid plexus. We used immunohisto chemical methods to compare the characteristics of choroid plexuses ob tained postmortem from 15 patients. Six had a diagnosis of Alzheimer's disease, five had multi-infarct dementia (MID), and one suffered from mixed dementia. Similar tissue from three age-matched, non-demented c ontrols was studied as well. Age-related psammoma bodies, lipofucsin, and flattened epithelial cells were present in all cases. Specific alt erations were evident in Alzheimer's disease patients only. These were comprised of pseudolinear deposits of immunoglobulin (Ig)G and coarse deposits of C1q along the thickened and segmented epithelial BM, and were associated with IgM in five cases. Although no lymphoid infiltrat ion was demonstrated, MHC Class II+ macrophages were observed in the p lexus stroma, and numerous epithelial cells were class II+. These obse rvations suggest that immune alterations, possibly of autoimmune origi n, may be involved in Alzheimer's disease, leading to severe lesions o f the choroid plexus. Such anomalies could be responsible for some of the alterations of cerebrospinal fluid (CSF) production or composition noted in this disease. (C) 1994 by W.B. Saunders Company