IMMUNOCYTOCHEMICAL DETECTION OF ANTI-HIPPOCAMPAL ANTIBODIES IN ALZHEIMERS-DISEASE AND NORMAL CEREBROSPINAL-FLUID

Immunocytochemical staining was performed to investigate the presence of anti-hippocampal antibodies in cerebrospinal fluid (CSF) from patie nts with probable Alzheimer's disease (AD) (n = 19), aged normal contr ols (n = 9), and young normal controls (n = 10). Marked staining of ne urons in the granule cell layer of the dentate gyrus and in pyramidal neurons in CA1-3 of the rat hippocampus was observed in 5 AD CSF sampl es (26%), 1 aged control sample (11%), and 1 young control sample (10% ). These differences were not statistically significant. One of the im munoreactive AD CSF specimens also contained high concentrations of C5 b-9, the membrane attack complex. The infrequent occurrence of anti-hi ppocampal antibodies in AD CSF, and the detection of similar immunorea ctivity in control CSF specimens, suggest that these antibodies are un likely to play a role in the neurodegenerative process in most individ uals with AD. However, elevated C5b-9 concentration in an AD CSF speci men with marked immunoreactivity to hippocampal neurons suggests the p ossibility that anti-neuronal antibodies may contribute to complement activation in some AD patients.