Cerebral amyloid angiopathy. Frequency, significance and immunohistochemistry.

For the assessment of the anatomical distribution of cerebral amyloid angiopathy (CAA) as well as that of amyloid plaques (AP), 955 post-mortem brain specimens from 653 patients (aged 14 to 95 years) were made available from a general hospital. Using histological and immunohistochemical techniques, we demonstrated amyloid angiopathy chiefly in the occipital, parietal and temporal regions. Senile plaques were mostly found in parietal, temporal and occipital areas. In our cases, neurofibrillary tangles were rarely prominent in the regions examined. There was often a significant difference in the frequency of amyloid angiopathy and of plaques in distinct areas between men and women. Congophilic angiopathy was associated with senile plaques in 82.3%, and neurofibrillary tangles with plaques in 76.9%. In comparison, the correlation of amyloid plaques with CAA (32.5%) and of plaques with neurofibrillary tangles (11.5%) was less pronounced. There was a strong association of cerebral vascular amyloid with age in both sexes, it was more pronounced in women than in men. Unexpectedly, CAA showed a decrease in frequency in men in the 7th and 8th decade of life. In addition, there was a positive correlation between the amount of CAA and spontaneous hemorrhages, but no correlation with ischemic encephalopathy. Immunohistochemistry showed that cerebral amyloid was neither amyloid of the AA- nor of the ATTR-(Antitransthyretin-, formerly anti-AF)-type. An antibody to the beta-protein (anti-A beta) showed cerebral vascular deposits to be congruent with the Congo red method, whereas senile plaques stained weakly and neurofibrillary tangles could not be stained at all with these antibodies.