Immunohistochemical study of α2 Macroglobulin receptor in Alzheimer and control postmortem human brain

Localization of the α2 macroglobulin receptor (α2MR) was studied in postmortem human brain tissue of Alzheimer disease (AD) and age-matched control cases with a monoclonal antibody (A2MRα2) to the receptor. In control cases α2MR was detected in neurons, glia, and some capillaries. Neuronal staining was most conspicuous in the hippocampus and entorhinal cortex. In AD, α2MR immunoreactivity was enhanced. The staining intensity of some neurons was increased, as was the number of positive glial cells. In addition, senile plaques, tangles, and dystrophic neurites were strongly stained. These results suggest that α2MR is involved in AD pathology.