HIV-p24-antigen-bearing macrophages are only present in brains of HIV-seropositive patients with AIDS-encephalopathy.

The central nervous system of HIV-seropositive patients with and without AIDS-encephalopathy was investigated by immunocytochemistry using the monoclonal antibody to the HIV-1 p24 core protein. Numerous p24-immunopositive mono- and multinucleated macrophages could only be detected in patients with typical histological pictures of an AIDS-encephalopathy. These findings allow the supposition that AIDS-dementia is a result of a relatively late infiltration of HIV-infected macrophages from the bloodstream into the brain and is not due to an impairment of neuronal and/or glial cells infected by HIV during the early stage of the disease.