Historical and current issues in HIV encephalitis, and the role of neuropathology in HIV disease: a pathological perspective

In the 1980s, after the HIV pandemic was recognised, neuropathology identified cerebral white matter lesions that were found in the brains of infected persons with a severe irreversible dementia syndrome, this became known as ‘HIV encephalitis’. Subsequent work in Europe and north America found subtle morphological abnormalities in cerebral neurones and their connections. With the advent of effective anti-retroviral therapies after 1996, the incidence of severe HIV-related dementia declined, as did investigative tissue pathology into this HIV brain disease. Currently, the intense interest over HIV neurocognitive impairment focuses on neuroimaging, comparative blood and cerebrospinal fluid analysis, viral subtype analysis, and the search for biomarkers that correlate with brain function. Tissue neuropathology in HIV is more restricted to the diagnosis of acute disease such as opportunistic infections and tumours, and confirmation of the acute CD8 + T-cell encephalitis syndrome. But correlative tissue pathology will still be needed as newer therapeutic measures are developed to prevent and manage chronic HIV brain impairment.