Neuropathology of the brain in HIV infection

The brains of 26 patients infected with the human immunodeficiency virus (HIV) were examined post mortem. All patients were men, aged 20-67 years (mean 38.8). 13 (50%) were homosexual, 3 (12%) were bisexual, 8 (31%) were haemophiliac, 1 was both an intravenous drug addict and homosexual, and 1 denied belonging to any risk group. Only 3 (12%) brains were normal, whereas 23 (88%) showed abnormalities that varied in severity and complexity. 11 were affected by more than one disease. In addition to neoplasms, opportunistic infections, and vascular lesions, 6 cases of HIV encephalitis were found, characterised by multinucleate giant cells which indicate the presence of HIV. Microglial-macrophage nodules (nodular encephalitis) occurred in 5 cases. Cerebral pathology differed between risk groups: all 6 patients with HIV encephalitis were homosexuals, whereas vascular lesions were more common in haemophiliacs. These observations have fundamental implications for clinical practice and indicate the importance of neuropathological examination in AIDS.