NEURONAL APOPTOSIS IN HIV-INFECTION IN ADULTS

Productive infection of the central nervous system by HN predominantly involves the white matter and basal ganglia, Involvement of the cereb ral cortex with neuronal loss is also described in AIDS patients but n ot in asymptomatic HN-positive patients. The mechanism of neuronal dam age is unknown. To enquire whether neuronal loss in AIDS may be due to an apoptotic process, we examined the cerebral cortex from 12 patient s who died from AIDS using two different methods: in situ end labellin g and gel electrophoresis of DNA to demonstrate DNA fragmentation. Non e of the patients had cerebral opportunistic infection or tumour. Four patients had no significant neuropathological changes, eight patients had variable cerebral atrophy and four of them also had productive HI V infection of the brain. These patients were compared with four HIV-p ositive asymptomatic patients, five seronegative asymptomatic controls , and two seronegative patients with Alzheimer's disease. We demonstra ted neuronal apoptosis in the cortex in all AIDS patients, as well as in the Alzheimer's patients. Apoptosis was not observed in the asympto matic cases whether seropositive or seronegative. Neuronal apoptosis w as more severe in atrophic brains, and did not directly correlate with productive HIV infection, suggesting an indirect mechanism of neurona l damage is most likely.