Apoptotic neurons in brains from paediatric patients with HIV-1 encephalitis and progressive encephalopathy.
The pathogenesis of human immunodeficiency virus type 1 (HIV-1) associated dementia in adults involves neuronal loss from discrete areas of the neocortex and subcortical regions, but the mechanism for neuronal death is poorly understood. Gene-directed cell death resulting in apoptosis is thought to be a normal feature of neuronal development, but little is known about neuronal apoptosis in disease states. We investigated whether HIV-1 infection of the central nervous system is spatially associated with apoptosis of neurons. Using an in situ technique to identify newly cleaved 3'-OH ends of DNA as a marker for apoptosis, we demonstrate the presence of apoptotic neurons in cerebral cortex and basal ganglia of children that had HIV-1 encephalitis with progressive encephalopathy. Furthermore, an association was observed between the localization of apoptotic neurons and perivascular inflammatory cell infiltrates containing HIV-1 infected macrophages and multinucleated giant cells. Apoptotic neurons and p24-positive macrophages were observed infrequently in cerebral cortex and basal ganglia in children with HIV-1 infection without encephalitis or clinical encephalopathy. In nine control (HIV-1 negative) brains, ranging from the first post-natal month of life to 16.5 years of age, infrequent neuronal apoptosis was observed in three cases. These findings suggest that neuronal apoptosis is unlikely to be associated with post-natal development except in early post-natal germinal matrix, and that it may instead represent the end result of specific pathological processes, such as HIV-1 encephalitis.
D000293:Adolescent; D017209:Apoptosis; D001479:Basal Ganglia / Q000473:pathology; D002540:Cerebral Cortex / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D004660:Encephalitis / Q000175:diagnosis* / Q000473:pathology*; D005260:Female; D015497:HIV-1; D006801:Humans; D007223:Infant; D008297:Male; D017628:Microglia; D009474:Neurons / Q000473:pathology*