Brains of AIDS patients do often display characters of HIV specificity, in the presence or not of opportunistic lesions. Mesodermal nodules with giant cells, and a peculiar primary demyelination, the progressive diffuse leukoencephalopathy of Kleihues et al., which can be found only in brains with giant cells, have been pointed out as typical. In 100 intra venous drug user patients, younger than 32 years (mean age: 26) the HIV specificity described was observed on 49 occasions. All these patients presented with Seitelberger's glio-neuronal poliodystrophy (GP), quite similar to that encountered in several kinds of encephalopathies. Nevertheless, in 35 of the patients with HIV typical findings, there was in the cortex and some other grey matter regions, an amount of diffuse mesodermal elements uncommon in encephalopathies, and so relevant as to contradict the notion itself of this kind of cerebral lesion, where inflammatory events ought not to appear. This aspect of HIV encephalopathy was indicated by us as GP plus. An optic microscopy examination of the cortex allowed us to establish how in GP plus the neuronal changes are more severe and apparently older than in the other patients considered. The fact that the astrocytes did not behave differently in the two aspects of encephalopathy lead us to conclude that GP plus sets in through processes distinct from those in encephalopathy tout-court, and to put forward that it is a further character of HIV specificity.

Adult Autopsy AIDS Dementia Complex/*PATHOLOGY Cerebral Cortex/*PATHOLOGY English Abstract Histological Techniques Human Neurons/PATHOLOGY Substance Dependence/*PATHOLOGY Temporal Lobe/PATHOLOGY JOURNAL ARTICLE

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