Human immunodeficiency virus within the brains of children with AIDS.

Infants and children with symptomatic human immunodeficiency virus (HIV) infection frequently develop neurologic disease with symptoms and signs of acquired microcephaly, developmental delays, encephalopathy, pyramidal tract signs, and less often, movement disorders and ataxia. However, clinical courses vary and, based upon progression of neurologic findings, we have classified them into 2 broad categories; progressive (loss of previously acquired language and cognitive skills) and plateau (failure to acquire additional developmental skills). We have used immunocytochemistry to localize HIV within the brains of neurologically involved children with AIDS. Interestingly, the brains of those children with a progressive neurologic course showed readily detectable HIV antigen, while those with a plateau course showed little or no detectable HIV. These findings suggest that in children with symptomatic HIV infection, the progressive neurologic deterioration is due to continued presence of HIV within deep white matter and gray matter, while the plateau neurologic course is due to HIV induced damage followed by either limited penetration of virus into the central nervous system, or clearance of virus below detectable limits.