[Neuropathology of human type 1 immunodeficiency virus infection]

The nervous system may be affected at any stage in the course of HIV-1 infection. Acute or subacute inflammatory demyelinating polyradiculoneuropathies occur often early and improve spontaneously. Distal symmetrical axonal, predominantly sensory, painful polyneuropathies occur in the late stages of the disease. Microvasculitis is frequent in the early neuropathies. Spastic and ataxic paraparesis associated with vacuolar myelopathy are rare and probably not related only to HIV-1. Aseptic lymphocytic meningitis may occur as the presenting or sole manifestation of HIV-1 infection. The more frequent subacute encephalitis, probably directly related to HIV-1, is late in the course of the disease. Microscopic changes are suggestive but non-specific (microglial nodules, multinucleated giant cells). According to some authors, HIV-1 infection of the central nervous system macrophages may be early and latent until associated pathologies (opportunistic infections, lymphoma) trigger the replication of HIV-1 by infected macrophages.