Hypothesis: AIDS encephalopathy is due to primary and persistent infection of the brain with a human retrovirus of the lentivirus subfamily.

Recent evidence has demonstrated that human T-lymphotropic retroviruses are present in the brain of patients with acquired immunodeficiency syndrome (AIDS). Studies by neuropathological, ultrastructural and nucleic acid hybridization techniques indicate that these human retroviruses are neurotropic as well as lymphotropic. Striking similarities to the animal retroviruses of the lentivirus subfamily provide a rationale to implicate these human retroviruses (lentiviruses) in the pathogenesis of AIDS encephalopathy.