Antibodies to HIV are produced within the central nervous system of all subjects with all categories of HIV infection.

Anti-HIV antibodies were found in the cerebrospinal fluid of all 41 subjects tested whose serum contained these antibodies. To ensure that locally produced antibody was being detected, a sensitive assay was used to demonstrate the integrity of the blood-brain barrier. Antibodies to ubiquitous adenovirus group antigens were sought, simultaneously, in CSF and serum. A lack of adenovirus antibodies in CSF of subjects seropositive for adenovirus was required before CSF anti-HIV antibodies could be considered to be produced within the central nervous system. Of the 41 subjects tested eight were asymptomatic, eight were clinically well but had persistent lymphadenopathy, 14 were immunodeficient and had constitutional symptoms (AIDS-related complex or ARC) and 11 had AIDS. Oligoclonal banding was detected in the CSF of 16 subjects and a pleocytosis was present in 24. Neither finding clustered with a particular stage of infection. It appears that HIV infection of T lymphocytes and the central nervous system occurs simultaneously, early in the course of the infection. All HIV infected subjects are at risk of developing primary neurological as well as immunological sequelae. Currently poorly understood resistance factors must protect both lymphocytes and nervous system tissue from damage by the HIV virus, as to date, the majority of infected subjects have not become immunodeficient or developed neurological disease.