This chapter discusses various aspects of the central nervous system complications directly associated with HIV-1—in particular, that of HIV dementia (HIVD) also known as the acquired immunodeficiency syndrome (AIDS) dementia complex (ADC). This syndrome—which is characterized by progressive motor and cognitive loss—was recognized early in the course of this epidemic and is generally accepted to be because of HIV itself, and not related to infection with any opportunistic organism. One can speculate about several scenarios resulting from the continued presence of replication-competent HIV within brain. In the worst case, a smoldering infection of the nervous system could lead to neurological deterioration without reinfection of systemic immune cells. The epidemiological data indicating that HIVD is a disease primarily associated with immunodeficiency suggest that the systemic immune system plays a role in maintaining virus residing within the central nervous system (CNS) under control. Advances with combination antiviral therapy have successfully reduced plasma viral load in a high proportion of individuals, leading to the speculation (previously almost heretical) that it may be possible to eradicate HIV completely from the systemic immune system.
