Neuronal Loss and Astrocyte Activation and Inflammation

94 The rates of reported HIV-associated central nervous system (CNS) complications have declined since the advent of potent antiretroviral therapy (Figure 1). Although our progress is impressive, a close look shows that HIV-associated neurocognitive disturbance is still an important issue despite the vast clinical improvements achieved with antiretroviral treatment. Systematic evaluation of more than 1000 clinic patients in the CNS HIV Antiretroviral Effects Research (CHARTER) cohort shows that neurologic impairment is present in 50% or more, a rate comparable to that in the pre–antiretroviral era (Figure 2). Many factors likely contribute to ongoing neurologic complications despite the ability of current drugs to profoundly suppress viral replication. These factors include ongoing viral replication and immune activation in the CNS, comorbid factors like the use of both nonprescription and prescription drugs, perhaps including antiretroviral drugs, coinfections like with hepatitis B and C, and genetic influences of both the virus and the host.