Elevated Cerebrospinal Fluid Glutamate in Patients With HIV-related Dementia-Reply

Abstract

In Reply. —Drs Gurwitz and Kloog raise some points regarding possible alternative interpretations of our data. Human immunodeficiency virus—related encephalitis is present in all patients with AIDS-related dementia, and its severity is correlated with the extent of viral infection and degree of dementia. 1 For this reason, we believe that an increased glutamate level in CSF can be directly explained by interaction of viral proteins or factors from virus-infected cells (cytokines, free radicals, and nitric oxide) with glutamate transporters within the central nervous system. The alternative explanation of increased CSF glutamate levels as a reflection of elevated plasma levels appears less likely, for several reasons. Plasma glutamate levels were similarly elevated in AIDS patients with and without dementia, 2 and BBB disruption also may be present in nondemented HIV-positive patients who have normal CSF glutamate levels. 3 Moreover, although glutamate levels are normally 10 times higher in blood than in CSF, in