Background: The prevalence of HIV-associated neurocognitive disorders is increasing as HIV-infected individuals are living longer. The clinical manifestations of the syndrome also continue to evolve under the influence of antiretroviral drugs and comorbidities such as drugs of abuse. However, there are no surrogate markers for the disease, either to identify it de novo or to track its progression, and there is no proven treatment with the exception of antiretroviral drugs.

Methods: Levels of nitric oxide, nitrate, and 3-nitrotyrosine (3-NT)–modified proteins were measured in the CSF of 46 patients with HIV infection stratified according to their neurocognitive status and history of IV drug use (IVD). The 3-NT–modified proteins were isolated and identified by tandem mass spectrometry, and the functional consequence of 3-NT modification of L-prostaglandin D synthase (L-PGDS), the most abundant protein, was determined.

Results: 3-NT–modified proteins were significantly elevated in patients with HIV infection who had progressive neurocognitive decline over the next 6 months and in patients with a history of IVD. Thirteen different proteins with 3-NT modification were identified in the CSF of these patients. L-PGDS was the most abundant. 3-NT modification of this protein resulted in loss of its enzymatic activity.

Conclusions: There is increased nitrosative stress in CSF of HIV-infected patients with active dementia and in patients with a history of IV drug use, measurement of which may serve as a surrogate marker for these patients. Nitrosative stress may also have important functional consequences and may impact the pathogenesis of HIV-associated neurocognitive disorders.