Higher Cerebrospinal Fluid Soluble Urokinase-type Plasminogen Activator Receptor, But Not Interferon γ-inducible Protein 10, Correlate With Higher Working Memory Deficits
Sergio M. De Almeida, Indianara Rotta, Bin Tang, Anya Umlauf, Florin Vaida, Mariana Cherner, Donald Franklin, Scott Letendre, Ronald J. Ellis, the HNRC Group
Abstract
BACKGROUND: We hypothesized that the induction of monocyte activation biomarkers, especially soluble urokinase-type plasminogen activator receptor (suPAR) and interferon γ-inducible protein 10 (IP-10), is lower in HIV-1C than HIV-1B, owing to a defective Tat cysteine dimotif (C30S). METHODS: A total of 68 paired cerebrospinal fluid (CSF) and blood samples from people with HIV (PWH), free of CNS opportunistic infections, from a Southern Brazil outpatient HIV clinic were evaluated such as HIV-1B subtype (n = 27), HIV-1C (n = 26), other (n = 15), and 19 HIV-negative controls. The levels of suPAR, IP-10, neopterin, and β2 microglobulin (β2m) in the CSF and serum were quantified using different immunoassays. RESULTS: Overall, in PWH, increases in CSF suPAR, CSF/serum suPAR, and CSF/serum β2m correlated with worse working memory deficits (r = 0.303, 0.353, and 0.289, respectively, all P < 0.05). The medians of IP-10, suPAR, neopterin, and β2m in CSF and serum and the CSF/serum ratio and suPAR index were comparable between the HIV-1B and HIV-1C subtypes. CSF IP-10 and neopterin and serum IP-10 and suPAR levels were higher in PWH than the HIV-negative controls (P = 0.015, P = 0.001, P < 0.0001, and P < 0.001, respectively). The serum β2m level was higher in HIV-associated dementia than neuropsychologically normal or asymptomatic (P = 0.024). DISCUSSION: We observed that higher levels of CSF suPAR and the suPAR quotient correlated with worse working memory deficit. Elevated levels of monocyte activation were similar in both HIV-1 B and C subtypes, providing no evidence of reduced neuropathogenicity of HIV-1 subtype C Tat compared with subtype B.