Neurocytoskeleton Proteins in Cerebrospinal Fluid of People With HIV-1 Subtypes B and C.

BACKGROUND: The objective was to compare the effect of HIV-1C and HIV-1B subtypes on neurofilament light (NfL) cerebrospinal fluid (CSF) levels and ratios of NfL to tau proteins. Additional comparisons were performed between people with HIV (PWH), participants with Alzheimer disease (AD), and HIV-negative controls (HIV-). We also calculated the diagnostic characteristics of CSF NfL and its ratios in HIV-associated neurocognitive disorder (HAND) diagnosis. METHODS: CSF NfL, T-tau, and P-tau181 concentrations were measured using immunoassays in a total of 108 CSF samples, including PWH (n = 68), HIV- (n = 16), and participants with AD (n = 24). These proteins were compared between HIV-1B (n = 27) and HIV-1C (n = 26) using multiple linear regression adjusted for nadir CD4 and plasma viral load suppression. Comparisons between PWH, HIV-, and participants with AD were adjusted for gender and age. RESULTS: CSF neurocytoskeleton proteins and their ratios were comparable in HIV-1B and HIV-1C. However, the HIV-1C group had a higher proportion of samples of CSF NfL above the reference value (n = 14, 53.85%) than the HIV-1B group (n = 8, 29.63%), P = 0.098. The values of CSF NfL were higher in the AD group [2578 (1864; 3500) pg/mL] than those in PWH [683 (500; 1197) pg/mL, P < 0.001] and control [660 (539; 802) pg/mL, P = 0.012] groups. The value of CSF NfL and its ratios for HAND diagnosis were poor. CONCLUSION: The effects of HIV-1B and HIV-1C on CSF NfL and tau ratios were comparable. The differences in CSF neurocytoskeleton proteins between PWH and individuals with AD suggested they might not share the same mechanisms of impairment. Further research is necessary to evaluate CSF NfL on the differential diagnoses of HAND with AD.

Inflammasome proteins in cerebrospinal fluid of brain-injured patients as biomarkers of functional outcome: clinical article.

OBJECT: Traumatic brain injury (TBI), the third most common CNS pathology, plagues 5.3 million Americans with permanent TBI-related disabilities. To evaluate injury severity and prognosis, physicians rely on clinical variables. Here, the authors seek objective, biochemical markers reflecting molecular injury mechanisms specific to the CNS as more accurate measurements of injury severity and outcome. One such secondary injury mechanism, the innate immune response, is regulated by the inflammasome, a molecular platform that activates caspase-1 and interleukin-1ß. METHODS: The authors investigated whether inflammasome components were present in the CSF of 23 patients with TBI and whether levels of inflammasome components correlate with outcome. The authors performed an immunoblot analysis of CSF samples from patients who suffered TBI and nontrauma controls and assessed the outcomes 5 months postinjury by using the Glasgow Outcome Scale. Data were analyzed using Mann-Whitney U-tests and linear regression analysis. RESULTS: Patients with severe or moderate cranial trauma exhibited significantly higher CSF levels of the inflammasome proteins ASC, caspase-1, and NALP-1 than nontrauma controls (p < 0.0001, p = 0.0029, and p = 0.0202, respectively). Expression of each protein correlated significantly with the Glasgow Outcome Scale score at 5 months postinjury (p < 0.05). ASC, caspase-1, and NALP-1 were significantly higher in the CSF of patients with unfavorable outcomes, including death and severe disability (p < 0.0001). CONCLUSIONS: NALP-1 inflammasome proteins are potential biomarkers to assess TBI severity, outcome, and the secondary injury mechanisms impeding recovery, serving as adjuncts to clinical predictors.

Synergy of serum and cerebrospinal fluid antibodies against axonal cytoskeletal proteins in patients with different neurological diseases.

Autoantibodies against different axonal cytoskeletal proteins [the light (NFL) and medium (NFM) subunit of neurofilament and tubulin (TUB)] in serum and cerebrospinal fluid may be generated in response to the release of cytoskeleton from damaged neurons. We studied the relationships among these autoantibodies. Paired cerebrospinal fluid (CSF) and serum samples were obtained from 47 multiple sclerosis (MS) patients, 14 patients with neurodegenerative diseases, 21 patients with various neurological diseases and 16 normal control subjects. Levels of antibodies against NFL, NFM and TUB were related to each other in CSF in all groups, whereas close association of anti-cytoskeletal antibodies in serum was found in the MS group only. A concordant spectrum of anti-cytoskeletal antibodies is present in serum of MS patients, unlike in other neurological patients. The synergy between the spectrum of anti-cytoskeletal antibodies in serum and CSF might be one of the immunological features typical for the MS patients.

Cerebrospinal fluid cytoskeleton proteins in patients with subcortical white-matter dementia.

The cerebrospinal fluid (CSF) levels of two cytoskeleton proteins, tau and the light subunit of neurofilament protein (NFL), both considered to reflect cerebral white-matter components, were investigated in a group of patients with a subtype of vascular dementia called 'subcortical white-matter dementia' (SWD). The group consisted of 25 demented patients with frontosubcortical brain syndromes, white-matter changes on computed tomography or magnetic resonance imaging and vascular disease or pronounced vascular risk factors. CSF-NFL was increased, whereas CSF-tau was normal, suggesting a differential involvement of the cytoskeleton in this patient group. The albumin ratio and the apolipoproteinE4 (ApoE4) allele status were also investigated. The albumin ratio was increased, indicating damage to the vessel walls with breakdown of the blood-brain barrier. No relationship was found between ApoE4 alleles and CSF levels of tau or NFL in this patient group. Besides presenting original data, the disease status of SWD is also discussed.