EFNS guidelines on disease-specific CSF investigations

Cerebrospinal fluid markers in sporadic Creutzfeldt-Jakob disease

Sporadic Creutzfeldt-Jakob disease (sCJD) is the commonest form of human prion diseases, accounting for about 85% of all cases. Current criteria for intra vitam diagnosis include a distinct phenotype, periodic sharp and slow-wave complexes at electroencephalography (EEG), and a positive 14-3-3-protein assay in the cerebrospinal fluid (CSF). In sCJD, the disease phenotype may vary, depending upon the genotype at codon 129 of the prion protein gene (PRNP), a site of a common methionine/valine polymorphism, and two distinct conformers of the pathological prion protein. Based on the combination of these molecular determinants, six different sCJD subtypes are recognized, each with distinctive clinical and pathologic phenotypes. We analyzed CSF samples from 127 subjects with definite sCJD to assess the diagnostic value of 14-3-3 protein, total tau protein, phosphorylated₁₈₁ tau, and amyloid beta (Aβ) peptide 1-42, either alone or in combination. While the 14-3-3 assay and tau protein levels were the most sensitive indicators of sCJD, the highest sensitivity, specificity and positive predictive value were obtained when all the above markers were combined. The latter approach also allowed a reliable differential diagnosis with other neurodegenerative dementias.

Cerebrospinal fluid and blood biomarkers of neuroaxonal damage in multiple sclerosis

Following emerging evidence that neurodegenerative processes in multiple sclerosis (MS) are present from its early stages, an intensive scientific interest has been directed to biomarkers of neuro-axonal damage in body fluids of MS patients. Recent research has introduced new candidate biomarkers but also elucidated pathogenetic and clinical relevance of the well-known ones. This paper reviews the existing data on blood and cerebrospinal fluid biomarkers of neuroaxonal damage in MS and highlights their relation to clinical parameters, as well as their potential predictive value to estimate future disease course, disability, and treatment response. Strategies for future research in this field are suggested.

Identification and preliminary characterization of ubiquitin C terminal hydrolase 1 (UCHL1) as a biomarker of neuronal loss in aneurysmal subarachnoid hemorrhage

By using two different approaches, ubiquitin C-terminal hydrolase 1 (UCHL1) was identified as a potential cerebrospinal fluid (CSF) biomarker of neuronal loss in aneurysmal subarachnoid hemorrhage (ASAH) and presumably other CNS damage and disease states. Appropriate antibodies and a sensitive ELISA were generated, and the release of UCHL1 into CSF was compared with that of pNF-H and S100beta in a cohort of 30 ASAH patients. Both UCHL1 and pNF-H showed persistent release into CSF in almost all patients in the second week postaneurysmal rupture (AR), and S100beta levels rapidly declined to baseline levels in 23 of 30 patients. Seven of thirty patients showed persistently elevated S100beta levels over the first 5 days post-AR and also had relatively higher levels of pNF-H and UCHL1 higher compared with the rest. These patients proved to have very poor outcomes, with 6 of 7 expiring. Patients who did reduce S100beta levels tended to have a better outcome if pNF-H and UCHL1 levels were also lower, and elevated UCHL1 levels in the second week post-AR were particularly predictive of poor outcome. Acute coordinated releases of large amounts of UCHL1, pNF-H, and S100beta in 16 of 30 patients were observed, suggesting sudden loss of brain tissues associated with secondary events. We conclude that measurement of the CSF levels of these proteins reveals details of ASAH progression and recovery and predicts patient outcome.

A highly sensitive electrochemiluminescence immunoassay for the neurofilament heavy chain protein

BACKGROUND

The loss of neurological function is closely related to axonal damage. Neurofilament subunits are concentrated in neurons and axons and have emerged as promising biomarkers for neurodegeneration. Electrochemiluminescence (ECL) based assays are known to be of superior sensitivity and require less sample volume than conventional ELISAs.

METHODS

We developed an ECL based solid-phase sandwich immunoassay to measure the neurofilament heavy chain protein (NfH(SMI35)) in CSF. We employed commercially available antibodies as previously used in a conventional ELISA (Petzold et al., 2003; Petzold and Shaw, 2007). The optimised and validated assay was applied in a reference cohort and defined patient groups.

RESULTS

Analytical sensitivity (background plus three SD) of our assay was 2.4 pg/ml. The mean intra-assay coefficient of variation (CV) was 4.8% and the inter-assay CV 8.4%. All measured control and patient samples produced signals well above background. Patients with multiple sclerosis (MS) (median 46.2 pg/ml, n=95), amyotrophic lateral sclerosis (ALS) (160.1 pg/ml, n=50), mild cognitive impairment/Alzheimer's disease (MCI/AD) (65.6 pg/ml, n=20), Guillain-Barre syndrome (GBS) (91.0 pg/ml, n=20) or subarachnoid hemorrhage (SAH) (345.0 pg/ml, n=20) had higher CSF NfH(SMI35) values than the reference cohort (27.1 pg/ml, n=73, p<0.0001 for each comparison).

CONCLUSION

The new ECL based assay for NfH(SMI35) in CSF is superior in terms of sensitivity, precision and accuracy to previously published methods (Petzold et al., 2003; Shaw et al., 2005; Teunissen et al., 2009). The improved performance and small sample volume requirement qualify this method in experimental settings and clinical trials designed to perform a number of tests on limited amounts of material.

Progressive Stroke-Like Symptoms in a Patient with Sporadic Creutzfeldt-Jakob Disease

Sporadic Creutzfeldt-Jakob disease (sCJD) is a rare neurodegenerative disorder in which accumulation of a pathogenic isoform of prion protein (PrP^Sc) induces neuronal damage with distinct pathologic features. The prognosis of sCJD is devastating: rapid clinical decline is followed by death generally within months after onset of symptoms. The classic clinical manifestations of sCJD are rapidly progressing dementia, myoclonus, and ataxia. However, the spectrum of clinical features can vary considerably. We describe a definite, neuropathologically verified sCJD in a 67-year-old woman who initially presented with progressive stroke-like symptoms: left-sided hemiparesis and ataxia within a few days. The initial brain magnetic resonance imaging (MRI) showed bilateral cortical hyperintensity on diffusion-weighted sequences (DWI) resembling multiple ischemic lesions. Despite anticoagulation with low-molecular-weight heparin, the patient deteriorated rapidly, became dysphagic and bedridden with myoclonic jerks on her left side extremities correlating with intermittent high-amplitude epileptiform discharges on electroencephalography (EEG). Basal ganglia hyperintense signal changes in addition to cortical ribboning were seen in DWI images of a follow-up MRI. Repeated EEG recordings showed an evolution to periodic sharp wave complexes. Protein 14-3-3 was positive in her cerebrospinal fluid specimen, in addition to an abnormally high total tau level. In the terminal stage the patient was in an akinetic, mutistic state with deteriorating consciousness. She died 19 days after admission to the hospital. Neuropathologic investigation corroborated the clinical diagnosis of sCJD with spongiform degeneration and immunohistochemical demonstration of the deposition of pathologic PrP^Sc.