André Huss

Neurofilament levels as biomarkers in asymptomatic and symptomatic familial amyotrophic lateral sclerosis.

Neurofilaments are elevated in the cerebrospinal fluid (CSF) and serum of amyotrophic lateral sclerosis (ALS) patients. However, timing of this increase is unknown. To characterize the premanifest disease phase, we performed a cross‐sectional study on asymptomatic (n = 12) and symptomatic (n = 64) ALS mutation carriers and family controls (n = 19). Neurofilaments NF‐L (neurofilament–light chain) and pNF‐H (phosphorylated neurofilament–heavy chain) are normal before symptom onset and increased by at least an order of magnitude at early symptom onset in CSF (pNF‐H) or serum and CSF (NF‐L). Thus, blood and CSF neurofilament levels are linked to the symptomatic phase of ALS and might serve as objective markers of structural damage to the nervous system. ANN NEUROL 2016;79:152–158

Neurofilaments levels as biomarkers in asymptomatic and symptomatic familial ALS

Neurofilaments are elevated in the cerebrospinal fluid (CSF) and serum of amyotrophic lateral sclerosis (ALS) patients. However, timing of this increase is unknown. To characterize the premanifest disease phase, we performed a cross‐sectional study on asymptomatic (n = 12) and symptomatic (n = 64) ALS mutation carriers and family controls (n = 19). Neurofilaments NF‐L (neurofilament–light chain) and pNF‐H (phosphorylated neurofilament–heavy chain) are normal before symptom onset and increased by at least an order of magnitude at early symptom onset in CSF (pNF‐H) or serum and CSF (NF‐L). Thus, blood and CSF neurofilament levels are linked to the symptomatic phase of ALS and might serve as objective markers of structural damage to the nervous system. ANN NEUROL 2016;79:152–158

Multicenter validation of CSF neurofilaments as diagnostic biomarkers for ALS

Abstract OBJECTIVE: Neurofilaments are leading neurochemical biomarkers for amyotrophic lateral sclerosis (ALS). Here, we investigated the effect of preanalytical factors on neurofilament concentrations in cerebrospinal fluid (CSF) in a “reverse” round-robin with 15 centers across Europe/U.S. METHODS: Samples from ALS and control patients (5/5 each center, n = 150) were analyzed for phosphorylated neurofilament heavy chain (pNfH) and neurofilament light chain (NfL) at two laboratories. RESULTS: CSF pNfH was increased (p < 0.05) in ALS in 10 out of 15 centers and NfL in 5 out of 12 centers. The coefficient of variation (CV%) of pNfH measurements between laboratories was 18.7 ± 19.1%. We calculated a diagnostic cut-off of >568.5 pg/mL for pNfH (sensitivity 78.7%, specificity 93.3%) and >1,431pg/mL for NfL (sensitivity 79.0%, specificity 86.4%). CONCLUSION: Values in ALS patients are already comparable between most centers, supporting eventual implementation into clinical routine. However, continuous quality control programs will be necessary for inclusion in the diagnostic work-up.

Diagnostic and prognostic significance of neurofilament light chain NF-L, but not progranulin and S100B, in the course of amyotrophic lateral sclerosis: Data from the German MND-net.

Abstract There is a need for diagnostic, prognostic, and monitoring blood biomarkers for ALS. We aimed to analyse and compare proposed candidate markers for disease progression in the course of ALS. Blood samples were taken from 125 ALS patients, including nine patients with C9orf72 or SOD1 mutation, at regular intervals of six months. ALS patients were characterized by the ALS functional rating scale (ALSFRS-R) and the Edinburgh Cognitive and Behavioural ALS Screen (ECAS). We quantified neurofilament light chain (NF-L), S100B, and progranulin (PGRN) and analysed it in relation to disease progression. Results showed that, at baseline, serum concentrations of NF-L but not PGRN or S100B discriminated significantly between ALS and controls. Within 24 months follow-up the marker concentrations remained stable. Baseline serum NF-L levels correlated with survival time, which was confirmed in subgroups with fast, intermediate, and slow disease progression and there was a weak association with disease duration. For S100B and PGRN we found an association with ALSFRS-R score changes and a trend for decreased levels in the fast progressor subgroup. In conclusion, serum NF-L in any ALS disease stage is a promising marker to support diagnosis and predict outcome, while serum PGRN and S100B are only of minor prognostic value.

The cerebrospinal fluid and barriers – anatomic and physiologic considerations

The cerebrospinal fluid (CSF) space consists of the intracerebral ventricles, subarachnoid spaces of the spine and brain (e.g., cisterns and sulci), and the central spinal cord canal. The CSF protects the central nervous system (CNS) in different ways involving metabolic homeostasis, supply of nutrients, functioning as lymphatic system, and regulation of intracranial pressure. CSF is produced by the choroid plexus, brain interstitium, and meninges, and it circulates in a craniocaudal direction from ventricles to spinal subarachnoid space from where it is removed via craniocaudal lymphatic routes and the venous system. The CSF is renewed 3-5 times daily and its molecular constituents are mainly blood-derived (80%), while the remainder consists of brain-derived and intrathecally produced molecules (20%). The CSF space is separated from the vascular system by the blood-CSF barrier (BCB), whereas the blood-brain barrier (BBB), responsible for maintaining the homeostasis of the brain, is located between brain parenchyma and vascular system. Although both barriers have similar functions, they differ with regard to their morphologic and functional properties. Both barrier systems are permeable not only for small molecules, but also for macromolecules and circulating cells. The transport of molecules across the BBB and BCB is regulated by passive diffusion (e.g., albumin, immunoglobulins) and facilitated or active transport (e.g., glucose). The extracellular space volume, potassium buffering, CSF circulation, and interstitial fluid absorption are mainly regulated by aquaporin-4 channels, which are abundantly located at the blood-brain and brain-CSF interfaces. The composition of CSF shows a high dynamic range, and the levels of distinct proteins vary due to several influencing factors, such as site of production (brain or blood-derived), site of sampling (ventricular or lumbar), CSF flow rate (BCB function), diurnal fluctuations of CSF production rate, and finally, molecular size of blood-derived proteins (IgM vs. albumin) and circadian rhythm (glucose, prostaglandin D synthase). Alterations of lumbar CSF are mainly influenced by processes of the CNS located adjacent to the ventricular and spinal CSF space and less by pathologies in cortical areas remote from the ventricles.

GFAP in early multiple sclerosis: A biomarker for inflammation

OBJECTIVE The role of Glial Fibrillic Acidic Protein (GFAP) as a potential biomarker for relapsing-remitting multiple sclerosis (RRMS) and clinically isolated syndrome (CIS) has been controversially discussed. The aim was to characterize the added value of GFAP levels in the CSF of RRMS and CIS patients in correlation with MRI lesion load. MATERIALS & METHODS GFAP levels in the CSF from 18 patients with RRMS, 8 patients with CIS and 35 controls were analyzed together with MRI data for acute and chronic inflammatory lesion load. RESULTS GFAP levels of patients vs. controls were higher (p=0.005), while there was no difference between GFAP levels in RRMS and CIS. There was no correlation between the number of supra- or infratentorial gadolinium enhancing lesions and GFAP levels, while there was a correlation between GFAP levels with infratentorial chronic inflammatory lesion load (p=0.0035). Most importantly, a highly significant correlation could be observed between GFAP levels and the intensity of gadolinium-enhancement as a parameter for the acute activity of inflammatory processes (p=0.0002). CONCLUSIONS GFAP seems to be a useful biomarker for highly active acute inflammation in patients with RRMS as well as with CIS.

Intrathecal immunoglobulin M production: A promising high-risk marker in clinically isolated syndrome patients: Intrathecal IgM in CIS

Markers predicting the course of patients with clinically isolated syndrome (CIS) toward multiple sclerosis (MS) are urgently needed. We evaluated the predictive values of intrathecal immunoglobulin (Ig) G and IgM production with different methods for conversion to definite MS according to revised McDonald 2010 criteria in a cohort of 126 CIS patients. Intrathecal IgM production showed the highest likelihood ratio for the conversion of CIS patients to definite MS at 6.3, whereas it was 1.4 for oligoclonal IgG bands. We conclude that the determination of intrathecal IgM is a valuable tool to predict the disease course of patients with CIS. Ann Neurol 2018;83:1032–1036

Validation of a multiplexing technique to determine the intrathecal, polyspecific antiviral immune response in multiple sclerosis

ABSTRACT Background: Beside the determination of oligoclonal bands (OCBs) as a diagnostic biomarker in multiple sclerosis (MS), the presence of an intrathecal production of antibodies against the neurotropic viruses measles (M), rubella (R) and Varicella-Zoster (Z), the so called MRZ reaction (MRZR) is an even more specific diagnostic biomarker in MS. Methods: We compared and validated the determination of the MRZR in 97 cerebrospinal fluid (CSF) and serum sample pairs of a bead-based multiplexing technique and a classical enzyme-linked immunosorbent assay (ELISA). Results: Conformity of 94% (M), 94% (R), 94% (Z), 96% (H) and 97% for the interpretation of the MRZR was obtained. Conclusion: Based on our findings of high conformity between the multiplex technique and classical ELISA, as well as the time and cost savings multiplexing allows, we conclude that the multiplexing technique is applicable as a diagnostic tool for the determination of the MRZR.