Cell-binding IgM in CSF is distinctive of multiple sclerosis and targets the iron transporter SCARA5.

Intrathecal IgM production in multiple sclerosis is associated with a worse disease course. To investigate pathogenic relevance of autoreactive IgM in multiple sclerosis, CSF from two independent cohorts, including multiple sclerosis patients and controls, were screened for antibody binding to induced pluripotent stem cell-derived neurons and astrocytes, and a panel of CNS-related cell lines. IgM binding to a primitive neuro-ectodermal tumour cell line discriminated 10% of multiple sclerosis donors from controls. Transcriptomes of single IgM producing CSF B cells from patients with cell-binding IgM were sequenced and used to produce recombinant monoclonal antibodies for characterization and antigen identification. We produced five cell-binding recombinant IgM antibodies, of which one, cloned from an HLA-DR + plasma-like B cell, mediated antigen-dependent complement activation. Immunoprecipitation and mass spectrometry, and biochemical and transcriptome analysis of the target cells identified the iron transport scavenger protein SCARA5 as the antigen target of this antibody. Intrathecal injection of a SCARA5 antibody led to an increased T cell infiltration in an experimental autoimmune encephalomyelitis (EAE) model. CSF IgM might contribute to CNS inflammation in multiple sclerosis by binding to cell surface antigens like SCARA5 and activating complement, or by facilitating immune cell migration into the brain.

Pharmacokinetic and pharmacodynamic properties of once-weekly insulin icodec in individuals with type 2 diabetes.

AIMS: To characterize the pharmacokinetic and pharmacodynamic properties of once-weekly insulin icodec in type 2 diabetes (T2D). MATERIALS AND METHODS: In an open-label trial, 46 individuals with T2D (18-75 years; body mass index 18.0-38.0 kg/m2 ; glycated haemoglobin ≤75 mmol/mol [≤9%]; basal insulin-treated) received subcutaneous once-weekly icodec for ≥8 weeks at individualized doses, aiming at a pre-breakfast plasma glucose concentration of 4.4 to 7.0 mmol/L (80-126 mg/dL) on the last three mornings of each weekly dosing interval. Frequent blood sampling to assess total serum icodec concentration (ie, albumin-bound and unbound) occurred from first icodec dose until 35 days after last dose. Icodec trough concentrations following initiation of once-weekly dosing were predicted by pharmacokinetic modelling. During the final 3 weeks of icodec treatment, while at steady state, the icodec glucose-lowering effect was assessed in three glucose clamps (target 7.5 mmol/L [135 mg/dL]): 0 to 36, 40 to 64 and 144 to 168 h post-dose, thus covering the initial, middle and last part of the 1-week dosing interval. Glucose-lowering effect during a complete dosing interval was predicted by pharmacokinetic-pharmacodynamic modelling. RESULTS: Model-predicted icodec steady state was attained after 3 to 4 weeks. At steady state, model-predicted daily proportions of glucose-lowering effect on days 1 to 7 of the 1-week dosing interval were 14.1%, 16.1%, 15.8%, 15.0%, 14.0%, 13.0% and 12.0%, respectively. Icodec duration of action was at least 1 week in all participants. Once-weekly icodec was overall safe and well tolerated in the current trial. CONCLUSIONS: The pharmacokinetic and pharmacodynamic characteristics of icodec in individuals with T2D support its potential as a once-weekly basal insulin.

High serum neurofilament light chain levels correlate with brain atrophy and physical disability in multiple sclerosis.

BACKGROUND AND PURPOSE: Serum neurofilament light chain (sNfL) is a promising biomarker of neuroaxonal damage in persons with multiple sclerosis (pwMS). In cross-sectional studies, sNfL has been associated with disease activity and brain magnetic resonance imaging (MRI) changes; however, it is still unclear to what extent in particular high sNfL levels impact on subsequent disease evolution. METHODS: sNfL was quantified by an ultrasensitive single molecule array (Simoa) in 199 pwMS (median age = 34.2 years, 64.3% female) and 49 controls. All pwMS underwent 3-T MRI to assess global and compartmental normalized brain volumes, T2-lesion load, and cortical mean thickness. Follow-up data and serum samples were available in 144 pwMS (median follow-up time = 3.8 years). Linear and binary logistic models were used to estimate the independent contribution of sNfL for changes in MRI and Expanded Disability Status Scale (EDSS). Age-corrected sNfL z-scores from a normative database of healthy controls were used for sensitivity analyses. RESULTS: High sNfL levels at baseline were associated with atrophy measures of the whole brain (standardized beta coefficient ßj = -0.352, p < 0.001), white matter (ßj = -0.229, p = 0.007), thalamus (ßj = -0.372, p = 0.004), and putamen (ßj = -1.687, p = 0.012). pwMS with high levels of sNfL at baseline and follow-up had a greater risk of EDSS worsening (p = 0.007). CONCLUSIONS: Already single time point elevation of sNfL has a distinct effect on brain volume changes over a short-term period, and repeated high levels of sNfL indicate accumulating physical disability. Serial assessment of sNfL may provide added value in the clinical management of pwMS.

Serum neurofilament levels correlate with retinal nerve fiber layer thinning in multiple sclerosis.

BACKGROUND: Serum neurofilament light chain (sNfL) levels and peripapillary retinal nerve fiber layer (pRNFL) are both emerging biomarkers of neuro-axonal damage in multiple sclerosis (MS). However, data on the relation between sNfL and pRNFL are scarce. OBJECTIVE: We aimed to determine the relation of sNfL levels with pRNFL thinning in a large cohort of relapsing-remitting (RR) MS patients. METHODS: We identified 80 patients from a prospective, 3-year observational study on retinal changes in RRMS with annual blood samples available. sNfL levels were measured using single-molecule array (SimoaTM) assay. Annualized loss of pRNFL (aLpRNFL) was determined by individual linear regression models. Correlations between single and repeated sNfL levels and aLpRNFL were analyzed using multivariate linear regression and mixed-effect models. RESULTS: After correction for sex, age, and baseline sNfL, an sNfL increase of 10 pg/mL was associated with an aLpRNFL of -0.7 µm (95% confidence interval (CI): (-1.3, -0.2), p < 0.001). Patients with ⩾2 sNfL measurements >75th percentile displayed higher aLpRNFL (2.2 µm, standard deviation (SD) 0.6) compared to patients with no sNfL measure >75th percentile (0.4 µm, SD 0.2, p < 0.001). Between 15% and 20% of the aLpRNFL variance could be predicted from sNfL levels. CONCLUSION: sNfL levels contribute to the prediction of retinal thinning in patients with RRMS, strengthening its value as a biomarker of neuro-axonal damage.

Cerebrospinal fluid mitochondrial DNA levels in patients with multiple sclerosis.

The role of cerebrospinal fluid (CSF) mitochondrial DNA (mtDNA) levels as biomarker in multiple sclerosis (MS) is unknown. We determined CSF mtDNA levels in a cohort of 237 individuals, including patients with MS and clinically isolated syndrome (CIS), inflammatory and non-inflammatory neurological controls, and cognitively healthy controls (HC). mtDNA concentration was measured by droplet digital polymerase chain reaction. CSF mtDNA levels were increased in all pathological conditions compared with HC, though no differences were observed between relapse-onset and progressive MS clinical forms, CIS patients and neurological controls. These findings do not support the determination of CSF mtDNA levels as a useful biomarker in MS clinical practice.

Prognostic value of free light chains lambda and kappa in early multiple sclerosis.

BACKGROUND: Cerebrospinal fluid (CSF) immunoglobulin free light chains (FLC) have been suggested as quantitative alternative to oligoclonal bands (OCB) in the diagnosis of multiple sclerosis (MS). However, little is known on their role in predicting clinical and paraclinical disease progression, particularly in early stages. OBJECTIVE: To assess the prognostic value of FLC in OCB-positive patients with clinically isolated syndrome (CIS) suggestive of MS and early MS. METHODS: We determined FLC kappa (KFLC) and lambda (LFLC) in CSF and serum by nephelometry in 61 patients (CIS ( n = 48), relapsing-remitting multiple sclerosis ( n = 13)) and 60 non-inflammatory neurological controls. Median clinical follow-up time in CIS was 4.8 years (interquartile range (IQR), 1.5-6.5 years). Patients underwent 3T magnetic resonance imaging (MRI) at baseline and follow-up (median time interval, 2.2 years; IQR, 1.0-3.7 years) to determine T2 lesion load (T2LL) and percent brain volume change (PBVC). RESULTS: CSF FLC were significantly increased in CIS/MS compared to controls (all p < 0.001). A lower KFLC/LFLC CSF ratio was associated with CIS-clinically definite multiple sclerosis (CDMS) conversion (hazard ratio (HR) = 2.89; 95% confidence interval (CI) = 1.17-7.14; p < 0.05). No correlations were found for FLC variables with T2LL or PBVC. CONCLUSION: Our study confirms increased intrathecal synthesis of FLC in CIS/MS which supports their diagnostic contribution. The KFLC/LFLC CSF ratio appears to have a prognostic value in CIS beyond OCB.

Natalizumab in cerebrospinal fluid and breastmilk of patients with multiple sclerosis.

Background: Natalizumab is a highly effective monoclonal antibody for the treatment of multiple sclerosis (MS), which can diffuse in different anatomical compartments, including cerebrospinal fluid (CSF) and milk. Objectives: Starting from incidental detection of natalizumab in the CSF of MS patients, the objective of this study was to develope a flow-cytometry-based assay and apply it to quantify natalizumab in body fluids, including milk collected from nursing patients over 180 days and in patients with neutralizing antibodies against natalizumab. Methods: CSF, milk and sera samples from patients with multiple sclerosis were tested by flow-cytometry for binding to a VLA-4 expressing cell line or to a control cell line. A standard curve was prepared by incubating the same cells with natalizumab at 50 µg/ml and serially diluted to 0.005 ng/ml. Binding specificity was confirmed using an anti-natalizumab neutralizing antibody. Results: Our assay was sensitive enough to detect natalizumab in CSF, with a lower detection limit of 1.5 ng/ml. Neutralizing antibodies against natalizumab inhibited binding to the cell line. In breastmilk, the peak concentration was observed during the first 2 weeks after infusion and the average concentration over the observation time was 173.3 ng/ml, with a trend toward increased average milk concentration over subsequent administrations. Conclusion: Routine use of such an assay would enable a better understanding of the safety of therapeutic antibody administration during pregnancy and lactation.

Decreased Cerebrospinal Fluid Antioxidative Capacity Is Related to Disease Severity and Progression in Early Multiple Sclerosis.

Background: Oxidative stress-induced neuronal damage in multiple sclerosis (MS) results from an imbalance between toxic free radicals and counteracting antioxidants, i.e., antioxidative capacity (AOC). The relation of AOC to outcome measures in MS still remains inconclusive. We aimed to compare AOC in cerebrospinal fluid (CSF) and serum between early MS and controls and assess its correlation with clinical/radiological measures. Methods: We determined AOC (ability of CSF and serum of patients to inhibit 2,2'-azobis(2-amidinopropane) dihydrochloride-induced oxidation of dihydrorhodamine) in clinically isolated syndrome (CIS)/early relapsing-remitting MS (RRMS) (n = 55/11) and non-inflammatory neurological controls (n = 67). MS patients underwent clinical follow-up (median, 4.5; IQR, 5.2 years) and brain MRI at 3 T (baseline/follow-up n = 47/34; median time interval, 3.5; IQR, 2.1 years) to determine subclinical disease activity. Results: CSF AOC was differently regulated among CIS, RRMS and controls (p = 0.031) and lower in RRMS vs. CIS (p = 0.020). Lower CSF AOC correlated with physical disability (r = -0.365, p = 0.004) and risk for future relapses (exp(ß) = 0.929, p = 0.033). No correlations with MRI metrics were found. Conclusion: Decreased CSF AOC was associated with increased disability and clinical disease activity in MS. While our finding cannot prove causation, they should prompt further investigations into the role of AOC in the evolution of MS.

CSF SERPINA3 Levels Are Elevated in Patients With Progressive MS.

OBJECTIVE: To identify biomarkers associated with progressive phases of MS and with neuroprotective potential. METHODS: Combined analysis of the transcriptional and proteomic profiles obtained in CNS tissue during chronic progressive phases of experimental autoimmune encephalomyelitis (EAE) with the transcriptional profile obtained during the differentiation of murine neural stem cells into neurons. Candidate biomarkers were measured by ELISA in the CSF of 65 patients with MS (29 with relapsing-remitting MS [RRMS], 20 with secondary progressive MS, and 16 with primary progressive MS [PPMS]) and 30 noninflammatory neurologic controls (NINCs). RESULTS: Integrative analysis of gene and protein expression data identified 2 biomarkers, the serine protease inhibitor Serpina3n and the calcium-binding protein S100A4, which were upregulated in chronic progressive EAE and whose expression was induced during neuronal differentiation. Immunofluorescence studies revealed a primarily neuronal expression of S100A4 and Serpina3n during EAE. CSF levels of SERPINA3, the human ortholog of murine Serpina3n, and S100A4 were increased in patients with MS compared with NINCs (SERPINA3: 1,320 vs 838.6 ng/mL, p = 0.0001; S100A4: 1.6 vs 0.8 ng/mL, p = 0.02). Within the MS group, CSF SERPINA3 levels were significantly elevated in patients with progressive forms, mainly patients with PPMS compared with patients with RRMS (1,617 vs 1,129 ng/mL, p = 0.02) and NINCs (1,617 vs 838.6 ng/mL, p = 0.0001). Of interest, CSF SERPINA3 levels significantly correlated with CSF neurofilament light chain levels only in the PPMS group (r = 0.62, p = 0.01). CONCLUSION: These results point to a role of SERPINA3 as a biomarker associated with the progressive forms of MS, particularly PPMS.

Serum neurofilament light levels in normal aging and their association with morphologic brain changes.

Neurofilament light (NfL) protein is a marker of neuro-axonal damage and can be measured not only in cerebrospinal fluid but also in serum, which allows for repeated assessments. There is still limited knowledge regarding the association of serum NfL (sNfL) with age and subclinical morphologic brain changes and their dynamics in the normal population. We measured sNfL by a single molecule array (Simoa) assay in 335 individuals participating in a population-based cohort study and after a mean follow-up time of 5.9 years (n = 103). Detailed clinical examination, cognitive testing and 3T brain MRI were performed to assess subclinical brain damage. We show that rising and more variable sNfL in individuals >60 years indicate an acceleration of neuronal injury at higher age, which may be driven by subclinical comorbid pathologies. This is supported by a close association of sNfL with brain volume changes in a cross-sectional and especially longitudinal manner.

Serum neurofilament light levels correlate with change of olfactory function in multiple sclerosis.

BACKGROUND: Serum neurofilament light chain levels (sNfL) and impairment of olfactory function emerge as biomarkers in multiple sclerosis (MS). However, the relation between sNfL and olfactory function in MS has not been investigated yet. OBJECTIVE: We aimed to determine whether sNfL levels correlate with olfactory function in relapsing-remitting (RR) MS. METHODS: We annually measured sNfL and olfactory function (Sniffin' Sticks test: Threshold (T) and combined discrimination-identification (DI) score) in 80 RRMS patients and compared sNfL to T and DI scores. RESULTS: T scores significantly correlated with sNfL levels at simultaneous measurement (-1.5 points, 95% CI: -2.6-0.5 per 10 pg/ml sNfL increase; p < 0.001 per 10 pg/ml sNfL increase), but not at temporally distant measurement. Patients with ≥2 sNfL measures above the 75th percentile displayed significantly larger DI decrease (median 3.0 points, IQR 2.0-4.5) compared to patients with no or only one sNfL measure above the 75th percentile (0.0, IQR -0.5-0.5, p < 0.001 and 1.0, IQR 0.0-3.30, p = 0.008, respectively). 13-18% of the variance in T and 22% in DI decrease could be predicted from sNfL levels. CONCLUSIONS: sNfL correlates with different qualities of olfactory function in patients with RRMS further strengthening the value of olfactory function as a biomarker of inflammation and axonal damage in MS.

The effect of disease modifying therapies on CD62L expression in multiple sclerosis.

BACKGROUND: The increasing armamentarium of disease-modifying therapies in multiple sclerosis is accompanied by potentially severe adverse effects. The cell-adhesion molecule CD62L, which facilitates leukocyte extravasation, has been proposed as a predictive marker for treatment tolerability. However, pre-analytical procedures might impact test results, thereby limiting its clinical usability. Whether the immediate analysis of CD62L expression of peripheral blood mononuclear cells can aid treatment decision making is yet unclear. OBJECTIVE: To investigate the effect of various disease-modifying therapies in multiple sclerosis on CD62L expression of CD3+CD4+ peripheral blood mononuclear cells in freshly collected blood samples. METHODS: We collected peripheral blood samples from patients with clinically isolated syndrome and multiple sclerosis (baseline/follow up n = 234/n = 98) and healthy controls (n = 51). CD62L+CD3+CD4+ expression was analysed within 1 hour by fluorescence-activated cell sorting. RESULTS: CD62L+CD3+CD4+ expression was significantly decreased in patients treated with natalizumab (n = 26) and fingolimod (n = 20) and increased with dimethyl-fumarate (n = 15) compared to patients receiving interferon/glatiramer acetate (n = 90/30) or no disease-modifying therapies (n = 53) and controls (n = 51) (p<0.001). CD62L expression showed temporal stability during unchanged disease-modifying therapy usage, but increased after natalizumab withdrawal and decreased upon fingolimod introduction. CONCLUSION: CD62L+CD3+CD4+ expression is altered in patients treated with different disease-modifying therapies when measured in freshly collected samples. The clinical meaning of CD62L changes under disease-modifying therapies warrants further investigation.

Serum neurofilament light is sensitive to active cerebral small vessel disease.

OBJECTIVE: To explore whether serum neurofilament light chain protein (NfL) levels are increased in patients with MRI-confirmed recent small subcortical infarcts (RSSI) compared to healthy controls and to determine the subsequent course and determinants of NfL levels in a longitudinal manner. METHODS: In a prospectively collected group of symptomatic patients with an RSSI (n = 79, mean age 61 ± 11 years, 67% male), we analyzed brain MRI and serum NfL using a Single Molecule Array (Simoa) assay at baseline and at 3 and 15 months after stroke. Community-dwelling healthy age- and sex-matched individuals with comparable severity of MRI white matter hyperintensities (WMH) (n = 53) served as controls. RESULTS: Patients with an RSSI had higher NfL baseline levels compared to controls (73.45 vs 34.59 pg/mL, p < 0.0001), and they were increasingly higher with the time from stroke symptom onset to blood sampling (median 4 days, range 1-11 days, rs = 0.51, p < 0.0001). NfL levels remained increased at the 3-month follow-up but returned to normal at 15 months after stroke. NfL levels were associated with RSSI size and baseline WMH severity and were especially high in patients with new, clinically silent cerebral small vessel disease (CSVD)-related lesions at follow-up. CONCLUSIONS: Serum NfL is increased in patients with an RSSI and the occurrence of new CSVD-related MRI lesions, even when clinically silent. This suggests NfL as a blood biomarker for active CSVD.