Background

Background
Neuromyelitis optica spectrum disorders (NMOSD), anti-MOG-antibody associated disease (MOGAD) and multiple sclerosis (MS) may be difficult to differentiate. Detection of antibodies (Ab) targeting AQP4 and MOG is the diagnostic gold standard for the former two diseases, but has limited sensitivity and long laboratory turnaround time. Neutrophil granulocyte (NG) invasion of brain tissue is a key differentiator of NMOSD from MS, and has also been described in MOGAD.

Objectives

Objectives
To examine the capability to differentiate NMOSD/MOGAD from MS by the profile of secreted primary (elastase (Ela); myeloperoxidase (MPO)) and secondary (matrix metalloproteinase-8 (MMP-8); neutrophil gelatinase-associated lipocalin (NGAL)) neutrophil granule products in CSF.

Methods

Methods
CSF from patients with NMOSD (n=42), MOGAD (n=6) and RRMS (n=41) were evaluated for Ela, MPO, MMP-8, NGAL, and compared with markers of neuronal (NfL) and astrocyte (GFAP, S100B) damage by conventional ELISA or single molecule array assay. CSFs from healthy controls (HC) (n=25) served as reference. The association between biomarkers and disease groups was assessed in linear models. The kinetic change of biomarkers in function of time since last relapse was modelled across disease groups. ROC curves and area under the curve (AUC) were calculated to estimate the potential to differentiate NMOSD/MOGAD from RRMS in acute disease phase (≤20 days after relapse), as well as between acute NMOSD and MOGAD. The association of biomarkers with EDSS in acute NMOSD and RRMS was assessed by linear models and Spearman correlation.

Results

Results
All disease groups had elevated NfL vs HC (p<0.01), while GFAP levels were increased only in NMOSD (p<0.01). In acute NMOSD, all 4 NG markers were increased vs HC and acute RRMS (all p<0.01). In MOGAD, Ela, MPO and MMP-8 were increased vs HC (p<0.025) and acute RRMS (p<0.04). AUC in ROC analyses comparing acute NMOSD/MOGAD vs acute RRMS was high (Ela and NGAL: 0.91; MPO: 0.82; MMP-8: 0.81). In acute NMOSD, S100B and GFAP levels were increased in 89% (AUC=0.82) and 83% (AUC=0.80) of patients, respectively, vs median values of MOGAD. In acute NMOSD, EDSS scores correlated with all 4 NG markers (all p<0.01), and GFAP (p<0.031), but not with NfL and S100B (both p=0.21).

Conclusions

Conclusion
NG-specific biomarkers correlate with current EDSS scores in NMOSD. They show high sensitivity and specificity for rapid differentiation of acute NMOSD and MOGAD vs RRMS, similar to those reported for Ab against AQP4 and MOG. As the 4 NG biomarkers can be measured within few hours, as compared to an up to 2-week turnaround time for gold-standard cell-based assays for AQP4 and MOG, they could support individual decision making for acute therapeutic intervention. Further, increased S100B and GFAP levels differentiate acute NMOSD from MOGAD. NG markers may have a role in the diagnosis of Ab-negative NMOSD.

Background

Pregnancy in MS typically goes along with reduced disease activity in the third trimester, followed by an increase in relapse frequency postpartum. Neurofilament light chain levels in serum (NfL) is a specific biomarker of neuroaxonal injury. Increased NfL levels are associated with relapses and MRI activity, while disease modifying treatment (DMT) response is reflected by a decrease of NfL.

Objectives

The objective of this study was to evaluate whether interrupting DMT due to pregnancy leads to increased NfL levels in MS.

Methods

We investigated prospectively documented pregnancies in the Swiss MS Cohort Study. Serum samples were collected 6- or 12-monthly and were analyzed by Simoa NF-light® assay. Uni- and multivariable mixed effect models were used to investigate associations between clinical characteristics and longitudinal NfL levels.

Results

We investigated 72 pregnancies in 63 relapsing MS patients (median age 31.4; disease duration 7.1 years; EDSS 1.5 at last visit before birth). In total, 433 samples were included: 92 during pregnancy or up to initiation of DMT but max. 9 months postpartum (pregnancy/post-partum period, pp), 167 prior to pp and 174 after the pp. Four patients had no DMT before, during and after pregnancy. DMT was continued in 13/72 pregnancies (>6 months during pregnancy: 6 rituximab/ocrelizumab, 4 natalizumab, 1 interferon-beta 1a i.m., 1 fingolimod and 1 glatiramer acetate). In univariable analysis, NfL levels were on average 22% higher during vs. outside the pp (β: 1.22, 95%CI: 1.10-1.35; p<0.001). We observed 29 relapses during the pp. In a multivariable analysis, relapses (within 120 days before serum sampling) were associated with 98% higher NfL (β: 1.98, 95%CI: 1.75-2.25; p<0.001); NfL was 7% higher per EDSS step increase (β: 1.07, 95%CI: 1.01-1.12; p=0.013) and on average 13% higher during vs. outside the pp (β: 1.13, 95%CI: 1.03-1.24; p=0.009). The effect of the pp on NfL disappeared after including DMT exposure (yes/no) at the sampling timepoint to the model (β:1.07, 95%CI: 0.97-1.18; p=0.178). Patients sampled during DMT had on average 12% lower NfL levels compared to patients without (β:0.88, 95%CI: 0.79-0.98; p=0.019).

Conclusions

Higher NfL levels were found during pp. This increase was independent of relapses suggesting increased subclinical disease activity during this time span. After including DMT into the model the effect of pregnancy on NfL disappeared: strategies allowing to continue DMT during pregnancy may be warranted.

Background

Neuromyelitis optica spectrum disorders (NMOSD) are autoimmune mediated astrocytopathies. Glial fibrillary acidic protein (GFAP) and S100B, two astrocyte specific, and neurofilament light chain (NfL), a neuron specific biomarker are reported to be elevated in CSF and serum or plasma in acute phases of NMOSD. Serum NfL is a predictor of relapse activity in multiple sclerosis (MS). However, whether serum levels of NfL (sNfL), GFAP (sGFAP) or S100B (sS100B) levels can be prognostic biomarkers for future acute disease activity in NMOSD has not been elucidated.

Objectives

To test the prognostic potential of sGFAP, sS100B and sNfL levels during remission phase as biomarker for future relapses in NMOSD with aquaporin-4-IgG.

Methods

Median values of sGFAP, sS100B and sNfL were calculated from 47 serum samples from 18 patients in remission (>180 days after last relapse), followed for up to 10 years, and marked cut-off levels for “high” and “low” sGFAP (141.6 pg/mL), sS100B (8.6 pg/mL), and sNfL (33.9 pg/mL), respectively. Kaplan-Meier analysis, univariable and a multivariable (adjusted for age, sex, time from recent relapse and treatment) Cox-hazard model were used to compare the time to and hazard risk of the next relapse between the high and low groups for all three markers.

Results

Twenty-five first post-relapse/remission phase samples from these 18 patients (11 had one relapse, 7 had two relapses) were selected for analyses. Patients in the high sGFAP group experienced future relapses earlier than those with low sGFAP levels (median 3710 versus 922 days, p = 0.0047) and had higher risk of future relapses (unadjusted hazard ratio (HR): 5.6 [95% CI 1.5–21.0], p = 0.010; adjusted hazard ratio: 9.5 [95% CI 1.9–47.0], p = 0.0061). In contrast, high sS100B and sNfL levels were unable to identify patients at increased risk for relapses.

Conclusions

We illustrate the prognostic capacity of an astrocyte specific marker, sGFAP, for future relapses in stable NMOSD. This further supports the value of this blood biomarker for potential future clinical application in guiding and monitoring treatment response of patients with NMOSD. The failure of sNfL as a neuronal marker in this capacity for NMOSD may reflect the pathogenetic differences between this disease and MS. The failure of sS100B may result from its pharmacokinetic profile as a short-lived marker in acute NMOSD, but not in stable disease.

Background

Serum neurofilament light chain (sNfL) reflects neuro-axonal damage and may qualify as a biomarker of suboptimal response to disease modifying therapy (DMT).

Objectives

To investigate the predictive value of sNfL in clinically isolated syndrome (CIS) and relapsing-remitting (RR) MS patients with established DMT for future MS disease activity in the Swiss MS Cohort Study.

Methods

All patients were on DMT for at least 3 months. sNfL was measured 6 or 12-monthly with the NF-light^®assay. The association between sNfL and age was modeled using a generalized additive model for location scale and shape. Z-scores (sNfLz) were derived thereof, reflecting the deviation of a patient sNfL value from the mean value of same age healthy controls (n=8865 samples). We used univariable mixed logistic regression models to investigate the association between sNfLz and the occurrence of clinical events (relapses, EDSS worsening [≥1.5 steps if EDSS 0; ≥1.0 if 1.0-5.5 or ≥0.5 if >5.5] in the following year in all patients, and in those fulfilling NEDA-3 criteria (no relapses, EDSS worsening, contrast enhancing or new/enlarging T2 lesions in brain MRI, based on previous year). We combined sNfLz with clinical and MRI measures of MS disease activity in the previous year (EDA-3) in a multivariable mixed logistic regression model for predicting clinical events in the following year.

Results

sNfL was measured in 1062 patients with 5192 longitudinal samples (median age 39.7 yrs; EDSS 2.0; 4.1% CIS, 95.9% RRMS; median follow-up 5 yrs). sNfLz predicted clinical events in the following year (OR 1.21 [95%CI 1.11-1.36], p<0.001, n=4624). This effect increased in magnitude with increasing sNfLz (sNfLz >1: OR 1.41 [95%CI 1.15-1.73], p=0.001; >1.5: OR 1.80 [95%CI 1.43-2.28], p<0.001; >2: OR 2.33 [95%CI 1.74-3.14], p<0.001). Similar results were found for the prediction of future new/enlarging T2 lesions and brain volume loss. In the multivariable model, new/enlarging T2 lesions (OR 1.88 [95%CI 1.13-3.12], p=0.016) and sNfLz>1.5 (OR 2.18 [95%CI 1.21-3.90], p=0.009) predicted future clinical events (n=853), while previous EDSS worsening, previous relapses and current contrast enhancement did not. In NEDA-3 patients, change of sNfLz (per standard deviation) was associated with a 37% increased risk of clinical events in the subsequent year (OR 1.37 [95%CI 1.04-1.78], p=0.025, n=587).

Conclusions

Our data support the value of sNfL levels, beyond the NEDA3 concept, for treatment monitoring in MS clinical practice.

Background

Intrathecal IgM synthesis was reported to be associated with higher clinical disease activity and severity. We found an association also with earlier use of high efficacy treatments in relapsing MS (RMS).

Objectives

To explore whether patients with intrathecal IgM synthesis show a) higher serum neurofilament light chain levels (sNfL) as a reflection of neuronal damage, or b) signs of increased disease severity in cerebral MRI, in patients with RMS followed in the Swiss MS Cohort Study.

Methods

487 patients were categorized by presence of oligoclonal IgG bands (OCGB) and intrathecally produced IgG/M:

1) OCGB-/IgG-/IgM- (reference [ref]);

2) OCGB+/IgG-/IgM-;

3) OCGB+/IgG+/IgM- and

4) OCGB+/IgG+/IgM+.

sNfL was measured (at baseline and every 6- or 12 months) with the NF-light^® assay. Age-dependent sNfL z-scores (sNfLz) were modelled in 8865 healthy control samples to reflect the deviation of a patient sNfL value compared to mean values observed in same age healthy controls. Yearly T2 lesion number and occurrence of new/enlarging T2 lesions were automatically assessed in cerebral MRIs and checked manually. Contrast enhancing lesions (CEL) were manually quantified. Linear or negative binomial mixed models were used to investigate the associations between the four CSF Ig patterns and longitudinal sNfLz and MRI measures, adjusted for DMT and other covariates.

Results

IgM+ patients had higher sNfLz vs reference (estimate 0.50 [CI 0.12, 0.89], p=0.011), whereas those with only OCGB+ (0.11 [-0.28, 0.50], p=0.582) or with OCGB+/IgG+ (0.20 [-0.16, 0.56], p=0.270) did not (n=2970 observations). This was confirmed when analyzing only untreated patients adjusting for T2 and CEL numbers (1.16 [0.47, 1.86], p<0.01 vs 0.58 [-0.11, 1.27], p=0.1022 vs 0.51 [-0.11, 1.13], p=0.108 vs ref, respectively) (n=234).

IgM+ patients had 2.28-fold more T2 lesions ([1.51, 3.44], p<0.01) vs ref; for patients with only OCGB+ (1.61 [1.07, 2.43], p=0.0237) or OCGB+/IgG+ (1.58 [CI 1.08, 2.32], p=0.0179) (n=1580) this association was weaker.

IgM+ was associated with a 2.47-fold risk for new/enlarging T2 lesions on yearly follow-up MRIs vs ref (2.47 [1.28, 4.78], p<0.01) but not the two other patient groups (1.84 [CI 0.93; 3.65], p=0.0799 and 1.61 [CI 0.87; 2.95], p=0.1280) (n=861).

Conclusions

Intrathecal IgM synthesis was consistently associated with quantitative measures of neuro-axonal injury and disease severity in RMS. Our findings strongly support the clinical utiliy of this biomarker.

Background

In relapsing MS, blood NfL has emerged as a promising biomarker of disease activity and worsening. The ability of serum NfL (sNfL) to detect relapse-independent disability progression is less well established.

Objectives

We investigated whether patients followed in the Swiss Multiple Sclerosis Cohort (SMSC) without any relapses during follow-up, had higher sNfL levels when experiencing confirmed disability progression independent of relapses (PIRA) as compared to stable patients. Secondly, we explored whether baseline (BL) sNfL could predict PIRA.

Methods

BL and 6- or 12-monthly follow-up sNfL were measured by Simoa NF-light^® assay in 4608 samples from 806 relapse-free MS patients and 8865 serum samples from 4133 healthy controls (median age 45 yrs). Age-dependent sNfL z-scores (sNfLz) were modeled in healthy controls using a generalised additive model for location scale and shape to reflect the deviation of a patient sNfL value from the mean value of same age healthy controls. PIRA was defined as an EDSS increase of ≥1.5 steps if baseline EDSS 0, ≥1.0 if 1.0-5.5, or ≥0.5 if >5.5, confirmed after ≥6 months. We used mixed effects models to investigate the association between PIRA, clinical parameters, disease modifying treatment, and log(sNfL) as dependent variable at each sampling. The predictive value of BL sNfLz was investigated by uni- and multivariable Cox proportional hazards models.

Results

806 (4608 samples) of 1399 patients in the SMSC did not experience relapses during a median follow-up of 4.7 years (57.6%; BL: 715 RRMS, 43 SPMS, 48 PPMS; median age 42 yrs; samples/patient: 5; EDSS 2.0). PIRA occurred in 153/806 (19.0%). In a multivariable model, sNfL was positively associated with age (1.7%/year [95%CI 1.5;2.0], p<0.001) and EDSS at BL (7.6%/step, [5.8;9.6], p<0.001), whereas it was decreased when sampled during monoclonal antibody therapy (-10.8%, [-14.7;-6.6], p<0.001) or oral MS treatments (-10.4%, [-14.1;-6.5%], p<0.001) as compared to untreated timepoints. Importantly, patients experiencing PIRA had 11.6% higher sNfL levels, compared with stable patients (4.5;19.2, p=0.001). The hazard of future PIRA increased by 23.5% (8.3;40.8, p=0.002) per 1 standard deviation higher BL sNfLz. This finding was confirmed after adjusting for age, EDSS score and treatment at BL (27.8%, [11.5;46.5], p<0.001; sNfLz > 2: 2.5-fold risk [95%CI 1.7-3.9], p<0.001 for PIRA event vs. sNfLz < 2).

Conclusions

Our data support the value of sNfL to capture and predict neuro-axonal injury leading to disability progression independent from relapses.

Background

Serum neurofilament light chain (sNfL) levels reflect neuroaxonal damage and relate to disease activity in MS. sNfL may qualify as well as a biomarker of suboptimal treatment response to disease modifying therapies (DMT). Establishment of age-dependent reference ranges in healthy controls is a prerequisite for developing this biomarker for clinical use.

Objectives

To compare on-treatment sNfL levels with values from a healthy control cohort and to investigate the effect of DMTs on sNfL levels in patients from the Swiss MS Cohort Study.

Methods

sNfL was measured (at baseline and every 6- or 12 months) with the NF-light® assay. Age-dependent sNfL z-scores (sNfLz) were modeled in healthy controls using a generalized additive model for location scale and shape to reflect the deviation of a patient sNfL value from the mean value of same age healthy controls. Linear mixed models were used to investigate the associations between clinical characteristics, DMT and longitudinal sNfLz. Interaction terms and splines were used to model sNfLz and for comparison log(NfL), and their dynamics under treatment.

Results

sNfL was measured in 1368 patients with 7550 longitudinal samples (baseline: median age: 41.9 yrs; 5.4% CIS, 83.2% RRMS, 5.6% SPMS, 5.8% PPMS; median EDSS: 2.0; median follow-up: 4.6 yrs) and 4133 healthy controls with 8865 samples (median age: 44.8 yrs). In the multivariable model, sNfLz increased with EDSS (0.131/step, [95% CI 0.101;0.161]), recent (<120 days) relapse (0.739 [0.643;0.835]) decreased with age (-0.014/year [-0.02;-0.009]), and time on DMT (-0.040/year [-0.054;-0.027]); sNfLz were lower when sampled while on more effective DMT (oral versus platform injectables: -0.229 [-0.344;-0.144]; monoclonal antibodies (mAB) versus platform injectables: -0.349 [-0.475;-0.224]), (p<0.001 for all associations). sNfLz were inversely associated with the hierarchy in efficacy of mAB over orals and orals over platform therapies with regard to slope and extent of decrease (interaction between time under DMT and DMT class: p<0.001). sNfLz, but not log(NfL) showed normalization of sNfL levels by mAB to healthy control levels.

Conclusions

The dynamic change of sNfLz on DMT reflects closely their relative clinical efficacy and is more meaningful than log(sNfL) by excluding age as a confounding factor. Use of sNfLz based on a large normative database as an age-independent sNfL measure improves the accuracy of the sNfL signal and hence their clinical utility.

Background

Ocrelizumab is the first drug approved as disease modifying treatment for primary progressive (PP) multiple sclerosis (MS). As a humanized monoclonal antibody targeting CD20 cells, it is widely known that ocrelizumab treatment results in B cells depletion, but less is known about the effects of this drug in other blood leukocyte subsets of PPMS patients.

Objectives

To explore the changes induced by ocrelizumab in blood immune cells of PPMS patients to further understand their effects in the abnormal inflammatory response.

Methods

Multi-centre prospective longitudinal study including fifty‐three PPMS patients who initiated ocrelizumab treatment. Effector, memory, and regulatory cells were analyzed by flow cytometry at baseline and after 6 months of treatment. To assess differences between baseline and after 6 months, Wilcoxon matched paired tests were used and p values were corrected using Bonferroni test.

Results

Ocrelizumab decreased numbers of naïve and memory B cells (p<0.0001) and those of B cells producing interleukin (IL)-6, IL-10, granulocyte-macrophage colony-stimulating factor and tumor necrosis factor-alpha (p<0.0001 in all cases). A reduction of CD20+ T cell numbers (p=0.02) and percentages (p<0.0001) was also observed. We also detected a clear remodelation of the T cell compartment characterized by relative increases of the naïve/effector ratio in CD4+ (p=0.002) and CD8+ (p=0.002) T cells, and relative decreases of CD4+ (p=0.03) and CD8+ (p=0.004) T cells producing interferon-gamma. Total monocyte numbers increased (p=0.002), with no changes in those producing inflammatory cytokines. All these changes resulted in a reduction of serum neurofilament light chain (sNfL) levels (p=0.009).

Conclusions

Effector B cell depletion by ocrelizumab treatment induces changes in the T cell response of PPMS patients towards a low inflammatory profile. This resulted in a decrease of sNfL levels.