Background

Multiple-Sclerosis-Partners-Advancing-Technology-Health-Solutions (MSPATHS) is an international multicentre digital database that collects clinical information provided directly by patients together with standardized MRI and biomarkers.

Objectives

We identify a Benign multiple sclerosis (BMS) population using Patient-Determined-Disease-Steps (PDDS) as a proxy for EDSS. We describe its physical and non-physical characteristics, and explore the features that best discriminate BMS.

Methods

Cross-sectional study of MSPATHS patients (Feb 2019). In patients with disease duration ≥10 years, BMS was considered when PDDS score<2. We compared BMS and non-BMS in terms of (1)socio-demographic and clinical characteristics, (2)physical status (lower and upper extremity function by Neuro-QoL (LUEF-NQ) and neurological performance tests: walking speed test (WST), manual dexterity test (MDT), processing speed test (PST), contrast sensitivity test (CST)) and non-physical symptoms (anxiety, depression, fatigue, among other NQ domains), and (3)MRI (gadolinium enhancement and new T2 lesions). We built a random forest model to estimate the importance of each variable. Cohen’s d was used for descriptive statistics to categorize differences in small (d=0.2-0.5), medium (d=0.5-0.8) and large (d>0.8). A sensitivity analysis with a 1:1 matched cohort by disease duration was performed.

Results

From 15,257 patients included, 8,349 had a disease duration ≥10 years and 3,852 (46.1%) were classified as BMS. (1)BMS and non-BMS patients were similar for gender, age at disease onset and diagnosis, ethnicity, years of education and smoking status. Compared to non-BMS, BMS had small differences in disease duration (median, 17.2 (12,9-23,4) vs. 20.9 (15,1-28,8 years); d=0.39) but medium/large differences in (2)physical status (LUEF-NQ d=2.06 and 1.53, WST d=0.81, MDT d=0.97, PST d=0.82 and CST d=0.56), as well as, in all non-physical symptoms evaluated by NQ (anxiety d=0.53, depression d=0.69, fatigue d=0.84, stigma d=1.32, cognition d=0.69, social role satisfaction (SRS) d=1.11 and participation (SRP) d=1.19). (3)No differences were found on MRI activity. With 0.88 sensitivity and 0.86 specificity, LUEF-NQ was the most contributing variable for the random forest followed by stigma, SRP, WST, and SRS. The sensitivity analysis showed similar results.

Conclusions

PDDS seems to be a useful disability proxy to identify BMS when using digital technology. LUEF-NQ, stigma, SRP and SRS seem to better discriminate BMS.

Background

Rituximab (RTX) is an anti-CD20 monoclonal antibody, widely used as an off-label treatment for multiple sclerosis (MS). Despite well-known efficacy and safety, RTX regimen has not yet been standardized.

Objectives

We aimed to compare efficacy and safety data of two different rituximab doses at two large Catalan multiple sclerosis centres.

Methods

A two-centre ambispective study considering all MS patients that have received at least one RTX cycle until February 2020 was conducted. In Barcelona centre (BC), RTX regimen used was 2g intravenously (IV), at least during 3 cycles, followed by 1g every 6 months, while in Girona centre (GC), was 2g IV, at least the first cycle, followed by 500mg every 6 months. Patients were clinically followed every 6 months with lab tests, and brain MRI scans were performed at baseline and yearly thereafter. Baseline clinical, radiological and demographic characteristics were collected. Annual relapse rate (ARR), contrast-enhancing lesions (CELs) and new T2 lesions at one and third year on treatment, as well as EDSS changes at last follow-up visit, were evaluated. Also, the dynamics of CD19% lymphocytes and IG immunoglobulin (IgG) values in serum, as well as the incidence of adverse events (AE) were described.

Results

A total of 303 patients (249 at BC and 54 at GC) were included. Main reason to start RTX was clinical progression plus inflammatory activity (clinical, radiological or both) (45.8% BC vs 79.6% GC). No differences on age at RTX onset, gender and disease duration were found between both centres. At baseline, mean ARR was 0.37±0.6 (BC) vs. 0.33±0.5 (GC); median EDSS was 5.5 (1-9.0) (BC) vs. 6.0 (1-8.0) (GC); and proportion of MRI with CELs was 32.4% (BC) vs. 42.6% (GC). ARR decrease to 0.05 (87.5%, p<0.001) for BC vs. 0.03 (90.3%, p=0.018) for GC at first year, and to 0.08 (88.3%, p=0.016) vs. 0 (100%, p=0.172) at third year. Considering only progressive MS phenotypes, 79.4% vs. 71.4% of patients remained stable or improved the EDSS. Regarding MRI findings, percentages of patients with CELs and new T2 lesions (BC vs GC) were 2.7% vs. 8% and 19% vs. 16% at one year; and 0% vs. 0% and 12% vs. 0% at third year. AE incidence was higher at BC during the first year (14.8% vs 4.1%). No difference in the dynamics of CD19% lymphocytes was found, while IgG values decreased significantly in the BC cohort throughout the first 3 years.

Conclusions

In the treatment of multiple sclerosis, low doses of rituximab seem to offer similar effectiveness with better safety profile than high doses.

Background

In the present pandemic, gathering information regarding Multiple Sclerosis (MS) patients with COVID-19 is needed.

Objectives

To investigate the incidence of COVID-19 in a Barcelona cohort of MS patients, to describe the characteristics of MS patients with COVID-19, and to identify risk factors for susceptibility and severity.

Methods

Retrospective cohort study of adult MS patients included from February to May 2020. COVID-19 and non-affected cases were identified through a COVID-19 mail survey and clinical visits. Demographic, clinical, MS characteristics, and laboratory data (lymphocyte and CD19+ count, immunoglobulins, and vitamin D) were obtained. Serological SARS-CoV-2 testing was performed in all suspected cases. We examined the relationship between the previously mentioned variables with COVID-19 susceptibility and severity.

Results

Out of the 2903 surveys sent, a total of 875 were answered. 117 (13.37%) patients were excluded for not meeting inclusion criteria. 48 out of 758 were suspected COVID-19 and the remaining were classified as non-COVID-19. The estimated incidence was 6.3%. 45 additional suspected COVID-19 cases were detected in clinical visits. In the multivariate analysis, COVID-19 susceptibility was associated with being younger (OR 0.54, IC95% 0.34-0.87,p<0.01), having had contact with a confirmed case (OR 193.20, IC95% 55.34-674.43,p<0.01), living in Barcelona (OR 2.35, IC95% 1.08-5.09, p=0.03) and a longer MS disease duration (OR 1.43, IC95% 1.10-1.85,p<0.01). In patients treated with an anti-CD20 therapy, COVID-19 susceptibility increased with treatment duration (OR 3.36, IC95% 1.42-7.96, p<0.01). 19 (20.43%) of the 93 COVID-19 cases were hospitalized, 9(9.68%) presented a severe course and 2(2.15%) of them died. In the univariate analysis, older patients with comorbidities, a progressive and longer MS duration, and without disease-modifying therapies, presented a more severe disease although these results were not observed in the multivariate analysis. Out of the 79 (84.9%) with serological test, 45.6% had generated antibodies and 17.6% in patients receiving anti-CD20. No relation of lymphopenia, vitamin D, or immunoglobulins levels with COVID-19 susceptibility or severity was found.

Conclusions

MS patients present similar incidence, risk factors, and outcomes for COVID-19 than the general population. Patients treated with an anti-CD20 therapy for a longer period of time might be in a higher risk of COVID-19 and of generating lower antibody response.

Background

Oligoclonal bands (OB) are part of the 2017 McDonald criteria but their determination is rater-dependent. Kappa free light chains (KFLC) are determined quantitatively and could be an alternative to OB, but a vendor-specific index cut-off is needed.

Objectives

To compare the proportion of patients with clinically isolated syndromes (CIS) and positive OB and a KFLC index equal or greater than 6.6 (KFLC-6.6, Leurs CE Mult Scler 2020) or 10.61 (KFLC-10.61, Gaetani L J Neuroimmunol 2020). To compare the diagnostic properties of OB, KFLC-6.6 and KFLC-10.61 for 2nd attack and 2017 MRI dissemination in space (DIS) and time (DIT).

Methods

MRIs were obtained 3-5 months after the CIS, at 1 year and every 5 years. OB were determined by isoelectric focusing combined with immunoblotting. We selected 228 patients with sufficient data to assess DIS and DIT, OB determination and enough remnant frozen samples to measure KFLC by turbidimetry (Optilite, The Binding Site). We compared the proportion of patients with positive OB, KFLC-6.6 and KFLC-10.61 and the 3-year diagnostic properties for the following outcomes: 2nd attack (n=179) and MRI DIS and DIT (n=192).

Results

Of all patients, 146 (64.0%) had OB, 147 (65.5%) KFLC-6.6 and 137 (60.1%) KFLC-10.61. In total, 130 (57.0%) had OB and KFLC-6.6, 16 (7.0%) only OB, 17 (7.5%) only KFLC-6.6 and 65 (28.5%) had neither. As for OB and KFLC-10.61, 122 (53.5%) had both, 24 (10.5%) only OB, 15 (6.6%) only KFLC-10.61 and 67 (29.4%) had neither. At baseline, the criteria were fulfilled by patients with OB, KFLC-6.6 and KFLC-10.61 as follows: DIS 109/135 (80.7%), 114 (84.4%) and 106 (78.5%); DIT 70/87 (80.5%), 78 (89.7%) and 74 (85.1%); DIS plus DIT 64/78 (81.2), 71 (91.0%) and 67 (85.9); DIS plus OB 109 (100.0%), 101 (92.7%) and 94 (86.2); and McDonald 111/130 (85.4%), 113 (86.9%) and 106 (81.5%). The diagnostic properties of OB, KFLC-6.6 and KFLC-10.61 for 2nd attack were sensitivity 77.8, 85.6 and 78.0; specificity 44.9, 48.3 and 51.7; and accuracy 61.5, 67.0 and 65.4. Results for MRI DIS plus DIT were sensitivity 81.8, 87.9 and 82.6; specificity 66.7, 70.0 and 73.3; and accuracy 77.1, 82.3 and 79.7.

Conclusions

KFLC-10.61 had the greatest specificity and KFLC-6.6 the best overall diagnostic properties. The results were probably due to the higher proportion of positive KFLC patients with DIT compared to those with positive OB, suggesting KFLC-6.6 could be used as an alternative to OB in the McDonald criteria.

Background

In the constantly evolving field of MS, personalized medicine is still one of the most important unmet need that requires further attention

Objectives

We aimed to develop a dynamic risk calculator to predict the long-term prognosis of MS in the context of a large MS Centre in Catalonia

Methods

This is an observational study based on data prospectively acquired from a deeply phenotyped CIS cohort from Barcelona. We first built a natural history baseline risk score (BRS) for predicting moderate disability, integrating baseline prognostic factors: Sex, age at CIS, CIS topography, number of T2 lesions, contrast-enhancing lesions (CEL) and oligoclonal bands. This BRS was designed as follows: For untreated patients, we built a Weibull model to estimate the median time to confirmed EDSS 3.0 and with these estimates we identified risk groups based on the median of the cut-offs of 2000 survival trees. Then we obtained the BRS of the full cohort. In patients with more than ten years of follow-up, we performed an inverse probability weighting to balance patients during their follow up for the propensity of being treated or lost to follow-up. The weights were estimated via a proportional hazards (PH) Cox model considering both baseline information (CIS year, BRS) and time-dependent (diagnosis status, new T2 lesions, CEL and cumulative number of relapses). Finally, a weighted PH Cox model was built to estimate the time to confirmed EDSS 3.0 considering the BRS and time-dependent events (new T2 lesions, cumulative number of relapses and first or second-line treatment use). Sensitivity analyses using other disability outcomes and different follow-ups were conducted.

Results

Of 956 patients, 577 (60.4%) were untreated before confirmed EDSS 3.0. Two BRS were obtained: low and high-BRS. Of 400 patients followed for more than ten years, 226 (56.5%) were low-BRS and 174 (43.5%) were high-BRS. High-BRS showed a HR=2.16 95%CI (1.16,4.02). Each new T2 lesion presented HR=1.04 95%CI (1.00,1.08) and each new relapse HR=1.46 95%CI (1.23,1.74). Being on second-line treatment showed a protective effect (HR=0.23 95%CI (0.06,0.94)) but no association was found for first-line treatments (HR=1.32 95%CI (0.67,2.60). Sensitivity analyses confirmed the association between BRS, new T2 lesions and the accumulation of relapses with the prognosis. However, treatment results were inconclusive.

Conclusions

Presenting a high-BRS doubles the risk of reaching moderate disability. Each new lesion and new relapse increses the risk by 4% and 46%, respectively; and second-line treatments seem to be protective. If validated, this risk calculator could be a crucial step to personalized medicine.

Background

Teriflunomide is an oral first-line treatment of patients with relapsing-remitting multiple sclerosis (RRMS) that has been shown to decrease clinical relapses, reduce brain magnetic resonance imaging (MRI) activity, and slow progression of disability. However, the drug exhibits only limited effectiveness and does not produce clinical benefits in a proportion of MS patients.

Objectives

We aimed to identify differentially expressed genes and cellular pathways associated with the responder and non-responder status in RRMS patients treated with teriflunomide by means of RNA sequencing (RNA-seq).

Methods

RRMS patients treated with teriflunomide were classified into those with No evidence of disease activity (NEDA 3) and those with EDA after 12 months of treatment. Eleven responders [8 females; mean age (standard deviation): 45.8 years (4.5)] and 10 non-responders [8 females; 41.8 years (10.3)] were included in the study. RNA-seq was performed in RNA samples isolated from peripheral blood mononuclear cells before and after 12 months of teriflunomide treatment. 100 bp, paired-end RNA sequencing was performed by using DNAseq^TM Technology. Comparative analysis of differentially expressed genes between responders and non-responders was performed at baseline and after 12 months of treatment. Pathway analysis was based on KEGG database using statistically significant genes.

Results

Pathway analysis revealed the type I interferon (IFN) signaling pathway as the most significantly associated with the responder phenotype after 12 months of teriflunomide treatment (p<0.0001). In this context, expression levels for genes known to be predominantly or selectively induced by type I IFNs such as SP100, ZBP1, IFI27, ISG20, IFITM1, IFITM2, MX1, STAT1, PARP9, IFI35, RGS1, RSAD2, IFI44L, IRF1, DDX58, IFI6, IFIT1 and IFIT5 were significantly reduced by the effect of teriflunomide after 12 months of treatment in responders compared to non-responders. At baseline, expression levels for type I IFN genes were similar between responders and non-responders.

Conclusions

Type I IFNs are known to activate dendritic cells, enhance humoral immunity, and favor Th1 immune responses. A down-regulation of type I IFN genes after 12 months of treatment may explain the beneficial effect of teriflunomide in responders. Mechanistic studies are currently underway to investigate the functional implication of the type I interferon signaling pathway in the response to teriflunomide.

Background

There is a growing body of literature highlighting the role that wearable and mobile remote monitoring technology (RMT) can play in the assessment of Multiple Sclerosis (MS) and how it could improve clinical care and improve efficiency of research.

The Remote Assessment of Disease and Relapse in the Central Nervous System (RADAR-CNS) study is a pan-European consortium aimed to improve the management of different CNS disorders such as MS, Epilepsy or Major Depression using smartphones and wearable devices.

Most of the available data are based in small monocentric studies, however the full validation of these digital devices requires multicenter, well designed studies providing information on feasibility and acceptability.

Objectives

We aimed to describe the outcomes of the recruitment process in the Multiple Sclerosis (MS) RADAR-CNS disability and fatigue study (D&F).

Methods

The study was run in three European centers. Main eligibility criteria for D&F study were patients with relapsing-reminting or secondary progressive MS with an EDSS score between 2.0 and 6.0. Passive and active data were continuously collected through wearables (FitBit) and mobile phones (Android) and compared to the on-site visit every 3 months. The study duration is 2 years. The study sample size was 400 patients.

Results

The enrolment of the D&F study extended for a period of 18 months. We identified 4094 potential candidates (min-max 885-1789). At the end of the recruitment period, 678 (16.6%; min-max 0-24.2%) remained in the pre-screening phase. 3416 (min-max 885-1454) patients were assessed for eligibility. Out of those, 2372 (69.4%; min-max 53.3-87.1%) were excluded for not fulfilling the eligibility criteria: 1520 (64.1%; 15.0-87.1%) did not meet the EDSS score, 254 (10.7%; 0.2-49.6%) would not be suitable in the investigators opinion and 598 (25.2%; 3.0-60.3) did not have an Android. Out of the 1044 (30.6%; 12.9-46.7) eligible candidates, 644 (61.7%; 13.8-79.7%) declined to participate. A total of 400 (90-162) patients, 9.8% of the potential candidates, were enrolled into the study.

Conclusions

Our study illustrates the primary challenges in recruiting MS patients in RMT studies related to eligibility, both clinical and technological criteria, followed by reasons related to patients preferences. There is variability in the recruitment approach between centers. In future studies, developing technology for all types of phones and more attractive assessment for patients should be considered.

Background

Ponesimod (PON), an orally active, highly selective and reversible modulator of sphingosine-1-phosphate receptor 1, reduces circulating lymphocytes by sequestration in lymphoid organs. In the phase-3 OPTIMUM study (NCT02425644), PON showed superior efficacy vs teriflunomide (TER) in patients with relapsing multiple sclerosis (RMS).

Objectives

To evaluate prespecified MRI-based endpoints and no evidence of disease activity (NEDA) status in patients with RMS.

Methods

Patients (18-55 years) with RMS (expanded disability status scale scores: 0-5.5) were randomized (1:1) to receive PON 20 mg or TER 14 mg for 108 weeks. MRI endpoints included: percentage change from baseline to week 108 in brain volume (SIENA, Structural Image Evaluation, using Normalization of Atrophy), mean number of new gadolinium-enhancing (Gd+) T1 lesions and volume/count of new/enlarging T2-weighted (T2) lesions. NEDA-3 (absence of confirmed relapse, 12-week confirmed disability accumulation, Gd+T1 and new/enlarging T2 lesions on annual MRIs) and NEDA-4 status (NEDA-3 and no average annual brain volume decrease ≥0.4%) were evaluated from baseline to week 108.

Results

985/1133 (86.9%) randomized patients completed the study. MRI findings for PON vs TER from baseline to week 108, respectively, were: least square (LS) mean percent change from baseline in brain volume: −0.91% vs −1.25% (difference: 0.34%, 95% CLs: 0.17;0.50, p<0.0001); LS mean difference (PON−TER) in change from baseline in total T2 lesion load: −399.2 mm³ (95% CLs: −651.5;−146.8, p=0.002); mean number of new/enlarging T2 lesions per year: 1.40 vs 3.16 (rate ratio [RR]: 0.44, 95% CLs: 0.36;0.54, p<0.0001); PON vs TER odds ratio (OR [95% CL]) for absence of new/enlarging T2 lesions: 1.71 (1.30;2.25, p=0.0001); mean number of new Gd+T1 lesions per scan: 0.18 vs 0.43 (RR: 0.42, 95% CLs: 0.31;0.56, p<0.0001); PON vs TER (OR [95% CL]) for absence of new Gd+T1 lesions: 2.18 (1.61;2.95, p<0.0001). At week 108, 28.2% (159/564) PON vs 18.3% (102/558) TER patients (OR: 1.70, 95% CLs: 1.27;2.28, p=0.0004) achieved NEDA-3; 15.0% (79/526) PON vs 8.5% (45/532) TER patients (OR: 1.85, 95% CLs: 1.24;2.76, p=0.0026) achieved NEDA-4. The most common reason for not achieving NEDA-3 or NEDA-4 status was presence of new/enlarging T2 lesions.

Conclusions

PON showed benefit vs TER for all MRI outcomes including brain volume loss and a significantly higher proportion of patients achieved NEDA-3 and NEDA-4 status, supporting the effects observed on clinical endpoints.

Background

Similar to other neurodegenerative disorders, the onset of progressive MS is related to age, a factor known to amplify neurodegeneration. Recent studies have shown that exposure of aged mice to a young blood circulation through parabiosis or administration of young blood plasma (plasma from 3-month-old mice) reverses cognitive deficits observed with normal ageing.

Objectives

We aimed to search for soluble factors in the serum of patients with progressive MS that are affected by age and are differentially decreased in patients compared to healthy controls (HC) of similar age.

Methods

Protein levels were determined in serum samples from a cohort of 30 untreated MS patients (15 patients with secondary progressive MS - SPMS - and 15 with primary progressive MS - PPMS) and 25 HC. Progressive MS patients were classified according to age and clinical characteristics into the following three groups (each group containing 10 patients, 5 with SPMS and 5 with PPMS): (i) 40 ± 3 years old, disease duration <10 years, EDSS <4.5; (ii) 50 ± 3 years old, disease duration between 10-20 years, EDSS between 4.5-6; and (iii) 60 ± 3 years old, disease duration >20 years, EDSS >6.5. HC were classified based on age into the following groups (each group containing 5 individuals): 20, 30, 40, 50, and 60 ± 3 years old. To maximize the breadth and depth of serum proteome coverage, the top 70 abundant proteins in serum were depleted. Afterwards, samples were subjected to mass spectrometry.

Results

After depletion of the most abundant proteins in serum, a total of 2,059 molecules were detected in all 55 samples. The maSigPro package (R Bioconductor) was used to identify proteins with significantly divergent expression profiles as a function of time. A quadratic regression model was fit for each molecule and 823 proteins, among the 2059 analyzed, were found differentially expressed (FDR < 0.05) between the MS group and HC. The serum levels of the following proteins were significantly decreased by ageing in progressive MS patients compared with HC and were selected for further studies: PLXDC2, Neudesin, Myostatin, Myocilin, and EMMPRIN.

Conclusions

Protein expression profiling associated with ageing in progressive MS patients and HC lead to the identification of number of promising candidates associated with neurotrophic functions, myelination, and nervous system development. Results obtained by mass spectrometry need to be validated by targeted immunoassays.

Background

The highly effective therapies for multiple sclerosis (MS) could potentially interfere in the immune response against novel antigens, but evidence is lacking.

Objectives

To evaluate the immunogenicity to the hepatitis B virus vaccine (HBV-v) in MS patients who are candidate to highly effective therapies.

Methods

This is an observational retrospective cohort study. MS patients were eligible if they had a complete HBV-v primo-vaccination course (40 mcg or adjuvated 20 mcg HBV-v at months 0, 1, 2 and 6-12) and a post-vaccination serology at least 1 month after the last dose, to assess the response to the vaccine. Seroprotection status (VHB surface antigen antibody titers of at least 10 UI/L) and geometric mean antibody titers were evaluated taking into account the time of vaccination in relation to the specific MS disease-modifying therapies (DMT). We considered the DMT received at baseline (onset of vaccination) as well as, the possible treatment change over the course of vaccination.

Results

153 patients were included, with mean age 48 (SD 8.6) years, of which 68% were female. Mean disease duration was 13.8 (SD 9.4) years. Median EDSS was 4 (IQR 3). 78 patients (51%) were under DMT at the onset of vaccination and 115 (75.2%) patients changed their DMT during the course of vaccination. The global seroprotection rate was 66.7% (IC 95% 58.6-74.1). The highest seroprotection rate was observed in non-treated patients (N=17; 94.1% 95%CI 71.3-99.0) and in those treated with injectables, dimethyl fumarate, teriflunomide or natalizumab (N=31; 96.8% 95%CI 83.3%-99.9%). Starting anti-CD20 therapy during the course of vaccination reduced the seroprotection rate regardless of the preceding therapeutic situation: 1) non-treated patients (N=40; 52.5% 95%CI 36.1%-68.5%), 2) treated with injectables, dimethylfumarate, teriflunomide or natalizumab (N=33; 48.5% 95%CI 30.8%-66.5%) and 3) treated with fingolimod (N=11; 18.2% 95%CI 23%-51.8%). Onset of AntiCD20 also resulted in a significant decrease in the antibody titers (p<0.001) compared to those without AntiCD20. There was a dose-gradient effect in the achieved seroprotection with the number of vaccine doses administered before the onset of the anti-CD20 therapy (16.7%, 30%, 66.7% and 92.9% with one, two, three and four doses, respectively).

Conclusions

MS patients on anti-CD20 therapy mount deficient immune responses to VHB vaccination and therefore, vaccination should be completed in advance of treatment onset.

Background

Cladribine is a synthetic purine nucleoside analogue with immunosuppressive functions that has demonstrated beneficial effects in patients with relapsing-remitting multiple sclerosis (MS) and that may also regulate the immune function as an analogue of adenosine receptors. Although the effect of cladribine is well studied on immune cells, it remains unveiled how it affects the immune function of glial populations of the central nervous system.

Objectives

In the context of MS, we aimed to test the effect of cladribine on proliferation, survival and cytokine release of human astrocytes.

Methods

To assess the effect of cladribine on cell survival and proliferation, primary human astrocytes were cultured with cladribine at high concentrations (2µM, 0.2µM), at the mean estimated brain exposure of the drug (0.02µM) and at a low concentration (0.002µM) for 72h. The percentages of dead and proliferating cells were determined by flow cytometry. To assess the effect of cladribine on cytokine release, human astrocytes were stimulated for 6h with 20ng/ml IL1-β and TNF-α. The stimulus was withdrawn and cells were cultured for additional 18h. Cladribine was added for the whole 24h of culture. Supernatants were harvested to quantify IL1-β, IL6, TNF-α and GM-CSF release by Luminex. To assess the effect of cladribine independently of deoxycytidine kinase (DCK), deoxycytidine was also added to human astrocytes.

Results

Only high concentrations of cladribine induced death on human astrocytes (2µM: 35.89%±7.62 or 0.2µM: 7.27%±3.12 vs control: 3.17%1.84±; p<0.0001 and p=0.156, respectively) and inhibited their proliferative capacity (2µM: 0.96%±1.14 or 0.2µM: 14.06%±5.44 vs control: 33.06%±1.42; both p-values<0.0001). Additionally, the percentage of proliferating cells in the 2µM and 0.2µM conditions presented a limited capacity of proliferation (measured as the Relative Intensity of Proliferation Staining respect to basal; 2µM: 0.24±0.04 and 0.2µM: 0.55±0.22, both p-values<0.0001). When DCK activity was blocked by deoxycytidine, cell death and proliferation were reversed to control condition values. We are currently determining the effect of cladribine on pro-inflammatory cytokine release by human astrocytes.

Conclusions

The mean estimated brain exposure to cladribine does not influence cell survival or proliferation of human astrocytes neither in a DCK-dependent nor in a DCK-independent manner, suggesting that cladribine does not affect the normal astrocyte function in MS patients.

Background

MS patients show a significant decrease in Clostridia clusters XIVa and IV in the gut microbiome. We have previously reported that a mixture of human gut-derived 17 Clostridia strains, which belong to Clostridia clusters XIVa, IV, and XVIII, improved the clinical outcome of experimental autoimmune encephalomyelitis (EAE) mice as a therapeutic approach. The clinical improvement was related to lower histopathological signs in the central nervous system (CNS) and to an enhanced immunoregulatory response of regulatory T (Treg) cells in the periphery.

Objectives

We aimed to study in depth the mechanism of action of the treatment with Clostridia strains in Experimental Autoimmune Encephalomyelitis

Methods

In two independent experiments, myelin oligodendrocyte glycoprotein (MOG)-immunized C57BL6/J mice were treated with Clostridia strains (n=15) or vehicle (n=15) via oral gavage from 13-14 days post-immunization (dpi) until the end of the experiment (28 dpi). At 28 dpi, spleens and spinal cords were collected to perform transcriptome studies and serum was collected to determine the short-chain fatty acid (SCFA) levels. In three independent experiments, MOG-immunized C57BL6/J mice were orally gavaged with butyrate (n=19) or vehicle (n=18) from 13-15 dpi until 28 dpi. Then, spinal cords were collected to perform histopathological studies.

Results

Therapeutic administration of Clostridia strains ameliorated EAE clinical course, as previously reported. Transcriptome studies revealed increased antiinflammatory responses related to interferon beta in the periphery and lower activation, differentiation, and proliferation of immune cells in the CNS. Higher levels of the immunomodulatory SCFA butyrate were detected in the serum of Clostridia-treated mice. Therefore, we studied the therapeutic effect of butyrate on EAE. We observed a slight therapeutic impact on EAE clinical course that was connected to a noticeable improve concerning axonal damage and a tendency to lower demyelination, inflammation, and astrogliosis in the CNS.

Conclusions

Clostridia strains perform their therapeutic effect on EAE enhancing the immunoregulatory response of Treg cells and antiinflammatory responses related to interferon beta signaling pathway in the periphery. The beneficial outcome exerted by the oral administration of the 17 Clostridia strains was not exclusively related to the production of the SCFA butyrate.

Background

The debut of multiple sclerosis (MS) at an older age associates with increased risk of presenting a primary progressive form, an earlier conversion to the secondary progressive form and a greater disability accumulation. These facts could be due to the impact of immunosenescence (ISC) in elderly MS patients.

Objectives

To study the impact of aging on clinical outcome, histopathology of the central nervous system (CNS) and peripheral immune system in experimental autoimmune encephalomyelitis (EAE).

Methods

8-week old and 40-week old C57BL/6JRccHsd female mice immunized with MOG_35-55 were used. Histopathological and immunological studies were performed in non-immunized mice (basal) and in EAE mice 14 days post-immunization (dpi) and 28 dpi. Immunofluorescence staining was performed in spinal cords to evaluate T cell infiltration (CD3), demyelination (MBP), reactive astrogliosis (GFAP), reactive microglia (LEA) and axonal damage (SMI32). Immune cell subsets and intracellular cytokines were analyzed in splenocytes by flow cytometry. Polyclonal and MOG-specific capacity of proliferation were assessed in splenocytes. Differences between young and old mice in each EAE time point and along disease course were analyzed.

Results

Old mice (OM) showed a more severe EAE clinical outcome compared to young ones. Different patterns along EAE course were observed for inflammation, axonal damage and reactive microglia (increased at 28 dpi in OM) as well as for reactive astroglia (decreased at 14 dpi in OM) in the CNS. The adaptive immune cell subsets showed more age-related changes in OM, presenting a different pattern along EAE course: naïve CD8+ T cells (decreased basally and at 28 dpi), effector/effector memory CD4+PD1+ T cells (increased basally and at 14 dpi), regulatory CD39+ T cells (increased basally and at 14 dpi) and MHC-II+ B cells (increased basally and at 14 dpi). Regarding innate immune cells, immature NK cells increased and mature NK cells decreased along EAE course in OM, and NKT cells also presented a different pattern along EAE course (decreased basally and at 28 dpi in OM). Cytokine producing T cells were increased in OM. No differences were observed in splenocyte-proliferative capacity.

Conclusions

Aging has an impact on EAE outcome being more severe in old mice. Major changes take place in the CNS and in the adaptive immune cell subsets in the periphery. Altogether suggest that age modifies the immunopathogenic mechanisms of EAE.