Anti-CD20 therapies decrease humoral immune response to SARS-CoV-2 in patients with multiple sclerosis or neuromyelitis optica spectrum disorders

BACKGROUND

SARS-CoV-2 seroconversion rate after COVID-19 may be influenced by disease-modifying therapies (DMTs) in patients with multiple sclerosis (MS) or neuromyelitis optica spectrum disorders (NMO-SD).

OBJECTIVE

To investigate the seroprevalence and the quantity of SARS-CoV-2 antibodies in a cohort of patients with MS or NMO-SD.

METHODS

Blood samples were collected in patients diagnosed with COVID-19 between 19 February 2020 and 26 February 2021. SARS-CoV-2 antibody positivity rates and Ig levels (anti-S IgG titre, anti-S IgA index, anti-N IgG index) were compared between DMTs groups. Multivariate logistic and linear regression models were used to estimate the influence of DMTs and other confounding variables on SARS-CoV-2 serological outcomes.

RESULTS

119 patients (115 MS, 4 NMO, mean age: 43.0 years) were analysed. Overall, seroconversion rate was 80.6% within 5.0 (SD 3.4) months after infection. 20/21 (95.2%) patients without DMT and 66/77 (85.7%) patients on DMTs other than anti-CD20 had at least one SARS-CoV-2 Ig positivity, while this rate decreased to only 10/21 (47.6%) for patients on anti-CD20 (p<0.001). Being on anti-CD20 was associated with a decreased odd of positive serology (OR, 0.07 (95% CI 0.01 to 0.69), p=0.02) independently from time to COVID-19, total IgG level, age, sex and COVID-19 severity. Time between last anti-CD20 infusion and COVID-19 was longer (mean (SD), 3.7 (2.0) months) in seropositive patients compared with seronegative patients (mean (SD), 1.9 (1.5) months, p=0.04).

CONCLUSIONS

SARS-CoV-2 antibody response was decreased in patients with MS or NMO-SD treated with anti-CD20 therapies. Monitoring long-term risk of reinfection and specific vaccination strategies in this population may be warranted.

TRIAL REGISTRATION NUMBER

NCT04568707.

Post-vaccine COVID-19 in patients with multiple sclerosis or neuromyelitis optica

INTRODUCTION

Recent studies suggested that anti-CD20 and fingolimod may be associated with lower anti-spike protein-based immunoglobulin-G response following COVID-19 vaccination. We evaluated if COVID-19 occurred despite vaccination among patients with multiple sclerosis (MS) and neuromyelitis optica (NMO), using the COVISEP registry.

CASE SERIES

We report 18 cases of COVID-19 after two doses of BNT162b2-vaccination, 13 of which treated with anti-CD20 and four with fingolimod. COVID-19 severity was mild.

DISCUSSION

These results reinforce the recommendation for a third COVID-19 vaccine dose among anti-CD20 treated patients and stress the need for a prospective clinical and biological study on COVID-19 vaccine efficacy among MS and NMO patients.

Natalizumab Versus Fingolimod in Patients with Relapsing-Remitting Multiple Sclerosis: A Subgroup Analysis From Three International Cohorts

INTRODUCTION

Natalizumab has proved to be more effective than fingolimod in reducing disease activity in relapsing-remitting multiple sclerosis (RRMS). Whether this association is universal for all patient groups remains to be determined.

OBJECTIVE

The aim of this study was to compare the relative effectiveness of natalizumab and fingolimod in RRMS subgroups defined by the baseline demographic and clinical characteristics of interest.

METHODS

Patients with RRMS who were given natalizumab or fingolimod were identified in a merged cohort from three international registries. Efficacy outcomes were compared across subgroups based on patients' sex, age, disease duration, Expanded Disability Status Scale (EDSS) score, and disease and magnetic resonance imaging (MRI) activity 12 months prior to treatment initiation. Study endpoints were number of relapses (analyzed with weighted negative binomial generalized linear model) and 6-month confirmed disability worsening and improvement events (weighted Cox proportional hazards model), recorded during study therapy. Each patient was weighted using inverse probability of treatment weighting based on propensity score.

RESULTS

A total of 5148 patients (natalizumab 1989; fingolimod 3159) were included, with a mean ± standard deviation age at baseline of 38 ± 10 years, and the majority (72%) were women. The median on-treatment follow-up was 25 (quartiles 15-41) months. Natalizumab was associated with fewer relapses than fingolimod (incidence rate ratio [IRR]; 95% confidence interval [CI]) in women (0.76; 0.65-0.88); in those aged ≤ 38 years (0.64; 0.54-0.76); in those with disease duration ≤ 7 years (0.63; 0.53-0.76); in those with EDSS score < 4 (0.75; 0.64-0.88), < 6 (0.80; 0.70-0.91), and ≥ 6 (0.52; 0.31-0.86); and in patients with pre-baseline relapses (0.74; 0.64-0.86). A higher probability of confirmed disability improvement on natalizumab versus fingolimod (hazard ratio [HR]; 95% CI) was observed among women (1.36; 1.10-1.66); those aged > 38 years (1.34; 1.04-1.73); those with disease duration > 7 years (1.33; 1.01-1.74); those with EDSS score < 6 (1.21; 1.01-1.46) and ≥ 6 (1.93; 1.11-3.34); and patients with no new MRI lesion (1.73; 1.19-2.51).

CONCLUSIONS

Overall, in women, younger patients, those with shorter disease durations, and patients with pre-treatment relapses, natalizumab was associated with a lower frequency of multiple sclerosis relapses than fingolimod. It was also associated with an increased chance of recovery from disability among most patients, particularly women and those with no recent MRI activity.

A meta-analysis comparing first-line immunosuppressants in neuromyelitis optica

Objective

As phase III trials have shown interest in innovative but expensive drugs in the treatment of neuromyelitis optica spectrum disorder (NMOSD), data are needed to clarify strategies in the treatment of neuromyelitis optica (NMO). This meta‐analysis compares the efficacy of first‐line strategies using rituximab (RTX), mycophenolate mofetil (MMF), or azathioprine (AZA), which are still widely used.

Methods

Studies identified by the systematic review of Huang et al. (2019) were selected if they considered at least two first‐line immunosuppressants among RTX, MMF, and AZA. We updated this review. The Medline, Cochrane Central Register of Controlled Trials, Embase, and ClinicalTrials databases were queried between November 2018 and April 2020. To be included, the hazard ratio (HR) [95% CI] for the time to first relapse after first‐line immunosuppression had to be available, calculable, or provided by the authors.

Results

We gathered data from 919 NMO patients (232 RTX‐, 294 MMF‐, and 393 AZA‐treated patients). The risk of first relapse after first‐line immunosuppression was 1.55 [1.04, 2.31] (p = 0.03) for MMF compared with RTX, 1.42 [0.87, 2.30] (p = 0.16) for AZA compared with RTX, and 0.94 [0.58, 1.54] (p = 0.08) for MMF compared with AZA.

Interpretation

The findings suggest that RTX is more efficient than MMF as a first‐line therapy. Even if the results of our meta‐analysis cannot conclude that RTX has a better efficacy in delaying the first relapse than AZA, the observed effect difference between both treatments combined with the results of previous studies using as outcome the annualized relapse rate may be in favor of RTX.

Comparative effectiveness of dimethyl fumarate in multiple sclerosis

AIMS

To assess the effectiveness of dimethyl fumarate (DMF) on annual rate of relapse subject to treatment (ARRt) and disability progression in multiple sclerosis (MS) compared to injectable immunomodulators (IMM), teriflunomide (TERI) and fingolimob (FTY), in real-life setting.

METHODS

A population-based cohort study was conducted using data of the French nationwide claims database, SNDS. All patients initiating IMM, TERI, FTY or DMF between 1 July 2015 and 12 December 2017, with 4.5 years of database history and 1-3.5 years of follow-up were included in this study. DMF patients were 1:1 matched to IMM, TERI or FTY using a high dimensional propensity score. Negative binomial regression and a logistic regression model were used to estimate the relative risk (RR ± [95% CI]) of ARRt and the odds ratio (OR ± [95% CI]) of disability progression, respectively.

RESULTS

Overall, 9304 subjects were identified: 29.0% initiated DMF, 33.2% TERI, 5.6% FTY and 32.2% an IMM. The matched cohorts consisted of 1779 DMF-IMM patients, 1679 DMF-TERI patients, and 376 DMF-FTY patients. DMF significantly reduced ARRt compared to IMM (RR 0.72 [0.61-0.86]) and TERI (0.81 [0.68-0.96]) and did not show any significant difference when compared with FTY. The risk of the progression of MS-specific disability was not significantly different for any matched cohorts.

CONCLUSION

DMF is associated with lower risk of treated relapse for patients with RRMS than other first-line RRMS agents (TERI and IIM).

MSCopilot: New smartphone-based digital biomarkers correlate with Expanded Disability Status Scale scores in people with Multiple Sclerosis

BACKGROUND

A previous clinical study showed the high specificity, sensitivity and reliability of MSCopilot, a software medical device designed by Ad Scientiam for the self-assessment of people with Multiple Sclerosis (PwMS), compared to the traditional Multiple Sclerosis Functional Composite (MSFC). We conducted further analyses to assess MSCopilot's performance with respect to the Expanded Disability Status Scale (EDSS).

METHODS

The data of 116 PwMS were analysed. We studied the correlations between MSCopilot scores and the EDSS, and their ability to distinguish PwMS with high and low EDSS through a study of the distribution of the digital test scores as well as logistic regression models. The same analyses were performed using the MSFC tests.

RESULTS

MSCopilot composite scores were as highly correlated to the EDSS (|r| = 0.65, p < 0.01) as their MSFC counterparts, confirming the known correlation of the MSFC with the EDSS. In a linear regression framework, the Walking digital tests have good explanatory power, especially for PwMS with EDSS > 3.5 (R²_adj=0.47). The mean values of each MSCopilot subscore were significantly different between patients with an EDSS > 3.5 and others (p < 0.05), which could not be proved for the MSFC Cognition tests. MSCopilot4 was the best model to predict an EDSS score > 3.5 (AUC = 0.92).

CONCLUSION

These analyses confirm the reliability of MSCopilot and show interesting correlations with the EDSS (similar results obtained with the MSFC). MSCopilot was able to highlight nuances in the different stages of MS the MSFC could not capture.

How to switch disease-modifying treatments in multiple sclerosis: Guidelines from the French Multiple Sclerosis Society (SFSEP)

BACKGROUND

Today, there are no recommendations on switching disease-modifying treatments (DMTs) in multiple sclerosis (MS).

OBJECTIVES

To establish guidelines on switching DMTs MS.

METHODS

A Steering Committee composed of seven MS experts from the French Group for Recommendations in Multiple Sclerosis (France4MS) defined 15 proposals. These proposals were then submitted to a Rating Group, composed of 48 French MS experts, for evaluation. The proposals were classified as 'appropriate', 'inappropriate' or 'uncertain'.

RESULTS

Switching from a first-line therapy to another first-line therapy or a second-line therapy could be done without a washout period. Switching from a second-line therapy to a first-line therapy could be done without a washout period with fingolimod or natalizumab, after 3 months with ocrelizumab or mitoxantrone, and, if disease activity occurs with alemtuzumab or cladribine. The switch from a second-line therapy to another second-line therapy could be done after a washout period of 1 month with fingolimod or natalizumab, after 3 months with ocrelizumab, after 6 months with mitoxantrone, and, if disease activity occurs, with alemtuzumab or cladribine.

CONCLUSION

This expert consensus approach provides physicians with some guidelines on optimizing the benefit/risk ratio when switching DMTs in patients with MS.

Altered Immune Phenotypes and HLA-DQB1 Gene Variation in Multiple Sclerosis Patients Failing Interferon β Treatment

Background

Interferon beta (IFNβ) has been prescribed as a first-line disease-modifying therapy for relapsing-remitting multiple sclerosis (RRMS) for nearly three decades. However, there is still a lack of treatment response markers that correlate with the clinical outcome of patients.

Aim

To determine a combination of cellular and molecular blood signatures associated with the efficacy of IFNβ treatment using an integrated approach.

Methods

The immune status of 40 RRMS patients, 15 of whom were untreated and 25 that received IFNβ1a treatment (15 responders, 10 non-responders), was investigated by phenotyping regulatory CD4⁺ T cells and naïve/memory T cell subsets, by measurement of circulating IFNα/β proteins with digital ELISA (Simoa) and analysis of ~600 immune related genes including 159 interferon-stimulated genes (ISGs) with the Nanostring technology. The potential impact of HLA class II gene variation in treatment responsiveness was investigated by genotyping HLA-DRB1, -DRB3,4,5, -DQA1, and -DQB1, using as a control population the Milieu Interieur cohort of 1,000 French healthy donors.

Results

Clinical responders and non-responders displayed similar plasma levels of IFNβ and similar ISG profiles. However, non-responders mainly differed from other subject groups with reduced circulating naïve regulatory T cells, enhanced terminally differentiated effector memory CD4⁺ T_EMRA cells, and altered expression of at least six genes with immunoregulatory function. Moreover, non-responders were enriched for HLA-DQB1 genotypes encoding DQ8 and DQ2 serotypes. Interestingly, these two serotypes are associated with type 1 diabetes and celiac disease. Overall, the immune signatures of non-responders suggest an active disease that is resistant to therapeutic IFNβ, and in which CD4⁺ T cells, likely restricted by DQ8 and/or DQ2, exert enhanced autoreactive and bystander inflammatory activities.

Perturbed Microbiota/Immune Homeostasis in Multiple Sclerosis

Objective

Based on animal models and human studies, there is now strong suspicion that host/microbiota mutualism in the context of gut microbial dysbiosis could influence immunity and multiple sclerosis (MS) evolution. Our goal was to seek evidence of deregulated microbiota-induced systemic immune responses in patients with MS.

Methods

We investigated gut and systemic commensal-specific antibody responses in healthy controls (n = 32), patients with relapsing-remitting MS (n = 30), and individuals with clinically isolated syndromes (CISs) (n = 15). Gut microbiota composition and diversity were compared between controls and patients by analysis of 16S ribosomal ribonucleic acid (rRNA) sequencing. Autologous microbiota and cultivable bacterial strains were used in bacterial flow cytometry assays to quantify autologous serum IgG and secretory IgA responses to microbiota. IgG-bound bacteria were sorted by flow cytometry and identified using 16S rRNA sequencing.

Results

We show that commensal-specific gut IgA responses are drastically reduced in patients with severe MS, disease severity being correlated with the IgA-coated fecal microbiota fraction (r = −0.647, p < 0.0001). At the same time, IgA-unbound bacteria elicit qualitatively broad and quantitatively increased serum IgG responses in patients with MS and CIS compared with controls (4.1% and 2.5% vs 1.9%, respectively, p < 0.001).

Conclusions

Gut and systemic microbiota/immune homeostasis are perturbed in MS. Our results argue that defective IgA responses in MS are linked to a breakdown of systemic tolerance to gut microbiota leading to an enhanced triggering of systemic IgG immunity against gut commensals occurring early in MS.

The effectiveness of natalizumab vs fingolimod-A comparison of international registry studies

BACKGROUND

Natalizumab and fingolimod were the first preparations recommended for disease breakthrough in priorly treated relapsing-remitting multiple sclerosis. Of three published head-to-head studies two showed that natalizumab is the more effective to prevent relapses and EDSS worsening.

METHODS

By re-analyzing original published results from MSBase, France, and Denmark using uniform methodologies, we aimed at identifying the effects of differences in methodology, in the MS-populations, and at re-evaluating the differences in effectiveness between the two drugs. We gained access to copies of the individual amended databases and pooled all data. We used uniform inclusion/exclusion criteria and statistical methods with Inverse Probability Treatment Weighting.

RESULTS

The pooled analyses comprised 968 natalizumab- and 1479 fingolimod treated patients. The on-treatment natalizumab/fingolimod relapse rate ratio was 0.77 (p=0.004). The hazard ratio (HR) for a first relapse was 0.82 (p=0.030), and the HR for sustained EDSS improvement was 1.4 (p=0.009). There were modest differences between each of the original published studies and the replication study, but the conclusions of the three original studies remained unchanged: in two of them natalizumab was more effective, but in the third there was no difference between natalizumab and fingolimod.

CONCLUSION

The results were largely invariant to the epidemiological and statistical methods but differed between the MS populations. Generally, the advantage of natalizumab was confirmed.

Unexpected REM sleep excess associated with a pontine lesion in multiple sclerosis

NONE

Sleep disorders are prevalent in patients with multiple sclerosis. In contrast, a frank increase of rapid eye movement (REM) sleep time is a rare phenomenon, mostly described in the context of REM sleep rebound (after sleep deprivation, abrupt withdrawal of antidepressants or neuroleptics, and during the first night of ventilation for severe sleep apnea), but not in link with specific brain lesions. We incidentally found an isolated, marked increase in REM sleep time (200 min, 40% of total sleep time, normative values: 18.2-20.3%) and in rapid eye movements density during REM sleep in a patient with a secondary progressive multiple sclerosis, associated with an anterior pontine demyelinating lesion on magnetic resonance imaging. This result suggests that a network blocking REM sleep in the pons has been damaged.

Intra-database validation of case-identifying algorithms using reconstituted electronic health records from healthcare claims data

BACKGROUND

Diagnosis performances of case-identifying algorithms developed in healthcare database are usually assessed by comparing identified cases with an external data source. When this is not feasible, intra-database validation can present an appropriate alternative.

OBJECTIVES

To illustrate through two practical examples how to perform intra-database validations of case-identifying algorithms using reconstituted Electronic Health Records (rEHRs).

METHODS

Patients with 1) multiple sclerosis (MS) relapses and 2) metastatic castration-resistant prostate cancer (mCRPC) were identified in the French nationwide healthcare database (SNDS) using two case-identifying algorithms. A validation study was then conducted to estimate diagnostic performances of these algorithms through the calculation of their positive predictive value (PPV) and negative predictive value (NPV). To that end, anonymized rEHRs were generated based on the overall information captured in the SNDS over time (e.g. procedure, hospital stays, drug dispensing, medical visits) for a random selection of patients identified as cases or non-cases according to the predefined algorithms. For each disease, an independent validation committee reviewed the rEHRs of 100 cases and 100 non-cases in order to adjudicate on the status of the selected patients (true case/ true non-case), blinded with respect to the result of the corresponding algorithm.

RESULTS

Algorithm for relapses identification in MS showed a 95% PPV and 100% NPV. Algorithm for mCRPC identification showed a 97% PPV and 99% NPV.

CONCLUSION

The use of rEHRs to conduct an intra-database validation appears to be a valuable tool to estimate the performances of a case-identifying algorithm and assess its validity, in the absence of alternative.

Multiple sclerosis: Is there a risk of worsening after yellow fever vaccination?

BACKGROUND

Yellow fever vaccine (YFV) is not advised for multiple sclerosis (MS) patients because of the potential risk of post-vaccine relapses.

OBJECTIVE

To assess the risk of relapsing-remitting multiple sclerosis (RR-MS) worsening after YFV.

METHODS

Non-interventional observational retrospective, exposed/non-exposed cohort study nested in the French national cohort including MS.

RESULTS

128 RR-MS were included. The 1-year annualized relapse rate (ARR) following YFV did not differ between exposed: 0.219 (0.420) and non-exposed subjects: 0.208 (0.521) (p = 0.92). Time to first relapse was not different between groups (adjusted hazard ratio (HR) = 1.33; 95% confidence interval (CI) = 0.53-3.30, p = 0.54).

CONCLUSION

These results suggest that YFV does not worsen the course of RR-MS.

Human papillomavirus lesions in 16 MS patients treated with fingolimod: Outcomes and vaccination

Few cases of human papillomavirus (HPV) diseases have been reported in multiple sclerosis (MS) patients treated with fingolimod. We describe a case series of 16 MS patients (11 women, 5 men) developing HPV lesions after the onset of fingolimod, without previous HPV history. Fingolimod had to be discontinued in six patients. Six patients received vaccination for HPV, with good tolerance. Our report highlights that systematic HPV screening and discussion about HPV vaccination before fingolimod onset are crucial. In case of occurrence of HPV lesions during fingolimod treatment, a comprehensive workup of HPV disease is necessary, with discussion of HPV vaccination to prevent secondary lesions. Prevalence studies of HPV lesions are needed in MS patients with the different disease-modifying therapies.

Pregnancy in Patients With AQP4-Ab, MOG-Ab, or Double-Negative Neuromyelitis Optica Disorder

OBJECTIVE

To analyze the effects of pregnancy on neuromyelitis optica spectrum disorder (NMOSD) according to patients' serostatus and immunosuppressive therapy (IST).

METHODS

We performed a retrospective multicenter international study on patients with NMOSD. Patients were tested for aquaporin-4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) antibodies (Ab). Informative pregnancies were reported when NMOSD onset occurred before or during pregnancy or up to 12 months postpartum. The mean annualized relapse rate (ARR) was calculated for the 12 months before conception, for each trimester of pregnancy, and postpartum. Events such as miscarriage, abortion, and preeclampsia were reported. IST was considered if taken in the 3 months before or during pregnancy.

RESULTS

We included 89 pregnancies (46 with AQP4-Ab, 30 with MOG-Ab, and 13 without either Ab) in 58 patients with NMOSD. Compared to the prepregnancy period, the ARR was lower during pregnancy in each serostatus group and higher during the postpartum period in patients with AQP4-Ab (p < 0.01). Forty-eight percent (n = 31) of pregnancies occurred during IST and these patients presented fewer relapses during pregnancy and the 12 months postpartum than untreated patients (26% vs 53%, p = 0.04). Miscarriages occurred in 10 (11%) pregnancies, and were mainly in patients with AQP4-Ab (with or without IST) and a previous history of miscarriage. Preeclampsia was reported in 2 (2%) patients who were AQP4-Ab-positive.

CONCLUSION

We found a rebound in the ARR during the first postpartum trimester that was higher than the prepregnancy period only in AQP4-Ab-positive patients. Taking IST just before or during pregnancy reduces the risk of relapses in these conditions.

The long-term outcome of MOGAD: An observational national cohort study of 61 patients

BACKGROUND AND OBJECTIVE

The prognosis in myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is a matter of debate. Our aim was to assess the long-term outcomes of patients with MOGAD.

METHODS

We retrospectively analysed the clinical and paraclinical data of patients from the French nationwide observatory study NOMADMUS who tested positive for MOG antibodies (MOG-IgG) and who had clinical follow-up of at least 8 years from their first episode.

RESULTS

Sixty-one patients (median [range] age at onset 27 [3-69] years), with a median (mean; range) follow-up of 177 (212.8; 98-657) months, were included. Among 58 patients with a relapsing course, 26.3% relapsed in the first year after onset. Of the 61 patients, 90.2% experienced at least one episode of optic neuritis. At last visit, the median (mean; range) Expanded Disability Status Scale (EDSS) score was 1 (2.12; 0-7.5), 12.5% had an EDSS score ≥6 and 37.5% had an EDSS score ≥3. Of 51 patients with final visual acuity (VA) data available, 15.7% had VA ≤0.1 in at least one eye and 25.5% had VA ≤0.5 in at least one eye. Bilateral blindness (VA ≤0.1) was present in 5.9% of patients. Finally, 12.5% of patients presented bladder dysfunction requiring long-term urinary catheterization. No factor associated significantly with a final EDSS score ≥3 or with final VA ≤0.1 was found.

CONCLUSION

Overall long-term favourable outcomes were achieved in a majority of our patients, but severe impairment, in particular visual damage, was not uncommon.

Staggered enforcement of infection control and prevention measures following four consecutive potential laboratory exposures to imported Brucella melitensis

From 2015 until 2020, Brucella melitensis was isolated four times in our microbiology laboratory. All patients had travelled in endemic-areas. Immediately after the first occurrence, all laboratory staff were risk-stratified and preventive and protective measures were applied according to CDC guidelines. Nineteen workers were exposed and needed chemoprophylaxis and follow-up. At each subsequent occurrence, risk analysis was performed, and additional measures were implemented accordingly, leading to a progressive reduction of exposed staff members to none the fourth time. We describe here the additional measures that permitted this important exposure reduction.

Thalamic energy dysfunction is associated with thalamo-cortical tract damage in multiple sclerosis: A diffusion spectroscopy study

BACKGROUND

Diffusion-weighted ¹H magnetic resonance spectroscopy (DW-MRS) allows to quantify creatine-phosphocreatine brain diffusivity (ADC(tCr)), whose reduction in multiple sclerosis (MS) has been proposed as a proxy of energy dysfunction.

OBJECTIVE

To investigate whether thalamic ADC(tCr) changes are associated with thalamo-cortical tract damage in MS.

METHODS

Twenty patients with MS and 13 healthy controls (HC) were enrolled in a DW-MRS and DW imaging (DWI) study. From DW-MRS, ADC(tCr) and total N-acetyl-aspartate diffusivity (ADC(tNAA)) were extracted in the thalami. Three thalamo-cortical tracts and one non-thalamic control tract were reconstructed from DWI. Fractional anisotropy (FA), mean (MD), axial (AD), and radial diffusivity (RD), reflecting microstructural integrity, were extracted for each tract. Associations between thalamic ADC(tCr) and tract metrics were assessed using linear regression models adjusting for age, sex, thalamic volume, thalamic ADC(tNAA), and tract-specific lesion load.

RESULTS

Lower thalamic ADC(tCr) was associated with higher MD and RD of thalamo-cortical projections in MS (MD: p = 0.029; RD: p = 0.017), but not in HC (MD: p = 0.625, interaction term between thalamic ADC(tCr) and group = 0.019; RD: p = 0.320, interaction term = 0.05). Thalamic ADC(tCr) was not associated with microstructural changes of the control tract.

CONCLUSION

Reduced thalamic ADC(tCr) correlates with thalamo-cortical tract damage in MS, showing that pathologic changes in thalamic energy metabolism are associated with structural degeneration of connected fibers.