Differential Runx3, Eomes, and T-bet expression subdivides MS-associated CD4+ T cells with brain-homing capacity.

Multiple sclerosis (MS) is a common and devastating chronic inflammatory disease of the CNS. CD4+ T cells are assumed to be the first to cross the blood-central nervous system (CNS) barrier and trigger local inflammation. Here, we explored how pathogenicity-associated effector programs define CD4+ T cell subsets with brain-homing ability in MS. Runx3- and Eomes-, but not T-bet-expressing CD4+ memory cells were diminished in the blood of MS patients. This decline reversed following natalizumab treatment and was supported by a Runx3+ Eomes+ T-bet- enrichment in cerebrospinal fluid samples of treatment-naïve MS patients. This transcription factor profile was associated with high granzyme K (GZMK) and CCR5 levels and was most prominent in Th17.1 cells (CCR6+ CXCR3+ CCR4-/dim ). Previously published CD28- CD4 T cells were characterized by a Runx3+ Eomes- T-bet+ phenotype that coincided with intermediate CCR5 and a higher granzyme B (GZMB) and perforin expression, indicating the presence of two separate subsets. Under steady-state conditions, granzyme Khigh Th17.1 cells spontaneously passed the blood-brain barrier in vitro. This was only found for other subsets including CD28- cells when using inflamed barriers. Altogether, CD4+ T cells contain small fractions with separate pathogenic features, of which Th17.1 seems to breach the blood-brain barrier as a possible early event in MS.

Ultrastructural Axon-Myelin Unit Alterations in Multiple Sclerosis Correlate with Inflammation.

OBJECTIVE: Changes in the normal-appearing white matter (NAWM) in multiple sclerosis (MS) may contribute to disease progression. Here, we systematically quantified ultrastructural and subcellular characteristics of the axon-myelin unit in MS NAWM and determined how this correlates with low-grade inflammation. METHODS: Human brain tissue obtained with short postmortem delay and fixation at autopsy enables systematic quantification of ultrastructural characteristics. In this study, we performed high-resolution immunohis tochemistry and quantitative transmission electron microscopy to study inflammation and ultrastructural characteristics of the axon-myelin unit in MS NAWM (n = 8) and control white matter (WM) in the optic nerve. RESULTS: In the MS NAWM, there were more activated and phagocytic microglia cells (HLA+ P2RY12- and Iba1+ CD68+ ) and more T cells (CD3+ ) compared to control WM, mainly located in the perivascular space. In MS NAWM compared to control WM, there were, as expected, longer paranodes and juxtaparanodes and larger overlap between paranodes and juxtaparanodes. There was less compact myelin wrapping, a lower g-ratio, and a higher frequency of axonal mitochondria. Changes in myelin and axonal mitochondrial frequency correlated positively with the number of active and phagocytic microglia and lymphocytes in the optic nerve. INTERPRETATION: These data suggest that in MS NAWM myelin detachment and uncompact myelin wrapping occurs, potassium channels are unmasked at the nodes of Ranvier, and axonal energy demand is increased, or mitochondrial transport is stagnated, accompanied by increased presence of activated and phagocytic microglia and T cells. These subclinical alterations to the axon-myelin unit in MS NAWM may contribute to disease progression. ANN NEUROL 2023;93:856-870.

Disentangling the heterogeneity of multiple sclerosis through identification of independent neuropathological dimensions.

Multiple sclerosis (MS) is a heterogeneous neurological disorder with regards to clinical presentation and pathophysiology. Here, we investigated the heterogeneity of MS by performing an exploratory factor analysis on quantitative and qualitative neuropathology data collected for 226 MS donors in the Netherlands Brain Bank autopsy cohort. Three promising dimensions were identified and subsequently validated with clinical, neuropathological, and genetic data. Dimension 1 ranged from a predominance of remyelinated and inactive lesions to extensive pathological changes, higher proportions of active and mixed lesions, and foamy microglia morphology. This pattern was positively correlated with more severe disease, the presence of B and T cells, and neuroaxonal damage. Scoring high on dimension 2 was associated with active lesions, reactive sites, and the presence of nodules. These donors had less severe disease, a specific pattern of cortical lesions, and MS risk variants in the human leukocyte antigen region, the latter indicating a connection between disease onset and this neuropathological dimension. Donors scoring high on dimension 3 showed increased lesional pathology with relatively more mixed and inactive lesions and ramified microglia morphology. This pattern was associated with longer disease duration, subpial cortical lesions, less involvement of the adaptive immune system, and less axonal damage. Taken together, the three dimensions may represent (1) demyelination and immune cell activity associated with pathological and clinical progression, (2) microglia (re)activity and possibly lesion initiation, and (3) loss of lesion activity and scar formation. Our findings highlight that a thorough understanding of the interplay between multiple pathological characteristics is crucial to understand the heterogeneity of MS pathology, as well as its association with genetic predictors and disease outcomes. The scores of donors on the dimensions can serve as an important starting point for further disentanglement of MS heterogeneity and translation into observations and interventions in living cohorts with MS.

Benefits of early highly effective versus escalation treatment strategies in relapsing multiple sclerosis estimated using a treatment-sequence model.

BACKGROUND: Uncertainty about disproportionate impact on health care budgets limits implementation of early highly effective treatment (EHT) in multiple sclerosis (MS). OBJECTIVE: To estimate cost-effectiveness of escalation versus EHT disease-modifying treatment (DMT) sequences. METHODS: Using a health-economic approach, we analysed health benefits (relapse rate reduction, disability prevention), direct/indirect DMT and societal costs of escalation versus EHT DMT sequences. In scenario analyses, we allowed (1) earlier use of alemtuzumab (ALE) and (2) a single retreatment with cladribine (CLA). RESULTS: In our model, we showed that the ratio between costs and quality-adjusted life years (QALYs) for the most cost-effective EHT and escalation sequence results into a similar net health benefit with higher costs and also higher QALYs associated with an EHT versus escalation strategy. Earlier use of ALE is more cost-effective than in later lines, even when aggravating the impact of its side-effects tenfold. Retreatment with CLA was more cost-effective in both escalation and EHT sequences. CONCLUSIONS: Certain EHT sequences are equally cost-effective to escalation sequences and are likely to result in more health at uncertain additional costs. The favourable cost-benefit ratio of CLA and ALE suggests that a wider application of affordable highly effective therapies could promote the cost-effectiveness both EHT and escalation approaches.

Real-world challenges in the diagnosis of primary progressive multiple sclerosis.

BACKGROUND AND PURPOSE: Despite the 2017 revisions to the McDonald criteria, diagnosing primary progressive multiple sclerosis (PPMS) remains challenging. To improve clinical practice, the aim was to identify frequent diagnostic challenges in a real-world setting and associate these with the performance of the 2010 and 2017 PPMS diagnostic McDonald criteria. METHODS: Clinical, radiological and laboratory characteristics at the time of diagnosis were retrospectively recorded from designated PPMS patient files. Possible complicating factors were recorded such as confounding comorbidity, signs indicative of alternative diagnoses, possible earlier relapses and/or incomplete diagnostic work-up (no cerebrospinal fluid examination and/or magnetic resonance imaging brain and spinal cord). The percentages of patients fulfilling the 2010 and 2017 McDonald criteria were calculated after censoring patients with these complicating factors. RESULTS: A total of 322 designated PPMS patients were included. Of all participants, it was found that n = 28/322 had confounding comorbidity and/or signs indicative of alternative diagnoses, n = 103/294 had possible initial relapsing and/or uncertainly progressive phenotypes and n = 73/191 received an incomplete diagnostic work-up. When applying the 2010 and 2017 diagnostic PPMS McDonald criteria on n = 118 cases with a full diagnostic work-up and a primary progressive disease course without a better alternative explanation, these were met by 104/118 (88.1%) and 98/118 remaining patients (83.1%), respectively (p = 0.15). CONCLUSION: Accurate interpretation of the initial clinical course, consideration of alternative diagnoses and a full diagnostic work-up are the cornerstones of a PPMS diagnosis. When these conditions are met, the 2010 and 2017 McDonald criteria for PPMS perform similarly, emphasizing the importance of their appropriate application in clinical practice.

Multiple sclerosis risk variants influence the peripheral B-cell compartment early in life in the general population.

BACKGROUND AND PURPOSE: Multiple sclerosis (MS) is associated with abnormal B-cell function, and MS genetic risk alleles affect multiple genes that are expressed in B cells. However, how these genetic variants impact the B-cell compartment in early childhood is unclear. In the current study, we aim to assess whether polygenic risk scores (PRSs) for MS are associated with changes in the blood B-cell compartment in children from the general population. METHODS: Six-year-old children from the population-based Generation R Study were included. Genotype data were used to calculate MS-PRSs and B-cell subset-enriched MS-PRSs, established by designating risk loci based on expression and function. Analyses of variance were performed to examine the effect of MS-PRSs on total B-cell numbers (n = 1261) as well as naive and memory subsets (n = 675). RESULTS: After correction for multiple testing, no significant associations were observed between MS-PRSs and total B-cell numbers and frequencies of subsets therein. A naive B-cell-MS-PRS (n = 26 variants) was significantly associated with lower relative, but not absolute, naive B-cell numbers (p = 1.03 × 10-4 and p = 0.82, respectively), and higher frequencies and absolute numbers of CD27+ memory B cells (p = 8.83 × 10-4 and p = 4.89 × 10-3 , respectively). These associations remained significant after adjustment for Epstein-Barr virus seropositivity and the HLA-DRB1*15:01 genotype. CONCLUSIONS: The composition of the blood B-cell compartment is associated with specific naive B-cell-associated MS risk variants during childhood, possibly contributing to MS pathophysiology later in life. Cell subset-specific PRSs may offer a more sensitive tool to define the impact of genetic risk on the immune system in diseases such as MS.

White matter lesions in multiple sclerosis are enriched for CD20dim CD8+ tissue-resident memory T cells.

Brain CD8+ CD69+ tissue-resident memory T (TRM ) cells comprise a CD20dim subset, which is proportionally larger in CD103-negative TRM cells. In multiple sclerosis (MS) lesions, CD20dim TRM -cell proportions are increased. CD20-expression is associated with higher levels of CXCR6, Ki-67, and granzyme B, supporting CD20dim TRM cells as a relevant subset in MS.

The association of Epstein-Barr virus infection with CXCR3+ B-cell development in multiple sclerosis: impact of immunotherapies.

Epstein-Barr virus (EBV) infection of B cells is associated with increased multiple sclerosis (MS) susceptibility. Recently, we found that CXCR3-expressing B cells preferentially infiltrate the CNS of MS patients. In chronic virus-infected mice, these types of B cells are sustained and show increased antiviral responsiveness. How EBV persistence in B cells influences their development remains unclear. First, we analyzed ex vivo B-cell subsets from MS patients who received autologous bone marrow transplantation (n = 9), which is often accompanied by EBV reactivation. The frequencies of nonclass-switched and class-switched memory B cells were reduced at 3-7 months, while only class-switched B cells returned back to baseline at 24-36 months posttransplantation. At these time points, EBV DNA load positively correlated to the frequency of CXCR3+ , and not CXCR4+ or CXCR5+ , class-switched B cells. Second, for CXCR3+ memory B cells trapped within the blood of MS patients treated with natalizumab (anti-VLA-4 antibody n = 15), latent EBV infection corresponded to enhanced in vitro formation of anti-EBNA1 IgG-secreting plasma cells under GC-like conditions. These findings imply that EBV persistence in B cells potentiates brain-homing and antibody-producing CXCR3+ subsets in MS.

Effectiveness and Cost-Effectiveness of 360 Disease-Modifying Treatment Escalation Sequences in Multiple Sclerosis.

OBJECTIVES: The rapid expansion in treatment options for relapsing-remitting multiple sclerosis (RRMS) of the past decade requires clinical decision making on the sequential prescription of these treatments. Here, we compare 360 treatment escalation sequences for patients with RRMS in terms of health outcomes and societal costs in The Netherlands. METHODS: We use a microsimulation model with a societal perspective, developed in collaboration with MS neurologists, to estimate the effectiveness and cost-effectiveness of 360 treatment sequences starting with first-line therapies in RRMS. This model integrated data on disease progression, disease-modifying treatment efficacy, clinical decision rules, age-dependent relapse rates, quality of life, healthcare, and societal costs. RESULTS: Costs and health outcomes were overlapping among different treatment escalation sequences. In our model for RRMS treatment, optimal lifetime health outcomes (20.24 ± 1.43 quality-adjusted life-years [QALYs], 6.11 ± 0.30 relapses) were achieved with the sequence peginterferon-dimethyl fumarate-ocrelizumab-natalizumab-alemtuzumab. The most cost-effective sequence (peginterferon-glatiramer acetate-ocrelizumab-cladribine-alemtuzumab) yielded numerically worse health outcomes per patient (19.59 ± 1.43 QALYs, 6.64 ± 0.43 relapses), but resulted in €98 127 ± €19 134 less costs than the most effective treatment sequence. CONCLUSIONS: Effectiveness estimates of treatments have overlapping confidence intervals but the treatment sequence that yields most QALYs is not the most cost-effective option, also when taking uncertainty into account. It is important that neurologists are aware of cost constraints and its relationship with prescription behavior, but treatment decisions should be individually tailored.

Prognostic value of natural killer cell/T cell ratios for disease activity in multiple sclerosis.

BACKGROUND AND PURPOSE: Natural killer (NK) cells may play a role in multiple sclerosis (MS). Ratios of NK cells to CD4+ T cells have been proposed as a biomarker for the therapeutic effect of stem cell transplantation in MS. The objectives here were to explore the relevance of this ratio in MS patients by analysing NK and T cell subsets, as well as their prognostic value for disease activity. METHODS: Baseline peripheral blood mononuclear cells of 50 relapsing-remitting MS patients, participating in our vitamin D supplementation study (SOLARIUM), were analysed with flow cytometry. Disease activity was measured as new magnetic resonance imaging lesions, relapses and mean plasma neurofilament light chain levels after 48 weeks of follow-up. RESULTS: The proportion of NK cells correlated negatively with CD4+ T cells (R = -0.335, p = 0.001) and interleukin 17A (IL-17A+ ) CD4+ T cells (R = -0.203, p = 0.043). Participants with magnetic resonance imaging activity or relapses displayed lower NK/IL-17A+  CD4+ T cell ratios (p =0.025 and p = 0.006, respectively). The NK/IL-17A+  CD4+ T cell ratio correlated negatively with neurofilament light chain levels (R = -0.320, p = 0.050). Vitamin D supplementation did not affect these ratios. CONCLUSIONS: Our data suggest a protective role of an expanded NK cell compartment compared to the CD4+ T cell subset fractions in relapsing-remitting MS patients. NK/CD4+ T cell ratios may be a prognostic biomarker for disease activity in MS.

T cell composition and polygenic multiple sclerosis risk: A population-based study in children.

BACKGROUND AND PURPOSE: Patients with multiple sclerosis (MS) have altered T cell function and composition. Common genetic risk variants for MS affect proteins that function in the immune system. It is currently unclear to what extent T cell composition is affected by genetic risk factors for MS, and how this may precede a possible disease onset. Here, we aim to assess whether an MS polygenic risk score (PRS) is associated with an altered T cell composition in a large cohort of children from the general population. METHODS: We included genotyped participants from the population-based Generation R study in whom immunophenotyping of blood T cells was performed at the age of 6 years. Analyses of variance were used to determine the impact of MS-PRSs on total T cell numbers (n = 1261), CD4+ and CD8+ lineages, and subsets therein (n= 675). In addition, T-cell-specific PRSs were constructed based on functional pathway data. RESULTS: The MS-PRS negatively correlated with CD8+ T cell frequencies (p = 2.92 × 10-3 ), which resulted in a positive association with CD4+ /CD8+ T cell ratios (p = 8.27 × 10-9 ). These associations were mainly driven by two of 195 genome-wide significant MS risk variants: the main genetic risk variant for MS, HLA-DRB1*15:01 and an HLA-B risk variant. We observed no significant associations for the T-cell-specific PRSs. CONCLUSIONS: Our results suggest that MS-associated genetic variants affect T cell composition during childhood in the general population.

Tissue-resident memory T cells invade the brain parenchyma in multiple sclerosis white matter lesions.

Multiple sclerosis is a chronic inflammatory, demyelinating disease, although it has been suggested that in the progressive late phase, inflammatory lesion activity declines. We recently showed in the Netherlands Brain Bank multiple sclerosis-autopsy cohort considerable ongoing inflammatory lesion activity also at the end stage of the disease, based on microglia/macrophage activity. We have now studied the role of T cells in this ongoing inflammatory lesion activity in chronic multiple sclerosis autopsy cases. We quantified T cells and perivascular T-cell cuffing at a standardized location in the medulla oblongata in 146 multiple sclerosis, 20 neurodegenerative control and 20 non-neurological control brain donors. In addition, we quantified CD3+, CD4+, and CD8+ T cells in 140 subcortical white matter lesions. The location of CD8+ T cells in either the perivascular space or the brain parenchyma was determined using CD8/laminin staining and confocal imaging. Finally, we analysed CD8+ T cells, isolated from fresh autopsy tissues from subcortical multiple sclerosis white matter lesions (n = 8), multiple sclerosis normal-appearing white matter (n = 7), and control white matter (n = 10), by flow cytometry. In normal-appearing white matter, the number of T cells was increased compared to control white matter. In active and mixed active/inactive lesions, the number of T cells was further augmented compared to normal-appearing white matter. Active and mixed active/inactive lesions were enriched for both CD4+ and CD8+ T cells, the latter being more abundant in all lesion types. Perivascular clustering of T cells in the medulla oblongata was only found in cases with a progressive disease course and correlated with a higher percentage of mixed active/inactive lesions and a higher lesion load compared to cases without perivascular clusters in the medulla oblongata. In all white matter samples, CD8+ T cells were located mostly in the perivascular space, whereas in mixed active/inactive lesions, 16.3% of the CD8+ T cells were encountered in the brain parenchyma. CD8+ T cells from mixed active/inactive lesions showed a tissue-resident memory phenotype with expression of CD69, CD103, CD44, CD49a, and PD-1 and absence of S1P1. They upregulated markers for homing (CXCR6), reactivation (Ki-67), and cytotoxicity (GPR56), yet lacked the cytolytic enzyme granzyme B. These data show that in chronic progressive multiple sclerosis cases, inflammatory lesion activity and demyelinated lesion load is associated with an increased number of T cells clustering in the perivascular space. Inflammatory active multiple sclerosis lesions are populated by CD8+ tissue-resident memory T cells, which show signs of reactivation and infiltration of the brain parenchyma.

Vitamin D3 supplementation and neurofilament light chain in multiple sclerosis.

OBJECTIVES: Low circulating vitamin D levels are associated with an increased risk of active MRI lesions and relapses in several cohorts with relapsing remitting multiple sclerosis (RRMS). Randomized controlled supplementation trials are, however, negative on their primary endpoints, while secondary MRI endpoints suggest anti-inflammatory effects. Circulating levels of neurofilament light chain (NfL) are a biomarker of disease activity in RRMS. We explored whether 48-week high-dose vitamin D3 supplements were associated with lower circulating NfL levels. MATERIALS & METHODS: Of N = 40 Dutch interferon beta-treated participants with RRMS of the SOLAR trial, plasma samples at baseline and 48-week follow-up were available. Of these participants, N = 24 were supplemented with 14 000 IU/d vitamin D3 and N = 16 with placebo. Twenty-five hydroxyvitamin D3 (25(OH)D3 ) levels were measured with LC-MS/MS, and NfL levels were measured in duplicate with Simoa. RESULTS: Serum 25(OH)D3 levels at 48 weeks were increased in the vitamin D3 when compared to placebo group (median level 281 [IQR 205-330] vs 72 [39-88] nmol/L; P < .01). NfL levels at 48 weeks did not differ between the treatment groups (median level 25.4 [IQR 19.6-32.2] vs 25.3 [17.9-30.1] pg/mL; P = .74). Higher week 48 NfL level showed a trend toward association with a higher risk of combined unique active lesions on the week 48 MRI scan (OR 2.39 [95% CI 0.93-6.12] for each 10 pg/mL increase; P = .07). CONCLUSIONS: Supplementation of high-dose vitamin D3 for 48 weeks was not associated with lower NfL levels. This study does not support an effect of vitamin D3 on this biomarker of neuro-axonal injury.

Mycoplasma Pneumoniae and Antibodies against Galactocerebroside in a 9-Year-Old Boy with Encephalitis.

We report the case of a 9 year-old boy, presenting with an acute encephalitis with cerebrospinal fluid pleiocytosis. MRI showed T2/FLAIR (fluid attenuated inversion recovery) hyperintense signals of basal ganglia and cortex, EEG (electro encephalogram) showed diffuse slowing with epileptic discharges. A repetitively elevated IgM/IgG serologic response against Mycoplasma pneumoniae was observed with polymerase chain reaction in serum and cerebrospinal fluid remaining negative. No other pathogen or antigen could be identified. High IgG and IgM levels against the glycolipid galactocerebroside were detected in serum but not in CSF. After treatment with corticosteroids, the patient fully recovered. Brain MRI and EEG investigation returned completely normal. Besides a primary infection of the central nervous system, M. pneumoniae is associated with a parainfectious encephalitis in children which may be mediated by antibodies to galactocerebroside.

Exploring the effect of vitamin D3 supplementation on the anti-EBV antibody response in relapsing-remitting multiple sclerosis.

BACKGROUND: Epstein-Barr virus (EBV) infection and vitamin D insufficiency are potentially interacting risk factors for multiple sclerosis (MS). OBJECTIVES: To investigate the effect of high-dose vitamin D3 supplements on antibody levels against the EBV nuclear antigen-1 (EBNA-1) in patients with relapsing-remitting multiple sclerosis (RRMS) and to explore any underlying mechanism affecting anti-EBNA-1 antibody levels. METHODS: This study utilized blood samples from a randomized controlled trial in RRMS patients receiving either vitamin D3 (14,000 IU/day; n = 30) or placebo ( n = 23) over 48 weeks. Circulating levels of 25-hydroxyvitamin-D, and anti-EBNA-1, anti-EBV viral capsid antigen (VCA), and anti-cytomegalovirus (CMV) antibodies were measured. EBV load in leukocytes, EBV-specific cytotoxic T-cell responses, and anti-EBNA-1 antibody production in vitro were also explored. RESULTS: The median antibody levels against EBNA-1, but not VCA and CMV, significantly reduced in the vitamin D3 group (526 (368-1683) to 455 (380-1148) U/mL) compared to the placebo group (432 (351-1280) to 429 (297-1290) U/mL; p = 0.023). EBV load and cytotoxic T-cell responses were unaffected. Anti-EBNA-1 antibody levels remained below detection limits in B-cell cultures. CONCLUSION: High-dose vitamin D3 supplementation selectively reduces anti-EBNA-1 antibody levels in RRMS patients. Our exploratory studies do not implicate a promoted immune response against EBV as the underlying mechanism.