Alemtuzumab is a humanized monoclonal antibody against CD52 (cluster of differentiation 52) and is approved for the therapy of relapsing-remitting multiple sclerosis. The application of alemtuzumab ...leads to a rapid, but long-lasting depletion predominantly of CD52-bearing B and T cells with reprogramming effects on immune cell composition resulting in the restoration of tolerogenic networks. Alemtuzumab has proven high efficacy in clinical phase II and III trials, where interferon β-1a was used as active comparator. However, alemtuzumab is associated with frequent and considerable risks. Most importantly secondary autoimmune disease affects 30%-40% of patients, predominantly impairing thyroid function. Extensive monitoring and early intervention allow for an appropriate risk management. However, new and reliable biomarkers for individual risk stratification and treatment response to improve patient selection and therapy guidance are a significant unmet need. Only a deeper understanding of the underlying mechanisms of action (MOA) will reveal such markers, maximizing the best potential risk-benefit ratio for the individual patient. This review provides and analyses the current knowledge on the MOA of alemtuzumab. Most recent data on efficacy and safety of alemtuzumab are presented and future research opportunities are discussed.
Background:
Monitoring neuronal injury remains one key challenge in early relapsing-remitting multiple sclerosis (RRMS) patients. Upon axonal damage, neurofilament – a major component of the ...neuro-axonal cytoskeleton – is released into the cerebrospinal fluid (CSF) and subsequently peripheral blood.
Objective:
To investigate the relevance of serum neurofilament light chain (sNfL) for acute and chronic axonal damage in early RRMS.
Methods:
sNfL levels were determined in 74 patients (63 therapy-naive) with recently diagnosed clinically isolated syndrome (CIS) or RRMS using Single Molecule Array technology. Standardized 3 T magnetic resonance imaging (MRI) was performed at baseline and 1–3 consecutive follow-ups (42 patients; range: 6–37 months).
Results:
Baseline sNfL correlated significantly with T2 lesion volume (r = 0.555, p < 0.0001). There was no correlation between baseline sNfL and age, Expanded Disability Status Scale (EDSS) score or other calculated MRI measures. However, T2 lesion volume increased (r = 0.67, p < 0.0001) and brain parenchymal volume decreased more rapidly in patients with higher baseline sNfL (r = −0.623, p = 0.0004). Gd-enhancing lesions correlated positively with sNfL levels. Initiation of disease-modifying treatment led to a significant decrease in sNfL levels.
Conclusion:
sNfL indicates acute inflammation as demonstrated by correlation with Gd+ lesions. It is a promising biomarker for neuro-axonal damage in early multiple sclerosis (MS) patients, since higher baseline sNfL levels predicted future brain atrophy within 2 years.
We present experimental and numerical studies of broad-area semiconductor lasers with chaotic ray dynamics. The emission intensity distributions at the cavity boundaries are measured and compared to ...ray tracing simulations and numerical calculations of the passive cavity modes. We study two different cavity geometries, a D-cavity and a stadium, both of which feature fully chaotic ray dynamics. While the far-field distributions exhibit fairly homogeneous emission in all directions, the emission intensity distributions at the cavity boundary are highly inhomogeneous, reflecting the non-uniform intensity distributions inside the cavities. The excellent agreement between experiments and simulations demonstrates that the intensity distributions of wave-chaotic semiconductor lasers are primarily determined by the cavity geometry. This is in contrast to conventional Fabry-Perot broad-area lasers for which the intensity distributions are to a large degree determined by the nonlinear interaction of the lasing modes with the semiconductor gain medium.
Lasers can exhibit nonlinear and chaotic dynamics driven by the interaction of multiple lasing modes, and investigating the different scenarios of mode competition and bifurcations of their dynamics ...is of great interest on a fundamental level as well as in view of applications. We study the dynamics of a broad-area vertical-cavity surface-emitting laser (VCSEL) in solitary continuous-wave operation with a comprehensive investigation of its polarization state, lasing spectra, near-field distributions, and temporal dynamics. Fluctuations at the frequency of birefringence splitting and other frequency components develop in a series of bifurcations. The bifurcations coincide with changes of the transverse lasing modes and/or the polarization state, demonstrating the importance of both the spatial and polarization degrees of freedom for mode competition. As a consequence, the inherent nonlinear dynamics of broad-area VCSELs is significantly more complex than the dynamics of VCSELs with a single spatial mode.
OBJECTIVETo determine the factors that influence B-cell repopulation after B-cell depletion therapy in neurologic patients and derive recommendations for monitoring and dosing of patients.
METHODSIn ...this study, we determined the association of body surface area (BSA; calculated by body weight and height with the Dubois formula), sex, pretreatment therapy, age, CSF data, and white blood cell counts with the risk and timing of B-cell repopulation, defined as 1% CD19 cells (of total lymphocytes), following 87 B cell–depleting anti-CD20 treatment cycles of 45 neurologic patients (28 women; mean age ± SD, 44.5 ± 15.0 years).
RESULTSPatients with a larger BSA had a higher probability to reach 1% CD19 cells than those with a smaller BSA (p < 0.05) following B-cell depletion therapy, although those patients had received BSA-adapted doses of rituximab (375 mg/m). Sex, pretreatment, age, CSF data, or absolute lymphocyte and leukocyte counts during treatment did not significantly influence CD19 B-cell recovery in the fully adjusted models. Intraindividual B-cell recovery in patients with several treatment cycles did not consistently change over time.
CONCLUSIONSB-cell repopulation after depletion therapy displays both high inter- and intra-individual variance. Our data indicate that a larger BSA is associated with faster repopulation of B cells, even when treatment is adapted to the BSA. A reason is the routinely used Dubois formula, underestimating a large BSA. In these patients, there is a need for a higher therapy dose. Because B-cell count–dependent therapy regimes are considered to reduce adverse events, B-cell monitoring will stay highly relevant. Patientsʼ BSA should thus be determined using the Mosteller formula, and close monitoring should be done to avoid resurgent B cells and disease activity.
•Sirt7 modulates the adaptive immune response in EAE.•Sirt7 does not influence the EAE disease course.•Sirt7 favors survival of adult born neurons in the hippocampus.•We find decreased hippocampal ...proliferation in EAE animals.
Epigenetic regulators are increasingly recognized as relevant modulators in the immune and nervous system. The class of sirtuins consists of NAD+-dependent histone deacetylases that regulate transcription. Sirtuin family member Sirt1 has already been shown to influence the disease course in an animal model of autoimmune neuroinflammation (experimental autoimmune encephalomyelitis (EAE). A role of Sirt7, a related epigenetic regulator, on immune system regulation has been proposed before, as these mice are more susceptible to develop inflammatory cardiomyopathy. Sirt7−/− animals showed no differences in clinical score compared to wild-type littermates after EAE induction with myelin oligodendrocyte glycoprotein (MOG) peptide 35-55, although we found subtle immune alterations at different phases of EAE and decreased survival of newly generated neurons in the hippocampus. Our data indicate that Sirt7 has a slight protective impact on both the adaptive immune system and neurogenesis. However, overall this epigenetic factor is not capable of impacting the acute or chronic phase of neuroinflammation.
IL-17-producing CD8
(Tc17) cells are enriched in active lesions of patients with multiple sclerosis (MS), suggesting a role in the pathogenesis of autoimmunity. Here we show that amelioration of MS ...by dimethyl fumarate (DMF), a mechanistically elusive drug, associates with suppression of Tc17 cells. DMF treatment results in reduced frequency of Tc17, contrary to Th17 cells, and in a decreased ratio of the regulators RORC-to-TBX21, along with a shift towards cytotoxic T lymphocyte gene expression signature in CD8
T cells from MS patients. Mechanistically, DMF potentiates the PI3K-AKT-FOXO1-T-BET pathway, thereby limiting IL-17 and RORγt expression as well as STAT5-signaling in a glutathione-dependent manner. This results in chromatin remodeling at the Il17 locus. Consequently, T-BET-deficiency in mice or inhibition of PI3K-AKT, STAT5 or reactive oxygen species prevents DMF-mediated Tc17 suppression. Overall, our data disclose a DMF-AKT-T-BET driven immune modulation and suggest putative therapy targets in MS and beyond.
Background
Patients with multiple sclerosis (MS) receiving immunomodulatory drugs were excluded from clinical trials on COVID-19 vaccines. Therefore, data regarding the efficacy of COVID-19 vaccines ...to induce humoral immunity in MS patients treated with B- and T-cell depleting agents is urgently warranted. Cladribine tablets are a high-efficacy disease-modifying treatment that exerts its therapeutic effect via sustained but transient lymphocyte depletion.
Aim
We report humoral responses in a German cohort of MS patients treated with cladribine tablets.
Methods
This retrospective analysis included patients ≥18 years who were treated with cladribine tablets for relapsing MS in the first or second year and were fully vaccinated against COVID-19. Two weeks after the second vaccination at the earliest, blood samples were obtained for the assessment of anti-SARS-CoV-2 IgG antibodies, lymphocyte counts, B-cells, CD4+ T-cells, and CD8+ T-cells. Anti-SARS-CoV-2 IgG antibodies were quantified with the LIAISON® SARS-CoV-2 TrimericS IgG assay. Positivity was defined at a cutoff value of 33.8 BAU/mL.
Results
In total, 38 patients (73.7% female, aged 23–66 years) were included in the analysis. Ten patients (26.3%) were treatment-naïve before initiating treatment with cladribine tablets. Most patients (84.2%) received mRNA vaccines. The time between the last dose of cladribine tablets and vaccination ranged between 2 and 96 weeks. Six patients (15.8%) were vaccinated within 4 weeks of their last cladribine dose. All patients achieved positive anti-SARS-CoV-2 IgG antibody levels. Humoral immune response was independent of age, time of vaccination in relation to the last cladribine dose, lymphocyte counts as well as B- and T-cell counts.
Conclusions
Treatment with cladribine tablets did not impair humoral response to COVID-19 vaccination. Time since last cladribine dose, age, prior therapy, lymphocyte count as well as B- and T-cell counts had no effect on seropositivity of anti-SARS-CoV-2 IgG antibodies.
Abstract
Background
T helper (Th) 17 cells are a highly plastic subset of T cells, which in the context of neuroinflammation, are able to acquire pathogenic features originally attributed to Th1 ...cells (resulting in so called ex-Th17 cells). Thus, a strict separation between the two T cell subsets in the context of experimental autoimmune encephalomyelitis (EAE) is difficult. High variability in culture and EAE induction protocols contributed to previous conflicting results concerning the differential contribution of Th1 and Th17 cells in EAE. Here, we systematically evaluate the role of different T cell differentiation and transfer protocols for EAE disease development and investigate the functional dynamics of encephalitogenic T cells directly within the inflamed central nervous system (CNS) tissue.
Methods
We compiled the currently used EAE induction protocols reported in literature and investigated the influence of the different Th1 and Th17 differentiation protocols as well as EAE induction protocols on the EAE disease course. Moreover, we assessed the cytokine profile and functional dynamics of both encephalitogenic Th1 and Th17 cells in the inflamed CNS using flow cytometry and intravital two-photon laser scanning microscopy. Lastly, we used astrocyte culture and adoptive transfer EAE to evaluate the impact of Th1 and Th17 cells on astrocyte adhesion molecule expression in vitro and in vivo.
Results
We show that EAE courses are highly dependent on in vitro differentiation and transfer protocols. Moreover, using genetically encoded reporter mice (B6.IL17A-EGFP.acRFP x 2d2/2d2.RFP), we show that the motility of interferon (IFN)γ-producing ex-Th17 cells more closely resembles Th1 cells than Th17 cells in transfer EAE. Mechanistically, IFNγ-producing Th1 cells selectively induce the expression of cellular adhesion molecules I-CAM1 while Th1 as well as ex-Th17 induce V-CAM1 on astrocytes.
Conclusions
The behavior of ex-Th17 cells in EAE lesions in vivo resembles Th1 rather than Th17 cells, underlining that their change in cytokine production is associated with functional phenotype alterations of these cells.
Abstract
Objective
Ongoing neuroaxonal damage is a major contributor to disease progression and long-term disability in multiple sclerosis. However, spatio-temporal distribution and ...pathophysiological mechanisms of neuroaxonal damage during acute relapses and later chronic disease stages remain poorly understood.
Methods
Here, we applied immunohistochemistry, single-molecule array, spatial transcriptomics, and microglia/axon co-cultures to gain insight into spatio-temporal neuroaxonal damage in experimental autoimmune encephalomyelitis (EAE).
Results
Association of spinal cord white matter lesions and blood-based neurofilament light (sNfL) levels revealed a distinct, stage-dependent anatomical pattern of neuroaxonal damage: in chronic EAE, sNfL levels were predominately associated with anterolateral lumbar lesions, whereas in early EAE sNfL showed no correlation with lesions in any anatomical location. Furthermore, neuroaxonal damage in late EAE was largely confined to white matter lesions but showed a widespread distribution in early EAE. Following this pattern of neuroaxonal damage, spatial transcriptomics revealed a widespread cyto- and chemokine response at early disease stages, whereas late EAE was characterized by a prominent glial cell accumulation in white matter lesions. These findings were corroborated by immunohistochemistry and microglia/axon co-cultures, which further revealed a strong association between CNS myeloid cell activation and neuroaxonal damage both in vivo and in vitro.
Interpretation
Our findings indicate that CNS myeloid cells may play a crucial role in driving neuroaxonal damage in EAE. Moreover, neuroaxonal damage can progress in a stage-dependent centripetal manner, transitioning from normal-appearing white matter to focal white matter lesions. These insights may contribute to a better understanding of neurodegeneration and elevated sNfL levels observed in multiple sclerosis patients at different disease stages.
Graphical Abstract
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