B-cell reconstitution and BAFF after alemtuzumab (Campath-1H) treatment of multiple sclerosis

Effectiveness of Autologous Hematopoietic Stem Cell Transplantation versus Alemtuzumab and Ocrelizumab in Relapsing Multiple Sclerosis: A Single Center Cohort Study

OBJECTIVE

To compare clinical and radiological outcomes among relapsing multiple sclerosis patients treated with autologous hematopoietic stem cell transplantation (AHSCT), alemtuzumab (ATZ), and ocrelizumab (OCR).

METHODS

From a London (UK) hospital-based observational cohort, modeled data were obtained from 621 relapsing-remitting multiple sclerosis patients, who were treated with AHSCT (n = 103), ATZ (n = 204), and OCR (n = 314), and were followed up for 43, 43, and 32 median months, respectively. The annualized relapse rate, new magnetic resonance imaging (MRI) lesions, and disability progression on Expanded Disability Status Scale were assessed.

RESULTS

AHSCT showed superior efficacy compared with ATZ and OCR. After 5-year follow up, the mean annualized relapse rate (0.026 vs 0.087; p < 0.001), the risk of relapses (HR 0.29, 95% CI 0.13-0.63; p = 0.002), and of MRI activity (HR 0.33, 95% CI 0.15-0.72; p = 0.006) were significantly lower in AHSCT versus ATZ group. Compared with OCR, after 3-year follow-up AHSCT showed a significantly lower annualized relapse rate (0.028 vs 0.073; p = 0.02) and a trend to reduced risk of relapse (HR 0.45, 95% CI 0.18-1.14; p = 0.09), but similar low rates (6%) of new MRI activity (HR 0.86, 95% CI 0.28-2.67; p = 0.80). In addition, there was a similar risk of Expanded Disability Status Scale progression in AHSCT, and both ATZ (HR 1.19, 95% CI 0.71-2.00; p = 0.50) and OCR (HR 1.08, 95% CI 0.57-2.04; p = 0.82) groups.

INTERPRETATION

AHSCT was followed by greater prevention of relapses compared with ATZ and OCR, and suppressed more profoundly MRI activity than ATZ, but similarly to OCR, albeit with shorter follow up. The risk of accumulating disability was similar among the treated groups. Studies with larger sample sizes and longer follow up may enable confirmation of these findings or detection of any additional differential effects. ANN NEUROL 2025.

Impact of High-Efficacy Therapies for Multiple Sclerosis on B Cells

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative autoimmune disorder of the central nervous system characterized by demyelination and neurodegeneration. Traditionally considered a T-cell-mediated disease, the crucial role of B lymphocytes in its pathogenesis, through different mechanisms contributing to inflammation and autoreactivity, is increasingly recognized. The risk of long-term disability in MS patients can be reduced by an early treatment initiation, in particular with high-efficacy therapies. The aim of this review is to provide an overview of the mechanisms of action of high-efficacy therapies for MS, with a focus on their impact on B cells and how this contributes to the drugs' efficacy and safety profiles. Anti-CD20 monoclonal antibodies, Alemtuzumab, Cladribine and sequestering therapies encompassing Natalizumab and S1P receptors modulators will be discussed and emerging therapies, including Bruton's Tyrosine Kinase inhibitors, will be presented.

Modulator of VRAC Current 1 Is a Potential Target Antigen in Multiple Sclerosis

BACKGROUND AND OBJECTIVES

Multiple sclerosis (MS) is a chronic immune-mediated demyelinating disease of the CNS. Highlighted by the success of B-cell-depleting therapies such as the monoclonal anti-CD20 antibodies rituximab, ocrelizumab, and ofatumumab, B cells have been shown to play a central role in the immunopathology of the disease. Yet, the target antigens of the pathogenic B-cell response in MS remain unclear.

METHODS

We combined polyclonal B-cell stimulation of peripheral blood mononuclear cells with a human proteome-wide protein microarray to identify target antigens of MS by comparing samples from 20 patients with MS with 9 age-matched and sex-matched healthy controls. Results were verified by enzyme-linked immunosorbent assay (ELISA) in 3 independent validation cohorts (N = 47 patients with MS in remission; N = 20 patients with MS during relapse; N = 25 HCs; N = 30 patients with other noninflammatory neurologic diseases; N = 9 patients with other inflammatory neurologic diseases). Experimental autoimmune encephalomyelitis (EAE) was used as an animal model to evaluate the pathogenicity of the antibodies of choice.

RESULTS

Our results corroborate the existing concept of a highly diverse autoimmune response in MS. Yet, a significantly elevated antibody response against the membrane protein modulator of VRAC current 1 (MLC1) was noted in B-cell culture supernatants and serum samples of patients with MS. Furthermore, significantly elevated titers to MLC1 were observed in the CSF of patients with neuroinflammatory diseases other than MS. Neurons and astrocytes were identified as the main cell types expressing MLC1 in the brain of a patient with MS. Injection of anti-MLC1 antibodies into mice with EAE led to strong in vivo binding to cerebral cortical neurons and to the death of 4 of the 7 injected mice.

DISCUSSION

Future studies will have to address the diagnostic and prognostic value of MLC1-specific antibodies in neuroinflammatory disorders such as MS and characterize the functional role of MLC1 expression in neurons and astrocytes.

TRIAL REGISTRATION INFORMATION

The study has been registered in the German Clinical Trials Register (study number DRKS00015528).

CSF biomarkers of B-cell activation in multiple sclerosis: a clinical perspective

The role of B cells in the pathophysiology of multiple sclerosis (MS) extends beyond antibody synthesis, also involving the modulation of T lymphocytes and myeloid cells. B-cell activation within the Central Nervous System is associated with the release of various antibodies, cytokines, and chemokines, measurable in biofluids, thereby serving as biomarkers of the immune processes responsible for MS. To this purpose, a biomarker-based characterization of the disease through the combination of well-established markers, e.g., immunoglobulin (Ig) G index, IgG oligoclonal bands, Ig free light chains, with new promising markers, namely chemokine (C-X-C motif) ligand 13, and B-cell activating factor/A proliferation-inducing ligand, might represent a significant improvement in the management of people with MS.

The immunological bases of alemtuzumab as induction-therapy in pediatric-onset multiple sclerosis

Pediatric-Onset Multiple Sclerosis (POMS) is characterized by both white and grey matter inflammation, as well as by a higher risk of long-term physical and cognitive disability. The peculiar immunopathogenic mechanisms of POMS suggests that the use of induction therapies, including alemtuzumab (ALTZ), might be a promising approach, at least for postpuberal (> 11 yo) POMS. Although no data on the use of induction therapies in POMS are available from clinical trials currently, case series or case reports on the effect of alemtuzumab (ALTZ) have been recently published. In this review we have briefly revised the immunopathogenic features of POMS, as well as on how ALTZ might impact on them, reporting its efficacy observed in different POMS cohorts.

The effect of alemtuzumab on neurodegeneration in relapsing-remitting multiple sclerosis: A five-year prospective mono-center study

BACKGROUND

Relapsing-remitting multiple sclerosis (RRMS) is an inflammatory and neurodegenerative disease. After two or more short courses of alemtuzumab (ALZ), an immune reconstitution is achieved, which long-term results in reduced disease activity. We aimed to investigate the effect of ALZ on measures of neurodegeneration (i.e., brain atrophy, and retinal layer thinning).

METHODS

We designed an observational prospective mono-center study in RRMS patients initiating ALZ treatment. Patients were assessed at baseline (month 0) and thereafter annually for five years with clinical measures, synthetic magnetic resonance imaging (SyMRI) and optical coherence tomography (OCT), with a re-baseline SyMRI scan and an OCT exam 24 months after initiating ALZ. Persons with neurological symptoms but without evidence of neurological disease served as symptomatic controls (SCs, n = 27).

RESULTS

Forty-nine RRMS patients were included. Baseline median expanded disability status scale [2.0 (IQR 1.5)] was unchanged during follow-up, 71 % were progression-free, 33 % achieved no evidence of disease activity-3 (NEDA-3). Between baseline and month 60, SyMRI showed a reduction of brain parenchymal fraction (BPF) and grey matter (GM) volume in patients. The BPF reduction was greater in RRMS patients than in SCs (p < 0.05), and more pronounced in patients with high pre-baseline disease activity than in those without (p < 0.01). OCT showed significant thinning of macular ganglion cell and inner plexiform layers (mGCIPL) and in peripapillary retinal nerve fiber layer (pRNFL) in patients. In contrast, absolute values of white matter (WM) volume and myelin content (MyC) quantified by SyMRI, were stable or increased after re-baseline (month 24) and up to month 60, and this increase appeared limited to patients without high pre-baseline disease activity and to patients with NEDA-3 or disability worsening during follow-up. A strong positive correlation between WM volume and GM volume at baseline was lost after ALZ intervention for their delta values, i.e., change from re-baseline (month 24) to month 60. While the positive baseline correlation between WM volume and MyC increased for their delta values, the positive baseline correlation between GM volume and MyC changed to negative for their delta values.

CONCLUSION

We showed that neurodegeneration continued in RRMS patients under ALZ treatment, but it appeared to be limited to BPF and GM, and more pronounced in patients with disease activity. Our data suggest that patients who respond to ALZ treatment show signs of remyelination. OCT and SyMRI have potential to quantify measures of neurodegeneration that is affected by treatment intervention in RRMS.

Effect of alemtuzumab over sNfL and sGFAP levels in multiple sclerosis

Introduction

Alemtuzumab is a highly effective pulsed immune reconstitution therapy for multiple sclerosis (MS).

Aim

To evaluate serum neurofilament light chain (sNfL) and serum glial fibrillary acidic protein (sGFAP) in patients with relapsing-remitting MS who have been treated with Alemtuzumab over the course of 2 years.

Methods

This prospective study involved MS patients treated with Alemtuzumab at a referral MS center. Both sNfL and sGFAP were analyzed at baseline and then again at 6, 12, and 24 months post-treatment using the single molecule array (SiMoA) technique. We also recruited matched healthy controls (HCs) for comparison.

Results

The study included 46 patients (with a median age of 34.2 [Interquartile range (IQR), 28.7-42.3] years, 27 of which were women [58%]) and 76 HCs. No differences in demographic characteristics were observed between patients and HC. The median disease duration was 6.22 (IQR, 1.56-10.13) years. The median annualized relapse rate before treatment was 2 (IQR, 1-3). At baseline, sNfL and sGFAP levels were higher in MS patients (median of 18.8 [IQR, 10.7-52.7] pg/ml and 158.9 [IQR, 126.9-255.5] pg/ml, respectively) when compared to HC (6.11 [IQR, 2.03-8.54] pg/ml and 91.0 [72.6-109] pg/ml, respectively) (p<0.001 for both comparisons). The data indicates that 80% of patients had high (≥10 pg/ml) sNfL values at baseline. We observed a significant decrease in sNfL levels at 6 (65%, p = 0.02), 12 (70.8%, p<0.001), and 24 (78.1%, p<0.001) months. sNfL reached similar levels to HC only after 24 months of Alemtuzumab treatment. During the follow-up period, no changes were identified in the sGFAP values.

Conclusion

Alemtuzumab leads to the normalization of sNfL values in MS patients after 2 years of treatment, with no apparent effect on sGFAP values.

Impact of Disease-Modifying Therapies on Gut-Brain Axis in Multiple Sclerosis

Multiple sclerosis is a chronic, autoimmune-mediated, demyelinating disease whose pathogenesis remains to be defined. In past years, in consideration of a constantly growing number of patients diagnosed with multiple sclerosis, the impacts of different environmental factors in the pathogenesis of the disease have been largely studied. Alterations in gut microbiome composition and intestinal barrier permeability have been suggested to play an essential role in the regulation of autoimmunity. Thus, increased efforts are being conducted to demonstrate the complex interplay between gut homeostasis and disease pathogenesis. Numerous results confirm that disease-modifying therapies (DMTs) used for the treatment of MS, in addition to their immunomodulatory effect, could exert an impact on the intestinal microbiota, contributing to the modulation of the immune response itself. However, to date, the direct influence of these treatments on the microbiota is still unclear. This review intends to underline the impact of DMTs on the complex system of the microbiota-gut-brain axis in patients with multiple sclerosis.

Alemtuzumab following natalizumab is more effective in adult-onset than paediatric-onset multiple sclerosis

Background

Paediatric-onset multiple sclerosis (POMS) therapeutic approach derives from of adult-onset multiple sclerosis (AOMS) tailored algorithms.

Objectives

To evaluate in a common clinical scenario the efficacy and safety of alemtuzumab (ALZ) in POMS and AOMS.

Methods

All patients switching from natalizumab (NTZ) to ALZ for safety concerns (high anti-John Cunningham Virus Antibody Index value, anti-JCV Index) were enrolled in this single-centre, retrospective, case-control open-label study.

Results

Ten POMS and 27 AOMS were followed up for 51.3 months. After month 12, we found a lower risk of clinical or radiological relapses among AOMS patients and among patients with older age at ALZ (both p < 0.05). Survival analysis revealed an increased risk of relapse in POMS compared with AOMS (logrank p = 0.00498) and patients starting ALZ before age 22.75 years than the elder ones (logrank p = 0.0018). Survival analysis did not disclose any difference between AOMS and POMS (logrank p = 0.27) in terms of progression independent of any relapse activity (PIRA). In addition, no evidence of relapse-associated worsening was observed. Autoimmune events were reported by 5 AOMS and no POMS (29.4% versus 0.0%, p = 0.057), and survival analysis was not significant (logrank p = 0.0786).

Conclusion

ALZ seems more effective in AOMS than in POMS following NTZ. These findings underrate ALZ effectiveness when shifting from NTZ in POMS.

Extended interval dosing of ocrelizumab modifies the repopulation of B cells without altering the clinical efficacy in multiple sclerosis

BACKGROUND

Recent studies suggest that extended interval dosing of ocrelizumab, an anti-B cell therapy, does not affect its clinical effectiveness in most patients with multiple sclerosis (MS). However, it remains to be established whether certain B cell subsets are differentially repopulated after different dosing intervals and whether these subsets relate to clinical efficacy.

METHODS

We performed high-dimensional single-cell characterization of the peripheral immune landscape of patients with MS after standard (SID; n = 43) or extended interval dosing (EID; n = 37) of ocrelizumab and in non-ocrelizumab-treated (control group, CG; n = 28) patients with MS, using mass cytometry by time of flight (CyTOF).

RESULTS

The first B cells that repopulate after both ocrelizumab dosing schemes were immature, transitional and regulatory CD1d+ CD5+ B cells. In addition, we observed a higher percentage of transitional, naïve and regulatory B cells after EID in comparison with SID, but not of memory B cells or plasmablasts. The majority of repopulated B cell subsets showed an increased migratory phenotype, characterized by higher expression of CD49d, CD11a, CD54 and CD162. Interestingly, after EID, repopulated B cells expressed increased CD20 levels compared to B cells in CG and after SID, which was associated with a delayed repopulation of B cells after a subsequent ocrelizumab infusion. Finally, the number of/changes in B cell subsets after both dosing schemes did not correlate with any relapses nor progression of the disease.

CONCLUSIONS

Taken together, our data highlight that extending the dosing interval of ocrelizumab does not lead to increased repopulation of effector B cells. We show that the increase of CD20 expression on B cell subsets in EID might lead to longer depletion or less repopulation of B cells after the next infusion of ocrelizumab. Lastly, even though extending the ocrelizumab interval dosing alters B cell repopulation, it does not affect the clinical efficacy of ocrelizumab in our cohort of patients with MS.

A five-year observational prospective mono-center study of the efficacy of alemtuzumab in a real-world cohort of patients with multiple sclerosis

Background

Alemtuzumab (ALZ) is a pulsed immune reconstitution therapy for multiple sclerosis (MS).

Objective

To assess basic characteristics, therapeutic effects, and prognostic biomarkers on clinical and imaging parameters of disease activity for relapsing-remitting MS (RRMS) patients selected for ALZ, in a real-world long-term setting.

Methods

Fifty-one RRMS patients [female = 31; mean age 36 (standard deviation 7.1) years; median expanded disability status scale (EDSS) 2 (interquartile range (IQR) 1.5)] initiating ALZ treatment, were consecutively included. Patients were assessed at baseline and thereafter annually for 5 years with clinical measures, symbol digit modality test (SDMT), and magnetic resonance imaging (MRI). Concentrations of glial fibrillary acidic protein (GFAP), reflecting astrogliosis, and neurofilament light (NfL), reflecting axonal damage, were measured in cerebrospinal fluid (CSF) and serum samples collected at baseline and after 2 years in CSF, and annually in serum. Control subjects were symptomatic controls (SCs, n = 27), who were examined at baseline and after 5 years without evidence of neurological disease.

Results

While the mean annualized relapse rate was significantly reduced from baseline at each year of follow-up, disability was essentially maintained at a median EDSS of 1.5 and IQR between 1.13 and 2.25. New MRI activity was recorded in 26 patients (53%) over 5 years. The proportion of patients who achieved no evidence of disease activity (NEDA-3), 6-months confirmed disability worsening (CDW), and 6-months confirmed disability improvement (CDI) at 5 years were 33, 31, and 31%, respectively. The SDMT score was reduced for patients (p < 0.001), but unchanged for SCs. ALZ treatment did not change GFAP levels, whereas there was a significant decrease for RRMS patients in median CSF and serum NfL levels at follow-up [CSF month 24: 456 pg./mL (IQR 285.4) (p = 0.05); serum month 24: 6.7 pg/mL (IQR 4.7) (p < 0.01); serum month 60: 7.2 pg/mL (IQR 4.7) (p < 0.01)], compared to baseline [CSF: 1014 pg/mL (IQR 2832.5); serum 8.6 pg/mL (IQR 17.4)].

Conclusion

In this real-world mono-center population, we observed a progression-free survival of 69%, cumulative NEDA-3 of 33%, and reduced NfL levels, over a five-year follow-up. This confirms ALZ as an effective pulsed immune reconstitution therapy that significantly reduces neuro axonal loss, and therefore has the potential to reduce long-term neurological disability. ALZ did not appear to affect astrogliosis.

Clinical relevance of thymic and bone marrow outputs in multiple sclerosis patients treated with alemtuzumab

Thymic and bone marrow outputs were evaluated in 13 sequential samples of 68 multiple sclerosis patients who initiated alemtuzumab and were clinically followed for 48 months. Three months after alemtuzumab infusions, the levels of new T lymphocytes were significantly reduced, but progressively increased reaching the highest values at 36 months, indicating the remarkable capacity of thymic function recovery. Newly produced B cells exceeded baseline levels as early as 3 months after alemtuzumab initiation. Heterogeneous patterns of new T- and B-cell recovery were identified, but without associations with age, sex, previous therapies, development of secondary autoimmunity or infections, and disease re-emergence. Trial registration version 2.0-27/01/2016.

Transcriptome alterations in peripheral blood B cells of patients with multiple sclerosis receiving immune reconstitution therapy

BACKGROUND

Multiple sclerosis (MS) is a chronic, inflammatory and neurodegenerative disease that leads to irreversible damage to the brain and spinal cord. The goal of so-called "immune reconstitution therapies" (IRTs) is to achieve long-term disease remission by eliminating a pathogenic immune repertoire through intense short-term immune cell depletion. B cells are major targets for effective immunotherapy in MS.

OBJECTIVES

The aim of this study was to analyze the gene expression pattern of B cells before and during IRT (i.e., before B-cell depletion and after B-cell repopulation) to better understand the therapeutic effects and to identify biomarker candidates of the clinical response to therapy.

METHODS

B cells were obtained from blood samples of patients with relapsing-remitting MS (n = 50), patients with primary progressive MS (n = 13) as well as healthy controls (n = 28). The patients with relapsing MS received either monthly infusions of natalizumab (n = 29) or a pulsed IRT with alemtuzumab (n = 15) or cladribine (n = 6). B-cell subpopulation frequencies were determined by flow cytometry, and transcriptome profiling was performed using Clariom D arrays. Differentially expressed genes (DEGs) between the patient groups and controls were examined with regard to their functions and interactions. We also tested for differences in gene expression between patients with and without relapse following alemtuzumab administration.

RESULTS

Patients treated with alemtuzumab or cladribine showed on average a > 20% lower proportion of memory B cells as compared to before IRT. This was paralleled by profound transcriptome shifts, with > 6000 significant DEGs after adjustment for multiple comparisons. The top DEGs were found to regulate apoptosis, cell adhesion and RNA processing, and the most highly connected nodes in the network of encoded proteins were ESR2, PHB and RC3H1. Higher mRNA levels of BCL2, IL13RA1 and SLC38A11 were seen in patients with relapse despite IRT, though these differences did not pass the false discovery rate correction.

CONCLUSIONS

We show that B cells circulating in the blood of patients with MS undergoing IRT present a distinct gene expression signature, and we delineated the associated biological processes and gene interactions. Moreover, we identified genes whose expression may be an indicator of relapse risk, but further studies are needed to verify their potential value as biomarkers.

Continued dysregulation of the B cell lineage promotes multiple sclerosis activity despite disease modifying therapies

A clear understanding of the origin and role of the different subtypes of the B cell lineage involved in the activity or remission of multiple sclerosis (MS) is important for the treatment and follow-up of patients living with this disease. B cells, however, are dynamic and can play an anti-inflammatory or pro-inflammatory role, depending on their milieu. Depletion of B cells has been effective in controlling the progression of MS, but it can have adverse side effects. A better understanding of the role of the B cell subtypes, through the use of surface biomarkers of cellular activity with special attention to the function of memory and other regulatory B cells (Bregs), will be necessary in order to offer specific treatments without inducing undesirable effects.

The emerging role of regulatory cell-based therapy in autoimmune disease

Autoimmune disease, caused by unwanted immune responses to self-antigens, affects millions of people each year and poses a great social and economic burden to individuals and communities. In the course of autoimmune disorders, including rheumatoid arthritis, systemic lupus erythematosus, type 1 diabetes mellitus, and multiple sclerosis, disturbances in the balance between the immune response against harmful agents and tolerance towards self-antigens lead to an immune response against self-tissues. In recent years, various regulatory immune cells have been identified. Disruptions in the quality, quantity, and function of these cells have been implicated in autoimmune disease development. Therefore, targeting or engineering these cells is a promising therapeutic for different autoimmune diseases. Regulatory T cells, regulatory B cells, regulatory dendritic cells, myeloid suppressor cells, and some subsets of innate lymphoid cells are arising as important players among this class of cells. Here, we review the roles of each suppressive cell type in the immune system during homeostasis and in the development of autoimmunity. Moreover, we discuss the current and future therapeutic potential of each one of these cell types for autoimmune diseases.

Targeting B cell dysregulation with emerging therapies in autoimmune demyelinating disorders

The depletion of B cells has proven to be beneficial in the treatment of autoimmune demyelinating disorders. The high efficacy of these therapies has highlighted the importance of B cells in autoimmunity and prompted investigations into specific B cell subsets that may be aberrant. Recently, a rise in the trialling of alternative B cell-targeting therapies that inhibit targets such as Bruton's tyrosine kinase, interleukin-6 receptor and fragment crystallisable neonatal receptor has also been observed. These agents interfere with specific dysregulated functions of B cells in contrast to the broad removal of many B cell subsets with depletion agents. The therapeutic benefit of these emerging agents will help delineate the contributions of B cells in demyelinating disorders and holds great potential for future treatment.

Specific Patterns of Immune Cell Dynamics May Explain the Early Onset and Prolonged Efficacy of Cladribine Tablets: A MAGNIFY-MS Substudy

BACKGROUND AND OBJECTIVES

Cladribine tablets cause a reduction in lymphocytes with a predominant effect on B-cell and T-cell counts. The MAGNIFY-MS substudy reports the dynamic changes on multiple peripheral blood mononuclear cell (PBMC) subtypes and immunoglobulin (Ig) levels over 12 months after the first course of cladribine tablets in patients with highly active relapsing multiple sclerosis (MS).

METHODS

Immunophenotyping was performed at baseline (predose) and at the end of months 1, 2, 3, 6, and 12 after initiating treatment with cladribine tablets. Assessments included lymphocyte subtype counts of CD19⁺ B cells, CD4⁺ and CD8⁺ T cells, CD16⁺ natural killer cells, plasmablasts, and Igs. Immune cell subtypes were analyzed by flow cytometry, and serum IgG and IgM were analyzed by nephelometric assay. Absolute cell counts and percentage change from baseline were assessed.

RESULTS

The full analysis set included 57 patients. Rapid reductions in median CD19⁺, CD20⁺, memory, activated, and naive B-cell counts were detected, reaching nadir by month 2. Thereafter, total CD19⁺, CD20⁺, and naive B-cell counts subsequently reconstituted, but memory B cells remained reduced by 93%-87% for the remainder of the study. The decrease in plasmablasts was slower, reaching nadir at month 3. Decrease in T-cell subtypes was also slower and more moderate compared with B-cell subtypes, reaching nadir between months 3 and 6. IgG and IgM levels remained within the normal range over the 12-month study period.

DISCUSSION

Cladribine tablets induce a specific pattern of early and sustained PBMC subtype dynamics in the absence of relevant Ig changes: While total B cells were reduced dramatically, T cells were affected significantly less. Naive B cells recovered toward baseline, naive CD4 and CD8 T cells did not, and memory B cells remained reduced. The results help to explain the unique immune depletion and repopulation architecture regarding onset of action and durability of effects of cladribine tablets while largely maintaining immune competence.

TRIAL REGISTRATION INFORMATION

ClinicalTrials.gov Identifier: NCT03364036. Date registered: December 06, 2017.

Antibody-mediated cell depletion therapies in multiple sclerosis

Development of disease-modifying therapies including monoclonal antibody (mAb)-based therapeutics for the treatment of multiple sclerosis (MS) has been extremely successful over the past decades. Most of the mAb-based therapies approved for MS deplete immune cell subsets and act through activation of cellular Fc-gamma receptors expressed by cytotoxic lymphocytes and phagocytes, resulting in antibody-dependent cellular cytotoxicity or by initiation of complement-mediated cytotoxicity. The therapeutic goal is to eliminate pathogenic immune cell components and to potentially foster the reconstitution of a new and healthy immune system. Ab-mediated immune cell depletion therapies include the CD52-targeting mAb alemtuzumab, CD20-specific therapeutics, and new Ab-based treatments which are currently being developed and tested in clinical trials. Here, we review recent developments in effector mechanisms and clinical applications of Ab-based cell depletion therapies, compare their immunological and clinical effects with the prototypic immune reconstitution treatment strategy, autologous hematopoietic stem cell transplantation, and discuss their potential to restore immunological tolerance and to achieve durable remission in people with MS.

Peripheral B-cell dysregulation is associated with relapse after long-term quiescence in patients with multiple sclerosis

B cells play a major role in multiple sclerosis (MS), with many successful therapeutics capable of removing them from circulation. One such therapy, alemtuzumab, is thought to reset the immune system without the need for ongoing therapy in a proportion of patients. The exact cells contributing to disease pathogenesis and quiescence remain to be identified. We utilized mass cytometry to analyze B cells from the blood of patients with relapse-remitting MS (RRMS) before and after alemtuzumab treatment, and during relapse. A complementary RRMS cohort was analyzed by single-cell RNA sequencing. The R package "Spectre" was used to analyze these data, incorporating FlowSOM clustering, sparse partial least squares-discriminant analysis and permutational multivariate analysis of variance. Immunoglobulin (Ig)A+ and IgG1 + B-cell numbers were altered, including higher IgG1 + B cells during relapse. B-cell linker protein (BLNK), CD40 and CD210 expression by B cells was lower in patients with RRMS compared with non-MS controls, with similar results at the transcriptomic level. Finally, alemtuzumab restored BLNK, CD40 and CD210 expression by IgA+ and IgG1 + B cells, which was altered again during relapse. These data suggest that impairment of IgA+ and IgG1 + B cells may contribute to MS pathogenesis, which can be restored by alemtuzumab.

Implication of genetic variants in primary microRNA processing sites in the risk of multiple sclerosis

Background

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system with a well-established genetic contribution to susceptibility. Over 200 genetic regions have been linked to the inherited risk of developing MS, but the disease-causing variants and their functional effects at the molecular level are still largely unresolved. We hypothesised that MS-associated single-nucleotide polymorphisms (SNPs) affect the recognition and enzymatic cleavage of primary microRNAs (pri-miRNAs).

Methods

Our study focused on 11 pri-miRNAs (9 primate-specific) that are encoded in genetic risk loci for MS. The levels of mature miRNAs and potential isoforms (isomiRs) produced from those pri-miRNAs were measured in B cells obtained from the peripheral blood of 63 MS patients and 28 healthy controls. We tested for associations between SNP genotypes and miRNA expression in cis using quantitative trait locus (cis-miR-eQTL) analyses. Genetic effects on miRNA stem-loop processing efficiency were verified using luciferase reporter assays. Potential direct miRNA target genes were identified by transcriptome profiling and computational binding site assessment.

Findings

Mature miRNAs and isomiRs from hsa-mir-26a-2, hsa-mir-199a-1, hsa-mir-4304, hsa-mir-4423, hsa-mir-4464 and hsa-mir-4492 could be detected in all B-cell samples. When MS patient subgroups were compared with healthy controls, a significant differential expression was observed for miRNAs from the 5’ and 3’ strands of hsa-mir-26a-2 and hsa-mir-199a-1. The cis-miR-eQTL analyses and reporter assays pointed to a slightly more efficient Drosha-mediated processing of hsa-mir-199a-1 when the MS risk allele T of SNP rs1005039 is present. On the other hand, the MS risk allele A of SNP rs817478, which substitutes the first C in a CNNC sequence motif, was found to cause a markedly lower efficiency in the processing of hsa-mir-4423. Overexpression of hsa-mir-199a-1 inhibited the expression of 60 protein-coding genes, including IRAK2, MIF, TNFRSF12A and TRAF1. The only target gene identified for hsa-mir-4423 was TMEM47.

Interpretation

We found that MS-associated SNPs in sequence determinants of pri-miRNA processing can affect the expression of mature miRNAs. Our findings complement the existing literature on the dysregulation of miRNAs in MS. Further studies on the maturation and function of miRNAs in different cell types and tissues may help to gain a more detailed functional understanding of the genetic basis of MS.

Funding

This study was funded by the Rostock University Medical Center (FORUN program, grant: 889002), Sanofi Genzyme (grant: GZ-2016-11560) and Merck Serono GmbH (Darmstadt, Germany, an affiliate of Merck KGaA, CrossRef Funder ID: 10.13039/100009945, grant: 4501860307). NB was supported by the Stiftung der Deutschen Wirtschaft (sdw) and the FAZIT foundation. EP was supported by the Landesgraduiertenförderung Mecklenburg-Vorpommern.

Objectively assessed physiological, physical, and cognitive function along with patient-reported outcomes during the first 2 years of Alemtuzumab treatment in multiple sclerosis: a prospective observational study

INTRODUCTION

In persons with multiple sclerosis (pwMS), little evidence exist on the effects of Alemtuzumab on physiological, physical, and cognitive function along with patient-reported outcomes, despite these domains are being rated as highly important. Therefore, our purpose was to perform a prospective observational study to examine these outlined outcomes during the first two years of Alemtuzumab treatment in pwMS.

METHODS

In n = 17 relapsing-remitting pwMS, physiological function [body composition; bone mineral content; muscle strength; aerobic capacity], physical function [6-min walk test (6MWT, primary outcome); timed 25 ft walk test (T25FWT); six spot step test (SSST); 9-step stair ascend (9SSA); timed up and go test (TUG); 5 × sit to stand test (5STS)], cognitive function [selective reminding test (SRT); symbol digit modalities test (SDMT)], and patient-reported outcomes [multiple sclerosis impact scale-29 (MSIS29); 12-item multiple sclerosis walking scale (MSWS12); modified fatigue impact scale (MFIS); hospital anxiety and depression scale (HADS)] were assessed prior to Alemtuzumab treatment initiation as well as 3, 6, 12, and 24 months into the treatment.

RESULTS

Improvements were observed at 24-month follow-up in T25FWT (+ 8%), SSST (+ 10%), SDMT (+ 5.2 points, 53% improved more than the clinical cut-off score) and SRT, whereas the primary outcome 6MWT, and all other remaining outcomes, remained stable throughout the Alemtuzumab treatment period.

CONCLUSION

The present findings suggest that Alemtuzumab treatment in relapsing-remitting pwMS can improve certain domains of physical function (short distance walking) and cognitive function (processing speed, memory), and furthermore stabilize physiological and physical function along with patient-reported outcomes.

TRIAL REGISTRATION

Registered at clinicaltrials.gov: NCT03806387.

Monoclonal Antibodies in the Treatment of Relapsing Multiple Sclerosis: an Overview with Emphasis on Pregnancy, Vaccination, and Risk Management

Monoclonal antibodies have become a mainstay in the treatment of patients with relapsing multiple sclerosis (RMS) and provide some benefit to patients with primary progressive MS. They are highly precise by specifically targeting molecules displayed on cells involved in distinct immune mechanisms of MS pathophysiology. They not only differ in the target antigen they recognize but also by the mode of action that generates their therapeutic effect. Natalizumab, an [Formula: see text]4[Formula: see text]1 integrin antagonist, works via binding to cell surface receptors, blocking the interaction with their ligands and, in that way, preventing the migration of leukocytes across the blood-brain barrier. On the other hand, the anti-CD52 monoclonal antibody alemtuzumab and the anti-CD20 monoclonal antibodies rituximab, ocrelizumab, ofatumumab, and ublituximab work via eliminating selected pathogenic cell populations. However, potential adverse effects may be serious and can necessitate treatment discontinuation. Most importantly, those are the risk for (opportunistic) infections, but also secondary autoimmune diseases or malignancies. Monoclonal antibodies also carry the risk of infusion/injection-related reactions, primarily in early phases of treatment. By careful patient selection and monitoring during therapy, the occurrence of these potentially serious adverse effects can be minimized. Monoclonal antibodies are characterized by a relatively long pharmacologic half-life and pharmacodynamic effects, which provides advantages such as permitting infrequent dosing, but also creates disadvantages regarding vaccination and family planning. This review presents an overview of currently available monoclonal antibodies for the treatment of RMS, including their mechanism of action, efficacy and safety profile. Furthermore, we provide practical recommendations for risk management, vaccination, and family planning.

Alemtuzumab for refractory primary systemic vasculitis-a randomised controlled dose ranging clinical trial of efficacy and safety (ALEVIATE)

Background

Primary systemic vasculitis (PSV) is a heterogeneous group of autoimmune conditions. There is an unmet need for alternative therapies that lead to sustained remission in patients with refractory disease. Alemtuzumab, an anti-CD52 antibody, depletes lymphocytes for prolonged periods and, in retrospective studies, has induced sustained, treatment-free remissions in patients with refractory/relapsing vasculitis but has raised safety concerns of infection and secondary autoimmunity. This phase IIb clinical trial aimed to assess the efficacy and safety of alemtuzumab, at two different doses, in inducing remission in refractory vasculitis patients.

Methods

The ALEVIATE trial was a randomised, prospective, open-label, dose ranging clinical trial. Patients with refractory ANCA-associated vasculitis (AAV) or Behçet’s disease (BD) were randomised to receive either 60 mg or 30 mg alemtuzumab. Treatments were administered at baseline and 6 months or earlier where clinically appropriate. A maximum of three treatments were allowed within the 12-month study period.

Results

Twenty-three patients received at least one dose of alemtuzumab. Twelve had AAV, and 11 a diagnosis of BD. The median age was 40 years (range 28–44), with a prior disease duration of 61 months (42–103). Sixteen (70%) achieved either complete (6/23, 26%) or partial (10/23, 44%) response at 6 months. Eight (35%) maintained remission to the end of the trial without relapse. Ten severe adverse events were observed in 7 (30%) patients; 4 were related to alemtuzumab. There were no differences in clinical endpoints between the 60 and 30 mg alemtuzumab treatment groups.

Conclusion

In a selected group of refractory vasculitis patients, alemtuzumab led to remission in two thirds of patients at 6 months. Remission was maintained to 12 months in a third of the patients, and the safety profile was acceptable.

Trial registration

ClinicalTrials.gov identifier: NCT01405807, EudraCT Number: 2009-017087-17. Registered on April 07, 2011.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02761-6.

Experimental laboratory biomarkers in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a chronic autoimmune disorder of the central nervous system; the cause of this condition remains unknown. Researchers have analyzed different biomarkers related to MS. Here, experimental laboratory biomarkers for MS are identified and analyzed.

METHODS

The current study examined articles investigating biomarkers for MS. Records were obtained from the PubMed, LILACS, and EBSCO databases using an identical search strategy and terms that included "multiple sclerosis," "MS," and "biomarkers." In the current review, we also focus on lesser known biomarkers that have not yet been established for use in clinical practice.

RESULTS

Previous studies have explored molecular substances that may help diagnose MS and manage its adverse effects. Commonly studied factors include neurofilaments, sCD163, CXCL13, NEO, NF‑L, OPN, B cells, T cells, and integrin-binding proteins.

CONCLUSIONS

Interactions between environmental and genetic factors have been implicated in the development of MS. Previous investigations have identified a wide range of biomarkers that can be used for diagnosis and disease management. These molecules and their associated studies provide vital insight and data to help primary physicians improve clinical and health outcomes for MS patients.

Regulatory B Cell Therapy in Kidney Transplantation

In the context of kidney injury, the role of Bregs is gaining interest. In a number of autoimmune diseases, the number and/or the function of Bregs has been shown to be impaired or downregulated, therefore restoring their balance might be a potential therapeutic tool. Moreover, in the context of kidney transplantation their upregulation has been linked to tolerance. However, a specific marker or set of markers that define Bregs as a unique cell subset has not been found and otherwise multiple phenotypes of Bregs have been studied. A quest on the proper markers and induction mechanisms is now the goal of many researchers. Here we summarize the most recent evidence on the role of Bregs in kidney disease by describing the relevance of in vitro and in vivo Bregs induction as well as the potential use of Bregs as cell therapy agents in kidney transplantation.

Treatment With CD52 Antibody Protects Neurons in Experimental Autoimmune Encephalomyelitis Mice During the Recovering Phase

Multiple sclerosis (MS) is a chronic autoimmune disease driven by T and B lymphocytes. The remyelination failure and neurodegeneration results in permanent clinical disability in MS patients. A desirable therapy should not only modulate the immune system, but also promote neuroprotection and remyelination. To investigate the neuroprotective effect of CD52 antibody in MS, both C57BL/6J and SJL mice with experimental autoimmune encephalomyelitis (EAE) were treated with CD52 antibody at the peak of disease. Treatment with CD52 antibody depleted T but not B lymphocytes in the blood, reduced the infiltration of T lymphocytes and microglia/macrophages in the spinal cord. Anti-CD52 therapy attenuated EAE scores during the recovery phase. It protected neurons immediately after treatment (within 4 days) as shown by reducing the accumulation of amyloid precursor proteins. It potentially promoted remyelination as it increased the number of olig2/CC-1-positive mature oligodendrocytes and prevented myelin loss in the following days (e.g., 14 days post treatment). In further experiments, EAE mice with a conditional knockout of BDNF in neurons were administered with CD52 antibodies. Neuronal deficiency of BDNF attenuated the effect of anti-CD52 treatment on reducing EAE scores and inflammatory infiltration but did not affect anti-CD52 treatment-induced improvement of myelin coverage in the spinal cord. In summary, anti-CD52 therapy depletes CD4-positive T lymphocytes, prevents myelin loss and protects neurons in EAE mice. Neuronal BDNF regulates neuroprotective and anti-inflammatory effect of CD52 antibody in EAE mice.

Efficacy and safety of alemtuzumab treatment in a real-world cohort of patients with multiple sclerosis

Alemtuzumab is a monoclonal anti-CD52 antibody prescribed to treat relapsing-remitting multiple sclerosis (RRMS). Alemtuzumab affects the balance of the immune system by depleting circulating lymphocytes, leading to the formation of a new immune repertoire less likely to induce autoimmune attack against CNS myelin. We collected real-world data of RRMS patients treated with alemtuzumab. We assessed relapse rate, disability progression, and MRI-related disease activity over a 24 month period. Our study included 35 RRMS patients (19 female and 16 male) with a mean age of 37.3 years (SD = 10.5). The patient cohort had a mean disease duration of 10.4 years, median previous disease modifying treatments (DMTs) of 3.0, and a median expanded disability status scale (EDSS) score of 4.0 (IQR 2.5-6.0). Neurological disability remained stable during treatment and there was no statistically significant change in EDSS score. Prior to treatment, the median relapse rate was 2.0 (IQR 1.0-3.0); after treatment the median relapse rate was 0.0. This 2.0 decrease in relapse rate is statistically significant (p < 0.0001). Moreover, the treated patients exhibited a statistically significant decrease in gadolinium (GD) enhancing lesions on MRI [both in number (p < 0.005) and volume (p < 0.005)]. Thirty-three percent of patients reached NEDA-3 (no evidence of disease activity) status by the end of treatment. In a real-world setting, alemtuzumab treatment significantly decreased relapse rate and GD-enhancing lesions while preventing disability progression. Tolerability of treatment was high, with patients experiencing only minor adverse events.

Anti-CD52 antibody treatment in murine experimental autoimmune encephalomyelitis induces dynamic and differential modulation of innate immune cells in peripheral immune and central nervous systems

Anti‐CD52 antibody (anti‐CD52‐Ab) leads to a rapid depletion of T and B cells, followed by reconstitution of immune cells with tolerogenic characteristics. However, very little is known about its effect on innate immune cells. In this study, experimental autoimmune encephalomyelitis mice were administered murine anti‐CD52‐Ab to investigate its effect on dendritic cells and monocytes/macrophages in the periphery lymphoid organs and the central nervous system (CNS). Our data show that blood and splenic innate immune cells exhibited significantly increased expression of MHC‐II and costimulatory molecules, which was associated with increased capacity of activating antigen‐specific T cells, at first day but not three weeks after five daily treatment with anti‐CD52‐Ab in comparison with controls. In contrast to the periphery, microglia and infiltrating macrophages in the CNS exhibited reduced expression levels of MHC‐II and costimulatory molecules after antibody treatment at both time‐points investigated when compared to controls. Furthermore, the transit response of peripheral innate immune cells to anti‐CD52‐Ab treatment was also observed in the lymphocyte‐deficient SCID mice, suggesting the changes are not a direct consequence of the mass depletion of lymphocytes in the periphery. Our study demonstrates a dynamic and tissue‐specific modulation of the innate immune cells in their phenotype and function following the antibody treatment. The findings of differential modulation of the microglia and infiltrating macrophages in the CNS in comparison with the innate immune cells in the peripheral organs support the CNS‐specific beneficial effect of alemtuzumab treatment on inhibiting neuroinflammation in multiple sclerosis patients.

Immune Regulatory Cell Bias Following Alemtuzumab Treatment in Relapsing-Remitting Multiple Sclerosis

Alemtuzumab is a highly effective treatment for relapsing-remitting multiple sclerosis. It selectively targets the CD52 antigen to induce profound lymphocyte depletion, followed by recovery of T and B cells with regulatory phenotypes. We previously showed that regulatory T cell function is restored with cellular repletion, but little is known about the functional capacity of regulatory B-cells and peripheral blood monocytes during the repletion phase. In this study (ClinicalTrials.gov ID# NCT03647722) we simultaneously analyzed the change in composition and function of both regulatory lymphocyte populations and distinct monocyte subsets in cross-sectional cohorts of MS patients prior to or 6, 12, 18, 24 or 36 months after their first course of alemtuzumab treatment. We found that the absolute number and percentage of cells with a regulatory B cell phenotype were significantly higher after treatment and were positivity correlated with regulatory T cells. In addition, B cells from treated patients secreted higher levels of IL-10 and BDNF, and inhibited the proliferation of autologous CD4⁺CD25^- T cell targets. Though there was little change in monocytes populations overall, following the second annual course of treatment, CD14⁺ monocytes had a significantly increased anti-inflammatory bias in cytokine secretion patterns. These results confirmed that the immune system in alemtuzumab-treated patients is altered in favor of a regulatory milieu that involves expansion and increased functionality of multiple regulatory populations including B cells, T cells and monocytes. Here, we showed for the first time that functionally competent regulatory B cells re-appear with similar kinetics to that of regulatory T-cells, whereas the change in anti-inflammatory bias of monocytes does not occur until after the second treatment course. These findings justify future studies of all regulatory cell types following alemtuzumab treatment to reveal further insights into mechanisms of drug action, and to identify key immunological predictors of durable clinical efficacy in alemtuzumab-treated patients.

Lymphocyte Counts and Multiple Sclerosis Therapeutics: Between Mechanisms of Action and Treatment-Limiting Side Effects

Although the detailed pathogenesis of multiple sclerosis (MS) is not completely understood, a broad range of disease-modifying therapies (DMTs) are available. A common side effect of nearly every MS therapeutic agent is lymphopenia, which can be both beneficial and, in some cases, treatment-limiting. A sound knowledge of the underlying mechanism of action of the selected agent is required in order to understand treatment-associated changes in white blood cell counts, as well as monitoring consequences. This review is a comprehensive summary of the currently available DMTs with regard to their effects on lymphocyte count. In the first part, we describe important general information about the role of lymphocytes in the course of MS and the essentials of lymphopenic states. In the second part, we introduce the different DMTs according to their underlying mechanism of action, summarizing recommendations for lymphocyte monitoring and definitions of lymphocyte thresholds for different therapeutic regimens.

Role of B Cell Profile for Predicting Secondary Autoimmunity in Patients Treated With Alemtuzumab

Objective

To explore if baseline blood lymphocyte profile could identify relapsing remitting multiple sclerosis (RRMS) patients at higher risk of developing secondary autoimmune adverse events (AIAEs) after alemtuzumab treatment.

Methods

Multicenter prospective study including 57 RRMS patients treated with alemtuzumab followed for 3.25 [3.5-4.21] years, (median [interquartile range]). Blood samples were collected at baseline, and leukocyte subsets determined by flow cytometry. We had additional samples one year after the first cycle of alemtuzumab treatment in 39 cases.

Results

Twenty-two patients (38.6%) developed AIAEs during follow-up. They had higher B-cell percentages at baseline (p=0.0014), being differences mainly due to plasmablasts/plasma cells (PB/PC, p=0.0011). Those with no AIAEs had higher percentages of CD4+ T cells (p=0.013), mainly due to terminally differentiated (TD) (p=0.034) and effector memory (EM) (p=0.031) phenotypes. AIAEs- patients also showed higher values of TNF-alpha-producing CD8+ T cells (p=0.029). The percentage of PB/PC was the best variable to differentiate both groups of patients. Baseline values >0.10% closely associated with higher AIAE risk (Odds ratio [OR]: 5.91, 95% CI: 1.83-19.10, p=0.004). When excluding the 12 patients with natalizumab, which decreases blood PB/PC percentages, being the last treatment before alemtuzumab, baseline PB/PC >0.1% even predicted more accurately the risk of AIAEs (OR: 11.67, 95% CI: 2.62-51.89, p=0.0007). The AIAEs+ group continued having high percentages of PB/PC after a year of alemtuzumab treatment (p=0.0058).

Conclusions

A PB/PC percentage <0.1% at baseline identifies MS patients at low risk of secondary autoimmunity during alemtuzumab treatment.​

Product review on MAbs (alemtuzumab and ocrelizumab) for the treatment of multiple sclerosis

Traditionally, the management of active relapsing remitting MS was based on the, so-called, maintenance therapy, which is characterized by continuous treatment with particular disease modifying therapy (DMT), and a return of disease activity when the drug is discontinued. Another approach is characterized by a short treatment course of a DMT, which is hypothesized to act as an immune reconstitution therapy (IRT), with the potential to protect against relapses for years after a short course of treatment. Introduction of monoclonal antibodies in the treatment of MS has revolutionized MS treatment in the last decade. However, given the increasingly complex landscape of DMTs approved for MS, people with MS and neurologists are constantly faced with the question which DMT is the most appropriate for the given patient, a question we still do not have an answer to. In this product review, we will discuss the first DMT that acts as IRT, an anti-CD52 monoclonal antibody alemtuzumab and an anti CD20 monoclonal antibody, ocrelizumab that has the potential to act as an IRT, but is administered continuously. Special emphasis will be given on safety in the context of COVID-19 pandemics and vaccination strategies.

HUMORAL RESPONSE TO SARS-CoV-2 AND COVID-19 VACCINES IN PATIENTS WITH MULTIPLE SCLEROSIS TREATED WITH IMMUNE RECONSTITUTION THERAPIES

Background

It has been generally accepted that people with MS (PwMS) should be vaccinated against COVID-19. The aim of our investigation was to evaluate the humoral response to natural SARS-CoV-2 infection and to two COVID-19 vaccines (BNT162b2 Pfizer-BioNTech and Beijing/Sinopharm BBIBP-CorV) in our cohort of PwMS under high efficacy disease modifying therapies (DMTs), cladribine and alemtuzumab.

Methods

Twenty two PwMS treated at the Clinic of Neurology, in Belgrade, who developed COVID-19 and/or were vaccinated against SARS-CoV-2, during treatment with cladribine and alemtuzumab, were included. Out of 18 patients treated with cladribine, 11 developed COVID-19, and 11 were vaccinated against SARS-CoV-2 (four with mRNA vaccine, 7 with Sinopharm). Four MS patients under alemtuzumab were vaccinated against SARS-CoV-2; three with mRNA, and one with Sinopharm vaccine. SARS-Cov-2 IgG response was measured using ELISA anti-spike protein-based serology (INEP, Belgrade, Serbia).

Results

All 7 patients under cladribine treatment who suffered from COVID-19, developed IgG antibodies, 2.0-5.5 months after last symptoms. All four (100%) patients under cladribine who were vaccinated with Pfizer-BioNTech vaccine, and three out of seven (42.9%) vaccinated with Sinopharm, developed antibodies. All 4 patients under alemtuzumab developed antibodies after vaccination. In all cases, seroprotection occurred, irrespective of timing of vaccination and absolute lymphocyte count.

Conclusion

Our findings in a small number of highly active PwMS in whom, lymphodepleting, immune reconstitution therapies, were applied in order to successfully manage MS, indicate that in a number of these patients it was possible to develop at the same time seroprotection in these patients after COVID-19 vaccination in these complex circumstances.

Alopecia Universalis Occurring after Alemtuzumab Treatment for Multiple Sclerosis. A Two-Year Follow-Up of Two Patients

Alopecia Universalis (AU) is the most severe form of Alopecia Areata and is caused by cytotoxic T-cells reacting with follicular autoantigens, producing complete loss of scalp and body hair. Alemtuzumab is a highly efficacious monoclonal antibody used in the treatment of Multiple Sclerosis (MS), but it causes secondary autoimmunity in up to 40% of patients. Many factors are believed to contribute to this process, but pathogenic mechanisms are not well clear. To date, three cases of AU after treatment with Alemtuzumab have been reported. In this paper we report the cases of two patients who developed AU 12 months after the second cycle of Alemtuzumab, with a review of the literature. One year after the end of the second cycle, two female patients in their thirties experienced complete hair loss. The first case was temporally associated with a significant drop in vitamin D (VD) levels. The second case was accompanied by joint swelling. Both patients had thyroid alterations and showed no hair regrowth after a 2-year follow-up. AU must be considered among the secondary autoimmune manifestations of Alemtuzumab treatment. We emphasize the need for appropriate patient screening and thorough clinical surveillance for factors predisposing patients to secondary autoimmunity.

B cells in multiple sclerosis - from targeted depletion to immune reconstitution therapies

Increasing evidence indicates the involvement of B cells in the pathogenesis of multiple sclerosis (MS), but their precise roles are unclear. In this Review, we provide an overview of the development and physiological functions of B cells and the main mechanisms through which B cells are thought to contribute to CNS autoimmunity. In MS, abnormalities of B cell function include pro-inflammatory cytokine production, defective B cell regulatory function and the formation of tertiary lymphoid-like structures in the CNS, which are the likely source of abnormal immunoglobulin production detectable in the cerebrospinal fluid. We also consider the hypothesis that Epstein-Barr virus (EBV) is involved in the B cell overactivation that leads to inflammatory injury to the CNS in MS. We also review the immunological effects - with a focus on the effects on B cell subsets - of several successful therapeutic approaches in MS, including agents that selectively deplete B cells (rituximab, ocrelizumab and ofatumumab), agents that less specifically deplete lymphocytes (alemtuzumab and cladribine) and autologous haematopoietic stem cell transplantation, in which the immune system is unselectively ablated and reconstituted. We consider the insights that these effects on B cell populations provide and their potential to further our understanding and targeting of B cells in MS.

COVID-19 Vaccine and Hematopoietic Stem Cell Transplantation

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Memory B Cells in Multiple Sclerosis: Emerging Players in Disease Pathogenesis

Multiple Sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. Once thought to be primarily driven by T cells, B cells are emerging as central players in MS immunopathogenesis. Interest in multiple B cell phenotypes in MS expanded following the efficacy of B cell-depleting agents targeting CD20 in relapsing-remitting MS and inflammatory primary progressive MS patients. Interestingly, these therapies primarily target non-antibody secreting cells. Emerging studies seek to explore B cell functions beyond antibody-mediated roles, including cytokine production, antigen presentation, and ectopic follicle-like aggregate formation. Importantly, memory B cells (Bmem) are rising as a key B cell phenotype to investigate in MS due to their antigen-experience, increased lifespan, and rapid response to stimulation. Bmem display diverse effector functions including cytokine production, antigen presentation, and serving as antigen-experienced precursors to antibody-secreting cells. In this review, we explore the cellular and molecular processes involved in Bmem development, Bmem phenotypes, and effector functions. We then examine how these concepts may be applied to the potential role(s) of Bmem in MS pathogenesis. We investigate Bmem both within the periphery and inside the CNS compartment, focusing on Bmem phenotypes and proposed functions in MS and its animal models. Finally, we review how current immunomodulatory therapies, including B cell-directed therapies and other immunomodulatory therapies, modify Bmem and how this knowledge may be harnessed to direct therapeutic strategies in MS.

The Role of B Cells in Primary Progressive Multiple Sclerosis

The success of ocrelizumab in reducing confirmed disability accumulation in primary progressive multiple sclerosis (PPMS) via CD20-targeted depletion implicates B cells as causal agents in the pathogenesis of PPMS. This review explores the possible mechanisms by which B cells contribute to disease progression in PPMS, specifically exploring cytokine production, antigen presentation, and antibody synthesis. B cells may contribute to disease progression in PPMS through cytokine production, specifically GM-CSF and IL-6, which can drive naïve T-cell differentiation into pro-inflammatory Th1/Th17 cells. B cell production of the cytokine LT-α may induce follicular dendritic cell production of CXCL13 and lead indirectly to T and B cell infiltration into the CNS. In contrast, production of IL-10 by B cells likely induces an anti-inflammatory effect that may play a role in reducing neuroinflammation in PPMS. Therefore, reduced production of IL-10 may contribute to disease worsening. B cells are also capable of potent antigen presentation and may induce pro-inflammatory T-cell differentiation via cognate interactions. B cells may also contribute to disease activity via antibody synthesis, although it's unlikely the benefit of ocrelizumab in PPMS occurs via antibody decrement. Finally, various B cell subsets likely promulgate pro- or anti-inflammatory effects in MS.

CD52 Is Elevated on B cells of SLE Patients and Regulates B Cell Function

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by B cell dysregulation and breaks in tolerance that lead to the production of pathogenic autoantibodies. We performed single-cell RNA sequencing of B cells from healthy donors and individuals with SLE which revealed upregulated CD52 expression in SLE patients. We further demonstrate that SLE patients exhibit significantly increased levels of B cell surface CD52 expression and plasma soluble CD52, and levels of soluble CD52 positively correlate with measures of lupus disease activity. Using CD52-deficient JeKo-1 cells, we show that cells lacking surface CD52 expression are hyperresponsive to B cell receptor (BCR) signaling, suggesting an inhibitory role for the surface-bound protein. In healthy donor B cells, antigen-specific BCR-activation initiated CD52 cleavage in a phospholipase C dependent manner, significantly reducing cell surface levels. Experiments with recombinant CD52-Fc showed that soluble CD52 inhibits BCR signaling in a manner partially-dependent on Siglec-10. Moreover, incubation of unstimulated B cells with CD52-Fc resulted in the reduction of surface immunoglobulin and CXCR5. Prolonged incubation of B cells with CD52 resulted in the expansion of IgD+IgMlo anergic B cells. In summary, our findings suggest that CD52 functions as a homeostatic protein on B cells, by inhibiting responses to BCR signaling. Further, our data demonstrate that CD52 is cleaved from the B cell surface upon antigen engagement, and can suppress B cell function in an autocrine and paracrine manner. We propose that increased expression of CD52 by B cells in SLE represents a homeostatic mechanism to suppress B cell hyperactivity.

Multiple Sclerosis and SARS-CoV-2 Vaccination: Considerations for Immune-Depleting Therapies

Several concerns have been raised about the use of immunodepleting agents including alemtuzumab, cladribine and CD20-depleting antibodies in people with multiple sclerosis (pwMS) during the coronavirus disease (COVID) 2019 pandemic. As the end of the pandemic is not yet in sight, vaccination against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) may be an elegant strategy to overcome the potential hazards associated with initiating and continuing treatment with immune-depleting agents. In this review, we summarize the immunological effects of immune-depleting therapy and underlying considerations for the hitherto existing recommendations that suggest a restricted use of immune-deleting therapies during the pandemic. Moreover, we critically discuss open questions regarding vaccination in general and against SARS-CoV-2 in pwMS.

Regulatory B cells: TIM-1, transplant tolerance, and rejection

Regulatory B cells (Bregs) ameliorate autoimmune disease and prevent allograft rejection. Conversely, they hinder effective clearance of pathogens and malignancies. Breg activity is mainly attributed to IL-10 expression, but also utilizes additional regulatory mechanisms such as TGF-β, FasL, IL-35, and TIGIT. Although Bregs are present in various subsets defined by phenotypic markers (including canonical B cell subsets), our understanding of Bregs has been limited by the lack of a broadly inclusive and specific phenotypic or transcriptional marker. TIM-1, a broad marker for Bregs first identified in transplant models, plays a major role in Breg maintenance and induction. Here, we expand on the role of TIM-1⁺  Bregs in immune tolerance and propose TIM-1 as a unifying marker for Bregs that utilize various inhibitory mechanisms in addition to IL-10. Further, this review provides an in-depth assessment of our understanding of Bregs in transplantation as elucidated in murine models and clinical studies. These studies highlight the major contribution of Bregs in preventing allograft rejection, and their ability to serve as highly predictive biomarkers for clinical transplant outcomes.

Induction and Donor Specific Antibodies in Low Immunologic Risk Kidney Transplant Recipients

BACKGROUND

Optimal induction for patients without pretransplant donor-specific antibodies (DSAs) is poorly defined. The goal of this study was to compare the incidence of de novo DSA (dnDSA) and graft outcomes between induction therapies in patients with a negative virtual crossmatch (VXM).

METHODS

A retrospective chart review was performed, identifying 782 patients with a negative VXM who underwent kidney transplantation at a single, high-volume institution between January 2013 and May 2017. Kaplan-Meier analysis was used to assess the incidence of dnDSA and allograft survival between induction therapies in this group. dnDSA is defined as the development of new post-transplant DSA, at any MFI level.

RESULTS

Induction therapy included alemtuzumab (N=87, 11%), basiliximab (N=522, 67%), and anti-thymocyte globulin (ATG; N=173, 22%). One-year graft survival was similar between groups (alemtuzumab, 100%; basiliximab, 98%; ATG, 99%). Incidence of acute rejection at 1 year was <2% and not different between the three groups. Alemtuzumab was associated with the highest incidence of dnDSA at 14%, compared with 5% and 8% in basiliximab and ATG groups, respectively, at 1 year (P=0.009). In multivariate regression analyses, alemtuzumab retained its significant association with a dnDSA HR of 2.5 (95% CI, 1.51 to 4.25; P=0.0004).

CONCLUSIONS

In summary, alemtuzumab was associated with a higher rate of dnDSA development in patients with a negative VXM; however, this finding was not associated with rejection or graft failure.

Ozanimod to Treat Relapsing Forms of Multiple Sclerosis: A Comprehensive Review of Disease, Drug Efficacy and Side Effects

Multiple sclerosis (MS) is a prevalent and debilitating neurologic condition characterized by widespread neurodegeneration and the formation of focal demyelinating plaques in the central nervous system. Current therapeutic options are complex and attempt to manage acute relapse, modify disease, and manage symptoms. Such therapies often prove insufficient alone and highlight the need for more targeted MS treatments with reduced systemic side effect profiles. Ozanimod is a novel S1P (sphingosine-1-phosphate) receptor modulator used for the treatment of clinically isolated syndrome, relapsing–remitting, and secondary progressive forms of multiple sclerosis. It selectively modulates S1P1 and S1P5 receptors to prevent autoreactive lymphocytes from entering the CNS where they can promote nerve damage and inflammation. Ozanimod was approved by the US Food and Drug Administration (US FDA) for the management of multiple sclerosis in March 2020 and has been proved to be both effective and well tolerated. Of note, ozanimod is associated with the following complications: increased risk of infections, liver injury, fetal risk, increased blood pressure, respiratory effects, macular edema, and posterior reversible encephalopathy syndrome, among others. Further investigation including head-to-head clinical trials is warranted to evaluate the efficacy of ozanimod compared with other S1P1 receptor modulators.

The critical role of Faecalibacterium prausnitzii in human health: An overview

Faecalibacterium prausnitzii (F. prausnitzii) is one of the most abundant bacterial species in the colon of healthy human adults and representing more than 5% of the total bacterial population. Recently, it has been known as a major actor in human intestinal health and a biosensor. Changes in this species population richness and quantity have been observed in many illnesses and several investigations have reported that abundance of F. prausnitzii is reduced in different intestinal disorders. In the current review, we aim to consider literature from various library databases and electronic searches (Science Direct, PubMed, and Google Scholar) which were randomly collected and serve as an overview of different features of F. prausnitzii including metabolites, anti-inflammatory action, and correlation of dysbiosis of this bacterium with various complications in human.

Casting a wider protective net: Anti-infective vaccine strategies for patients with hematologic malignancy and blood and marrow transplantation

Patients who have hematologic malignancies are at high risk for infections but vaccinations may be effective prophylaxis. The increased infection risk derives from immune defects secondary to malignancy, the classic example being CLL, and chemotherapies and immunotherapy used to treat the malignancies. Therapy of hematologic malignancies is being revolutionized by introduction of novel targeted agents and immunomodulatory medications, improving the survival of patients. At the same time those agents uniquely change the infection risk and response to immunizations. This review will summarize current vaccine recommendations for patients with hematologic malignancies including patients who undergo hematopoietic cell transplant.

A real-world cohort analysis of alemtuzumab outcomes in relapsing multiple sclerosis

Multiple sclerosis (MS) is a chronic and progressive neurological disease characterized by recurrent episodes of inflammatory demyelination of the brain and spinal cord. Alemtuzumab has been previously shown in large phase III trials to be an effective therapy in reducing MS clinical flares as well as new radiological activity and atrophy rates. The purpose of this study was to examine real-world effectiveness and safety data from a large cohort of people treated with alemtuzumab at an academic medical center, including those who failed B-cell depletion therapy. Over an average of 2.6 years follow-up, there were small but significant improvements in neurological disability scores, and a 61% rate of the composite "No Evidence of Disease Activity" (NEDA-3) outcome at 2-year follow-up. There were no substantial safety issues encountered in our review; rates of adverse events were similar or below those reported in Phase III trials. We compare and contrast our results to other available real-world data using alemtuzumab in multiple sclerosis.

Regulation of neuroinflammation by B cells and plasma cells

The remarkable success of anti-CD20 B cell depletion therapies in reducing the burden of multiple sclerosis (MS) disease has prompted significant interest in how B cells contribute to neuroinflammation. Most focus has been on identifying pathogenic CD20⁺ B cells. However, an increasing number of studies have also identified regulatory functions of B lineage cells, particularly the production of IL-10, as being associated with disease remission in anti-CD20-treated MS patients. Moreover, IL-10-producing B cells have been linked to the attenuation of inflammation in experimental autoimmune encephalomyelitis (EAE), the animal model of MS. In addition to IL-10-producing B cells, antibody-producing plasma cells (PCs) have also been implicated in suppressing neuroinflammation. This review will examine regulatory roles for B cells and PCs in MS and EAE. In addition, we speculate on the involvement of regulatory PCs and the cytokine BAFF in the context of anti-CD20 treatment. Lastly, we explore how the microbiota could influence anti-inflammatory B cell behavior. A better understanding of the contributions of different B cell subsets to the regulation of neuroinflammation, and factors that impact the development, maintenance, and migration of such subsets, will be important for rationalizing next-generation B cell-directed therapies for the treatment of MS.

Long-term peripheral immune cell profiling reveals further targets of oral cladribine in MS

OBJECTIVES

To expand the knowledge about the immunological consequences of cladribine (CLAD), a pulsed immune reconstitution therapy approved for active multiple sclerosis (MS), beyond the known short-term effects on peripheral immune cell subsets.

METHODS

In this study, we characterized depletion and restitution kinetics as well as cytokine profiles of peripheral immune cell subsets in 18 patients with MS following treatment with oral CLAD. The methods involved blood collection prior to CLAD and every three months over a period of 24 months, and extensive characterization of various immune cells subsets by multiparametric flow cytometry.

RESULTS

We found a selectivity of CLAD towards central memory T cells and memory B cells and detected a hyper-repopulation of maturing B cells. Counts of classical (-65%) and various nonclassical TH17 cells (-84% to -87%) were markedly reduced 24 months after treatment start, and were comparable with depletion rates of class-switched memory B-cell phenotypes (-87% to -95%). The nadir of TH cells was more pronounced in the second treatment year. We observed a proportional surge of CD20 T-cell subsets and an expansion of regulatory T, B and NK cells. Natural killer T cells (NKT) were only depleted in year two and did not recover.

INTERPRETATION

Peripheral immune cell profiling revealed more differentiated insights into the immunological effects of CLAD. While some immune cell subsets expanded, we also observed additive depleting effects after the second treatment course. Further studies are required to elucidate whether these changes are paramount for the consistent and prolonged disease-modifying effect of CLAD.