Immunological consequences of "immune reconstitution therapy" in multiple sclerosis: A systematic review

Exploring autoimmune endocrine diseases induced by monoclonal antibodies used as multiple sclerosis pharmacotherapy: a systematic review

Multiple sclerosis (MS) is an autoimmune neurodegenerative disease that targets myelin, leading to inflammation and neuron death. Monoclonal antibodies (MAb) have long been used to control the progression and exacerbations of this disorder, which may induce secondary autoimmune disease as a rare adverse event. This systematic review aimed to gather data of case reports around this subject and to explain the mechanism behind their occurrence. PubMed, Scopus, and Google scholar were searched for published case reports until February 21st 2024. The Joanna Briggs Institute (JBI) critical appraisal checklist was used to assess the quality of the included studies. In total, 20 articles met the inclusion criteria and were reviewed by the authors. The most autoimmune disorders were thyroiditis and as expected induced by alemtuzumab. Ocrelizumab had one secondary autoimmune complication reported. MAbs used in MS immunotherapy have shown to induce secondary autoimmune disorders including endocrine complications, which have been reported in many case reports. It is recommended to use these agents with caution and monitor patients for symptoms of the aforementioned conditions.

Narrative Review on the Use of Cladribine Tablets as Exit Therapy for Stable Elderly Patients with Multiple Sclerosis

The number of ageing people with relapsing multiple sclerosis (RMS) is increasing. The efficacy of disease-modifying therapies (DMTs) for RMS declines with age. Also, older persons with MS may be more susceptible to infections, hospitalisations and malignancy. Aging people with MS have higher rates of comorbidities versus aged-matched controls, increasing the individual risk of disability. We review the therapeutic properties of cladribine tablets (CladT) in ageing people with RMS, with regard to their utility for allowing these individuals to cease continuous administration of a DMT (i.e. to act as an "exit therapy"). CladT is thought to be an immune reconstitution therapy, in that two short courses of oral treatment 1 year apart provide suppression of MS disease activity in responders that far outlasts the duration of treatment and post-treatment reductions in lymphocyte counts. Post hoc analyses, long-term follow-up of populations with RMS in randomised trials, and real-world evidence suggest that the efficacy of CladT is probably independent of age, although more data in the elderly are still needed. No clear adverse signals for lymphopenia or other adverse safety signals have emerged with increasing age, although immunosenescence in the setting of age-related "inflammaging" may predispose elderly patients to a higher risk of infections. Updating vaccination status is recommended, especially against pneumococci and herpes zoster for older patients, to minimise the risk of these infections. CladT may be a useful alternative treatment for ageing people with MS who often bear a burden of multiple comorbidities and polypharmacy and who are more exposed to the adverse effects of continuous immunosuppressive therapy.

Repeated iv anti-CD20 treatment in multiple sclerosis: Long-term effects on peripheral immune cell subsets

OBJECTIVE

Repeated intravenous administration of anti-CD20 depleting monoclonal antibodies 6 months apart is among the highly effective treatment options in multiple sclerosis (MS). Here, we aimed to investigate peripheral immune cell subset depletion kinetics following either rituximab (RTX) or ocrelizumab (OCR) infusions in people with MS (pwMS).

METHODS

We studied pwMS treated de-novo with either RTX (n = 7) or OCR (n = 8). The examinations were scheduled before the initiation of anti-CD20 therapy and every 12 weeks for up to 15 months. Immunophenotyping of immune cell subsets in peripheral blood was performed by multiparametric fluorescence cytometry.

RESULTS

A significant, persistent decrease of CD19+ B cells was observed already with the first anti-CD20 infusion (p < 0.0001). A significant proportional reduction of memory B cells within the B-cell pool was achieved only after two treatment cycles (p = 0.005). We observed a proportional increase of immature (p = 0.04) and naive B cells (p = 0.004), again only after the second treatment cycle. As for the peripheral T-cell pool, we observed a continuous proportional increase of memory T helper (TH) cells/central memory TH cells (p = 0.02/p = 0.008), while the number of regulatory T cells (Treg) decreased (p = 0.007). The percentage of B-cell dependent TH17.1 central memory cells dropped after the second treatment cycle (p = 0.02). No significant differences in the depletion kinetics between RTX and OCR were found.

INTERPRETATION

Peripheral immune cell profiling revealed more differentiated insights into the prompt and delayed immunological effects of repeated intravenous anti-CD20 treatment. The observation of proportional changes of some pathogenetically relevant immune cell subsets only after two infusion cycles deserves further attention.

Effects of High Efficacy Multiple Sclerosis Disease Modifying Drugs on the Immune Synapse: A Systematic Review

BACKGROUND

Co-signaling and adhesion molecules are important elements for creating immune synapses between T lymphocytes and antigen-presenting cells; they positively or negatively regulate the interaction between a T cell receptor with its cognate antigen, presented by the major histocompatibility complex.

OBJECTIVES

We conducted a systematic review on the effects of High Efficacy Disease Modifying Drugs (HEDMDs) for Multiple Sclerosis (MS) on the co-signaling and adhesion molecules that form the immune synapse.

METHODS

We searched EMBASE, MEDLINE, and other sources to identify clinical or preclinical reports on the effects of HEDMDs on co-signaling and adhesion molecules that participate in the formation of immune synapses in patients with MS or other autoimmune disorders. We included reports on cladribine tablets, anti- CD20 monoclonal antibodies, S1P modulators, inhibitors of Bruton's Tyrosine Kinase, and natalizumab.

RESULTS

In 56 eligible reports among 7340 total publications, limited relevant evidence was uncovered. Not all co-signaling and adhesion molecules have been studied in relation to every HEDMD, with more data being available on the anti-CD20 monoclonal antibodies (that affect CD80, CD86, GITR and TIGIT), cladribine tablets (affecting CD28, CD40, ICAM-1, LFA-1) and the S1P modulators (affecting CD86, ICAM-1 and LFA-1) and less on Natalizumab (affecting CD80, CD86, CD40, LFA-1, VLA-4) and Alemtuzumab (affecting GITR and CTLA-4).

CONCLUSION

The puzzle of HEDMD effects on the immune synapse is far from complete. The available evidence suggests that distinguishing differences exist between drugs and are worth pursuing further.

Should autologous hematopoietic stem cell transplantation be offered as a first-line disease modifying therapy to patients with multiple sclerosis?

In multiple sclerosis (MS), progression independent of new focal inflammation may commence shortly after disease onset, and it is increasingly revealed that the risk of disability accrual is reduced by early use of high-efficacy disease-modifying therapies (HE-DMTs). People with aggressive MS may therefore benefit from early treatment with autologous haematopoietic stem cell transplantation (AHSCT), a procedure inducing maximal immunosuppression followed by immune reconstitution, demonstrated to be superior to DMTs in one randomized clinical trial. However, in current practice prior failure to HE-DMTs is typically required to establish the indication for AHSCT. In the present article, the available evidence on the potential role of AHSCT as first-line treatment in aggressive MS and the rationale for its early use will be summarized. Proposed definitions of aggressive MS that could help identifying MS patients eligible for early treatment with AHSCT will also be discussed.

Expert Narrative Review of the Safety of Cladribine Tablets for the Management of Relapsing Multiple Sclerosis

Cladribine tablets (CladT) is a highly active oral disease-modifying therapy (DMT) for the management of relapsing multiple sclerosis (RMS). CladT acts as an immune reconstitution therapy, in that two short courses of treatment 1 year apart have been shown to suppress disease activity for a prolonged period in most patients, without need for continued DMT. Each course of CladT induces a profound reduction in B lymphocytes that recovers over months, and serious lymphopenia (Grade 3-4) is uncommon. Smaller reductions in levels of T lymphocytes occur slightly later: on average, these remain within the normal range and repopulate progressively. A larger effect occurs on CD8 vs. CD4 cells. Reactivation of latent or opportunistic infections (e.g. varicella zoster, tuberculosis) is mostly associated with very low lymphocyte counts (< 200/mm3). Screening and managing pre-existing infections, vaccinating non-exposed patients and delaying the 2nd year of treatment with CladT to allow lymphocytes to recover to > 800/mm3 (if necessary) are important for avoiding infections and higher-grade lymphopenia. There was no demonstrable or apparent effect of CladT on the efficacy of vaccinations, including against Covid-19. Adverse events consistent with drug-induced liver injury (DILI) represent a rare but potentially serious complication of CladT therapy in spontaneous adverse event reporting; patients should be screened for liver dysfunction before starting treatment. Ongoing hepatic monitoring is not required, but CladT must be withdrawn if signs and symptoms of DILI develop. There was a numerical imbalance for malignancies when comparing cladribine to placebo in the clinical programme, particularly in short-term data, but recent evidence shows that the risk of malignancy with CladT is similar to the background rate in the general population and to that with other DMTs. Overall, CladT is well tolerated with a favorable safety profile appropriate for the management of RMS.

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.

Could Mathematics be the Key to Unlocking the Mysteries of Multiple Sclerosis?

Multiple sclerosis (MS) is an autoimmune, neurodegenerative disease that is driven by immune system-mediated demyelination of nerve axons. While diseases such as cancer, HIV, malaria and even COVID have realised notable benefits from the attention of the mathematical community, MS has received significantly less attention despite the increasing disease incidence rates, lack of curative treatment, and long-term impact on patient well-being. In this review, we highlight existing, MS-specific mathematical research and discuss the outstanding challenges and open problems that remain for mathematicians. We focus on how both non-spatial and spatial deterministic models have been used to successfully further our understanding of T cell responses and treatment in MS. We also review how agent-based models and other stochastic modelling techniques have begun to shed light on the highly stochastic and oscillatory nature of this disease. Reviewing the current mathematical work in MS, alongside the biology specific to MS immunology, it is clear that mathematical research dedicated to understanding immunotherapies in cancer or the immune responses to viral infections could be readily translatable to MS and might hold the key to unlocking some of its mysteries.

Expert opinion on the long-term use of cladribine tablets for multiple sclerosis: Systematic literature review of real-world evidence

BACKGROUND

Treatment with cladribine tablets (CladT), an immune reconstitution therapy for relapsing multiple sclerosis (RMS), involves two short courses of treatment in Year 1 and Year 2. Most patients achieve sustained efficacy with CladT, but a small proportion may experience new disease activity (DA). Following completion of the indicated dose, physicians may have questions relating to the long-term management of these patients. Since the EU approval of CladT over 5 years ago, real-world evidence (RWE) is increasing and may provide some insights and guidance for clinical practice. We describe a systematic literature review (SLR) of RWE and provide expert opinions relating to six questions regarding the long-term use of CladT.

METHODS

Pertinent clinical questions were developed by a steering committee (SC) of 14 international multiple sclerosis (MS) experts regarding breakthrough DA in Year 1, new DA after 2 years or more of treatment, long-term management of stable patients, and whether additional courses of CladT may be required or safe. An SLR was performed in EMBASE and PubMed using the population, intervention, comparators, outcomes, study design (PICOS) framework to identify relevant studies within the last 15 years. Searches of key congress proceedings for the last 2-3 years were also performed. Following review of the results and RWE, the SC drafted and agreed on expert opinion statements for each question.

RESULTS

A total of 35 publications reporting RWE for CladT were included in this review. In the real world, breakthrough DA in Year 1 is of low incidence (1.1-21.9%) but can occur, particularly in patients switching from anti-lymphocyte trafficking agents. In most patients, this DA did not lead to treatment discontinuation. Reported rates of DA after the full therapeutic effect of CladT has been achieved (end of Year 2, 3 or 4) range from 12.0 to 18.7% in the few studies identified. No RWE was identified to support management decisions for stable patients in Year 5 or later. Views among the group were also diverse on this question and voting on expert opinion statements was required. Only two studies reported the administration of additional courses of CladT, but detailed safety outcomes were not provided.

CONCLUSIONS

RWE for the long-term use of CladT in the treatment of RMS is increasing, however, gaps in knowledge remain. Where possible, the RWE identified through the SLR informed expert statements, but, where RWE is still lacking, these were based solely on experiences and opinion, providing some guidance on topics and questions that occur in daily clinical practice. More real-world studies with longer-term follow-up periods are needed and highly anticipated.

The Place of Immune Reconstitution Therapy in the Management of Relapsing Multiple Sclerosis in France: An Expert Consensus

The treatment strategy in relapsing multiple sclerosis (RMS) is a complex decision requiring individualization of treatment sequences to maximize clinical outcomes. Current local and international guidelines do not provide specific recommendation on the use of immune reconstitution therapy (IRT) as alternative to continuous immunosuppression in the management of RMS. The objective of the program was to provide consensus-based expert opinion on the optimal use of IRT in the management of RMS. A Delphi method was performed from May 2022 to July 2022. Nineteen clinical assertions were developed by a scientific committee and sent to 14 French clinical experts in MS alongside published literature. Two consecutive reproducible anonymous votes were conducted. Consensus on recommendations was achieved when more than 75% of the respondents agreed or disagreed with the clinical assertions. After the second round, consensus was achieved amongst 16 out of 19 propositions: 13 clinical assertions had a 100% consensus, 3 clinical assertions a consensus above 75% and 3 without consensus. Expert-agreed consensus is provided on topics related to the benefit of the early use of IRT from immunological and clinical perspectives, profiles of patients who may benefit most from the IRT strategy (e.g. patients with family planning, patient preference and lifestyle requirements). These French expert consensuses provide up-to-date relevant guidance on the use of IRT in clinical practice. The current program reflects status of knowledge in 2022 and should be updated in timely manner when further clinical data in IRT become available.

Real-Life Experience of the Effects of Cladribine Tablets on Lymphocyte Subsets and Serum Neurofilament Light Chain Levels in Relapsing Multiple Sclerosis Patients

Although cladribine induces sustained reductions in peripheral T and B lymphocytes, little is known about its effect on axonal damage reduction in multiple sclerosis (MS), which could be demonstrated by assessing the serum neurofilament light chain (sNfL) levels. We investigated the reduction/reconstitution of different lymphocyte subsets (LS) by verifying the correlation with no evidence of disease activity (NEDA) and the variation in sNfL levels during cladribine treatment. We analysed 33 highly active relapsing MS patients and followed them up for 12 ± 3.3 months; blood samples were collected at treatment start (W0) and after 8, 24 and 48 weeks. Seventeen patients (60.7%) showed NEDA during the first treatment. At week 8, we observed a significant decrease in B memory cells, B regulatory 1 CD19+/CD38+ and B regulatory 2 CD19+/CD25+, a significant increase in T regulatory CD4+/CD25+, a slight increase in T cytotoxic CD3+/CD8+ and a non-significant decrease in T helper CD3+/CD4+. Starting from week 24, the B subsets recovered; however, at week 48, CD19+/CD38+ and CD19+/CD25+ reached values near the baseline, while the Bmem were significantly lower. The T cell subsets remained unchanged except for CD4+/CD25+, which increased compared to W0. The LS changes were not predictive of NEDA achievement. The sNfL levels were significantly lower at week 24 (p = 0.046) vs. baseline. These results could demonstrate how cladribine, by inflammatory activity depletion, can also reduce axonal damage, according to the sNfL levels.

The genealogy, methodology, similarities and differences of immune reconstitution therapies for multiple sclerosis and neuromyelitis optica

Immune reconstitution therapies (IRTs) are a type of short course procedure or pharmaceutical agent within the MS pharmacopeia. They emanate from oncology and induce transient incomplete lympho-ablation with or without myelo-ablation, resulting in potential prolonged immunomodulation. Thus, they provide significant prophylaxis from disease activity without retreatment. Modern IRT for autoimmunity encompasses a heterogeneous group of pulsed lympho- and non-myelo-ablative treatments designed to re-boot the adaptive immune system in a quasi-permanent manner - a re-induction of ontogeny. IRT is the extensive debulking of an auto-aggressive immune system to attempt to reach the Holy Grail of immune tolerance. This incomplete yet significant lympho-ablation induces lymphoproliferation, reduces pathogenic clonal cells, causes thymopoiesis and results in the induction of immune tolerance. Lympho-ablation with immune reconstitution can result in minimal residual autoimmunity. There is a resetting of the immune thermostat - i.e., the immunostat. IRTs have the potential to provide prolonged periods of disease inactivity without retreatment in part through the immunological results of their pulsatile lymphocyte depletion. It is vital to increase our understanding of how IRTs alter a patient's immune response to the antigenic target of the disease so that we can devise newer, more durable and safer forms of such agents. What common features do extant IRTs (i.e., stem cell transplant, alemtuzumab and oral cladribine) have to produce the durable therapeutic response without long term treatment in neuroimmunological diseases such as MS (multiple sclerosis) and NMOSD (neuromyelitis optica spectrum disorders)? Can we learn from these critical features to predict what other maneuvers or agents might effect similar clinical results with equal or greater efficacy and safety?

Impact of previous disease-modifying treatment on safety and efficacy in patients with MS treated with AHSCT

BACKGROUND

Autologous haematopoietic stem cell transplantation (AHSCT) is a highly effective treatment for multiple sclerosis (MS). The impact of previous long-lasting disease-modifying treatments (DMT) for safety and efficacy of AHSCT is unknown.

OBJECTIVE

To explore whether previous DMTs with long-lasting effects on the immune system (anti-CD20 therapy, alemtuzumab and cladribine) affect treatment-related complications, long-term outcome and risk of new MS disease activity in patients treated with AHSCT.

METHODS

Retrospective observational study of 104 relapsing remitting patients with MS treated by AHSCT in Sweden and Norway from 2011 to 2021, grouped according to the last DMT used ≤6 months prior to AHSCT. The primary outcomes were early AHSCT-related complications (mortality, neutropenic fever and hospitalisation length), long-term complications (secondary autoimmunity) and proportion of patients with No Evidence of Disease Activity (NEDA-3 status): no new relapses, no MRI activity and no disease progression during the follow-up.

RESULTS

The mean follow-up time was 39.5 months (range 1-95). Neutropenic fever was a common AHSCT-related complication affecting 69 (66%) patients. There was no treatment-related mortality. During the follow-up period, 20 patients (19%) were diagnosed with autoimmunity. Occurrence of neutropenic fever, hospitalisation length or secondary autoimmunity did not vary dependent on the last DMT used prior to AHSCT. A total of 84 patients (81%) achieved NEDA-3 status, including all patients (100%) using rituximab, alemtuzumab or cladribine before AHSCT.

CONCLUSION

This study provides level 4 evidence that AHSCT in patients previously treated with alemtuzumab, cladribine or rituximab is safe and efficacious.

Thinking outside the box: non-canonical targets in multiple sclerosis

Multiple sclerosis (MS) is an immune-mediated disease of the central nervous system that causes demyelination, axonal degeneration and astrogliosis, resulting in progressive neurological disability. Fuelled by an evolving understanding of MS immunopathogenesis, the range of available immunotherapies for clinical use has expanded over the past two decades. However, MS remains an incurable disease and even targeted immunotherapies often fail to control insidious disease progression, indicating the need for new and exceptional therapeutic options beyond the established immunological landscape. In this Review, we highlight such non-canonical targets in preclinical MS research with a focus on five highly promising areas: oligodendrocytes; the blood-brain barrier; metabolites and cellular metabolism; the coagulation system; and tolerance induction. Recent findings in these areas may guide the field towards novel targets for future therapeutic approaches in MS.

Cladribine Tablets for Relapsing-Remitting Multiple Sclerosis: A Clinician's Review

Multiple sclerosis (MS) is a chronic neurodegenerative disease characterized by inflammation and demyelination for which there is currently no cure; therefore, the aim of therapy is to reduce the risk of relapse and disability progression. The treatment options for MS have increased greatly in recent years with the development of several disease-modifying therapies (DMTs) and the advent of immune reconstitution therapy (IRT). IRTs are administered in short-dosing periods to produce long-term effects on the immune system. Treatment with an IRT is based on the 3Rs: reduction, repopulation, and reconstitution of lymphocytes, which leads to restoration of immune effector functions. Cladribine tablets represent a selective, high-efficacy, oral form of IRT for patients with MS that targets lymphocytes and spares innate immune cells. Patients require only two weekly treatment courses, with each course comprising two treatment weeks, in Years 1 and 2; therefore, cladribine tablets are associated with a lower monitoring burden than many other DMTs, while short dosing periods can help to improve adherence. This review provides an overview of IRT and offers the clinician's perspective on the current MS treatment landscape, with a focus on practical advice for the management of patients undergoing treatment with cladribine tablets based on the most recent evidence available, including risks associated with COVID-19 and recommendations for vaccination in patients with MS.

Real-world evidence for cladribine tablets in multiple sclerosis: further insights into efficacy and safety

Cladribine (CLAD) is a purine nucleoside analog approved in tablet form to treat highly active multiple sclerosis (MS). CLAD tablets are the first oral therapy with an infrequent dosing schedule, administered in two annual treatment courses, each divided into two treatment cycles comprising 4–5 days of treatment. The efficacy and safety of CLAD tablets have been verified in randomized controlled clinical trials. Clinical observational studies are performed in more representative populations and over more extended periods, and thus provide valuable complementary insights. Here, we summarize the available evidence for CLAD tablets from post-marketing trials, including two observational, four long-term extensions, and two comparative studies. The patients in the post-marketing setting differed from the cohort recruited in the pivotal phase III trials regarding demographics and MS-related disability. The limited number of studies with small cohorts corroborate the disease-modifying capacity of oral CLAD and report on a durable benefit after active treatment periods. Skin-related adverse events were common in the studies focusing on safety aspects. In addition, single cases of CLAD-associated autoimmune events have been reported. Lastly, CLAD tablets appear safe regarding COVID-19 concerns, and patients mount a robust humoral immune response to SARS-CoV‑2 vaccination. We conclude that the current real-world evidence for CLAD tablets as immune reconstitution therapy for treatment of MS is based on a small number of studies and a population distinct from the cohorts randomized in the pivotal phase III trials. Further research should advance the understanding of long-term disease control after active treatment periods and the mitigation of adverse events.

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.

Microbial-Driven Immunological Memory and Its Potential Role in Microbiome Editing for the Prevention of Colorectal Cancer

Over the last several years, many advances have been made in understanding the role of bacteria in the pathogenesis of gastrointestinal cancers. Beginning with Helicobacter pylori being recognized as the first bacterial carcinogen and the causative agent of most gastric cancers, more recent studies have examined the role of enteric microbes in colorectal cancer. In the digestive tract, these communities are numerous and have a complex interrelationship with local immune/inflammatory responses that impact the health of the host. As modifying the microbiome in the stomach has decreased the risk of gastric cancer, modifying the distal microbiome may decrease the risk of colorectal cancers. To date, very few studies have considered the notion that mucosal lymphocyte-dependent immune memory may confound attempts to change the microbial components in these communities. The goal of this review is to consider some of the factors impacting host-microbial interactions that affect colorectal cancer and raise questions about how immune memory responses to the local microbial consortium affect any attempt to modify the composition of the intestinal microbiome.

Cladribine Alters Immune Cell Surface Molecules for Adhesion and Costimulation: Further Insights to the Mode of Action in Multiple Sclerosis

Cladribine (CLAD) is a deoxyadenosine analogue prodrug which is given in multiple sclerosis (MS) as two short oral treatment courses 12 months apart. Reconstitution of adaptive immune function following selective immune cell depletion is the presumed mode of action. In this exploratory study, we investigated the impact of CLAD tablets on immune cell surface molecules for adhesion (CAMs) and costimulation (CoSs) in people with MS (pwMS). We studied 18 pwMS who started treatment with CLAD and 10 healthy controls (HCs). Peripheral blood mononuclear cells were collected at baseline and every 3 months throughout a 24-month period. We analysed ICAM-1, LFA-1, CD28, HLADR, CD154, CD44, VLA-4 (CD49d/CD29), PSGL-1 and PD-1 with regard to their expression on B and T cells (T helper (Th) and cytotoxic T cells (cT)) and surface density (mean fluorescence intensity, MFI) by flow cytometry. The targeted analysis of CAM and CoS on the surface of immune cells in pwMS revealed a higher percentage of ICAM-1 (B cells, Th, cT), LFA-1 (B cells, cT), HLADR (B cells, cT), CD28 (cT) and CD154 (Th). In pwMS, we found lower frequencies of Th and cT cells expressing PSGL-1 and B cells for the inhibitory signal PD-1, whereas the surface expression of LFA-1 on cT and of HLADR on B cells was denser. Twenty-four months after the first CLAD cycle, the frequencies of B cells expressing CD44, CD29 and CD49d were lower compared with the baseline, together with decreased densities of ICAM-1, CD44 and HLADR. The rate of CD154 expressing Th cells dropped at 12 months. For cT, no changes were seen for frequency or density. Immune reconstitution by oral CLAD was associated with modification of the pro-migratory and -inflammatory surface patterns of CAMs and CoSs in immune cell subsets. This observation pertains primarily to B cells, which are key cells underlying MS pathogenesis.

A global view of comorbidity in multiple sclerosis: a systematic review with a focus on regional differences, methodology, and clinical implications

Multiple sclerosis (MS) is a chronic autoimmune disorder of the central nervous system which is associated with numerous comorbidities. These include cardiovascular disease, psychiatric and neurologic disturbances, restless leg syndrome, migraine, cancer, autoimmune diseases, and metabolic disorders. Comorbid disease is an important consideration for clinicians treating patients with MS; early presentation of comorbidities can obscure or delay MS diagnosis, as well as significantly impacting the disease course. Improved understanding of comorbidities and their emergence in MS populations is important for improving the quality of life and optimizing treatment for patients. Therefore, we evaluated published studies reporting epidemiologic data on comorbidities and their associated impact on disease progression in patients with MS (PwMS). The prevalence of neurologic, cardiovascular, metabolic, and autoimmune comorbidities was elevated in PwMS in general, and furthermore, this adversely affected a broad range of outcomes. Compared with PwMS, cancer rates in people without MS or the general population were lower, which should prompt further studies into the mechanisms of both diseases. Studies were under-represented in many regions owing to the latitudinal gradient of MS and possible underfunding of studies.

Disease-modifying therapies and SARS-CoV-2 vaccination in multiple sclerosis: an expert consensus

Coronavirus disease (COVID-19) appeared in December 2019 in the Chinese city of Wuhan and has quickly become a global pandemic. The disease is caused by the severe acute respiratory syndrome coronavirus type-2 (SARS-CoV-2), an RNA beta coronavirus phylogenetically similar to SARS coronavirus. To date, more than 132 million cases of COVID19 have been recorded in the world, of which over 2.8 million were fatal ( https://coronavirus.jhu.edu/map.html ). A huge vaccination campaign has started around the world since the end of 2020. The availability of vaccines has raised some concerns among neurologists regarding the safety and efficacy of vaccination in patients with multiple sclerosis (MS) taking immunomodulatory or immunosuppressive therapies.

Graves' disease with spontaneous resolution following ocrelizumab in primary progressive multiple sclerosis

Objectives. Immune reconstitution therapies (IRT), which include antibody-based cell-depleting therapies targeting CD52+ (alemtuzumab) or CD20+ (rituximab, ocrelizumab) leukocytes, are approved for the treatment of multiple sclerosis. Thyroid autoimmunity is a common adverse effect of alemtuzumab treatment, Graves' disease (GD) being the most prevalent manifestation. To date, thyroid autoimmunity events have not been reported with CD20-targeting monoclonal antibodies. Case Report. A 59-year-old woman with primary progressive multiple sclerosis with no prior personal history of thyroid disease or autoimmunity, was diagnosed with GD 6 months following the first ocrelizumab infusion. She was asymptomatic and had no signs of ophthalmopathy. Due to the temporal association of GD diagnosis with ocrelizumab infusion, absence of symptoms and our experience with alemtuzumab-induced GD, we decided for an active surveillance strategy and antithyroid drugs were not started. She underwent spontaneous resolution of hyperthyroidism with thyroid-stimulating hormone (TSH) receptor antibodies (TRAb) negativity and a mild and transitory period of subclinical hypothyroidism, while she continued the biannually ocrelizumab administration schedule. To present date, she has maintained close clinical and biochemical surveillance with normal TSH, free thyroxine (fT4) and free triiodothyronine (fT3) levels and undetectable TRAb. Conclusions. This is the first case of GD reported after ocrelizumab administration. The timing, onset and course of this case is similar to alemtuzumab-induced GD, usually interpreted as an "immune reconstitution syndrome"; however, ocrelizumab cell count depletion is inferior in severity, cell population affected and duration of depletion. This case highlights the importance of pre-screening and follow-up with thyroid function tests in patients treated with ocrelizumab. As a novel therapeutic antibody, further investigation is required to unravel the causes of thyroid autoimmunity.

[Autologous hematopoietic cells for severe autoimmune diseases: Guidelines of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) for immune monitoring and biobanking]

Autologous hematopoietic cell transplantation (AHCT) is a new treatment option for patients with severe autoimmune diseases (AD), based on the use of intensive or myeloablative chemotherapy to eradicate the pathogenic autoreactive immune cells and to allow the installation of a new and tolerant immune system during immune reconstitution process. Immune reconstitution analysis after AHCT is required for patients clinical follow-up and to further identify biological and immunological markers of the clinical response to develop individualized AHCT protocols. These MATHEC-SFGM-TC good clinical practice guidelines were developed by a multidisciplinary group of experts including members of the french reference center for stem Cell Therapy in Auto-immune Diseases (MATHEC), hematologists from the French speaking Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) and experts in immune monitoring and biobanking. The objectives are to provide practical recommandations for immune monitoring and biobanking of samples in patients with AD undergoing AHCT, for routine care purposes and investigational studies.

Dopaminergic Receptor Targeting in Multiple Sclerosis: Is There Therapeutic Potential?

Dopamine is a neurotransmitter that mediates neuropsychological functions of the central nervous system (CNS). Recent studies have shown the modulatory effect of dopamine on the cells of innate and adaptive immune systems, including Th17 cells, which play a critical role in inflammatory diseases of the CNS. This article reviews the literature data on the role of dopamine in the regulation of neuroinflammation in multiple sclerosis (MS). The influence of dopaminergic receptor targeting on experimental autoimmune encephalomyelitis (EAE) and MS pathogenesis, as well as the therapeutic potential of dopaminergic drugs as add-on pathogenetic therapy of MS, is discussed.

Digital Twins for Multiple Sclerosis

An individualized innovative disease management is of great importance for people with multiple sclerosis (pwMS) to cope with the complexity of this chronic, multidimensional disease. However, an individual state of the art strategy, with precise adjustment to the patient's characteristics, is still far from being part of the everyday care of pwMS. The development of digital twins could decisively advance the necessary implementation of an individualized innovative management of MS. Through artificial intelligence-based analysis of several disease parameters - including clinical and para-clinical outcomes, multi-omics, biomarkers, patient-related data, information about the patient's life circumstances and plans, and medical procedures - a digital twin paired to the patient's characteristic can be created, enabling healthcare professionals to handle large amounts of patient data. This can contribute to a more personalized and effective care by integrating data from multiple sources in a standardized manner, implementing individualized clinical pathways, supporting physician-patient communication and facilitating a shared decision-making. With a clear display of pre-analyzed patient data on a dashboard, patient participation and individualized clinical decisions as well as the prediction of disease progression and treatment simulation could become possible. In this review, we focus on the advantages, challenges and practical aspects of digital twins in the management of MS. We discuss the use of digital twins for MS as a revolutionary tool to improve diagnosis, monitoring and therapy refining patients' well-being, saving economic costs, and enabling prevention of disease progression. Digital twins will help make precision medicine and patient-centered care a reality in everyday life.

Long-term Clinical Outcomes of Hematopoietic Stem Cell Transplantation in Multiple Sclerosis

OBJECTIVE

To determine whether autologous hematopoietic stem cell transplantation (aHSCT) is able to induce durable disease remission in people with multiple sclerosis (MS), we analyzed the long-term outcomes after transplantation in a large cohort of patients with MS.

METHODS

To be included, a minimum dataset (consisting of age, MS phenotype, Expanded Disability Status Scale [EDSS] score at baseline, information on transplantation technology, and at least 1 follow-up visit after transplantation) was required.

RESULTS

Two hundred ten patients were included (relapsing-remitting [RR] MS 122 [58%]). Median baseline EDSS score was 6 (1-9); mean follow-up was 6.2 (±5.0) years. Among patients with RRMS, disability worsening-free survival (95% confidence interval [CI]) was 85.5% (76.9%-94.1%) at 5 years and 71.3% (57.8%-84.8%) at 10 years. In patients with progressive MS, disability worsening-free survival was 71.0% (59.4%-82.6%) and 57.2% (41.8%-72.7%) at 5 and 10 years, respectively. In patients with RRMS, EDSS significantly reduced after aHSCT (p = 0.001; mean EDSS change per year -0.09 [95% CI -0.15% to -0.04%]). In patients with RRMS, the use of the BCNU+Etoposide+Ara-C+Melphalan (BEAM) + anti-thymocyte globulin (ATG) conditioning protocol was independently associated with a reduced risk of no evidence of disease activity 3 failure (hazard ratio 0.27 [95% CI 0.14-0.50], p < 0.001). Three patients died within 100 days from aHSCT (1.4%); no deaths occurred in patients transplanted after 2007.

CONCLUSIONS

aHSCT prevents disability worsening in the majority of patients and induces durable improvement in disability in patients with RRMS. The BEAM + ATG conditioning protocol is associated with a more pronounced suppression of clinical relapses and MRI inflammatory activity.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that for people with MS, aHSCT induces durable disease remission in most patients.

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.

Second-generation immunotherapeutics in multiple sclerosis: can we discard their precursors?

Options for disease-modifying therapies in multiple sclerosis have increased over the past two decades. Among these innovations are interferon-β, glatiramer acetate, fumaric acid and dihydroorotate dehydrogenase inhibitors, an antibody targeting the migration of immune cells, a compound that traps immune cells in lymphoid organs by sphingosine 1-phosphate receptor (S1PR) modulation and immune-reconstitution therapies. Second-generation drugs such as pegylated interferon-β, advanced CD20 depleting antibodies, more-specific S1PR modulators and new formulations have been developed to achieve higher efficacy while exhibiting fewer side effects. In this review, we address the shortcomings of the parent drugs, present the pros and cons of the second-generation therapies and summarize upcoming developments in the field of immunotherapy for multiple sclerosis.

Immunology of COVID-19 and disease-modifying therapies: The good, the bad and the unknown

Objective

The outbreak of the SARS‐CoV‐2 pandemic, caused by a previously unknown infectious agent, posed unprecedented challenges to healthcare systems and unmasked their vulnerability and limitations worldwide. Patients with long‐term immunomodulatory/suppressive therapies, as well as their physicians, were and are concerned about balancing the risk of infection and effects of disease‐modifying therapy. Over the last few months, knowledge regarding SARS‐CoV‐2 has been growing tremendously, and the first experiences of infections in patients with multiple sclerosis (MS) have been reported.

Methods

This review summarizes the currently still limited knowledge about SARS‐CoV‐2 immunology and the commonly agreed modes of action of approved drugs in immune‐mediated diseases of the central nervous system (MS and neuromyelitis optica spectrum disorder). Specifically, we discuss whether immunosuppressive/immunomodulatory drugs may increase the risk of SARS‐CoV‐2 infection and, conversely, may decrease the severity of a COVID‐19 disease course.

Results

At present, it can be recommended in general that none of those therapies with a definite indication needs to be stopped per se. A possibly increased risk of infection for most medications is accompanied by the possibility to reduce the severity of COVID‐19.

Conclusions

Despite the knowledge gain over the last few months, current evidence remains limited, and, thus, further clinical vigilance and systematic documentation is essential.

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.

The Meaning of Immune Reconstitution after Alemtuzumab Therapy in Multiple Sclerosis

Alemtuzumab is a monoclonal antibody that binds to CD52, a protein present on the surface of mature lymphocytes, but not on the stem cells from which these lymphocytes are derived. It is currently used as an immune reconstitution therapy in patients with relapsing-remitting multiple sclerosis. Alemtuzumab treatment is an intermittent infusion that induces long-term remission of Multiple Sclerosis also in the treatment-free period. After the robust T and B cell depletion induced by alemtuzumab, the immune system undergoes radical changes during its reconstitution. In this review, we will discuss the current knowledge on the reconstitution of the lymphocyte repertoire after alemtuzumab treatment and how it could affect the development of side effects, which led to its temporary suspension by the European Medical Agency.

Immune Reconstitution Therapy or Continuous Immunosuppression for the Management of Active Relapsing-Remitting Multiple Sclerosis Patients? A Narrative Review

The majority of disease-modifying drugs (DMDs) available for the management of active relapsing-remitting multiple sclerosis (RMS) depend on continuous drug intake for maintained efficacy, with escalation to a more active drug when an unacceptable level of disease activity returns. Among continuously applied regimens, interferons and glatiramer acetate act as immunomodulators, while dimethyl fumarate, fingolimod, ocrelizumab, natalizumab and teriflunomide are associated with continuous immunosuppression. By contrast, immune reconstitution therapy (IRT) provides efficacy that outlasts a short course of treatment. Autologous hemopoietic stem cell transplantation is perhaps the classic example of IRT, but this invasive and intensive therapy has challenging side-effects. A short treatment course of a pharmacologic agent hypothesized to act as an IRT, such as Cladribine Tablets 3.5 mg/kg or alemtuzumab, can provide long-term suppression of MS disease activity, without need for continuous treatment (the anti-CD20 mechanism of ocrelizumab has the potential to act as an IRT, but is administered continuously, at 6-monthly intervals). Cladribine Tablets 3.5 mg/kg shows some selectivity in targeting adaptive immunity with a lesser effect on innate immunity. The introduction of IRT-like disease-modifying drugs (DMDs) challenges the traditional maintenance/escalation mode of treatment and raises new questions about how disease activity is measured. In this review, we consider a modern classification of DMDs for MS and its implications for the care of patients in the IRT era.