T-cell responses after haematopoietic stem cell transplantation for aggressive relapsing-remitting multiple sclerosis

Immunological outcomes of autologous hematopoietic stem cell transplantation for multiple sclerosis: a systematic review

Background

Autologous hematopoietic stem cell transplantation (AHSCT) is an extensive procedure that allows for the depletion of the immune system and its restoration from hemopoietic stem cells. The approach has been modified for the treatment of severe immune-mediated illnesses, including multiple sclerosis (MS), after being initially devised for the treatment of hematological malignancies.

Objective

This systematic review aims to determine and consolidate the information on the short-term and long-term immunological effects of AHSCT on the cellular level in MS patients.

Methods

The PubMed, Scopus, and Web of Science servers were used to conduct a systematic search in compliance with the PRISMA guidelines. The results were tabulated and analyzed.

Results

A total of 17 studies (10 clinical trials, 6 cohort studies, and 1 case-control study) were included in the final analysis, and 383 MS patients were analyzed. A significant decline in the cell count of CD4 T cells was reported when compared to the CD8 T cells, B cells, and NK cells. B cell count returned to baseline in 71.4% of the studies at the end of 6 months. The NK cell count was found to be above the baseline in 62.5% of studies.

Conclusion

AHSCT has been proven to be one of the most effective treatment modalities for MS in recent studies. However, debilitating complications due to immunological outcomes of the procedure have led to increased morbidity. Further research into this domain will help boost the success rate and efficacy of AHSCT.

Dynamics of T cell repertoire renewal following autologous hematopoietic stem cell transplantation in multiple sclerosis

Autologous hematopoietic stem cell transplantation (aHSCT) is a highly effective treatment of multiple sclerosis (MS). It depletes autoreactive cells and subsequently renews adaptive immune cells. The possible proinflammatory potential of surviving T cells early after aHSCT has not been studied. Here, we examined the dynamics of new and surviving T cells in 27 patients after aHSCT by multidimensional flow cytometry, T cell receptor (TCR) sequencing, specificity testing, telomere length profiling, and HLA genotyping. Early after aHSCT, naïve T cells are barely detectable, whereas effector memory (EM) T cells quickly reconstitute to pre-aHSCT values. EM CD4+T cells early after aHSCT have shorter telomeres, have higher expression of senescence and exhaustion markers, and proliferate less than those before aHSCT. We find a median TCR repertoire overlap of 26% between the early post-aHSCT EM CD4+T cells and pre-aHSCT, indicating persistence of EM CD4+T cells early after transplantation. The EM CD4+TCR repertoire overlap declines to 15% at 12 months after aHSCT, whereas the naïve TCR repertoire entirely renews. HLA-DR–associated EM CD4+T cell reactivity toward MS-related antigens decreased after aHSCT, whereas reactivity toward EBV increased. Our data show substantial survival of pre-aHSCT EM CD4+T cells early after transplantation but complete renewal of the T cell repertoire by nascent T cells later.

[Multiple sclerosis: interventions to halt disease : Which patients can be considered for autologous stem cell transplantation]

BACKGROUND

Autologous hematopoietic stem cell transplantation (aHSCT) for treatment of multiple sclerosis (MS) is gaining increasing prominence in the therapeutic landscape. This review article focuses on describing the evidence and European guidelines for aHSCT so that neurologists in Germany can consider this treatment option for appropriate MS patients. In this context, it must be taken into consideration that in every case a cost transfer must be individually applied for.

AIM

To provide information for neurologists considering aHSCT for patients with MS.

MATERIAL AND METHODS

In this narrative review articles from PubMed were pooled and analyzed.

RESULTS AND DISCUSSION

High quality data from randomized, controlled clinical trials are required to compare the efficacy of aHSCT to the currently available highly effective disease-modifying therapies (DMT) so that reliable conclusions can be drawn regarding the relationship between the risks and benefits of aHSCT in MS; however, the studies discussed in this review provide important points of reference for patient selection and the transplantation protocol. Further advice is available from the European Society for Blood and Marrow Transplantation (EBMT) for experienced centers considering aHSCT. The available data and the European guidelines suggest that patients aged less than 45 years, an expanded disability status scale (EDSS) ≤ 5.5, highly active MS, a disease duration of less than 10 years, an ineffective course of DMT or rapidly progressive MS may be eligible for aHSCT and should be referred to an experienced center for further assessment.

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.

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?

Stem Cell Therapy in Neuroimmunological Diseases and Its Potential Neuroimmunological Complications

Background: Since the 1990s, transplantations of hematopoietic and mesenchymal stem cells (HSCT and MSCT) and dendritic cell (DCT) have been investigated for the treatment of neurological autoimmune disorders (NADs). With the growing number of transplanted patients, awareness of neuroimmunolgical complications has increased. Therefore, an overview of SCT for the most common NADs and reports of secondary immunity after SCT is provided. Methods: For this narrative review, a literature search of the PubMed database was performed. A total of 86 articles reporting on different SCTs in NADs and 61 articles dealing with immune-mediated neurological complications after SCT were included. For multiple sclerosis (MS), only registered trials and phase I/II or II studies were considered, whereas all available articles on other disorders were included. The different transplantation procedures and efficacy and safety data are presented. Results: In MS patients, beneficial effects of HSCT, MSCT, and DCT with a decrease in disability and stabilization of disease activity have been reported. These effects were also shown in other NADs mainly in case reports. In seven of 132 reported patients with immune-mediated neurological complications, the outcome was fatal. Conclusions: Phase III trials are ongoing for MS, but the role of SCT in other NADs is currently limited to refractory patients due to occasional serious complications.

Haematopoietic Stem Cell Transplantation Results in Extensive Remodelling of the Clonal T Cell Repertoire in Multiple Sclerosis

Autologous haematopoietic stem cell transplantation (AHSCT) is a vital therapeutic option for patients with highly active multiple sclerosis (MS). Rates of remission suggest AHSCT is the most effective form of immunotherapy in controlling the disease. Despite an evolving understanding of the biology of immune reconstitution following AHSCT, the mechanism by which AHSCT enables sustained disease remission beyond the period of lymphopenia remains to be elucidated. Auto-reactive T cells are considered central to MS pathogenesis. Here, we analyse T cell reconstitution for 36 months following AHSCT in a cohort of highly active MS patients. Through longitudinal analysis of sorted naïve and memory T cell clones, we establish that AHSCT induces profound changes in the dominant T cell landscape of both CD4+ and CD8+ memory T cell clones. Lymphopenia induced homeostatic proliferation is followed by clonal attrition; with only 19% of dominant CD4 (p <0.025) and 13% of dominant CD8 (p <0.005) clones from the pre-transplant repertoire detected at 36 months. Recovery of a thymically-derived CD4 naïve T cell repertoire occurs at 12 months and is ongoing at 36 months, however diversity of the naïve populations is not increased from baseline suggesting the principal mechanism of durable remission from MS after AHSCT relates to depletion of putative auto-reactive clones. In a cohort of MS patients expressing the MS risk allele HLA DRB1*15:01, public clones are probed as potential biomarkers of disease. AHSCT appears to induce sustained periods of disease remission with dynamic changes in the clonal T cell repertoire out to 36 months post-transplant.

Sustained immunotolerance in multiple sclerosis after stem cell transplant

Objective

Autologous haematopoietic stem cell transplantation (AHSCT) has the potential to induce sustained periods of disease remission in multiple sclerosis (MS), which is an inflammatory disease of the central nervous system (CNS) characterised by demyelination and axonal degeneration. However, the mechanisms associated with durable treatment responses in MS require further elucidation.

Methods

To characterise the longer term immune reconstitution effects of AHSCT at 24 and 36 months (M) post‐transplant, high‐dimensional immunophenotyping of peripheral blood mononuclear cells from 22 MS patients was performed using two custom‐designed 18‐colour flow cytometry panels.

Results

The higher baseline frequencies of specific pro‐inflammatory immune cells (T‐helper‐17 (Th17) cells, mucosal‐associated invariant T‐cells and CNS‐homing T‐conventional (T‐conv) cells observed in MS patients were decreased post‐AHSCT by 36M. This was accompanied by a post‐AHSCT increase in frequencies and absolute counts of immunoregulatory CD56^hi natural killer cells at 24M and terminally differentiated CD8⁺CD28⁻CD57⁺ cells until 36M. A sustained increase in the proportion of naïve B‐cells, with persistent depletion of memory B‐cells and plasmablasts was observed until 36M. Reconstitution of the B‐cell repertoire was accompanied by a reduction in the frequency of circulating T‐follicular helper cells (cTfh) expressing programmed cell death‐1 (PD1⁺) at 36M. Associations between frequency dynamics and clinical outcomes indicated only responder patients to exhibit a decrease in Th17, CNS‐homing T‐conv and PD1⁺ cTfh pro‐inflammatory subsets at 36M, and an increase in CD39⁺ T‐regulatory cells at 24M.

Interpretation

AHSCT induces substantial recalibration of pro‐inflammatory and immunoregulatory components of the immune system of MS patients for up to 36M post‐transplant.

Approaches to Establishing Tolerance in Immune Mediated Diseases

The development of rational approaches to restore immune tolerance requires an iterative approach that builds on past success and utilizes new mechanistic insights into immune-mediated pathologies. This article will review concepts that have evolved from the clinical trial experience of the Immune Tolerance Network, with an emphasis on lessons learned from the innovative mechanistic studies conducted for these trials and new strategies under development for induction of tolerance.

Immune reconstitution therapy in NMOSD

IMPORTANCE

NMO spectrum disorders [NMOSD] is a relapsing autoimmune disorder with attacks of optic neuritis (ON) and transverse myelitis (TM). A large proportion of NMOSD patients have no or a partial recovery after relapse.

OBSERVATIONS

The neuro-immunological community now has a number of indicated agents for NMOSD therapy including eculizumab [Soliris®], inebilizumab (Uplizna®) and satralizumab (Enspryng®) with different mechanisms of action (MOA), rapidity of the onset of action (OOA) and issues of long-term safety. Autologous hematopoietic stem cell transplantation (AHSCT) may be another therapeutic option.

CONCLUSIONS AND RELEVANCE

The advantages of eculizumab are preservation of immunosurveillance, immediate onset of action and persistent efficacy but frequent IV administration and cost are important drawbacks. Inebilizumab allows a slight decrease in relapse free subjects over time but decreases B and plasmablast cell disease-inducing pathogenic antibody production. However, inebilizumab may cause immunosuppression. Satralizumab is immunomodulatory and self-administration but has delayed onset of action. AHSCT may be the best therapeutic option for the prevention and therefore the progression of NMO. In NMO, control the complement (eculizumab), reconstitute the immune system (AHSCT), transition to immunomodulation (satralizumab) and reserve immunosuppression (inebilizumab) as 4th line. AHSCT might also be used as rescue therapy for severe breakthrough disease after NMO-DMTs.

Autologous Hematopoietic Stem Cell Transplantation (AHSCT): An Evolving Treatment Avenue in Multiple Sclerosis

Autologous hematopoietic stem cell transplantation (AHSCT) is considered as the novel approach to improve multiple sclerosis (MS) patients with disease-modifying therapies (DMTs)-resistance. The results obtained from different studies indicate that AHSCT increases the life quality of MS patients. Several factors are known to be influenced on the successful rate of AHSCT in patients with MS. The individuals aged <40 years with a short duration of MS disease have been demonstrated to show a better response to AHSCT administration. Furthermore, this treatment approach was more effective in relapsing remitting MS (RRMS) patients than progressive MS (PMS). Different clinical trials revealed that AHSCT with a low density conditioning regimen could be suggested as a suitable candidate approach in the management of MS. Several molecular and cellular mechanisms are known to be involved in the resetting of the immune system following the AHSCT infusion in MS patients. These mechanisms play a role in the depletion of auto-reactive lymphocytes and immune system renewal. In the present review, we discuss different clinical and molecular aspects of AHSCT application in the alleviation of MS symptoms.

Autologous hematopoietic stem-cell transplantation in neurological disorders: current approach and future directions

INTRODUCTION

Autologous hematopoietic stem-cell transplantation (AHSCT) has become increasingly popular in recent years as an effective treatment of immune-mediated neurological diseases. Treatment-related mortality has significantly reduced primarily through better patient selection, optimization of transplant technique, and increased center experience.

AREA COVERED

Multiple sclerosis is the main indication, but people with neuromyelitis optica spectrum disorder, stiff-person spectrum disorder, chronic inflammatory demyelinating polyneuropathy, myasthenia gravis, and other immune-mediated neurological disorders also have been treated. The review herein discusses the use of AHSCT in these neurological disorders, the importance of patient selection and transplant technique optimization and future directions.

EXPERT OPINION

Phase II and III clinical trials have confirmed the safety and efficacy of AHSCT in multiple sclerosis and recent phase II clinical trials have also suggested its safety and efficacy in chronic inflammatory demyelinating polyneuropathy and neuromyelitis optica spectrum disorder, with the evidence in other neurological disorders limited to individual case reports, small case series, and registry data. Therefore, further randomized controlled clinical trials are required to assess its safety and efficacy in other neurological conditions. However, in rare neurological conditions, pragmatic treatment trials or registry-based studies may be more realistic options for gathering efficacy and safety data.

Aggressive multiple sclerosis (1): Towards a definition of the phenotype

While the major phenotypes of multiple sclerosis (MS) and relapsing-remitting, primary and secondary progressive MS have been well characterized, a subgroup of patients with an active, aggressive disease course and rapid disability accumulation remains difficult to define and there is no consensus about their management and treatment. The current lack of an accepted definition and treatment guidelines for aggressive MS triggered a 2018 focused workshop of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) on aggressive MS. The aim of the workshop was to discuss approaches on how to describe and define the disease phenotype and its treatments. Unfortunately, it was not possible to come to consensus on a definition because of unavailable data correlating severe disease with imaging and molecular biomarkers. However, the workshop highlighted the need for future research needed to define this disease subtype while also focusing on its treatment and management. Here, we review previous attempts to define aggressive MS and present characteristics that might, with additional research, eventually help characterize it. A companion paper summarizes data regarding treatment and management.

Dawn of Monitoring Regulatory T Cells in (Pre-)clinical Studies: Their Relevance Is Slowly Recognised

Regulatory T cells (Tregs) have a prominent role in the control of immune homeostasis. Pharmacological impact on their activity or balance with effector T cells could contribute to (impaired) clinical responses or adverse events. Monitoring treatment-related effects on T cell subsets may therefore be part of (pre-)clinical studies for medicinal products. However, the extent of immune monitoring performed in studies for marketing authorisation and the degree of correspondence with data available in the public domain is not known. We evaluated the presence of T cell immunomonitoring in 46 registration dossiers of monoclonal antibodies indicated for immune-related disorders and published scientific papers. We found that the depth of Treg analysis in registration dossiers was rather small. Nevertheless, data on treatment-related Treg effects are available in public academia-driven studies (post-registration) and suggest that Tregs may act as a biomarker for clinical responses. However, public data are fragmented and obtained with heterogeneity of experimental approaches from a diversity of species and tissues. To reveal the potential added value of T cell (and particular Treg) evaluation in (pre-)clinical studies, more cell-specific data should be acquired, at least for medicinal products with an immunomodulatory mechanism. Therefore, extensive analysis of T cell subset contribution to clinical responses and the relevance of treatment-induced changes in their levels is needed. Preferably, industry and academia should work together to obtain these data in a standardised manner and to enrich our knowledge about T cell activity in disease pathogenesis and therapies. This will ultimately elucidate the necessity of T cell subset monitoring in the therapeutic benefit-risk assessment.

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

Immune reconstitution therapy (IRT) is an emerging concept for the treatment of multiple sclerosis (MS) that is given intermittently and can induce long-term remission of MS that is sustained in treatment-free periods. A systematic literature review was performed to identify and summarize current knowledge regarding the short- and long-term immunological consequences of different IRTs and CD20 depleting therapies on the cellular level in patients with MS. A total of 586 articles published between January 2010 and September 2019 were identified and screened; 44 studies met inclusion criteria for the review. All the treatments considered appeared to produce both qualitative and quantitative changes in the immune cell populations of patients with MS that resulted in a more anti-inflammatory immune profile. Autologous hematopoietic stem cell transplantation produced the longest-lasting and greatest effects on a wide range of immune cells. Many patients achieved prolonged depletion of the adaptive immune system when alemtuzumab and cladribine tablets were administered as short courses of therapy; however, a proportion of patients required retreatment to maintain these effects. Alemtuzumab may produce greater depletion of both CD4+ and CD8+ T cells than cladribine tablets, although both treatments similarly deplete B cells. Recovery of B cells before T cell recovery and hyperpopulation of B cells after alemtuzumab may contribute to secondary autoimmunity. Cladribine tablets had a greater effect on B cells than T cells, and no hyperpopulation of B cells was observed after treatment with cladribine tablets. Ocrelizumab and rituximab require regular repeated treatment every 6 months to maintain depletion of B and T cells. Effects of the drug treatments on the innate immune system were minor compared with those on the adaptive immune system. Additional characterization of the cellular changes occurring during IRT and CD20 depletion may lead to further improvement in the understanding of the pathogenesis of MS and the future development of therapies with even longer lasting effects. Although the treatments considered in this review improve quality of life and outcomes for patients with MS, a cure for this debilitating disease is not yet in sight.

Autologous haematopoietic stem cell transplantation and other cellular therapy in multiple sclerosis and immune-mediated neurological diseases: updated guidelines and recommendations from the EBMT Autoimmune Diseases Working Party (ADWP) and the Joint Accreditation Committee of EBMT and ISCT (JACIE)

These updated EBMT guidelines review the clinical evidence, registry activity and mechanisms of action of haematopoietic stem cell transplantation (HSCT) in multiple sclerosis (MS) and other immune-mediated neurological diseases and provide recommendations for patient selection, transplant technique, follow-up and future development. The major focus is on autologous HSCT (aHSCT), used in MS for over two decades and currently the fastest growing indication for this treatment in Europe, with increasing evidence to support its use in highly active relapsing remitting MS failing to respond to disease modifying therapies. aHSCT may have a potential role in the treatment of the progressive forms of MS with a significant inflammatory component and other immune-mediated neurological diseases, including chronic inflammatory demyelinating polyneuropathy, neuromyelitis optica, myasthenia gravis and stiff person syndrome. Allogeneic HSCT should only be considered where potential risks are justified. Compared with other immunomodulatory treatments, HSCT is associated with greater short-term risks and requires close interspeciality collaboration between transplant physicians and neurologists with a special interest in these neurological conditions before, during and after treatment in accredited HSCT centres. Other experimental cell therapies are developmental for these diseases and patients should only be treated on clinical trials.

Safety and efficacy of stem cell therapy for treatment of neural damage in patients with multiple sclerosis

Multiple sclerosis (MS) is a multifocal inflammatory disease that involves the central nervous system and associated with limbs paralysis and serious problems in sensation, limbs, visual and sphincter. This disease is a result of autoimmune mechanism in which autoantibodies target the self-myelin antigens and cause demyelination. Because of the myelin dysfunction, MS is clinically identified with neurological disabilities. Furthermore, it can be entered into the progressive phase because of irreversible neurodegeneration and axons damage. Unfortunately, there is no effective therapeutic method for this disease and current medications have been focused on amelioration of symptoms and chronic inflammation. Although current immunotherapies ameliorate the reactivity of autoimmune anti-myelin and MS relapse rate, there is no approved method for improvement of the disease progression and repairing of the damaged myelin. Therefore, finding an appropriate clinical treatment for improvement of neurological damages in MS patients is essential. Mesenchymal stem cells (MSCs) are multipotent cells with high proliferative and self-renewal capacities, as well as immunomodulatory and neuroregenerative effects. Bone marrow and adipose tissues derived MSCs have been considered for the treatment of different diseases because not only they can be easily isolated from these tissues, but also a patient can be served as a donor for himself without the risk of rejection. More importantly, autologous MSCs carry a safer pattern without the risk of malignant transformation. Here, we will discuss the effectiveness of MSCs therapy for MS patients by reviewing of clinical trials.

Outcomes and Cost-Effectiveness of Autologous Hematopoietic Cell Transplant for Multiple Sclerosis

PURPOSE OF REVIEW

This review presents a critical appraisal of the use of autologous hematopoietic cell transplant (AHCT) for the treatment of multiple sclerosis. We present the reader with a brief review on the AHCT procedure, its immunomodulatory mechanism of action in MS, the most recent evidence in support of its use in patients with relapsing-remitting multiple sclerosis (RRMS), as well as its cost considerations.

RECENT FINDINGS

The first meta-analysis of clinical trials of AHCT for patients with MS demonstrated durable 5-year progression-free survival rates and low treatment-related mortality. Recently, the first randomized controlled phase III clinical trial demonstrated AHCT to be superior to best available therapy for a subset of patients with RRMS. This led to the American society for transplant and cellular therapies (ASTCT) to recommend AHCT "for patients with relapsing forms of MS who have prognostic factors that indicate a high risk of future disability." AHCT should be considered for patients with RRMS with evidence of clinical activity who have failed 2 lines of therapy or at least one highly active disease-modifying therapy.

Pro-Thrombotic Activity of Blood Platelets in Multiple Sclerosis

The available data, including experimental studies, clearly indicate an excessive intravascular activation of circulating platelets in multiple sclerosis (MS) and their hyper-responsiveness to a variety of physiological activators. Platelet activation is manifested as an increased adhesion and aggregation and is accompanied by the formation of pro-thrombotic microparticles. Activated blood platelets also show an expression of specific membrane receptors, synthesis many of biomediators, and generation of reactive oxygen species. Epidemiological studies confirm the high risk of stroke or myocardial infarction in MS that are ischemic incidents, strictly associated with incorrect platelet functions and their over pro-thrombotic activity. Chronic inflammation and high activity of pro-oxidative processes in the course of MS are the main factors identified as the cause of excessive platelet activation. The primary biological function of platelets is to support vascular integrity, but the importance of platelets in inflammatory diseases is also well documented. The pro-thrombotic activity of platelets and their inflammatory properties play a part in the pathophysiology of MS. The analysis of platelet function capability in MS could provide useful information for studying the pathogenesis of this disease. Due to the complexity of pathological processes in MS, medication must be multifaceted and blood platelets can probably be identified as new targets for therapy in the future.

Effect of Nonmyeloablative Hematopoietic Stem Cell Transplantation vs Continued Disease-Modifying Therapy on Disease Progression in Patients With Relapsing-Remitting Multiple Sclerosis: A Randomized Clinical Trial

IMPORTANCE

Hematopoietic stem cell transplantation (HSCT) represents a potentially useful approach to slow or prevent progressive disability in relapsing-remitting multiple sclerosis (MS).

OBJECTIVE

To compare the effect of nonmyeloablative HSCT vs disease-modifying therapy (DMT) on disease progression.

DESIGN, SETTING, AND PARTICIPANTS

Between September 20, 2005, and July 7, 2016, a total of 110 patients with relapsing-remitting MS, at least 2 relapses while receiving DMT in the prior year, and an Expanded Disability Status Scale (EDSS; score range, 0-10 [10 = worst neurologic disability]) score of 2.0 to 6.0 were randomized at 4 US, European, and South American centers. Final follow-up occurred in January 2018 and database lock in February 2018.

INTERVENTIONS

Patients were randomized to receive HSCT along with cyclophosphamide (200 mg/kg) and antithymocyte globulin (6 mg/kg) (n = 55) or DMT of higher efficacy or a different class than DMT taken during the previous year (n = 55).

MAIN OUTCOMES AND MEASURES

The primary end point was disease progression, defined as an EDSS score increase after at least 1 year of 1.0 point or more (minimal clinically important difference, 0.5) on 2 evaluations 6 months apart, with differences in time to progression estimated as hazard ratios.

RESULTS

Among 110 randomized patients (73 [66%] women; mean age, 36 [SD, 8.6] years), 103 remained in the trial, with 98 evaluated at 1 year and 23 evaluated yearly for 5 years (median follow-up, 2 years; mean, 2.8 years). Disease progression occurred in 3 patients in the HSCT group and 34 patients in the DMT group. Median time to progression could not be calculated in the HSCT group because of too few events; it was 24 months (interquartile range, 18-48 months) in the DMT group (hazard ratio, 0.07; 95% CI, 0.02-0.24; P < .001). During the first year, mean EDSS scores decreased (improved) from 3.38 to 2.36 in the HSCT group and increased (worsened) from 3.31 to 3.98 in the DMT group (between-group mean difference, -1.7; 95% CI, -2.03 to -1.29; P < .001). There were no deaths and no patients who received HSCT developed nonhematopoietic grade 4 toxicities (such as myocardial infarction, sepsis, or other disabling or potential life-threatening events).

CONCLUSIONS AND RELEVANCE

In this preliminary study of patients with relapsing-remitting MS, nonmyeloablative HSCT, compared with DMT, resulted in prolonged time to disease progression. Further research is needed to replicate these findings and to assess long-term outcomes and safety.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00273364.

Immune Reconstitution After Autologous Hematopoietic Stem Cell Transplantation in Crohn's Disease: Current Status and Future Directions. A Review on Behalf of the EBMT Autoimmune Diseases Working Party and the Autologous Stem Cell Transplantation In Refractory CD-Low Intensity Therapy Evaluation Study Investigators

Patients with treatment refractory Crohn's disease (CD) suffer debilitating symptoms, poor quality of life, and reduced work productivity. Surgery to resect inflamed and fibrotic intestine may mandate creation of a stoma and is often declined by patients. Such patients continue to be exposed to medical therapy that is ineffective, often expensive and still associated with a burden of adverse effects. Over the last two decades, autologous hematopoietic stem cell transplantation (auto-HSCT) has emerged as a promising treatment option for patients with severe autoimmune diseases (ADs). Mechanistic studies have provided proof of concept that auto-HSCT can restore immunological tolerance in chronic autoimmunity via the eradication of pathological immune responses and a profound reconfiguration of the immune system. Herein, we review current experience of auto-HSCT for the treatment of CD as well as approaches that have been used to monitor immune reconstitution following auto-HSCT in patients with ADs, including CD. We also detail immune reconstitution studies that have been integrated into the randomized controlled Autologous Stem cell Transplantation In refractory CD-Low Intensity Therapy Evaluation trial, which is designed to test the hypothesis that auto-HSCT using reduced intensity mobilization and conditioning regimens will be a safe and effective means of inducing sustained control in refractory CD compared to standard of care. Immunological profiling will generate insight into the pathogenesis of the disease, restoration of responsiveness to anti-TNF therapy in patients with recurrence of endoscopic disease and immunological events that precede the onset of disease in patients that relapse after auto-HSCT.

Regenerating Immunotolerance in Multiple Sclerosis with Autologous Hematopoietic Stem Cell Transplant

Multiple sclerosis (MS) is an inflammatory disorder of the central nervous system where evidence implicates an aberrant adaptive immune response in the accrual of neurological disability. The inflammatory phase of the disease responds to immunomodulation to varying degrees of efficacy; however, no therapy has been proven to arrest progression of disability. Recently, more intensive therapies, including immunoablation with autologous hematopoietic stem cell transplantation (AHSCT), have been offered as a treatment option to retard inflammatory disease, prior to patients becoming irreversibly disabled. Empirical clinical observations support the notion that the immune reconstitution (IR) that occurs following AHSCT is associated with a sustained therapeutic benefit; however, neither the pathogenesis of MS nor the mechanism by which AHSCT results in a therapeutic benefit has been clearly delineated. Although the antigenic target of the aberrant immune response in MS is not defined, accumulated data suggest that IR following AHSCT results in an immunotolerant state through deletion of pathogenic clones by a combination of direct ablation and induction of a lymphopenic state driving replicative senescence and clonal attrition. Restoration of immunoregulation is evidenced by changes in regulatory T cell populations following AHSCT and normalization of genetic signatures of immune homeostasis. Furthermore, some evidence exists that AHSCT may induce a rebooting of thymic function and regeneration of a diversified naïve T cell repertoire equipped to appropriately modulate the immune system in response to future antigenic challenge. In this review, we discuss the immunological mechanisms of IR therapies, focusing on AHSCT, as a means of recalibrating the dysfunctional immune response observed in MS.

Immune response after autologous hematopoietic stem cell transplantation in type 1 diabetes mellitus

Background

This study explored the details of the immune response after autologous hematopoietic stem cell transplantation (AHSCT) treatment in type 1 diabetes mellitus.

Methods

Peripheral blood mononuclear cells (PBMCs) from 18 patients with type 1 diabetes mellitus were taken at baseline and 12 months after AHSCT or insulin-only therapy. The lymphocyte proliferation, mRNA expression and secretion of pro-inflammatory and anti-inflammatory cytokines belonging to T-helper type 1 (Th1), T-helper type 17 (Th17) and regulatory T (Treg) cells in PBMC culture supernatants were assessed.

Results

Compared with patients receiving insulin-only treatment, the patients receiving AHSCT treatment showed better residual C-peptide secretion, lower anti-GAD titers and less exogenous insulin dosages after 12 months of follow-up. AHSCT treatment was associated with significantly reduced Th1 and Th17 cell proportions as well as decreased IFN-γ, IL-2, IL-12p40 and IL-17A levels in the PBMC culture supernatants (all P < 0.05). Although there was no significant Treg cell expansion after AHSCT treatment, we observed increased IL-10, TGF-β and Foxp3 mRNA expression and increased TGF-β levels. However, we found no significant changes in the T-cell subpopulations after insulin treatment, except for higher IL-12p40 mRNA expression and a lower proportion of Treg cells.

Conclusions

AHSCT treatment was associated with decreased expansion and function of Th1 and Th17 cells, which may explain the better therapeutic effect of AHSCT compared with the traditional intensive insulin therapy.

Trial registration

Clinicaltrials.gov NCT00807651. Registered 18 December 2008.

Lymphocyte reconstitution following autologous stem cell transplantation for progressive MS

BACKGROUND

Autologous stem cell transplantation (ASCT) for progressive multiple sclerosis (MS) may reset the immune repertoire.

OBJECTIVE

The objective of this paper is to analyse lymphocyte recovery in patients with progressive MS treated with ASCT.

METHODS

Patients with progressive MS not responding to conventional treatment underwent ASCT following conditioning with high-dose cyclophosphamide and antithymocyte globulin. Lymphocyte subset analysis was performed before ASCT and for two years following ASCT. Neurological function was assessed by the EDSS before ASCT and for three years post-ASCT.

RESULTS

CD4+ T-cells fell significantly post-transplant and did not return to baseline levels. Recent thymic emigrants and naïve T-cells fell sharply post-transplant but returned to baseline by nine months and twelve months, respectively. T-regulatory cells declined post-transplant and did not return to baseline levels. Th1 and Th2 cells did not change significantly while Th17 cells fell post-transplant but recovered to baseline by six months. Neurological function remained stable in the majority of patients. Progression-free survival was 69% at three years.

CONCLUSION

This study demonstrates major changes in the composition of lymphocyte subsets following ASCT for progressive MS. In particular, ablation and subsequent recovery of thymic output is consistent with the concept that ASCT can reset the immune repertoire in MS patients.

Adoptive transfer of cytokine-induced immunomodulatory adult microglia attenuates experimental autoimmune encephalomyelitis in DBA/1 mice

Microglia are resident antigen-presenting cells in the central nervous system (CNS) that either suppress or promote disease depending on their activation phenotype and the microenvironment. Multiple sclerosis (MS) is a chronic inflammatory disease causing demyelination and nerve loss in the CNS, and experimental autoimmune encephalomyelitis (EAE) is an animal model of MS that is widely used to investigate pathogenic mechanisms and therapeutic effects. We isolated and cultured microglia from adult mouse brains and exposed them to specific combinations of stimulatory molecules and cytokines, the combination of IL-4, IL-10, and TGF-β yielding the optimal regime for induction of an immunosuppressive phenotype (M2). M2 microglia were characterized by decreased expression or production of CD86, PD-L1, nitric oxide, and IL-6, increased expression of PD-L2, and having a potent capacity to retain their phenotype on secondary proinflammatory stimulation. M2 microglia induced regulatory T cells, suppressed T-cell proliferation, and downmodulated M1-associated receptor expression in M1 macrophages. Myelin oligodendrocyte glycoprotein (MOG)-induced EAE was induced in DBA/1 mice and at different time points (0, 5, 12, or 15 days postimmunization) 3 × 10⁵ M2 microglia were transferred intranasally. A single transfer of M2 microglia attenuated the severity of established EAE, which was particularly obvious when the cells were injected at 15 days postimmunization. M2 microglia-treated mice had reduced inflammatory responses and less demyelination in the CNS. Our findings demonstrate that adult M2 microglia therapy represents a novel intervention that alleviated established EAE and that this therapeutic principle may have relevance for treatment of MS patients.

The cerebrospinal fluid cytokine signature of multiple sclerosis: a homogenous response that does not conform to the Th1/Th2/Th17 convention

In this cross-sectional study, we wanted to identify key cytokines characteristic of different stages of multiple sclerosis (MS). To this end, cerebrospinal fluid from patients with MS was investigated with a multiplexed fluorescent bead-based immunoassay. In total 43 cytokines were assessed and related to clinical and imaging data. Increased levels of CCL22, CXCL10 and sCD40L characterized relapsing-remitting MS patients with the presence of gadolinium-enhancing lesions; decreased CCL2 and increased CXCL1 and CCL5 were typical of relapsing-remitting MS patients irrespectively of the presence of gadolinium-enhancing lesions. These homogenous patterns of cytokine activation do not conform to conventional Th1/Th2/Th17 responses.

Autologous haematopoietic stem cell transplantation for aggressive multiple sclerosis: the Swedish experience

BACKGROUND

Autologous haematopoietic stem cell transplantation (HSCT) is a viable option for treatment of aggressive multiple sclerosis (MS). No randomised controlled trial has been performed, and thus, experiences from systematic and sustained follow-up of treated patients constitute important information about safety and efficacy. In this observational study, we describe the characteristics and outcome of the Swedish patients treated with HSCT for MS.

METHODS

Neurologists from the major hospitals in Sweden filled out a follow-up form with prospectively collected data. Fifty-two patients were identified in total; 48 were included in the study and evaluated for safety and side effects; 41 patients had at least 1 year of follow-up and were further analysed for clinical and radiological outcome. In this cohort, 34 patients (83%) had relapsing-remitting MS, and mean follow-up time was 47 months.

RESULTS

At 5 years, relapse-free survival was 87%; MRI event-free survival 85%; expanded disability status scale (EDSS) score progression-free survival 77%; and disease-free survival (no relapses, no new MRI lesions and no EDSS progression) 68%. Presence of gadolinium-enhancing lesions prior to HSCT was associated with a favourable outcome (disease-free survival 79% vs 46%, p=0.028). There was no mortality. The most common long-term side effects were herpes zoster reactivation (15%) and thyroid disease (8.4%).

CONCLUSIONS

HSCT is a very effective treatment of inflammatory active MS and can be performed with a high degree of safety at experienced centres.