MRI and CSF oligoclonal bands after autologous hematopoietic stem cell transplantation in MS

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.

Pathology-supported genetic testing as a method for disability prevention in multiple sclerosis (MS). Part I. Targeting a metabolic model rather than autoimmunity

In this Review (Part I), we investigate the scientific evidence that multiple sclerosis (MS) is caused by the death of oligodendrocytes, the cells that synthesize myelin, due to a lack of biochemical and nutritional factors involved in mitochondrial energy production in these cells. In MS, damage to the myelin sheaths surrounding nerve axons causes disruption of signal transmission from the brain to peripheral organs, which may lead to disability. However, the extent of disability is not deterred by the use of MS medication, which is based on the autoimmune hypothesis of MS. Rather, disability is associated with the loss of brain volume, which is related to the loss of grey and white matter. A pathology-supported genetic testing (PSGT) method, developed for personalized assessment and treatment to prevent brain volume loss and disability progression in MS is discussed. This involves identification of MS-related pathogenic pathways underpinned by genetic variation and lifestyle risk factors that may converge into biochemical abnormalities associated with adverse expanded disability status scale (EDSS) outcomes and magnetic resonance imaging (MRI) findings during patient follow-up. A Metabolic Model is presented which hypothesizes that disability may be prevented or reversed when oligodendrocytes are protected by nutritional reserve. Evidence for the validity of the Metabolic Model may be evaluated in consecutive test cases following the PSGT method. In Part II of this Review, two cases are presented that describe the PSGT procedures and the clinical outcomes of these individuals diagnosed with MS.

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

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

An unusual pattern in serum protein electrophoresis to take in mind: A case report

Here we described a case of an asymptomatic 73 years-old female patient in geriatric routine consultation, whose laboratory testing showed hyperproteinemia with accompanying hyperglobulinemia. A diagnosis of BGUS was made only after a correlation among SPEP, densitometry tracing and IFE results was established, evidencing a second peak, that was less evident and not reported at first. These biclonal conditions are of very low incidence in the clinical laboratory, requiring the laboratory professional to have particular skills for their identification. As far as is known, clinical findings in BGUS are similar to those found in MGUS. However, they remain not well understood. Therefore, for an accurate diagnosis of BGUS, the clinical laboratory technician must be trained and sensitized to detect a second M - protein as a band or peak; taking in mind the possible different scenarios in heavy and light chain typing.

Recent advances and remaining questions of autologous hematopoietic stem cell transplantation in multiple sclerosis

The judicious use of autologous hematopoietic stem cell transplantation (AHSCT) for MS requires understanding the potential benefits, identifying the most appropriate patient, and acknowledging the risks and differences between different protocols. Recently, AHSCT for MS is occurring more frequently, with a better safety profile than earlier studies. This review assesses recently published studies to determine the advances that have been made and remaining questions that future studies are poised to answer. We included studies from January 2016 to November 2020 with 20 or more patients. The benefits of AHSCT, including "no evidence of disease activity", functional and patient-reported outcomes, novel biomarkers such as brain atrophy or neurofilament light chain, and cost-effectiveness were assessed. The patient selection, treatment protocols, and safety outcomes differ between reports. The overall efficacy of AHSCT is better than standard treatments. Younger patients with highly active disease have greater chance for improvement, while patients who have comorbidities, failed more treatments, and are transitioning to a more progressive phase may not respond as well to AHSCT. The safety profiles for all AHSCT protocols is improving, however the durability of treatment response may not be the same for all protocols. The goal of AHSCT is to stop disease activity, avoid worsening disability, and obviate the need for further disease-modifying treatment, while improving patient quality of life and minimizing treatment-related risk. Results from currently enrolling randomized controlled trials, as well as ongoing registries, will provide more evidence for the safe and appropriate use of AHSCT.

Immune reconstitution therapies: concepts for durable remission in multiple sclerosis

New so-called immune reconstitution therapies (IRTs) have the potential to induce long-term or even permanent drug-free remission in people with multiple sclerosis (MS). These therapies deplete components of the immune system with the aim of allowing the immune system to renew itself. Haematopoietic stem cell transplantation, the oral formulation cladribine and the monoclonal antibodies alemtuzumab, rituximab and ocrelizumab are frequently categorized as IRTs. However, the evidence that IRTs indeed renew adaptive immune cell repertoires and rebuild a healthy immune system in people with MS is variable. Instead, IRTs might foster the expansion of those cells that survive immunosuppression, and this expansion could be associated with acquisition of new functional phenotypes. Understanding immunological changes induced by IRTs and how they correlate with clinical outcomes will be instrumental in guiding the optimal use of immune reconstitution as a durable therapeutic strategy. This Perspectives article critically discusses the efficacy and potential mechanisms of IRTs in the context of immune system renewal and durable disease remission in MS.

Plasma cell and B cell-targeted treatments for use in advanced multiple sclerosis

There is increasing evidence that agents that target peripheral B cells and in some instances plasma cells can exhibit marked effects on relapsing multiple sclerosis. In addition, B cells, including plasma cells, within the central nervous system compartment are likely to play an important role in disease progression in both relapsing and progressive MS. However, current B cell-targeting antibodies may not inhibit these, because of poor penetration into the central nervous system and often oligoclonal bands of immunoglobulin persist within the cerebrospinal fluid despite immunotherapy. Through targeting B cells and plasma cells in the CNS, it may be possible to obtain additional benefit above simple peripheral depletion of B cells. As such there are a number of inhibitors of B cell function and B cell depleting agents that have been developed for myeloma and B cell leukaemia and lymphoma, which could potentially be used off-label or as an experimental treatment for advanced (progressive) MS.

Potential mechanisms of action related to the efficacy and safety of cladribine

Oral cladribine is a novel treatment for relapsing multiple sclerosis (MS). This appears to be a semi-selective immune-reconstitution therapy that induces long-term therapy from short treatment cycles. It has a relatively good safety profile that currently does not require extensive monitoring associated with some continuous immunosuppressive and relatively non-selective immune reconstitution therapies. The efficacy and safety of cladribine relates to its particular physicochemical properties, the function of the lymphocyte subsets that are selectively targeted by the drug and the repopulation kinetics of these subsets. As such, there is marked and long-term depletion of memory B cell subsets, which probably relates to the therapeutic efficacy. This is also coupled with a more limited, but likewise long-term, depletion of CD4 T subsets. There is limited depletion of cells of the innate immune system and modest effects on CD8 and probably plasma cells, which provide immediate and durable protection from infection. Targeting of CD4 T regulatory cells, CD8 T suppressor cells and regulatory B cell subsets appears more limited as these populations recover rapidly and so repopulating pathogenic cells re-emerge into a regulatory environment. This appears to lead to re-establishment of immune-tolerance that produces long-term control of MS. Although this hypothesis contains a number of unknown details, it is based on knowledge about the biology of cladribine, basic immunology and the effects of other high-efficacy B and T cell depleting agents that exhibit stereotyped repopulation behaviours. These concepts are relatively simple to interrogate, and can be modified as new knowledge about the durability of disease control and safety with cladribine emerges.

B-Cell Therapies in Multiple Sclerosis

B cells play a vital function in multiple sclerosis (MS) pathogenesis through an array of effector functions. All currently approved MS disease-modifying therapies alter the frequency, phenotype, or homing of B cells in one way or another. The importance of this mechanism of action has been reinforced with the successful development and clinical testing of B-cell-depleting monoclonal antibodies that target the CD20 surface antigen. Ocrelizumab, a humanized anti-CD20 monoclonal antibody, was approved by the Food and Drug Administration (FDA) in March 2017 after pivotal trials showed dramatic reductions in inflammatory disease activity in relapsing MS as well as lessening of disability progression in primary progressive MS. These and other clinical studies place B cells at the center of the inflammatory cascade in MS and provide a launching point for development of therapies that target selective pathogenic B-cell populations.

Autologous stem cell transplantation as rescue therapy in malignant forms of multiple sclerosis

Malignant forms of multiple sclerosis (MS) represent a limited group of very aggressive demyelinating diseases, which rapidly progress to severe disability leading often to life-threatening conditions. On these clinical entities, currently available therapies for MS are not very effective. Recently, it has been demonstrated that intense immunosuppression followed by autologous stem cell transplantation (ASCT) can affect the clinical course of individuals with severe MS and completely abrogate the inflammatory activity detected by magnetic resonance imaging (MRI). We report on the treatment with intense immune ablation followed by ASCT of three patients with malignant MS whose clinical course indicated a dramatically poor prognosis. This procedure succeeded in halting the rapidly worsening course of disease. The effect was long lasting, as demonstrated by a sustained efficacy over a two-year period in two subjects and 12 months in the third case. In addition, a striking effect on inflammation-related MRI findings was obtained. These results support a role for intense immunosuppression followed by ASCT as treatment in rapidly evolving malignant MS cases unresponsive to conventional therapies.

Discordant functional and inflammatory parameters in multiple sclerosis patients after autologous haematopoietic stem cell transplantation

This article describes outcomes in four patients with advanced multiple sclerosis up to two years after autologous haematopoietic stem cell transplantation using a total-body irradiation-based preparative regimen. MRI and C SF analyses demonstrated clear suppression of the inflammatory processes. The results demonstrate however, a dissociation of inflammation parameters and functional disability findings raising questions about optimal future stem cell transplantatio n strategies for this disease.

Haematopoietic stem cell transplantation in autoimmune diseases: From basic science to clinical practice

Based on animal studies and serendipitous clinical cases, haematopoietic stem cell transplantation (HSCT) has been used since 1995 as a specific treatment for patients with severe treatment-resistant autoimmune disease (ADs). Despite other clinical developments for autoimmune diseases, including biological therapies, there has been an ongoing requirement for HSCT in some diseases and several thousand procedures have been registered in databases for a wide variety of diseases, predominantly for treatment with autologous HSCT. Currently, the main indications are multiple sclerosis, systemic sclerosis and Crohn's disease, which are supported by large series and randomised controlled trials (RCTs), whereas retrospective registry analyses support benefit in a range of rarer indications. Research into mechanisms of action has provided insight into how tolerance may be achieved with an intensive one-off treatment. In addition to the profound anti-inflammatory and immunosuppressive effects provided by the cytotoxic regimen, long-term responses in some diseases may be explained by 'resetting' the immune system through thymic reprocessing and generation of increased T-regulatory cell activity. This review aims to summarise the gradual evolution of HSCT in severe autoimmune diseases over the last 20 years, focussing on the recent publication of clinical and scientific studies, as well as evidence-based guidelines and recommendations.

Hematopoietic stem cell transplantation for multiple sclerosis: is it a clinical reality?

Hematopoietic stem cell transplantation (HSCT) is a treatment paradigm that has long been utilized for cancers of the blood and bone marrow but has gained some traction as a treatment paradigm for multiple sclerosis (MS). Success in the treatment of patients with this approach has been reported primarily when strict inclusion criteria are imposed that have eventuated a more precise understanding of MS pathophysiology, thereby governing trial design. Moreover, enhancing the yield and purity of hematopoietic stem cells during isolation along with the utility of appropriate conditioning agents has provided a clearer foundation for clinical translation studies. To support this approach, preclinical data derived from animal models of MS, experimental autoimmune encephalomyelitis, have provided clear identification of multipotent stem cells that can reconstitute the immune system to override the autoimmune attack of the central nervous system. In this review, we will discuss the rationale of HSCT to treat MS by providing the benefits and complications of the clinically relevant protocols, the varying graft types, and conditioning regimens. However, we emphasize that future trials based on HSCT should be focused on specific therapeutic strategies to target and limit ongoing neurodegeneration and demyelination in progressive MS, in the hope that such treatment may serve a greater catchment of patient cohorts with potentially enhanced efficiency and lower toxicity. Despite these future ambitions, a proposed international multicenter, randomized clinical trial of HSCT should be governed by the best standard care of treatment, whereby MS patients are selected upon strict clinical course criteria and long-term follow-up studies of patients from international registries are imposed to advocate HSCT as a therapeutic option in the management of MS.

Intrathecal IgG synthesis: a resistant and valuable target for future multiple sclerosis treatments

Intrathecal IgG synthesis is a key biological feature of multiple sclerosis (MS). When acquired early, it persists over time. A growing body of evidence suggests that intrathecal Ig-secreting cells may be pathogenic either by a direct action of toxic IgG or by locally secreting bystander toxic products. Intrathecal IgG synthesis depends on the presence of CNS lymphoid organs, which are strongly linked at anatomical level to cortical subpial lesions and at clinical level to the impairment slope in progressive MS. As a consequence, targeting CNS lymphoid lesions could be a valuable new target in MS, especially during the progressive phase. As intrathecal IgGs are end-products of these lymphoid lesions, intrathecal IgG synthesis may be considered as a specific marker of the persistence of these inflammatory lesions. Here we review the effect upon intrathecal IgG synthesis of all drugs ever used in MS. Except for steroids, all these therapeutic strategies, including rituximab, failed to decrease intrathecal IgG synthesis, with the exception of a questionable incomplete action of natalizumab. Thus, IgG synthesis is a robust marker of persistent intrathecal inflammation and its complete normalization should be one of the goals in future therapeutic strategies.

Cerebrospinal fluid analysis in the context of CNS demyelinating diseases

The central nervous system demyelinating diseases are a group of disorders with different etiologies, characterized by inflammatory lesions that are associated with loss of myelin and eventually axonal damage. In this group the most studied ones are multiple sclerosis (MS), neuromyelitis optic (NMO) and acute disseminated encephalomyelitis (ADEM). The cerebrospinal fluid is essential to differentiate between these different syndromes and to define multiple sclerosis, helping to assess the probability of Clinical Isolated Syndrome turn into multiple sclerosis.

Immunopathogenesis and immunotherapeutic approaches in multiple sclerosis

Multiple sclerosis is an organ-specific autoimmune disease, characterized pathologically by cell-mediated inflammation, demyelination and variable degrees of axonal loss. Although inflammation is considered central to the pathogenesis of multiple sclerosis, to date, the only licensed and hence widely used multiple sclerosis immunotherapies are interferon-beta, glatiramer acetate and mitoxantrone. This review discusses the immunopathogenesis of multiple sclerosis, focusing on a number of emerging immunotherapies. A number of new approaches likely to manipulate the immunopathogenesis of multiple sclerosis and which may ultimately allow for the development of more effective immunotherapy are also highlighted.

Biomarkers of treatment response in multiple sclerosis

Multiple sclerosis (MS) is considered a heterogeneous disease with respect to disease progression and treatment response, which have both remained highly unpredictable. With an increasing number of available disease modifying therapies, strategies for treatment allocation in the individual patient or subgroup of patients has become more important. Therefore biomarkers, which will identify subgroups of MS patients and predict treatment response early in the course of the disease, are urgently needed. Here we review current and emerging biomarkers, as well as study concepts for identification of new biomarkers in MS.

Intrathecal immune reset in multiple sclerosis: exploring a new concept

Multiple sclerosis impairment is mainly driven by the progressive phase, whose pathology remains elusive. No drug has yet been able to halt this phase so therapeutic management remains challenging. It was recently demonstrated that late disability correlates with the spreading of cortical subpial lesions, and tertiary lymphoid organs (TLO) were identified in close apposition with these lesions. TLO are of crucial importance since they are able to mount a complete local immune response, as observed in the intrathecal compartment from the moment MS is diagnosed (i.e. oligoclonal bands). This article examines the consequences of this intrathecal response: giving a worst clinical prognostic value and bearing arguments for possible direct brain toxicity, intrathecal secretion should be targeted by drugs abating both B-lymphocytes and plasma cells. Another consequence is that intrathecal secretion has value as a surrogate marker of the persistence of an ongoing intrathecal immune reaction after treatment. Although it is still unsure which mechanism or byproduct secreted by TLO triggers cortical lesions, we propose to target TLO components as a new therapeutic avenue in progressive MS. Whereas it was long considered that the inability of therapies to penetrate the blood-brain-barrier was a crucial obstacle, our proposed strategy will take advantage of the properties of the BBB to safely reset the intrathecal immune system in order to halt the slow axonal burning underlying secondary MS. We review the literature in support of the rationale for treating MS with intrathecal drugs dedicated to clearing the local immune response. Since many targets are involved, achieving this goal may require a combination of monoclonal antibodies targeting each cell sub-type. Hope might be rekindled with a one-shot intrathecal multi-drug treatment in progressive MS.

Genetic variants in the immunoglobulin heavy chain locus are associated with the IgG index in multiple sclerosis

OBJECTIVE

Intrathecal synthesis of immunoglobulin gamma (IgG) synthesis is frequently observed in patients with multiple sclerosis (MS). Whereas the extent of intrathecal IgG synthesis varies largely between patients, it remains rather constant in the individual patient over time. The aim of this study was to identify common genetic variants associated with the IgG index as a marker of intrathecal IgG synthesis in MS.

METHODS

We performed a genome-wide association study of the IgG index in a discovery series of 229 patients. For confirmation we performed a replication in 2 independent series comprising 256 and 153 patients, respectively. The impact of associated single nucleotide polymorphisms (SNPs) on MS susceptibility was analyzed in an additional 1,854 cases and 5,175 controls.

RESULTS

Significant association between the IgG index and 5 SNPs was detected in the discovery and confirmed in both replication series reaching combined p values of p = 6.5 × 10(-11) to p = 7.5 × 10(-16) . All identified SNPs are clustered around the immunoglobulin heavy chain (IGHC) locus on chromosome 14q32.33 and are in linkage disequilibrium (r(2) range, 0.71-0.95). The best associated SNP is located in an intronic region of the immunoglobulin gamma3 heavy chain gene. Additional sequencing identified the GM21* haplotype to be associated with a high IgG index. Further evaluation of the IGHC SNPs revealed no association with susceptibility to MS in our data set.

INTERPRETATION

The extent of intrathecal IgG in MS is influenced by the IGHC locus. No association with susceptibility to MS was found. Therefore GM haplotypes might affect intrathecal IgG synthesis independently of the underlying disease.

Autologous hematopoietic stem cell transplantation for autoimmune disease--is it now ready for prime time?

Current systemic therapies are rarely curative for patients with severe life-threatening forms of autoimmune disease (AID). During the past 15 years, autologous hematopoietic stem cell transplantation (HCT) has been demonstrated to cure some patients with severe AID refractory to all other available therapies, and thus AID has become an emerging indication for cell therapy. The sustained clinical effects after autologous HCT are better explained by qualitative change in the reconstituted immune repertoire rather than transient depletion of immune cells. Since 1996, more than 1300 AID patients have been registered by the European Group for Blood and Marrow Transplantation (EBMT) and almost 500 patients by the Center for International Blood and Marrow Transplant Research (CIBMTR). Autologous HCT is most commonly performed for patients with multiple sclerosis (MS) or systemic sclerosis (SSc). Systemic lupus, Crohn's disease, type I diabetes, and juvenile idiopathic arthritis are other common indications. Allogeneic transplants are still considered too toxic for use in AID, except for cases of immune cytopenia. Although biologic therapies have been effective at controlling the manifestations of the disease, they require continuous administration, thus raising questions about their increasing costs, morbidity, and mortality related to prolonged therapy. Perhaps it is a reasonable time to ask, "Is autologous HCT for severe AID now ready for prime time?" Yet, the paucity of controlled studies, the short-term toxicities, and the upcoming availability of second-generation biologic and targeted immunotherapies argues that perhaps HCT for AID should be still limited to clinical trials. In this article, we focus on the results of autologous HCT for MS and SSc because these are the two most commonly transplanted diseases. The promising data that is emerging may establish these diseases as standard indications for HCT.

Disappearance of cerebrospinal fluid oligoclonal bands after natalizumab treatment of multiple sclerosis patients

Intrathecal immunoglobulin synthesis in an oligoclonal pattern is the most common immunologic abnormality detected in MS patients. Various treatments, such as immunomodulators and immunosuppressors, have not been found to modify it. Natalizumab hinders migration of encephalitogenic T-cells into the central nervous system (CNS), reducing inflammatory response. Its impact on CSF oligoclonal bands (OCBs) has not been demonstrated. This report describes its effect in four out of six patients with multiple sclerosis after a mean of 10 infusions: the CSF was negative for OCBs at the second lumbar puncture. In conclusion, natalizumab treatment can reduce CSF OCBs to undetectable levels, although the clinical significance of this observation is not yet known.

Hematopoietic stem cell transplantation in multiple sclerosis

Intensive immunosuppresion followed by hematopoietic stem cell transplantation (HSCT) has been suggested as potential treatment in severe forms of multiple sclerosis (MS). Since 1995 ca. 400 patients have been treated with HSCT. Stabilization or improvement occurred in almost 70% of cases at least for 3 years post-transplant. Magnetic resonance revealed the capacity of autologous HSCT to suppress or markedly reduce gadolinium-enhancing lesions. The progression of brain atrophy declined after two years post-HSCT. The profound immunological changes following autologous HSCT may result in restoration of self-tolerance. Relatively young patients with active inflammatory lesions of relatively short duration and rapidly progressive disease, but still low disability scores, unresponsive to conventional therapy seem the best candidates for transplantation. Transplant-related mortality was 6% in the first EBMT report and 5.3% in the second one. No deaths were reported since 2001. Very high-intensity conditioning regimen is associated with higher risk of toxicity without significant increase in efficacy. The effects of transplantation and transplantation-related morbidity are dependent on patient-selection, time of transplantation and conditioning regimens used.This review is a comprehensive study of the results obtained in several single-center and multicenter studies. Patient characteristics, transplantations steps, toxicity and clinical outcome have been monitored and compared.

The prognostic significance of cerebrospinal fluid in multiple sclerosis

BACKGROUND

Multiple Sclerosis (MS) patients lacking CSF oligoclonal bands are purported to have a milder course of disease. We reviewed the natural history of oligoclonal band (OCB) - negative (OCB-) compared to OCB positive (OCB+) patients.

METHOD

A retrospective study of 451 MS patients.

RESULTS

Only 48/451 patients (10.6%) were CSF OCB-. The mean age at onset was 37.1+/-8.8 years with female:male ratio=2. First CNS location presentation was less well defined in OCB- vs. OCB+ patients with significantly more supratentorial presentation. The clinical course of OCB- vs OCB+ was somewhat different; 22.9 vs 15.1% PPMS; 18.8 vs 12.4% SPMS; and 56.3 vs 71% RRMS, respectively. There were significantly fewer WBC, less IgG and a lower IgG index in OCB- cases. Fewer OCB- cases fulfilled McDonald MRI criteria. There were no discernable differences in disease severity between the two groups as determined by the EDSS, progression index, MSSS, number of relapses or annualized relapse rate.

CONCLUSION

The presence of OCB correlates better with other indications of acute inflammatory MS, especially an RR course. This study suggests that the simple lack of OCB positivity does not necessarily insure a more benign disease course.

Immuno-therapeutic potential of haematopoietic and mesenchymal stem cell transplantation in MS

In the last few years there has been extraordinary progress in the field of stem cell research. Two types of stem cells populate the bone marrow: haematopoietic stem/progenitor cells (HSC) and mesenchymal stem cells (MSC). The capacity of HSC to repopulate the blood has been known and exploited therapeutically for at least four decades. Today, haematopoietic stem cell transplantation (HSCT) holds a firm place in the therapy of some haematological malignancies, and a potential role of HSCT for treatment of severe autoimmune diseases has been explored in small-scale clinical studies. Multiple sclerosis (MS) is the noncancerous immune mediated disease for which the greatest number of transplants has been performed to date. The results of clinical studies are double-faced: on the one hand, HSCT has demonstrated powerful effects on acute inflammation, arresting the development of focal CNS lesions and clinical relapses; on the other hand, the treatment did not arrest chronic worsening of disability in most patients with secondary progressive MS, suggesting limited or no beneficial effects on the chronic processes causing progressive disability. MSC are a more recent addition to the range of experimental therapies being developed to treat MS. While interest in MSC usage was originally raised by their potential capacity to differentiate into different cell lineages, recent work showing their interesting immunological properties has led to a revised concept, envisioning their utilization for immuno-modulatory purposes. In this review we will summarize the current clinical and experimental evidence on HSC and MSC and outline some key questions warranting further investigation in this exciting research area.

Autologous haematopoietic stem-cell transplantation in multiple sclerosis

Intense immunosuppression followed by autologous haematopoietic stem-cell transplantation has been assessed over the past few years as a possible new therapeutic strategy in severe forms of multiple sclerosis. Pioneering studies began in 1995, and since then, more than 400 patients worldwide have been treated with this procedure. Small uncontrolled studies show that about 60-70% of treated cases do not progress in the follow-up period of at least 3 years. Transplant-related mortality, which was 5-6% in the first reported series, has reduced in the past 5 years to 1-2%. Relapses dramatically decrease and inflammatory MRI activity is almost completely suppressed. Autologous haematopoietic stem-cell transplantation is associated with qualitative immunological changes in the blood, suggesting that, beyond its immunosuppressive potential, it could also have some beneficial effect for the resetting of the immune system. Patients with severe, rapidly worsening multiple sclerosis who are unresponsive to approved therapies could be candidates for this treatment, but its clinical efficacy has still to be shown in large, prospective, controlled studies.

Autologous and allogeneic hematopoietic stem cell transplantation for Multiple Sclerosis: perspective on mechanisms of action

Multiple Sclerosis (MS) is a frequent demyelinating immune-mediated disease of the central nervous system (CNS) that affects principally young adults and leads to severe physical and cognitive impairment. The current standard treatment makes use of the immune modulators beta-interferon, glatiramer acetate and natalizumab, or immunosuppressants such as mitoxantrone. However, these agents are only partially effective and in a number of patients fail to achieve satisfactory disease control. Autologous hematopoietic stem cell transplantation (HSCT) is being explored in the treatment of severe MS as a means of delivering high-dose immunosuppression followed by 'rescue' of the immuno-hematopoietic system with autologous HSC. The potential therapeutic benefit is based on the concept of so-called 'resetting' the immune system. The use of allogeneic HSCT as a possible therapeutic approach for severe MS is inspired by case reports of MS patients that underwent allogeneic HSCT for a concomitant hematological malignancy, and subsequently is supported by data from rodent models of MS. Allogeneic HSCT may offer specific therapeutic effects, such as the replacement of the autoreactive immune compartment by healthy allogeneic cells and the development of a graft-versus-autoimmunity (GVA) effect. Here, we review the currently available experimental and clinical evidence to support the role of autologous and allogeneic HSCT in MS.

[Immunoablation and autologous hematopoietic stem cell transplantation (AHSCT) in multiple sclerosis]

Numerous pathophysiological arguments supporting immunosuppression for multiple sclerosis have been collected during recent years. The relevance of intense immunosuppression, in terms of clinical benefit and early or late risk, remains a matter of discussion. Immunoablation followed by autologous hematopoietic stem cell transplantation (AHSCT) in multiple sclerosis uses intense immunosuppression, followed by reinjection of AHSC, a rescue procedure for the induced aplasia. This method targets disappearance of the immune disorder, and thus, in theory, the interruption of the disease course. Use of AHSCT to treat several types of autoimmune diseases has been performed with contrasted results. In multiple sclerosis, the experience has been gained over the past 10 years through short series of patients treated at a late stage of their disease. This article highlights the recent data of this particular treatment option in multiple sclerosis as well as the therapeutic aims that should be investigated in further trials.

Intense immunosuppression in patients with rapidly worsening multiple sclerosis: treatment guidelines for the clinician

Several lines of evidence link immunosuppression to inflammation in patients with multiple sclerosis (MS) and provide a rationale for the increasing use of immunosuppressive drugs in the treatment of MS. Treatment-refractory, clinically active MS can quickly lead to devastating and irreversible neurological disability and treating these patients can be a formidable challenge to the clinician. Patients with refractory MS have been treated with intense immunosuppression, such as cyclophosphamide or mitoxantrone, or with autologous haematopoeitic stem cell transplants. Evidence shows that intense immunosuppression might be effective in patients who are unresponsive to immunomodulating therapy, such as interferon beta and glatiramer acetate. Natalizumab, a new addition to the armamentarium for treating MS, might also have a role in the treatment of this MS phenotype. This Review describes the use of intense immunosuppressant drugs and natalizumab in patients with rapidly worsening MS and provides clinicians with guidelines for the use of these drugs in this patient group.

Emerging therapies for multiple sclerosis

This review examines the mode of action, safety profile and clinical efficacy of some of the most promising new therapeutic strategies for multiple sclerosis. Autologous hematopoietic stem cell transplantation can regenerate a new and tolerant immune system and is a potentially effective rescue therapy in a subset of patients with aggressive forms of MS refractory to approved immunomodulatory and immunosuppressive agents. High-dose cyclophosphamide without stem cell support is suggested to induce prolonged remissions through similar immunological mechanisms with less toxicity. Fingolimod (FTY720) is a novel oral immunomodulating agent that acts through preventing lymphocyte recirculation from lymphoid organs. Monoclonal antibody therapy has provided scientists and clinicians the opportunity to rationally direct the therapeutic intervention against specific molecules. Targeting molecules of the immune system such as CD52 (alemtuzumab), CD25 (daclizumab), VLA-4 (natalizumab) and CD20 (rituximab) have resulted in potent immunomodulatory effects through sometimes unpredicted mechanisms. The potential of immunoglobulins to induce remyelination in the CNS is being investigated in an attempt to develop therapies promoting tissue repair and functional recovery. The evidence supporting the potential of these emerging immunotherapies suggests that strong progress is being made in the development of effective cures for multiple sclerosis.

Resetting the adaptive immune system after autologous stem cell transplantation: lessons from responses to vaccines

Autologous stem cell transplantation (ASCT) to treat autoimmune diseases (AID) is thought to reset immunological memory directed against autoantigens. This hypothesis can only be studied indirectly because the exact nature of the pathogenetic autoantigens is unknown in most AID. Therefore, 19 children with juvenile idiopathic arthritis (JIA) or systemic lupus erythematodes (SLE) and 10 adults with multiple sclerosis (MS) were vaccinated with the T-cell-dependent neoantigen rabies and the recall antigen tetanus toxoid after, respectively before, bone marrow harvest. Both vaccinations were repeated after ASCT. All except two of the responders mounted a primary antibody response to rabies after revaccination, and 44% of the responders mounted a primary antibody response to tetanus boost after ASCT. These data show that immunological memory to a neoantigen is lost in most patients with AID after immunoablative pretreatment; however, memory to a recall antigen boosted before bone marrow harvest is only lost in part of the patients. Disease progression was arrested in all patients with JIA/SLE except one, but only in a minority of MS patients. Clinical outcome on a per case basis was not associated with the profile of the immune response toward the vaccination antigens after ASCT.

Failure of allogeneic bone marrow transplantation to arrest disease activity in multiple sclerosis

Multiple sclerosis (MS) is thought to be an autoimmune disease in which activated T-cells initiate a macrophage mediated destruction of CNS myelin. Bone marrow transplantation (BMT) is currently being evaluated in the treatment of MS in patients with aggressive disease activity. Autologous BMT could potentially reset the immune response to myelin antigens leading to immune tolerance and decreased disease activity. Allogeneic transplantation could reconstitute the immune system potentially arresting the progression of autoimmune disease. The purpose of this paper is to report a patient with MS who underwent allogeneic BMT for chronic myelogenous leukemia (CML) and showed continued evidence of active demyelinating disease by clinical and radiologic criteria over a period of two years. While this is only a single case report with inherent limitations, it suggests that the immune mediated destruction of CNS myelin in MS may not be prevented or aborted by immune system reconstitution, and is consistent with the idea that immune mediated tissue destruction in MS could be targeted against an abnormal antigen. Multiple Sclerosis 2007; 13: 1071—1075. http://msj.sagepub.com

Autologous Haematopoietic Stem Cell Transplantation for the Treatment of Multiple Sclerosis

Introduction: Autologous haematopoietic stem cell transplantation (auto-HSCT) has been performed for severe multiple sclerosis (MS) refractory to standard therapy with increasing frequency worldwide. However, experience in Asia employing this modality in MS has been limited. In this review, we explored the pathophysiology of autoimmunity and the underlying rationale for auto-HSCT in treating autoimmune diseases including MS, as well as existing published pre-clinical and clinical data. We aimed thereby to better understand the utility of treating MS with auto-HSCT and the feasibility of this procedure in Singapore. Methods: A Medline search was performed with the terms “haematopoietic stem cell transplantation”, “multiple sclerosis” and “autoimmune diseases” from 1996 to 2005. Both original papers and review articles were considered. Main Findings: The majority of publications were from Europe or the United States and most clinical series from single centres had relatively small numbers of patients. Worldwide, the number of patients reported has been less than 300 since 1997. Existing data support the feasibility and promise of this procedure and ongoing Phase III trials may serve to confirm this initial experience. Conclusion: Pre-clinical and early clinical data support the rationale for immunoablative therapy for autoimmune disorders. Auto-HSCT for severe MS is a feasible procedure and can be safely performed in centres with experience managing HSCT patients. Key words: Autoimmunity, Induction of tolerance, Progressive multiple sclerosis

Glial progenitor-based repair of demyelinating neurological diseases

Demyelinating diseases of the brain and spinal cord affect more than one-quarter million of Americans, with numbers reaching more than two million across the world. These patients experience not only the vascular, traumatic, and inflammatory demyelinations of adulthood but the congenital and childhood dysmyelinating syndromes of the pediatric leukodystrophies. Several disease-modifying strategies have been developed that slow disease progression, especially in the inflammatory demyelinations and in multiple sclerosis in particular. Yet, currently available disease modifiers typically influence the immune system and are neither intended to nor competent to reverse the structural neurologic damage attending acquired demyelination. Fortunately, however, the disorders of myelin lend themselves well to attempts at structural repair, because central oligodendrocytes are the primary, and often sole, victims of the underlying disease process. Given the relative availability and homogeneity of human oligodendrocyte progenitor cells, the disorders of myelin formation and maintenance may be especially compelling targets for cell-based neurologic therapy.

Autologous hematopoietic stem cell transplantation for very active relapsing-remitting multiple sclerosis: report of two cases

Autologous hematopoietic stem cell transplantation (AHSCT) has been proposed as a rescue treatment in multiple sclerosis (MS) patients not responding to first- or second-line therapies. To date, most of the treated cases had a secondary progressive disease course. However, patients with high inflammatory activity, but no secondary progression of the disease, could be candidates to take greater advantage of AHSCT. In this paper, we report two cases with very active, relapsing-remitting (RR) MS, who underwent AHSCT, and obtained a dramatic resolution to disease activity.

New insights into adaptive immunity in chronic neuroinflammation

Understanding the immune response in the central nervous system (CNS) is crucial for the development of new therapeutic concepts in chronic neuroinflammation, which differs considerably from other autoimmune diseases. Special immunologic properties of inflammatory processes in the CNS, which is often referred to as an immune privileged site, imply distinct features of CNS autoimmune disease in terms of disease initiation, perpetuation, and therapeutic accessibility. Furthermore, the CNS is a stress-sensitive organ with a low capacity for self-renewal and is highly prone to bystander damage caused by CNS inflammation. This leads to neuronal degeneration that contributes considerably to the phenotype of the disease. In this chapter, we discuss recent findings emphasizing the predominant role of the adaptive immune system in the pathogenesis of chronic neuroinflammation, that is, multiple sclerosis (MS) in patients and experimental autoimmune encephalomyelitis (EAE) in rodents. In addition, we report on efforts to translate these findings into clinical practice with the aim of developing selective treatment regimens.

B cells move to centre stage: novel opportunities for autoimmune disease treatment

The B-cell arm of the immune system has long been appreciated for its crucial role in pathogen resistance, but in the study of many autoimmune diseases, T cells have dominated the limelight for decades. However, the development of the B-cell-depleting antibody rituximab as a lymphoma therapy has provided a tool to probe the contribution made by B cells in several immune disorders. Recently, the success of B-cell depletion with rituximab in the treatment of rheumatoid arthritis has stimulated investigation of its effects in several other immune disorders, and considerable interest in the potential of drugs that can modulate B-cell function for the treatment of such diseases in general. This article discusses the role of B cells in a range of autoimmune disorders, including rheumatoid arthritis and systemic lupus erythematosus, and analyses approaches to therapeutic B-cell manipulation.

Autologous hematopoietic stem cell transplantation: a cure for multiple sclerosis?

Evaluation of: Muraro PA, Douek DC, Packer A et al.: Thymic output generates a new and diverse TCR repertoire after autologous stem cell transplantation in multiple sclerosis patients. J. Exp. Med. 201(5), 805–816 (2005). This study sought to determine the basis for the long-term suppression of inflammation in multiple sclerosis (MS) patients who receive autologous hematopoietic stem cell transplantation (auto-HSCT). The authors studied seven subjects who were clinically diagnosed with MS and who demonstrated neurological progression during the year prior to the study. Extensive fluorescence-activated cell sorting analysis for phenotype, as well as spectratyping and clonotyping of T cells, were performed in order to examine the size, composition and diversity of the T-cell pool throughout a 2-year post-transplantation period. They found that the suppression of inflammation in the brain, confirmed by magnetic resonance imaging studies, was not due to persistent lymphopenia, but rather due to the de novo regeneration of T cells. Despite the rejuvenation of a diverse T-cell repertoire in these patients, there was no significant improvement in terms of disability as scored by the expanded disability status score. This suggests that, in order for auto-HSCT to be beneficial in treating MS, the procedure must be performed early in the course of MS, when inflammation is abundant but neurodegeneration is limited.

B lineage cells in the inflammatory central nervous system environment: Migration, maintenance, local antibody production, and therapeutic modulation

B cells have long played an enigmatic role in the scenario of multiple sclerosis pathogenesis. This review summarizes recent progress in our understanding of B-cell trafficking, survival, and differentiation in the central nervous system (CNS). We propose four possible routes of intrathecal immunoglobulin-producing cells. The inflammatory CNS provides a unique, B-cell-friendly environment, in which B lineage cells, notably long-lived plasma cells, can survive for many years, perhaps even for a lifetime. These new findings offer a plausible explanation for the notorious persistence and stability of cerebrospinal fluid oligoclonal bands. Furthermore, we highlight similarities and differences of intrathecal immunoglobulin production in multiple sclerosis patients and patients with other CNS inflammatory conditions. Finally, we outline the possibly double-edged effects of B cells and immunoglobulin in the CNS and discuss various therapeutic strategies for targeting the B-cell response.

Intense T cell depletion followed by autologous bone marrow transplantation for severe multiple sclerosis

BACKGROUND

Certain stem cell transplantation procedures might slow down inflammatory pathology in multiple sclerosis (MS).

AIMS

To halt disease progression in aggressive MS by a bone marrow transplantation (BMT) protocol aimed at maximum T cell suppression.

METHODS

Autologous BMT was performed in 14 patients with rapid secondary progressive MS (median EDSS score at baseline, 6; median disease duration, five years). To accomplish rigorous T cell ablation, a strong conditioning protocol was chosen--cyclophosphamide, total body irradiation, and antithymocyte globulin. To minimise the possibility of reinfusing mature T cells in the graft, bone marrow, not peripheral blood, was used as the CD34+ stem cell source.

RESULTS

Median follow up was 36 months (range, 7-36). Post-transplant haemopoietic recovery was successful in all patients. Early toxicity included Epstein-Barr virus related post-transplantation lymphoproliferative disorder. Longterm effects were development of antithyroid antibodies (three) and myelodysplastic syndrome (one). One patient died of progressive disease five years after transplantation. Treatment failure, defined by EDSS increase sustained for six months or more, was seen in nine patients and stabilisation or improvement in five. Other clinical parameters generally showed the same outcome. No gadolinium enhanced lesions were seen on post-treatment magnetic resonance imaging, in either cerebral or spinal cord scans. However, cerebrospinal fluid oligoclonal bands remained positive in most cases.

CONCLUSIONS

This strong immunosuppressive regimen did not prevent clinical progression in patients with aggressive secondary MS. The lack of efficacy, together with some serious side effects, does not favour the use of similar rigorous T cell depleting protocols in the future.

Expansion of antibody reactivity in the cerebrospinal fluid of multiple sclerosis patients - follow-up and clinical implications

BACKGROUND

An intrathecal polyspecific antibody response is a well known finding in multiple sclerosis. However, little is known about the evolution of intrathecal antibodies over time and their impact on the disease progress. Therefore, we focused in this study on the intrathecal polyspecific antibody response in multiple sclerosis.

METHODS

Here we present a follow-up study of 70 patients with multiple sclerosis over 1 to 106 months. Serum and cerebrospinal fluid sample pairs were obtained from 1 to 5 consecutive lumbar punctures. CSF cell count, the IgG index, local IgG synthesis, oligoclonal bands and the antibody index for measles, rubella or varicella zoster were calculated. Results were analysed with regard to clinical characteristics of the patients.

RESULTS

Once an intrathecal antibody response was established, it persisted. De novo antibody response against measles virus developed in 7% of the patients between the first and the second spinal tap. In two of seven patients where 5 consecutive CSF samples were available, the intrathecal antibody response expanded from one to three antigens. Furthermore, an intrathecal measles antibody production was associated with a rapid progression of the disease.

CONCLUSION

These data stress the importance of activated B cells for the disease process and the clinical outcome in multiple sclerosis.

Short-lived plasma blasts are the main B cell effector subset during the course of multiple sclerosis

Multiple sclerosis is a chronic inflammatory and demyelinating disorder of the CNS with an unknown aetiology. Although intrathecal immunoglobulin G (IgG) synthesis is a key feature of the disease, little is still known about the B cell response in the CNS of multiple sclerosis patients. We analysed the phenotype and kinetics of different B cell subsets in patients with multiple sclerosis, infectious disease (IND) and non-inflammatory neurological disease (NIND). B cells were detected in the CSF of multiple sclerosis and IND patients, but were largely absent in NIND patients. In the CSF, the majority of B cells had a phenotype of memory B cells and short-lived plasma blasts (PB); plasma cells were absent from the compartment. The proportion of PB was highest in multiple sclerosis patients and patients with acute CNS infection. While PB disappeared rapidly from the CSF after resolution of infection in IND patients, these cells were present at high numbers throughout the disease course in multiple sclerosis patients. CSF PB numbers in multiple sclerosis patients strongly correlated with intrathecal IgG synthesis and inflammatory parenchymal disease activity as disclosed by MRI. This study identifies short-lived plasma blasts as the main effector B cell population involved in ongoing active inflammation in multiple sclerosis patients.

Haemopoietic stem cell transplantation in autoimmune diseases: a European perspective

The potential of haemopoietic stem cell transplantation (HSCT) for the treatment of autoimmune and inflammatory diseases was originally supported by almost three decades of animal experiments and by the serendipitous remissions of autoimmune disease observed in patients undergoing transplantation for haematological disorders. Improved safety of both autologous and allogeneic HSCT over the last decade has been followed by increasing acceptance of HSCT as an experimental treatment for severe autoimmune diseases that are resistant to conventional treatment. International databases have collated over 700 procedures performed specifically for a variety of autoimmune diseases. Phase III clinical trials are in progress for some diseases. This review provides a comprehensive update on the efficacy and toxicity of HSCT in severe autoimmune disease. Future directions in the context of other evolving therapies are discussed.

Autologous haematopoietic-stem-cell transplantation for multiple sclerosis

Intense immunosuppression followed by autologous haematopoietic-stem-cell transplantation (HSCT) is being assessed as a potential treatment for patients with severe multiple sclerosis (MS). The treatment was developed from research that showed autologous HSCT was as effective as allogeneic HSCT in the treatment of experimental autoimmune encephalomyelitis. The treatment is thought to eradicate the defective immune system, and the infused haematopoietic stem cells reconstitute an immune system that is more tolerant to the nervous system. About 250 patients with MS have been treated with autologous HSCT as part of phase I and phase II open trials. Autologous HSCT seems feasible in MS and assessment with clinical and MRI measures suggests it induces a profound and long-lasting suppression of inflammation. The course of MS seems to be stabilised after autologous HSCT, especially in ambulatory patients with evidence of active disease. Autologous HSCT deserves further study in randomised controlled trials.

Recovery from and consequences of severe iatrogenic lymphopenia (induced to treat autoimmune diseases)

To ascertain the consequences of severe leukopenia and the tempo of recovery, we studied the immunity of 56 adult patients treated for multiple sclerosis or systemic sclerosis with autologous CD34 cell transplantation using extremely lymphoablative conditioning. NK cell, monocyte, and neutrophil counts recovered to normal by 1 month; dendritic cell and B cell counts by 6 months; and T cell counts by 2 years posttransplant, although CD4 T cell counts remained borderline low. Initial peripheral expansion was robust for CD8 T cells but only moderate for CD4 T cells. Subsequent thymopoiesis was slow, especially in older patients. Importantly, levels of antibodies, including autoantibodies, did not drop substantially. Infections were frequent during the first 6 months, when all immune cells were deficient, and surprisingly rare (0.21 per patient year) at 7-24 months posttransplant, when only T cells (particularly CD4 T cells) were deficient. In conclusion, peripheral expansion of CD8 but not CD4 T cells is highly efficient. Prolonged CD4 lymphopenia is associated with relatively few infections, possibly due to antibodies produced by persisting pretransplant plasma cells.

Using stem cells in multiple sclerosis therapies

Stem cell transplantation approaches offer for the first time the opportunity to design therapeutic approaches for multiple sclerosis (MS) with curative intent. Here we discuss key observations and questions emerging from clinical trials of hematopoietic stem cell transplantation for MS and from studies of myelin/neural repair in experimental models of demyelinating disorders.