A three-year study of brain atrophy after autologous hematopoietic stem cell transplantation in rapidly evolving secondary progressive multiple sclerosis

Dynamics of Inflammatory and Neurodegenerative Biomarkers after Autologous Hematopoietic Stem Cell Transplantation in Multiple Sclerosis

Autologous hematopoietic stem cell transplantation (aHSCT) is a highly efficient treatment of multiple sclerosis (MS), and hence it likely normalizes pathological and/or enhances beneficial processes in MS. The disease pathomechanisms include neuroinflammation, glial cell activation and neuronal damage. We studied biomarkers that in part reflect these, like markers for neuroinflammation (C-X-C motif chemokine ligand (CXCL) 9, CXCL10, CXCL13, and chitinase 3-like 1 (CHI3L1)), glial perturbations (glial fibrillary acidic protein (GFAP) and in part CHI3L1), and neurodegeneration (neurofilament light chain (NfL)) by enzyme-linked immunosorbent assays (ELISA) and single-molecule array assay (SIMOA) in the serum and cerebrospinal fluid (CSF) of 32 MS patients that underwent aHSCT. We sampled before and at 1, 3, 6, 12, 24 and 36 months after aHSCT for serum, as well as before and 24 months after aHSCT for CSF. We found a strong increase of serum CXCL10, NfL and GFAP one month after the transplantation, which normalized one and two years post-aHSCT. CXCL10 was particularly increased in patients that experienced reactivation of cytomegalovirus (CMV) infection, but not those with Epstein-Barr virus (EBV) reactivation. Furthermore, patients with CMV reactivation showed increased Th1 phenotype in effector memory CD4+ T cells. Changes of the other serum markers were more subtle with a trend for an increase in serum CXCL9 early post-aHSCT. In CSF, GFAP levels were increased 24 months after aHSCT, which may indicate sustained astroglia activation 24 months post-aHSCT. Other CSF markers remained largely stable. We conclude that MS-related biomarkers indicate neurotoxicity early after aHSCT that normalizes after one year while astrocyte activation appears increased beyond that, and increased serum CXCL10 likely does not reflect inflammation within the central nervous system (CNS) but rather occurs in the context of CMV reactivation or other infections post-aHSCT.

The current standing of autologous haematopoietic stem cell transplantation for the treatment of multiple sclerosis

Autologous haematopoietic stem cell transplantation (aHSCT) is gaining traction as a valuable treatment option for patients affected by severe multiple sclerosis (MS), particularly the relapsing–remitting form. We describe the current literature in terms of clinical trials, observational and retrospective studies, as well as immune reconstitution following transplantation, with a focus on the conditioning regimens used for transplantation. The evidence base predominantly consists of non-randomised, uncontrolled clinical trials or data from retrospective or observational cohorts, i.e. very few randomised or controlled trials. Most often, intermediate-intensity conditioning regimens are used, with promising results from both myeloablative and lymphoablative strategies, as well as from regimens that are low and high intensity. Efficacy of transplantation, which is likely secondary to immune reconstitution and restored immune tolerance, is, therefore, not clearly dependent on the intensity of the conditioning regimen. However, the conditioning regimen may well influence the immune response to transplantation. Heterogeneity of conditioning regimens among studies hinders synthesis of the articles assessing post-aHSCT immune system changes. Factors associated with better outcomes were lower Kurtzke Expanded Disability Status Scale, relapsing–remitting MS, younger age, and shorter disease duration at baseline, which supports the guidance for patient selection proposed by the European Society for Blood and Marrow Transplantation. Interestingly, promising outcomes were described for patients with secondary progressive MS by some studies, which may be worth taking into account when considering treatment options for patients with active, progressive disease. Of note, a significant proportion of patients develop autoimmune disease following transplantation, with alemtuzumab-containing regimens associated with the highest incidence.

Autologous Hematopoietic Stem Cell Transplantation in Multiple Sclerosis Patients: Monocentric Case Series and Systematic Review of the Literature

Multiple sclerosis (MS) is a chronic, inflammatory and immune-mediated disease of the central nervous system (CNS), commonly affecting young adults and potentially associated with life-long disability. About 14 disease-modifying treatments (DMTs) are currently approved for the treatment of MS. However, despite the use of highly effective therapies, some patients exhibit a highly active disease with an aggressive course from onset and a higher risk of long-term disability accrual. In the last few years, several retrospective studies, clinical trials, meta-analyses and systematic reviews have investigated autologous hematopoietic stem cell transplantation (AHSCT) as a possible therapeutic option in order to address this unmet clinical need. These studies demonstrated that AHSCT is a highly efficacious and relatively safe therapeutic option for the treatment of highly active MS. Particularly, over recent years, the amount of evidence has grown, with significant improvements in the development of patient selection criteria, choice of the most suitable transplant technique and clinical experience. In this paper, we present six patients who received AHSCT in our MS center and we systematically reviewed recent evidence about the long-term efficacy and safety of AHSCT and the placement of AHSCT in the rapidly evolving therapeutic armamentarium for MS.

Brain volume change after high-dose immunosuppression and autologous hematopoietic cell transplantation for relapsing-remitting multiple sclerosis

BACKGROUND

Brain volume loss (BVL) is commonly observed after high-dose immunosuppression and autologous hematopoietic cell transplantation (HDIT/HCT) for treatment of multiple sclerosis (MS). To better understand the mechanisms of underlying BVL associated with this treatment, we characterized the time courses of whole-brain (WB), grey-matter (GM) and white-matter (WM) volume loss in relapsing-remitting MS (RRMS) patients who received BEAM-based HDIT/HCT.

METHODS

We used Jacobian integration to measure MRI-based WB, GM and WM volume changes up to 5 years after transplant in twenty-four RRMS participants who underwent BEAM-based HDIT/HCT. Using a two-piecewise mixed-effects model, we estimated the short-term (baseline to 1 year) and long-term (beyond 1 year) rates of BVL after HDIT/HCT. We also compared the rates based on the presence of gadolinium-enhancing lesions at baseline, and the maintenance of event-free survival during follow-up.

RESULTS

On average, accelerated short-term BVL of -1.37% (SE: 0.21), -0.86% (SE: 0.28) and -2.18% (SE: 0.26) occurred in WB, GM and WM, respectively. Baseline T1-weighted MRI WM lesion volume was a significant predictor in the WB (short-term) and the WM (short-term and long-term). The average rates of BVL after the initial acceleration were -0.22%/y (SE: 0.10), -0.13%/y (SE: 0.11) and -0.36%/y (SE: 0.11) in the WB, GM and WM, respectively. Participants with gadolinium-enhancing lesions at baseline had significantly higher short-term rates of GM (-1.56% vs. -0.27%, p = 0.01) and WB volume loss (-1.94% vs. -0.81%, p = 0.006) at 1 year follow-up as compared to those without gadolinium-enhancing lesions. WM volume loss was not significantly different (-2.59% vs. -1.66%, p = 0.16). Participants who maintained event-free survival had similar rates of BVL compared to those who did not.

CONCLUSIONS

BVL may accelerate for months after HDIT/HCT. However, over the long-term, adequate HDIT/HCT may reduce BVL rates to those similar to normal aging at the WB level.

Haematopoietic Stem Cell Transplantation for Multiple Sclerosis: Current Status

Autologous haematopoietic stem cell transplantation (AHSCT) is a treatment option for aggressive forms of multiple sclerosis (MS) that has been derived from haematological indications and repurposed for treatment of refractory autoimmune diseases. In the present review, a search for clinical studies on AHSCT was performed on the PubMed website and ClinicalTrials.gov databases. Papers were selected according to the following criteria: text written in English language, publication date between 2014 and August 2019, and reports including more than five patients. Prospective randomised and uncontrolled trials and retrospective case series were reviewed to examine the safety and efficacy of the procedure. Treatment protocols, pathological data and economic aspects of AHSCT were also succinctly covered. Growing evidence suggests that long-term suppression of inflammatory activity with stabilization or improvement of disability can be achieved in a high proportion of properly selected patients. More sophisticated outcome measures recently adopted, including effect on brain atrophy and disease biomarkers, are giving further insight into the effectiveness of transplant. The risks of the procedure have decreased to levels that can be considered acceptable for treatment of individuals with aggressive forms of MS. Careful selection of patients with an expected good benefit/risk profile, which is maximal when AHSCT is performed in early phases of the disease, and the expertise of transplant centres are critical to the success of treatment. Higher efficacy of AHSCT than with conventional treatments has recently been demonstrated by one randomised trial and further evidence is awaited from ongoing and planned trials comparing AHSCT with the most effective disease-modifying therapeutic agents.

Non-immunogenic Induced Pluripotent Stem Cells, a Promising Way Forward for Allogenic Transplantations for Neurological Disorders

Neurological disorder is a general term used for diseases affecting the function of the brain and nervous system. Those include a broad range of diseases from developmental disorders (e.g., Autism) over injury related disorders (e.g., stroke and brain tumors) to age related neurodegeneration (e.g., Alzheimer's disease), affecting up to 1 billion people worldwide. For most of those disorders, no curative treatment exists leaving symptomatic treatment as the primary mean of alleviation. Human induced pluripotent stem cells (hiPSC) in combination with animal models have been instrumental to foster our understanding of underlying disease mechanisms in the brain. Of specific interest are patient derived hiPSC which allow for targeted gene editing in the cases of known mutations. Such personalized treatment would include (1) acquisition of primary cells from the patient, (2) reprogramming of those into hiPSC via non-integrative methods, (3) corrective intervention via CRISPR-Cas9 gene editing of mutations, (4) quality control to ensure successful correction and absence of off-target effects, and (5) subsequent transplantation of hiPSC or pre-differentiated precursor cells for cell replacement therapies. This would be the ideal scenario but it is time consuming and expensive. Therefore, it would be of great benefit if transplanted hiPSC could be modulated to become invisible to the recipient's immune system, avoiding graft rejection and allowing for allogenic transplantations. This review will focus on the current status of gene editing to generate non-immunogenic hiPSC and how these cells can be used to treat neurological disorders by using cell replacement therapy. By providing an overview of current limitations and challenges in stem cell replacement therapies and the treatment of neurological disorders, this review outlines how gene editing and non-immunogenic hiPSC can contribute and pave the road for new therapeutic advances. Finally, the combination of using non-immunogenic hiPSC and in vivo animal modeling will highlight the importance of models with translational value for safety efficacy testing; before embarking on human trials.

Approved and Emerging Disease Modifying Therapies on Neurodegeneration in Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune, chronic, progressive disease leading to a combination of inflammation, demyelination, and neurodegeneration throughout the central nervous system (CNS). The outcome of these processes can be visualized in magnetic resonance imaging (MRI) scans as brain atrophy, or brain volume loss (BVL), as well as lesions, “black holes” and spinal cord atrophy. MRI outcomes such as BVL have been used as biomarkers of neurodegeneration and other measures of MS disease progression in clinical research settings. Several FDA-approved medications seek to alleviate disease progression by reducing the impact of such factors as demyelination and neurodegeneration, but there are still many shortcomings that current clinical research aims to mitigate. This review attempts to provide an overview of the FDA-approved medications available for treating multiple sclerosis and their effect on neurodegeneration, measured by BVL.

Impact of autologous haematopoietic stem cell transplantation on disability and brain atrophy in secondary progressive multiple sclerosis

Background:

Autologous haematopoietic stem cell transplantation (aHSCT) is a valuable option in aggressive relapsing–remitting multiple sclerosis (MS), but its efficacy in secondary progressive (SP)-MS is still controversial.

Objective:

Assessing efficacy of aHSCT in SP-MS by clinical-radiological outcomes.

Methods:

Open-label monocentric retrospective study enrolling consecutive SP-MS patients treated with BEAM-aHSCT in the period 1999–2016.

Results:

In total, 26 SP-MS patients with moderate–severe disability were included. Progression-free survival (PFS) at years 5 and 10 after aHSCT were, respectively, 42% and 30%. Out of 16 patients who worsened, only 6 patients (23% overall) maintained continuous disability accrual (CDA), whereas 10 patients stabilized following one single-step Expanded Disability Status Scale (EDSS) worsening. CDA-free survival was 74% at 5–10 years. No relapses or magnetic resonance imaging (MRI) activity were reported, thus no evidence of disease activity (NEDA)-3 corresponded to PFS. Annualized rate of brain atrophy (AR-BVL) normalized after 1 year in 55% of the cases analysed (12/22).

Conclusion:

BEAM-aHSCT halted CDA and normalized AR-BVL in most of the treated patients, inducing long-term remission of inflammatory activity at a median follow-up of 99 months (range 27–222). These data suggest that CDA might still be mainly driven by inflammation in a subgroup of SP-MS and could therefore be reversed by treatments. CDA should be analysed independently from any isolated disability worsening.

Application of advanced MRI techniques to monitor pharmacologic and rehabilitative treatment in multiple sclerosis: current status and future perspectives

Introduction: Advances in magnetic resonance imaging (MRI) technology and analyses are improving our understanding of the pathophysiology of multiple sclerosis (MS). Due to their ability to grade the presence of irreversible tissue loss, microstructural tissue abnormalities, metabolic changes and functional plasticity, the application of these techniques is also expanding our knowledge on the efficacy and mechanisms of action of different pharmacological and rehabilitative treatments. Areas covered: This review discusses recent findings derived from the application of advanced MRI techniques to evaluate the structural and functional substrates underlying the effects of pharmacologic and rehabilitative treatments in patients with MS. Current applications as outcome in clinical trials and observational studies, their interpretation and possible pitfalls in their use are discussed. Finally, how these techniques could evolve in the future to improve monitoring of disease progression and treatment response is examined. Expert commentary: The number of treatments currently available for MS is increasing. The application of advanced MRI techniques is providing reliable and specific measures to better understand the targets of different treatments, including neuroprotection, tissue repair, and brain plasticity. This is a fundamental progress to move toward personalized medicine and individual treatment selection.

Cell Therapy for Multiple Sclerosis

Cell therapy is considered a promising potential treatment for multiple sclerosis, perhaps particularly for the progressive form of the disease for which there are currently no useful treatments. Over the past two decades or more, much progress has been made in understanding the biology of MS and in the experimental development of cell therapy for this disease. Three quite distinct forms of cell therapy are currently being pursued. The first seeks to use stem cells to replace damaged myelin-forming oligodendrocytes within the CNS; the second aims, in effect, to replace the individual's misfunctioning immune system, making use of haematopoietic stem cells; and the third seeks to utilise endogenous stem cell populations by mobilisation with or without in vitro expansion, exploiting their various reparative and neuroprotective properties. In this article we review progress in these three separate areas, summarising the experimental background and clinical progress thus far made.

Defining Disease Activity and Response to Therapy in MS

OPINION STATEMENT

Disease activity in multiple sclerosis (MS) has classically been defined by the occurrence of new neurological symptoms and the rate of relapses. Definition of disease activity has become more refined with the use of clinical markers, evaluating ambulation, dexterity, and cognition. Magnetic resonance imaging (MRI) has become an important tool in the investigation of disease activity. Number of lesions as well as brain atrophy have been used as surrogate outcome markers in several clinical trials, for which a reduction in these measures is appreciated in most treatment studies. With the increasing availability of new medications, the overall goal is to minimize inflammation to decrease relapse rate and ultimately prevent long-term disability. The aim of this review is to give an overview on commonly used clinical and imaging markers to monitor disease activity in MS, with emphasis on their use in clinical studies, and to give a recommendation on how to utilize these measures in clinical practice for the appropriate assessment of therapeutic response.

Immunoablation and autologous haemopoietic stem-cell transplantation for aggressive multiple sclerosis: a multicentre single-group phase 2 trial

BACKGROUND

Strong immunosuppression, including chemotherapy and immune-depleting antibodies followed by autologous haemopoietic stem-cell transplantation (aHSCT), has been used to treat patients with multiple sclerosis, improving control of relapsing disease. We addressed whether near-complete immunoablation followed by immune cell depleted aHSCT would result in long-term control of multiple sclerosis.

METHODS

We did this phase 2 single-arm trial at three hospitals in Canada. We enrolled patients with multiple sclerosis, aged 18-50 years with poor prognosis, ongoing disease activity, and an Expanded Disability Status Scale of 3.0-6.0. Autologous CD34 selected haemopoietic stem-cell grafts were collected after mobilisation with cyclophosphamide and filgrastim. Immunoablation with busulfan, cyclophosphamide, and rabbit anti-thymocyte globulin was followed by aHSCT. The primary outcome was multiple sclerosis activity-free survival (events were clinical relapse, appearance of a new or Gd-enhancing lesion on MRI, and sustained progression of Expanded Disability Status Scale score). This study was registered at ClinicalTrials.gov, NCT01099930.

FINDINGS

Between diagnosis and aHSCT, 24 patients had 167 clinical relapses over 140 patient-years with 188 Gd-enhancing lesions on 48 pre-aHSCT MRI scans. Median follow-up was 6.7 years (range 3.9-12.7). The primary outcome, multiple sclerosis activity-free survival at 3 years after transplantation was 69.6% (95% CI 46.6-84.2). With up to 13 years of follow-up after aHSCT, no relapses occurred and no Gd enhancing lesions or new T2 lesions were seen on 314 MRI sequential scans. The rate of brain atrophy decreased to that expected for healthy controls. One of 24 patients died of transplantation-related complications. 35% of patients had a sustained improvement in their Expanded Disability Status Scale score.

INTERPRETATION

We describe the first treatment to fully halt all detectable CNS inflammatory activity in patients with multiple sclerosis for a prolonged period in the absence of any ongoing disease-modifying drugs. Furthermore, many of the patients had substantial recovery of neurological function despite their disease's aggressive nature.

FUNDING

Multiple Sclerosis Scientific Research Foundation.

Brain atrophy after bone marrow transplantation for treatment of multiple sclerosis

Background:

A cohort of patients with poor-prognosis multiple sclerosis (MS) underwent chemotherapy-based immune ablation followed by immune reconstitution with an autologous hematopoietic stem cell transplant (IA/aHSCT). This eliminated new focal inflammatory activity, but resulted in early acceleration of brain atrophy.

Objective:

We modeled the time course of whole-brain volume in 19 patients to identify the baseline predictors of atrophy and to estimate the average rate of atrophy after IA/aHSCT.

Methods:

Percentage whole-brain volume changes were calculated between the baseline and follow-up magnetic resonance imaging (MRI; mean duration: 5 years). A mixed-effects model was applied using two predictors: total busulfan dose and baseline volume of T1-weighted white-matter lesions.

Results:

Treatment was followed by accelerated whole-brain volume loss averaging 3.3%. Both the busulfan dose and the baseline lesion volume were significant predictors. The atrophy slowed progressively over approximately 2.5 years. There was no evidence that resolution of edema contributed to volume loss. The mean rate of long-term atrophy was −0.23% per year, consistent with the rate expected from normal aging.

Conclusion:

Following IA/aHSCT, MS patients showed accelerated whole-brain atrophy that was likely associated with treatment-related toxicity and degeneration of “committed” tissues. Atrophy eventually slowed to that expected from normal aging, suggesting that stopping inflammatory activity in MS can reduce secondary degeneration and atrophy.

Methemoglobin is an endogenous toll-like receptor 4 ligand-relevance to subarachnoid hemorrhage

Neuroinflammation is a well-recognized consequence of subarachnoid hemorrhage (SAH), and may be responsible for important complications of SAH. Signaling by Toll-like receptor 4 (TLR4)-mediated nuclear factor κB (NFκB) in microglia plays a critical role in neuronal damage after SAH. Three molecules derived from erythrocyte breakdown have been postulated to be endogenous TLR4 ligands: methemoglobin (metHgb), heme and hemin. However, poor water solubility of heme and hemin, and lipopolysaccharide (LPS) contamination have confounded our understanding of these molecules as endogenous TLR4 ligands. We used a 5-step process to obtain highly purified LPS-free metHgb, as confirmed by Fourier Transform Ion Cyclotron Resonance mass spectrometry and by the Limulus amebocyte lysate assay. Using this preparation, we show that metHgb is a TLR4 ligand at physiologically relevant concentrations. metHgb caused time- and dose-dependent secretion of the proinflammatory cytokine, tumor necrosis factor α (TNFα), from microglial and macrophage cell lines, with secretion inhibited by siRNA directed against TLR4, by the TLR4-specific inhibitors, Rs-LPS and TAK-242, and by anti-CD14 antibodies. Injection of purified LPS-free metHgb into the rat subarachnoid space induced microglial activation and TNFα upregulation. Together, our findings support the hypothesis that, following SAH, metHgb in the subarachnoid space can promote widespread TLR4-mediated neuroinflammation.

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.

Hematopoietic stem cell transplantation in multiple sclerosis

It is widely accepted that the main common pathogenetic pathway in multiple sclerosis (MS) involves an immune-mediated cascade initiated in the peripheral immune system and targeting CNS myelin. Logically, therefore, therapeutic approaches to the disease include modalities aiming at downregulation of the various immune elements that are involved in this immunological cascade. Since the introduction of interferons in 1993, more specific immunoactive drugs have been introduced, but still most of them can, at best, effectively modulate only the early relapsing phases of MS. The more progressed phases of the disease are not efficiently amendable by the existing immunomodulatory drugs. Moreover, localized and compartmentized inflammation in the CNS, which seems to be mostly responsible for the chronic axonal damage and resulting progression of disability, is less affected by the current drugs. A more radical approach to suppress all the inflammation in MS, including that into the CNS, could theoretically be achieved with high-dose immunosuppression using strong cytotoxic medications and resetting of the immune system by hematopoietic stem cell transplantation (HSCT). HSCT, both allogeneic and autologous, has been tried as a novel therapeutic approach in various autoimmune diseases. During the last 15 years several (mostly open) clinical studies evaluated the effect of HSTC on MS patients; the published papers showed that a high proportion of the HSCT-treated MS patients were stabilized, or even improved after the transplantation and have generally indicated a beneficial effect on disease progression. In this review, the rationale of HSCT and the summary of the results of the existing clinical trials are presented. Despite the fact that it is difficult to collectively summarize the results of all the trials, due to lack of uniformity in the conditioning and treatment protocols and of completed controlled studies, these clinical studies have provided a strong 'proof of concept' for HSCT in MS and have significantly contributed to our understanding of the advantages and disadvantages of each approach and HSCT protocol.

Updating the mild encephalitis hypothesis of schizophrenia

Schizophrenia seems to be a heterogeneous disorder. Emerging evidence indicates that low level neuroinflammation (LLNI) may not occur infrequently. Many infectious agents with low overall pathogenicity are risk factors for psychoses including schizophrenia and for autoimmune disorders. According to the mild encephalitis (ME) hypothesis, LLNI represents the core pathogenetic mechanism in a schizophrenia subgroup that has syndromal overlap with other psychiatric disorders. ME may be triggered by infections, autoimmunity, toxicity, or trauma. A 'late hit' and gene-environment interaction are required to explain major findings about schizophrenia, and both aspects would be consistent with the ME hypothesis. Schizophrenia risk genes stay rather constant within populations despite a resulting low number of progeny; this may result from advantages associated with risk genes, e.g., an improved immune response, which may act protectively within changing environments, although they are associated with the disadvantage of increased susceptibility to psychotic disorders. Specific schizophrenic symptoms may arise with instances of LLNI when certain brain functional systems are involved, in addition to being shaped by pre-existing liability factors. Prodrome phase and the transition to a diseased status may be related to LLNI processes emerging and varying over time. The variability in the course of schizophrenia resembles the varying courses of autoimmune disorders, which result from three required factors: genes, the environment, and the immune system. Preliminary criteria for subgrouping neurodevelopmental, genetic, ME, and other types of schizophrenias are provided. A rare example of ME schizophrenia may be observed in Borna disease virus infection. Neurodevelopmental schizophrenia due to early infections has been estimated by others to explain approximately 30% of cases, but the underlying pathomechanisms of transition to disease remain in question. LLNI (e.g. from reactivation related to persistent infection) may be involved and other pathomechanisms including dysfunction of the blood-brain barrier or the blood-CSF barrier, CNS-endogenous immunity and the volume transmission mode balancing wiring transmission (the latter represented mainly by synaptic transmission, which is often described as being disturbed in schizophrenia). Volume transmission is linked to CSF signaling; and together could represent a common pathogenetic link for the distributed brain dysfunction, dysconnectivity, and brain structural abnormalities observed in schizophrenia. In addition, CSF signaling may extend into peripheral tissues via the CSF outflow pathway along brain nerves and peripheral nerves, and it may explain the peripheral topology of neuronal dysfunctions found, like in olfactory dysfunction, dysautonomia, and even in peripheral tissues, i.e., the muscle lesions that were found in 50% of cases. Modulating factors in schizophrenia, such as stress, hormones, and diet, are also modulating factors in the immune response. Considering recent investigations of CSF, the ME schizophrenia subgroup may constitute approximately 40% of cases.

Feasibility of cell therapy in multiple sclerosis: a systematic review of 83 studies

Multiple Sclerosis is an inflammatory disease of the central nervous system in which T cells experience a second phase of activation, which ultimately leads to axonal demyelination and neurological disability. The recent advances in stem cell therapies may serve as potential treatments for neurological disorders. There are broad types of stem cells such as neural, embryonic, mesenchymal and hematopoietic stem cells with unprecedented hope in treating many debilitating diseases. In this paper we will review the substantial literature regarding experimental and clinical use of these stem cells and possible mechanisms in the treatment of MS. These results may pave the road for the utilization of stem cells for the treatment of MS.

Autologous hematopoietic stem cell transplantation in autoimmune diseases

The term 'autoimmune diseases' encompasses a spectrum of diseases whose clinical manifestations and, possibly, biological features vary widely. The results of conventional treatment are considered unsatisfactory in aggressive forms, with subsets of patients having short life expectancies. Relying on wide experimental evidence and more feeble clinical data, some research groups have used autologous hematopoietic stem cell transplantation (HSCT) in the most disabling autoimmune diseases with the aim of resetting the patient's immune system. Immunoablative conditioning regimens are preferred over their myeloablative counterparts, and some form of in vivo and/or ex vivo T-cell depletion is generally adopted. Despite 15 years' experience, published controlled clinical trials are still lacking, with the evidence so far available coming from pilot studies and registry surveys. In multiple sclerosis, clinical improvement, or at least lasting disease stabilization, can be achieved in the majority of the patients; nevertheless, the worst results are observed in patients with progressive disease, where no benefit can be expected from conventional therapy. Concerning rheumatologic diseases, wide experience has been acquired in systemic sclerosis, with long-term improvements in cutaneous disease being frequently reported, although visceral involvement remains unchanged at best. Autografting has proved to be barely effective in rheumatoid arthritis and quite toxic in juvenile idiopathic arthritis, whereas it leads to clinical remission and the reversal of visceral impairment in the majority of patients with systemic lupus erythematosus. A promising indication is Crohn's disease, in which long-term endoscopic remission is frequently observed. Growing experience with autologous HCST in autoimmune diseases has progressively reduced concerns about transplant-related mortality and secondary myelodysplasia/leukemia. Therefore, a sustained complete remission seems to be within the reach of autografting in some autoimmune diseases; in others, the indications, risks and benefits of autografting need to be better defined. Consequently, the search for new drugs should also be encouraged.

Evidence for acute neurotoxicity after chemotherapy

OBJECTIVE

Chronic neurotoxicity is a recognized long-term complication following chemotherapy in a range of diseases. Neurotoxicity adversely affects patients' quality of life. The objective of this study is to examine whether there is evidence of acute neurotoxicity.

METHODS

This prospective study included patients with secondary progressive multiple sclerosis (SPMS-BMT, n = 14) and hematological malignancies (HM-BMT, n = 17) receiving chemotherapy as preconditioning for bone marrow transplant. The control groups included SPMS patients matched for demographic and clinical data (SPMS-PL, n = 14) and healthy controls (n = 14). Neurodegeneration was assessed at baseline and longitudinally (months 1, 2, 3, 6, 9, 12, 24, and 36), combining a clinical scale for disability (Expanded Disability Status Scale [EDSS]), a serum protein biomarker for neurodegeneration (neurofilaments, NfH-SMI35), and brain atrophy measures (magnetic resonance imaging).

RESULTS

Disability progression was significantly more acute and severe following chemotherapy compared to placebo. Immediately after starting chemotherapy, serum NfH-SMI35 levels increased in 79% (p < 0.0001) of SPMS-BMT patients and 41% (p < 0.01) of HM-BMT patients compared to 0% of SPMS-PL patients or healthy controls. In SPMS-BMT serum NfH-SMI35 levels were > 100-fold higher 1 month after chemotherapy (29.73ng/ml) compared to baseline (0.28ng/ml, p < 0.0001). High serum NfH-SMI35 levels persisting for at least 3 months were associated with sustained disability progression on the EDSS (p < 0.05). Brain atrophy rates increased acutely in SPMS-BMT (-2.09) compared to SPMS-PL (-1.18, p < 0.05).

INTERPRETATION

Neurotoxicity is an unwanted acute side effect of aggressive chemotherapy.

Review article: stem cell therapies for inflammatory bowel disease - efficacy and safety

BACKGROUND

Drugs available for the treatment of inflammatory bowel disease fail to induce and maintain remission in a significant number of patients.

AIM

To assess the value of stem cell therapies for treatment of inflammatory bowel disease based on published studies.

METHODS

Publications were identified through a MEDLINE search using the Medical Subject Heading terms: inflammatory bowel diseases, or Crohn's disease, or ulcerative colitis, and stem cell, or stromal cell or transplant.

RESULTS

Haematopoietic stem cell therapy as a primary treatment for inflammatory bowel disease was originally supported by animal experiments, and by remissions in patients undergoing transplant for haematological disorders. Later, transplantation specifically performed for patients with refractory Crohn's disease showed long-lasting clinical remission and healing of inflammatory intestinal lesions. Use of autologous nonmyeloablative regimens and concentration of the procedures in centres with large experience are key in reducing treatment-related mortality. Initial trials of mesenchymal stem cell therapy with local injection in Crohn's perianal fistulas had positive results.

CONCLUSIONS

Autologous haematopoietic stem cell transplant changes the natural course of Crohn's disease, and may be a therapeutic option in patients with refractory disease if surgery is not feasible due to disease location or extension.

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.

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.