Non-myeloablative allogeneic hematopoietic stem cell transplantation for severe systemic sclerosis: graft-versus-autoimmunity without graft-versus-host disease?

Hematopoietic Cell Transplantation for Systemic Sclerosis-A Review

Systemic sclerosis (SSc) is an autoimmune, multi-organ, connective tissue disease associated with significant morbidity and mortality. Conventional immunosuppressive therapies demonstrate limited efficacy. Autologous hematopoietic stem cell transplantation (HCT) is more efficacious but carries associated risks, including treatment-related mortality. Here, we review HCT as a treatment for SSc, its efficacy and toxicity in comparison to conventional therapies, and the proposed mechanisms of action. Furthermore, we discuss the importance of and recent developments in patient selection. Finally, we highlight the knowledge gaps and future work required to further improve patient outcomes.

Cellular-Based Therapies in Systemic Sclerosis: From Hematopoietic Stem Cell Transplant to Innovative Approaches

Systemic sclerosis (SSc) is a systemic disease characterized by autoimmune responses, vasculopathy and tissue fibrosis. The pathogenic mechanisms involve a wide range of cells and soluble factors. The complexity of interactions leads to heterogeneous clinical features in terms of the extent, severity, and rate of progression of skin fibrosis and internal organ involvement. Available disease-modifying drugs have only modest effects on halting disease progression and may be associated with significant side effects. Therefore, cellular therapies have been developed aiming at the restoration of immunologic self-tolerance in order to provide durable remissions or to foster tissue regeneration. Currently, SSc is recommended as the 'standard indication' for autologous hematopoietic stem cell transplantation by the European Society for Blood and Marrow Transplantation. This review provides an overview on cellular therapies in SSc, from pre-clinical models to clinical applications, opening towards more advanced cellular therapies, such as mesenchymal stem cells, regulatory T cells and potentially CAR-T-cell therapies.

Haematopoietic stem cell transplantation for severe autoimmune diseases in children: A review of current literature, registry activity and future directions on behalf of the autoimmune diseases and paediatric diseases working parties of the European Society for Blood and Marrow Transplantation

Although modern clinical management strategies have improved the outcome of paediatric patients with severe autoimmune and inflammatory diseases over recent decades, a proportion will experience ongoing or recurrent/relapsing disease activity despite multiple therapies often leading to irreversible organ damage, and compromised quality of life, growth/development and long-term survival. Autologous and allogeneic haematopoietic stem cell transplantation (HSCT) have been used successfully to induce disease control and often apparent cure of severe treatment-refractory autoimmune diseases (ADs) in children. However, transplant-related outcomes are disease-dependent and long-term outcome data are limited in respect to efficacy and safety. Moreover, balancing risks of HSCT against AD prognosis with continually evolving non-transplant options is challenging. This review appraises published literature on HSCT strategies and outcomes in individual paediatric ADs. We also provide a summary of the European Society for Blood and Marrow Transplantation (EBMT) Registry, where 343 HSCT procedures (176 autologous and 167 allogeneic) have been reported in 326 children (<18 years) for a range of AD indications. HSCT is a promising treatment modality, with potential long-term disease control or cure, but therapy-related morbidity and mortality need to be reduced. Further research is warranted to establish the position of HSCT in paediatric ADs via registries and prospective clinical studies to support evidence-based interspeciality guidelines and recommendations.

Combining systemic and locally applied cellular therapies for the treatment of systemic sclerosis

Systemic sclerosis (SSc) is a complex autoimmune disease characterized by a functional and structural alteration of the microvascular network associated with cutaneous and visceral fibrosis lesions. Conventional therapies are based on the use of immunomodulatory molecules and symptomatic management but often prove to be insufficient, particularly for patients suffering from severe and rapidly progressive forms of the disease. In this context, cellular therapy approaches could represent a credible solution with the goal to act on the different components of the disease: the immune system, the vascular system and the extracellular matrix. The purpose of this review is to provide an overview of the cellular therapies available for the management of SSc. The first part will focus on systemically injected therapies, whose primary effect is based on immunomodulatory properties and immune system resetting, including autologous hematopoietic stem cell transplantation and intravenous injection of mesenchymal stem cells. The second part will discuss locally administered regenerative cell therapies, mainly derived from adipose tissue, developed for the management of local complications as hand and face disabilities.

Efficacy of Allogeneic Hematopoietic Cell Transplantation for Autoimmune Diseases

Allogeneic hematopoietic cell transplantation (HCT) may be efficacious for autoimmune diseases (AIDs), but its efficacy for individual AIDs is unknown. Factors influencing the likelihood of relapse for each AID are also unknown. This study aimed to determine the likelihood of relapse for each common AID and to generate hypotheses about factors influencing the likelihood of relapse. We reviewed charts of adult patients with nonhematologic AIDs who had undergone HCT in Alberta (n = 21) and patients described in the literature (n = 67). We used stringent inclusion criteria to minimize the inclusion of patients whose AID may have been cured before transplantation. We also used stringent definitions of AID relapse and remission. AID relapsed in 2 of 9 patients (22%) with lupus, in 4 of 12 (33%) with rheumatoid arthritis (RA), in 0 of 4 (0%) with systemic sclerosis (SSc), in 3 of 16 (19%) with psoriasis, in 1 of 12 (8%) with Behçet's disease (BD), in 1 of 15 (7%) with Crohn's disease (CD), in 0 of 5 (0%) with ulcerative colitis (UC), in 4 of 8 (50%) with multiple sclerosis (MS), and in 3 of 3 (100%) with type 1 diabetes mellitus (T1DM). Among highly informative patients (followed for >1 year after discontinuation of immunosuppressive therapy if no relapse, or donor AID status known if relapse), relapse occurred in 0 of 3 patients with lupus, in 2 of 7 with RA, in 0 of 2 with SSc, in 3 of 6 with psoriasis, in 0 of 3 with BD, in 0 of 10 with CD, in 0 of 3 with UC, in 2 of 3 with MS, and in 2 of 2 with T1DM. There appeared to be no associations between AID relapse and low intensity of pretransplantation chemoradiotherapy, multiple lines of AID therapy (surrogate for AID refractoriness) except perhaps for lupus, absence of serotherapy for graft-versus-host disease (GVHD) prophylaxis, lack of GVHD except perhaps for lupus, or incomplete donor chimerism. Even though remission commonly occurs after HCT in lupus, RA, SSc, psoriasis, BD, CD, and UC, HCT is efficacious for only a subset of patients. The efficacy appears to be unrelated to pretransplantation therapy, GVHD, or chimerism. Large studies are needed to determine the characteristics of patients likely to benefit from HCT for each AID.

A review of hematopoietic stem cell transplantation for autoimmune diseases: multiple sclerosis, systemic sclerosis and Crohn's disease. Position paper of the Brazilian Society of Bone Marrow Transplantation

Autoimmune diseases are an important field for the development of bone marrow transplantation, or hematopoietic stem cell transplantation. In Europe alone, almost 3000 procedures have been registered so far. The Brazilian Society for Bone Marrow Transplantation (Sociedade Brasileira de Transplantes de Medula Óssea) organized consensus meetings for the Autoimmune Diseases Group, to review the available literature on hematopoietic stem cell transplantation for autoimmune diseases, aiming to gather data that support the procedure for these patients. Three autoimmune diseases for which there are evidence-based indications for hematopoietic stem cell transplantation are multiple sclerosis, systemic sclerosis and Crohn's disease. The professional stem cell transplant societies in America, Europe and Brazil (Sociedade Brasileira de Transplantes de Medula Óssea) currently consider hematopoietic stem cell transplantation as a therapeutic modality for these three autoimmune diseases. This article reviews the evidence available.

Haematopoietic stem cell transplantation in systemic sclerosis

Three randomised controlled trials of haematopoietic stem cell transplantation (HSCT) in systemic sclerosis (SSc) demonstrated long-term survival benefits, induction of clinically meaningful, sustained improvement of forced vital capacity with improvements in skin thickening, vasculopathy and health-related quality of life, in contrast to a clinical decline in standard of care control groups. These benefits, however, must be weighed against the increased risk of transplant-related mortality. Further, with disease progression, severe extensive internal organ involvement and damage ensues, constituting an exclusion criterion for safety reasons, leaving a limited window whereby patients with SSc are eligible for HSCT. Although autologous HSCT offers the possibility of drug-free remission, relapse can occur, requiring re-initiation of disease modifying antirheumatic drugs. HSCT is also associated with secondary autoimmune diseases and gonadal failure. HSCT should be proposed for carefully selected patients with early rapidly progressive diffuse SSc whose clinical picture portends a poor prognosis for survival, but yet lacks advanced organ involvement.

[Allogeneic stem cell transplantation : An option for autoimmune diseases?]

According to experimental animal models and experiences of patients with coexisting autoimmune diseases, allogeneic stem cell transplantation has the potential to reestablish and maintain immunological tolerance. On the other hand, it is associated with significant treatment related mortality and may induce diverse immunological diseases by graft-versus-host reaction. Other than with severe aplastic anemia, it is not an established therapy for autoimmune diseases; it is under investigation in clinical trials and might be considered in severe, refractory immune cytopenia.

Hematopoietic stem cell transplantation for auto immune rheumatic diseases

Stem cells have their origins in the embryo and during the process of organogenesis, these differentiate into specialized cells which mature to form tissues. In addition, stem cell are characterized by an ability to indefinitely self renew. Stem cells are broadly classified into embryonic stem cells and adult stem cells. Adult stem cells can be genetically reprogrammed to form pluripotent stem cells and exist in an embroyonic like state. In the early phase of embryogenesis, human embryonic stem cells only exist transiently. Adult stem cells are omnipresent in the body and function to regenerate during the process of apoptosis or tissue repair. Hematopoietic stem cells (HSC) are adult stem cells that form blood and immune cells. Autoimmune responses are sustained due to the perennial persistence of tissue self autoantigens and/or auto reactive lymphocytes. Immune reset is a process leading to generation of fresh self-tolerant lymphocytes after chemotherapy induced elimination of self or autoreactive lymphocytes. This forms the basis for autologous HSC transplantation (HSCT). In the beginning HSCT had been limited to refractory autoimmune rheumatic diseases (AIRD) due to concern about transplant related mortality and morbidity. However HSCT for AIRD has come a long way with better understanding of patient selection, conditioning regime and supportive care. In this narrative review we have examined the available literature regarding the HSCT use in AIRD.

Stem cell therapies for systemic sclerosis

The presence of autoimmune diseases, including Systemic Sclerosis (SSc), suggest failure of the normal immune regulatory processes leading to activation and expansion of autoreactive effector immune cells. Recently, stem cell transplantation emerged as a novel rescue therapy for a variety of refractory autoimmune diseases. The therapeutic strategy involves the ablation of the aberrant self-reactive immune cells by chemotherapy and the regeneration of a new self-tolerant immune system formed by the transplanted stem cells. In the last few years, thousands of patients worldwide have received haematopoietic stem cell transplantation (HSCT), mostly autologous, as treatment for severe irreversible autoimmune diseases, with promising results. Here we review the results of published small series of SSc patients treated with allogeneic and autologous HSCT, as well as three randomized trials, exploring the safety and efficacy of autologous HSCT in SSc. Although the results are encouraging, nonetheless, the correct application of stem cell transplantation remains an area of active investigation. Results of larger randomized, double blind clinical trials, will certainly improve our knowledge of the appropriate clinical use of stem cell therapy in SSc patients.

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.

Emerging concepts in haematopoietic cell transplantation

Haematopoietic cell transplantation (HCT) is the most widely used form of cellular therapy. It is the only known cure for some haematological malignancies and has recently been used in additional clinical settings, such as allograft tolerance induction and treatment of autoimmune diseases. Recent advances have enabled HCT in a wider range of patients with improved outcomes. This Review summarizes the latest developments in this therapy, focusing on issues that will affect future advancement.

Allogeneic stem cell transplantation for rheumatic autoimmune diseases

Haematopoietic stem cell transplantation (HSCT) has evolved from an experimental concept to an effective treatment option for severe autoimmune diseases and has a unique ability to restore immune regulation. It is a complex multistep procedure involving the administration of high doses of immunosuppressive medication and transplantation of stem cells. Most HSCT procedures in autoimmune disease have involved autologous stem cells. In the case of allogeneic transplantation, stem cells are derived from peripheral blood or bone marrow of a healthy HLA-matched donor. Allogeneic HSCT has curative potential based on studies in experimental models of autoimmune disease, case reports, and a registry analysis but carries significant risks of rejection and graft-versus-host disease. Unless these risks become manageable, allogeneic HSCT should be offered only if all alternative treatment options have failed, if a patient has a suitable donor, and if a patient still has a chance to benefit significantly from the procedure.

Autologous stem cell transplantation for systemic sclerosis

Systemic sclerosis (SSc) is a generalised autoimmune disease, of yet unknown origin, with two major clinical subsets: the limited (lcSSc) and the diffuse cutaneous (dcSSc) forms, which can be distinguished by the extent of skin involvement, the autoantibody profile and the pattern of organ involvement. With an incidence of 1/10(5), SSc affects around 250,000 people in Europe and is responsible for significant morbidity with a 5-year mortality rate of at least 30% of all patients. In patients with rapidly progressive dcSSc, the 5-year mortality is estimated to be 40-50%. Hematopoietic stem cell transplantation (HSCT), mostly autologous but also allogeneic in some specific cases, has been employed worldwide since 1996 as a new therapeutic strategy in patients with a poor prognosis. In 2007, 150 HSCT procedures have been reported in the EBMT data base. We review herein both the short and the long-term reports from the various European and North American phase I-II studies, which have shown that autologous HSCT in selected patients with severe dcSSc results in sustained improvement of skin thickening and stabilisation of organ function up to seven years after transplantation. Based on these promising results, ongoing phase III trials have been designed in parallel, both in Europe (ASTIS) and in North America (SCOTT) aiming to analyse the respective benefits from autologous HSCT respectively without or with high dose irradiation. This review reports the current data concerning the effects of HSCT on survival, skin, and major organ function in patients with severe dcSSc.

Treatment of systemic sclerosis: potential role for stem cell transplantation

Hematopoietic stem cell transplantation may "reset" the immune reconstitution and induce self tolerance of autoreactive lymphocytes, and has been explored in the treatments for systemic sclerosis. Phase I/II trials have shown a satisfactory risk benefit ratio. The true benefit will be identified by two ongoing prospective, randomized phase III trials. Multipotent mesenchymal stromal cells (MSCs) possess antiproliferative, anti-inflammatory, and immunosuppressive properties. The use of MSCs has showed successful responses in patients with severe steroid-resistant acute graft versus host disease in phase II trials, and may be a potentially promising option for patients with systemic sclerosis.

Haematopoietic stem cell transplantation for autoimmune disorders

PURPOSE OF REVIEW

To summarize recent evidence and current trends in the use of haematopoietic stem cell transplantation (HSCT) for autoimmune diseases.

RECENT FINDINGS

Updates of published trials and data from the registries indicate a long-lasting, immunosuppression-free condition in about 50% of the patients who underwent an HSCT for a severe, progressive autoimmune disease. For all diseases, autologous HSCT is largely preferred for safety reasons, whereas allogeneic HSCT is to be considered only for carefully selected cases. Transplant-related mortality (TRM) has decreased in the past 5 years, due to both better selection of patients and the use of less intensive conditioning regimens. The most employed conditioning regimens in Europe are BCNU (carmustine), etoposide, ARA-C (cytosine arabinoside), M (melphalan) (BEAM)/anti-thymocyte globulin in multiple sclerosis and high-dose cyclophosphamide/anti-thymocyte globulin for all other diseases, with a trend for more intense regimens in North America. Multiple sclerosis and systemic sclerosis are currently the most frequent diagnoses. Prospective comparative trials are currently ongoing both in Europe and North America.

SUMMARY

Recent reports confirm the evidence that HSCT is able to induce a high rate of sustained remissions in most severe autoimmune diseases, unresponsive to conventional treatments. Valuable information is expected by the finalization of the ongoing prospective, comparative trials.

Stem cell transplantation for rheumatic autoimmune diseases

Immunoablative therapy and hematopoietic stem cell transplantation (HSCT) is an intensive treatment modality aimed at 'resetting' the dysregulated immune system of a patient with immunoablative therapy and allow outgrowth of a nonautogressive immune system from reinfused hematopoietic stem cells, either from the patient (autologous HSCT) or a healthy donor (allogeneic HSCT). HSCT has been shown to induce profound alterations of the immune system affecting B and T cells, monocytes, and natural killer and dendritic cells, resulting in elimination of autoantibody-producing plasma cells and in induction of regulatory T cells. Most of the available data have been collected through retrospective cohort analyses of autologous HSCT, case series, and translational studies in patients with refractory autoimmune diseases. Long-term and marked improvements of disease activity have been observed, notably in systemic sclerosis, systemic lupus erythematosus, and juvenile idiopathic arthritis, and treatment-related morbidity and mortality have improved due to better patient selection and modifications of transplant regimens. Treatment-related mortality has decreased to approximately 7%. Prospective, randomised, controlled clinical trials are ongoing or planned in systemic sclerosis, systemic lupus erythematosus, and several nonrheumatological conditions.

Long-term follow-up after nonmyeloablative allogeneic hematopoietic stem cell transplantation for systemic sclerosis

Systemic sclerosis (SSc) characteristically consists of fibrotic changes in various organs, and immunological abnormality is the main cause of the disease. Although high-dose immunosuppressive therapies with autologous or allogeneic hematopoietic stem cell support can reverse the disease course, they have a high treatment-related mortality. We report the successful use of nonmyeloablative allogeneic hematopoietic stem cell transplantation (HSCT) for SSc. A 40-year-old woman with diffuse scleroderma and interstitial pneumonia underwent allogeneic peripheral blood stem cell transplantation from an HLA-identical sibling after conditioning with low-dose total-body irradiation and fludarabine. Prophylaxis for graft-versus-host disease (GVHD) consisted of cyclosporine and mycophenolate mofetil. No infection or acute GVHD developed. One year after transplantation, the patient developed membranous glomerulopathy caused by chronic GVHD that was successfully treated with prednisolone. The patient's skin score decreased dramatically, and her pulmonary function is stable 4 years after transplantation. Nonmyeloablative allogeneic HSCT may be more effective than conventional therapies for SSc.