Haematopoietic SCT in autoimmune diseases in children: rationale and new perspectives

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.

An update on stem cell transplantation in autoimmune rheumatologic disorders

Stem cell transplant (SCT) has long been the standard of care for several hematologic, immunodeficient, and oncologic disorders. Recently, SCT has become an increasingly utilized therapy for refractory autoimmune rheumatologic disorders (ARDs). The efficacy of SCT in ARDs has been attributed to resetting an aberrant immune system either through direct immune replacement with hematopoietic stem cells or through immunomodulation with mesenchymal stem cells. Among ARDs, refractory systemic sclerosis (SSc) and systemic lupus erythematosus (SLE) are the most common indications for SCT. SCT has also been used in refractory rheumatoid arthritis, inflammatory myopathies, antiphospholipid syndrome, granulomatosis with polyangiitis, and pediatric ARDs. Complete responses have been reported in approximately 30 % of patients in all disease categories. Transplant-related mortality, however, remains a concern. Future large multi-center prospective randomized clinical trials will help to better define the specific role of SCT in the treatment of patients with ARDs.

Hematopoietic stem cell transplantation for curing children with severe autoimmune diseases: is this a valid option?

The cure of children with severe AD, especially patients with severe, progressive, and therapy-resistant autoimmunity, represents a challenge for current medical practice. The idea of HSCT as a promising therapeutic opportunity was borne accidentally from finding patients who, after undergoing HSCT for a hematological indication, were cured of a concomitant AD. Thus, over the last two decades, HSCT has been extensively investigated, and it has become an appealing therapy for rheumatological (juvenile rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis) and hematological diseases (immune cytopenias). Recently, interesting results have been also described in type 1 diabetes mellitus and Crohn's disease. Although the use of HSCT has been steadily rising in the last few years, many questions are still open, especially after the discoveries of many new biological agents. Given the low incidence of ADs in children, most of the data about the use of the HSCT for these diseases are taken from a mixed cohort of adults and children. The aim of this review is to summarize the published studies and to try to answer the question as to whether this procedure can be considered a promising approach.

Haematopoietic SCT in severe autoimmune diseases: updated guidelines of the European Group for Blood and Marrow Transplantation

In 1997, the first consensus guidelines for haematopoietic SCT (HSCT) in autoimmune diseases (ADs) were published, while an international coordinated clinical programme was launched. These guidelines provided broad principles for the field over the following decade and were accompanied by comprehensive data collection in the European Group for Blood and Marrow Transplantation (EBMT) AD Registry. Subsequently, retrospective analyses and prospective phase I/II studies generated evidence to support the feasibility, safety and efficacy of HSCT in several types of severe, treatment-resistant ADs, which became the basis for larger-scale phase II and III studies. In parallel, there has also been an era of immense progress in biological therapy in ADs. The aim of this document is to provide revised and updated guidelines for both the current application and future development of HSCT in ADs in relation to the benefits, risks and health economic considerations of other modern treatments. Patient safety considerations are central to guidance on patient selection and HSCT procedural aspects within appropriately experienced and Joint Accreditation Committee of International Society for Cellular Therapy and EBMT accredited centres. A need for prospective interventional and non-interventional studies, where feasible, along with systematic data reporting, in accordance with EBMT policies and procedures, is emphasized.

Emerging uses for pediatric hematopoietic stem cells

Many new therapies are emerging that use hematopoietic stem and progenitor cells. In this review, we focus on five promising emerging trends that are altering stem cell usage in pediatrics: (i) The use of hematopoietic stem cell (HSC) transplantation, autologous or allogeneic, in the treatment of autoimmune disorders is one. (ii) The use of cord blood transplantation in patients with inherited metabolic disorders such as Hurler syndrome shows great benefit, even more so than replacement enzyme therapy. (iii) Experience with the delivery of gene therapy through stem cells is increasing, redefining the potential and limitations of this therapy. (iv) It has recently been shown that human immunodeficiency virus (HIV) infection can be cured by the use of selected stem cells. (v) Finally, it has long been postulated that HSC-transplantation can be used to induce tolerance in solid-organ transplant recipients. A new approach to tolerance induction using myeloid progenitor cells will be described.

Allogeneic haematopoietic stem cell transplantation: individualized stem cell and immune therapy of cancer

The year 2009 marked the fiftieth anniversary of the first successful allogeneic haematopoietic stem cell transplant (HSCT). The field of HSCT has pioneered some of the most exciting areas of research today. HSCT was the original stem cell therapy, the first cancer immune therapy and the earliest example of individualized cancer therapy. In this Timeline article we review the history of the development of HSCT and major advances made in the past 50 years. We highlight accomplishments made by researchers who continue to strive to improve outcomes for patients and increase the availability of this potentially life-saving therapy for patients with otherwise incurable malignancies.

Autologous hematopoietic stem cell transplantation for childhood autoimmune disease

Autologous and allogeneic hematopoietic stem cell transplantation (HSCT) can be used in the management of patients with autoimmune disorders. Experience gained in adults has helped to better define the conditioning regimens required and appropriate selection of patients who are most likely to benefit from autologous HSCT. The field has been shifting toward the use of safer and less intense nonmyeloablative regimens used earlier in the disease course before patients accumulate extensive irreversible organ damage. This article reviews the experience of using autologous HSCT in treating the most common childhood autoimmune and rheumatic diseases, primarily juvenile idiopathic arthritis, systemic lupus erythematosus, and diabetes mellitus.

Theoretical and practical basis for early aggressive therapy in paediatric autoimmune disorders

PURPOSE OF REVIEW

The clinical practice of introducing anti-inflammatory therapies in paediatric autoimmune disorders has changed substantially in the last two decades. This is partly due to the fact that we are able to put disease into remission with potent drugs, and so the issue of when to introduce these drugs is important. This review will seek to highlight the consequences of chronic inflammation and the change to outcomes if adequate or 'aggressive' treatment is given early to induce remission.

RECENT FINDINGS

The review not only highlights publications on this topic over the past 12-18 months but also refers to key publications before when appropriate. The disorders reviewed are juvenile idiopathic arthritis, systemic lupus erythematosis, Wegener's granulomatosis, juvenile dermatomyositis, juvenile scleroderma and autoinflammatory syndromes.

SUMMARY

Outcomes can be influenced by potent anti-inflammatory therapies. Their use early in the evolution of the disorder in question can limit damage and allow the possibility of normal life and function in the child.

Study of thymic size and function in children and adolescents with treatment refractory systemic sclerosis eligible for immunoablative therapy

Following hematopoietic stem cell transplantation (HSCT), thymic reconstitution of peripheral T lymphocytes is essential to avoid a chronically immunodeficient state and disease recurrence. The purpose of this study was to determine if children and adolescents with treatment refractory SSc, awaiting HSCT, have sufficient thymic function to reconstitute T lymphocyte function after transplantation. Thirteen children with systemic scleroderma were enrolled and assessed by physical exam, chest MRI, measurement of autoantibodies, B and T cell immuno-phenotyping, and quantization of T cell receptor rearrangement excision circles (TREC) as a marker of thymopoiesis. MRI detected thymic tissue in 9/13 children. TREC levels were detectable in all but one child but were significantly reduced (p<0.001) when compared to a control population. SSc patients also had a reduced percentage of naïve (CD45RA+CD31+) CD4+ T lymphocytes, further indicating diminished thymopoiesis. Our data suggest that thymic function in children with SSc might be insufficient for an adequate immunoreconstitution following transplantation in some patients. A thorough evaluation of immune and thymic functions to identify those patients prior to HSCT is recommended.

Hematopoietic stem cell transplantation for pediatric autoimmune disease: where we stand and where we need to go

In children, autoimmune diseases and their therapies cause significant morbidity, especially in those with severe or refractory disease. The constant development of new immunosuppressants and targeted biological therapies leads to a unique 'moving target' with regard to the gold standard of treatment for these patients. However, incidental findings of cure after hematopoietic stem cell transplant (HSCT) in patients with concomitant benign or malignant hematologic disorders and autoimmune disease raise the question of whether HSCT can be used as upfront therapy for patients with severe autoimmune diseases. Animal data have been helpful in investigating both the efficacy of this modality and the mechanisms underlying cure. The potential for a therapeutic 'graft vs autoimmunity' (GVA) effect with an allogeneic approach highlights the already acknowledged need for clinical trials of allogeneic vs autologous transplant in these diseases where an autologous transplant would be the 'intuitive' albeit potentially erroneous choice. We critically review the data generated in the field thus far, and emphasize the need for an organized, interdisciplinary approach to conduct prospective clinical trials to answer these and other questions and advance the field.