Treatment of severe systemic lupus erythematosus with high-dose chemotherapy and haemopoietic stem-cell transplantation: a phase I study

Stem cell-based therapy for systemic lupus erythematous

Systemic lupus erythematosus (SLE), an autoimmune disease, is among the most prevalent rheumatic autoimmune disorders. It affects autologous connective tissues caused by the breakdown of self-tolerance mechanisms. During the last two decades, stem cell therapy has been increasingly considered as a therapeutic option in various diseases, including parkinson's disease, alzheimer, stroke, spinal cord injury, multiple sclerosis, inflammatory bowel disease, liver disease, diabete, heart disease, bone disease, renal disease, respiratory diseases, and hematological abnormalities such as anemia. This is due to the unique properties of stem cells that divide and differentiate to the specialized cells in the damaged tissues. Moreover, they impose immunomodulatory properties affecting the diseases caused by immunological abnormalities such as rheumatic autoimmune disorders. In the present manuscript, efficacy of stem cell therapy with two main types of stem cells, including mesenchymal stem cell (MSC), and hematopoietic stem cells (HSC) in animal models or human patients of SLE, has been reviewed. Taken together, MSC and HSC therapies improved the disease activity, and severity in kidney, lung, liver, and bone (improvement in the clinical manifestation). In addition, a change in the immunological parameters occurred (improvement in immunological parameters). The level of autoantibodies, including antinuclear antibody (ANA), and anti-double-stranded deoxyribonucleic acid antibodies (dsDNA Abs) reduced. A conversion of Th1/Th2 ratio (in favor of Th2), and Th17/Treg (in favor of Treg) was also detected. In spite of many advantages of MSC and HSC transplantations, including efficacy, safety, and increased survival rate of SLE patients, some complications, including recurrence of the disease, occurrence of infections, and secondary autoimmune diseases (SAD) were observed after transplantation that should be addressed in the next studies.

Translation of cell therapies to treat autoimmune disorders

Autoimmune diseases are a diverse and complex set of chronic disorders with a substantial impact on patient quality of life and a significant global healthcare burden. Current approaches to autoimmune disease treatment comprise broadly acting immunosuppressive drugs that lack disease specificity, possess limited efficacy, and confer undesirable side effects. Additionally, there are limited treatments available to restore organs and tissues damaged during the course of autoimmune disease progression. Cell therapies are an emergent area of therapeutics with the potential to address both autoimmune disease immune dysfunction as well as autoimmune disease-damaged tissue and organ systems. In this review, we discuss the pathogenesis of common autoimmune disorders and the state-of-the-art in cell therapy approaches to (1) regenerate or replace autoimmune disease-damaged tissue and (2) eliminate pathological immune responses in autoimmunity. Finally, we discuss critical considerations for the translation of cell products to the clinic.

Revisiting treatment-related cardiotoxicity in patients with malignant lymphoma-a review and prospects for the future

Treatment of malignant lymphoma has for years been represented by many cardiotoxic agents especially anthracyclines, cyclophosphamide, and thoracic irradiation. Although they are in clinical practice for decades, the precise mechanism of cardiotoxicity and effective prevention is still part of the research. At this article we discuss most routinely used anti-cancer drugs in chemotherapeutic regiments for malignant lymphoma with the focus on novel insight on molecular mechanisms of cardiotoxicity. Understanding toxicity at molecular levels may unveil possible targets of cardioprotective supportive therapy or optimization of current therapeutic protocols. Additionally, we review novel specific targeted therapy and its challenges in cardio-oncology.

Long-term follow-up of autologous peripheral blood hematopoietic stem cell transplantation for refractory lupus nephritis—a series study of 20 patients

Background

Autologous hematopoietic cell transplantation (ASCT) improves immunologic homeostasis in autoimmune diseases. ASCT-treated refractory lupus nephritis ( LN ) has been reported. Nevertheless, the long-term outcome of patients with refractory LN after ASCT remains unknown. This study reports the outcomes of 20 refractory lupus patients with 10-year of follow-up after receiving ASCT.

Methods

Twenty-two patients with LN refractory to immunosuppressive therapy were enrolled. Twenty patients were examined closely and two cases died within 100 days after ASCT. Hematopoietic cell mobilization with cyclophosphamide and granulocyte colony-stimulating factor (G-CSF) was followed by collection of CD34+ positively selected cells. The conditioning regimen consisted of intravenous cyclophosphamide, rabbit antithymocyte globulin, methylprednisolone, and G-CSF. All immunosuppressive therapies were discontinued at the start of mobilization and corticosteroids were tapered rapidly after ASCT.

Results

Data was collected from 22 patients with refractory LN treated by ASCT. 59% were female, duration of lupus before ASCT was 46 (33–71) months, and median duration of follow-up after ASCT was 89.5 (56–108) months. 20 long-term followed up patients had an average follow-up time of 92 months ( 63.25–109.5 ). Eighteen patients achieved complete remission, one patient reached partial remission, one patient without remission started peritoneal dialysis at month 12, and one patient received short-term renal replacement therapy before ASCT started hemodialysis at 84 months after transplantation. Nine patients relapsed 10 times during the follow-up, and three patients received rituximab. Two patients relapsed during pregnancy after complete response and the Apgar scores of infants were 9 and 10, respectively. All nine patients received glucocorticoids and immunosuppressive medication after relapse and responded again. The 10-year overall survival, 10-year disease-free survival rate, and 10-year renal survival were 100%, 35%, and 90%, respectively. The rate of relapse was 45%. Complications included hypocytosis, infection, B-type insulin resistance syndrome, and monoclonal immunoglobulinemia.

Conclusion

This study suggests ASCT is effective and safety in treating refractory LN and is beneficial to improve their long-term outcomes.

Stem Cell Therapy in Lupus

Systemic lupus erythematosus (SLE) is a chronic autoimmune and inflammatory disease with multiple organs and systems involved such as the kidney, lung, brain and the hematopoietic system. Although increased knowledge of the disease pathogenesis has improved treatment options, current immunosuppressive therapies have failed to prevent disease relapse in more than half of treated patients. Thus, the cell replacement therapy approach that aims to overcome adverse events of traditional treatment and improve recovery rate of refractory SLE is considered as an alternative treatment option. A large number of animal studies and clinical trials have shown stem cell therapy to be a promising therapeutic approach for the treatment of SLE. Since the first transplantation into human patients, several stem cell types have been applied in this field, including hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). In this review, we overview different cell sources of stem cells and applications of the stem cell therapy for treatment of SLE, as well as the comparison between HSCs transplantation (HSCT) and MSCs transplantation (MSCT).

Identification of the minimum requirements for successful haematopoietic stem cell transplantation

Historically, defining haematopoietic subsets, including self‐renewal, differentiation and lineage restriction, has been elucidated by transplanting a small number of candidate cells with many supporting bone marrow (BM) cells. While this approach has been invaluable in characterising numerous distinct subsets in haematopoiesis, this approach is arguably flawed. The haematopoietic stem cell (HSC) has been proposed as the critical haematopoietic subset necessary for transplantation. However, due to the presence of supporting cells, the HSC has never demonstrated sufficiency. Utilising the homeobox B5 (Hoxb5)‐reporter system, we found that neither long‐term (LT) HSCs nor short‐term (ST) HSCs alone were sufficient for long‐term haematopoietic reconstitution. Critically, reconstitution can be rescued by transplanting combined LT‐ and ST‐HSCs, without supporting cells; a fraction we term the ‘Minimum Subset for Transplantation’ (MST). The MST accounts for only 0·005% of nucleated cells within mouse BM, and this MST can be cultured, expanded and genetically modified while preserving its rapid haematopoietic engraftment potential. These results support the consideration of an MST approach for clinical translation, especially for gene therapy approaches that require HSC compartment modification.

Haemopoietic stem cell transplantation in Systemic lupus erythematosus: a systematic review

Despite advances in treating Systemic lupus erythematosus (SLE), a proportion of patients continue to face significant morbidity and mortality. Haemopoietic stem cell transplant (HSCT) has been recognized as an option for such patients. We analysed the evidence on efficacy and safety of HSCT in patients with SLE. A database search was done for articles on HSCT in SLE up to July 2017 in PUBMED, Cochrane library, LILACS and clinical trial registration databases to select prospective or retrospective studies with 8 or more patients. Of the 732 search results from the PUBMED, Cochrane and LILACS database search, following duplicate removal, 15 studies were eligible for detailed assessment. Findings of an additional trial were obtained from the clinical trial registration database. Data were extracted on study design, patient characteristics, nature of intervention, outcomes, complications and study quality. Case reports and small case series were summarised without detailed qualitative analysis. Most of the studies showed remission in the majority of patients. Relapse of the original disease increased with longer follow-up. Common adverse effects included: infections and secondary autoimmune disorders. Short follow up period and lack of randomised controlled trials were the main limitations restricting the generalizability of study results. A meta-analysis was not performed due to heterogeneity of studies. Although HSCT is a viable option in SLE, its exact clinical utility needs to be further evaluated in well-designed studies.

Management strategies and future directions for systemic lupus erythematosus in adults

Systemic lupus erythematosus (SLE) is an autoimmune disease characterised by the loss of self-tolerance and formation of nuclear autoantigens and immune complexes resulting in inflammation of multiple organs. The clinical presentation of SLE is heterogeneous, can involve one or more organs, including the skin, kidneys, joints, and nervous system, and take a chronic or relapsing and remitting disease course. SLE is most common in women and in those of non-white ethnicity. Because of the multitude of presentations, manifestations, and serological abnormalities in patients with SLE, diagnosis can be challenging. Therapeutic approaches predominantly involve immunomodulation and immunosuppression and are targeted to the specific organ manifestation, with the aim of achieving low disease activity. Despite many treatment advances and improved diagnostics, SLE continues to cause substantial morbidity and premature mortality. Current management strategies, although helpful, are limited by high failure rates and toxicity. An overreliance on corticosteroid therapy contributes to much of the long-term organ damage. In this Seminar, we outline the classification criteria for SLE, current treatment strategies and medications, the evidence supporting their use, and explore potential future therapies.

Molecular mechanism involved in cyclophosphamide-induced cardiotoxicity: Old drug with a new vision

Cyclophosphamide (CP) is an important anticancer drug which belongs to the class of alkylating agent. Cyclophosphamide is mostly used in bone marrow transplantation, rheumatoid arthritis, lupus erythematosus, multiple sclerosis, neuroblastoma and other types of cancer. Dose-related cardiotoxicity is a limiting factor for its use. CP-induced cardiotoxicity ranges from 7 to 28% and mortality ranges from 11 to 43% at the therapeutic dose of 170-180 mg/kg, i.v. CP undergoes hepatic metabolism that results in the production of aldophosphamide. Aldophosphamide decomposes into phosphoramide mustard & acrolein. Phosphoramide is an active neoplastic agent, and acrolein is a toxic metabolite which acts on the myocardium and endothelial cells. This is the first review article that talks about cyclophosphamide-induced cardiotoxicity and the different signaling pathways involved in its pathogenicity. Based on the available literature, CP is accountable for cardiomyocytes energy pool alteration by affecting the heart fatty acid binding proteins (H-FABP). CP has been found associated with cardiomyocytes apoptosis, inflammation, endothelial dysfunction, calcium dysregulation, endoplasmic reticulum damage, and mitochondrial damage. Molecular mechanism of cardiotoxicity has been discussed in detail through crosstalk of Nrf2/ARE, Akt/GSK-3β/NFAT/calcineurin, p53/p38MAPK, NF-kB/TLR-4, and Phospholamban/SERCA-2a signaling pathway. Based on the available literature we support the fact that metabolites of CP are responsible for cardiotoxicity due to depletion of antioxidants/ATP level, altered contractility, damaged endothelium and enhanced pro-inflammatory/pro-apoptotic activities resulting into cardiomyopathy, myocardial infarction, and heart failure. Dose adjustment, elimination/excretion of acrolein and maintenance of endogenous antioxidant pool could be the therapeutic approach to mitigate the toxicities.

Stem cells for lupus nephritis: a concise review of current knowledge

Lupus nephritis (LN), a common manifestation of systemic lupus erythematosus (SLE), accounts for significant morbidity and mortality in SLE patients. Since the available standard therapies and biologic agents for LN are yet to achieve the desired response and have considerable secondary effects, stem cell therapy has now emerged as a new approach. This therapy involves the transplantation of hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). Our current review will highlight the progress of stem cell therapy for LN, along with the challenges encountered and the future direction of this approach.

Autologous hematopoietic stem cell transplantation in Systemic Lupus Erythematosus and antiphospholipid syndrome: A systematic review

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) has been proposed as a therapeutic option for patients with Systemic Lupus Erythematosus (SLE) refractory to standard therapy. This therapeutic approach has been applied to other severe autoimmune diseases refractory to standard therapy with promising results.

AIM

To systematically review the literature and analyze the available evidence on HSCT therapy in patients with SLE and antiphospholipid syndrome (APS), with a focus on therapy efficacy and occurrence of adverse events.

METHODS

A detailed literature search, applied to Ovid MEDLINE, In-Process and Other Non-Indexed Citation and Ovid Medline 1986 to 2014, has been developed a priori to identify articles that reported findings from clinical and laboratory studies that investigated the effect of HCT in patients with SLE.

RESULTS

Twenty-five studies met all inclusion criteria, including a total of 279 SLE patients; of those, 54 patients also fulfilled the classification criteria of APS. The majority of the studies reported an improvement after HSCT in terms of diseases activity control (assessed with SLEDAI, or time-free from diseases) or overall survival. However, one study reported no net benefit of HSCT when compared to immunosuppression alone. One retrospective study reported an overall survival at 5years of 81% in 28 SLE patients. Of note, 5 cases (9.3%) of aPL negativization were reported after HSCT in the APS patients. When combining these studies and analyzing these patients with APS, 32 out of 44 (73%) were able to discontinue anticoagulation after HSCT. Our findings also demonstrate a total of 86 infections in the pool of patients (30.8%), 3 of which resulted in the death of the patient (1.3%). We observed an annual incidence of infection of 11.9% with a mean follow up of 36.2months.

CONCLUSION

Preliminary results of HSCT as a therapeutic option for SLE appear promising. Further studies are warranted in order to assess the safety of the procedure for both the occurrence of secondary autoimmune disease and the rate of infection. However, the rate of adverse effects confines this option to very selected cases of SLE patients resistant or refractory to standard approaches.

[Sarcoidosis flare after autologous stem cell transplantation: An immune paradox?]

INTRODUCTION

Sarcoidosis is a systemic granulomatous disorder of unknown cause. Apparition or flare of previously diagnosed sarcoidosis following hematopoietic stem cell transplantation (HSCT) has rarely been reported.

OBSERVATION

We report a 62-year-old woman who presented a radiological flare of sarcoidosis post-autologous stem cell transplantation for a POEMS syndrome. Imaging findings and lymph node histology, which revealed non-caseating granuloma, were consistent with the sarcoidosis diagnosis. The patient was asymptomatic and was kept free of treatment.

CONCLUSION

Sarcoidosis must be considered ahead of compatible clinicoradiological presentation occurring after HSCT. Sarcoidosis can mimic metastatic cancer or lymphatic relapse. Tissue biopsies and exclusion of differential diagnosis of granuloma diseases are warranted to confirm sarcoidosis diagnosis.

Stem Cell Therapy in the Treatment of Rheumatic Diseases and Application in the Treatment of Systemic Lupus Erythematosus

Current systemic therapies help to improve the symptoms and quality of life for patients with severe life-threatening rheumatic diseases but provide no curative treatment. For the past two decades, preclinical and clinical studies of stem cell transplantation (SCT) have demonstrated tremendous therapeutic potential for patients with autoimmune rheumatic diseases. Herein, the current advances on stem cell therapies, both in animal models and clinical studies, are discussed, with particular attention on systemic lupus erythematosus (SLE). Despite extensive research and promising data, our knowledge on mechanisms of action for SCT, its administration route and timing, the optimal dose of cells, the cells’ fate and distribution in vivo, and the safety and efficacy of the treatments remains limited. Further research on stem cell biology is required to ensure that therapeutic safety and efficacy, as observed in animal models, can be successfully translated in clinical trials. Current understanding, limitations, and future directions for SCT with respect to rheumatic diseases are also discussed.

Successful long-term treatment of systemic lupus erythematosus with rituximab maintenance therapy

Systemic lupus erythematosus(SLE) is a chronic, inflammatory autoimmune disease that may involve multiple organ systems. Treatment consists of immunosuppression, cytotoxic treatment, plasmapheresis and immunoglobuline therapy. Treatment of patients refractory to standard treatment approaches is difficult and results are poor. We describe a 39-year old patient with SLE sufferingfrom grand mal epilepsy due to cerebralvasculopathywith positivelupus anticoagulant, who was refractory to standard treatment modalities. The patient was treated with the anti-CD20 monoclonal antibody rituximab (375 mg/m2 ×4, repeated at weekly intervals). Rituximab applications were delivered in October 2000, March 2001 and October 2001. Since March 2002 she has received maintenance therapy with rituximab 375 mg/m2 every three months. A second female with refractory SLE was treated successfully in April 2002 and receives maintenance therapy every three months. Both patients responded well to rituximab therapy. The first patient showed a major improvement of her clinical condition, and 30 months after the beginning of the rituximab therapy she is free of any symptoms. inflammation parameters, ANA and lupus anticoagulantdeclined significantly after the treatment. The clinical conditionof the second patient improved dramatically, all inflammation parameters normalized and her circulating immunocomplexes disappeared. In conclusion, rituximab maintenance treatment may be a new effective therapy in SLE.

Immunomodulators in SLE: Clinical evidence and immunologic actions

Systemic lupus erythematosus (SLE) is a potentially fatal autoimmune disease. Current treatment strategies rely heavily on corticosteroids, which are in turn responsible for a significant burden of morbidity, and immunosuppressives which are limited by suboptimal efficacy, increased infections and malignancies. There are significant deficiencies in our immunosuppressive armamentarium, making immunomodulatory therapies crucial, offering the opportunity to prevent disease flare and the subsequent accrual of damage. Currently available immunomodulators include prasterone (synthetic dehydroeipandrosterone), vitamin D, hydroxychloroquine and belimumab. These therapies, acting via numerous cellular and cytokine pathways, have been shown to modify the aberrant immune responses associated with SLE without overt immunosuppression. Vitamin D is important in SLE and supplementation appears to have a positive impact on disease activity particularly proteinuria. Belimumab has specific immunomodulatory properties and is an effective therapy in those with specific serological and clinical characteristics predictive of response. Hydroxychloroquine is a crucial background medication in SLE with actions in many molecular pathways. It has disease specific effects in reducing flare, treating cutaneous disease and inflammatory arthralgias in addition to other effects such as reduced thrombosis, increased longevity, improved lipids, better glycemic control and blood pressure. Dehydroeipandrosterone is also an immunomodulator in SLE which can have positive effects on disease activity and has bone protective properties. This review outlines the immunologic actions of these drugs and the clinical evidence supporting their use.

Bone marrow-derived macrophages and the CNS: An update on the use of experimental chimeric mouse models and bone marrow transplantation in neurological disorders

The central nervous system (CNS) is a very unique system with multiple features that differentiate it from systemic tissues. One of the most captivating aspects of its distinctive nature is the presence of the blood brain barrier (BBB), which seals it from the periphery. Therefore, to preserve tissue homeostasis, the CNS has to rely heavily on resident cells such as microglia. These pivotal cells of the mononuclear lineage have important and dichotomous roles according to various neurological disorders. However, certain insults can overwhelm microglia as well as compromising the integrity of the BBB, thus allowing the infiltration of bone marrow-derived macrophages (BMDMs). The use of myeloablation and bone marrow transplantation allowed the generation of chimeric mice to study resident microglia and infiltrated BMDM separately. This breakthrough completely revolutionized the way we captured these 2 types of mononuclear phagocytic cells. We now realize that microglia and BMDM exhibit distinct features and appear to perform different tasks. Since these cells are central in several pathologies, it is crucial to use chimeric mice to analyze their functions and mechanisms to possibly harness them for therapeutic purpose. This review will shed light on the advent of this methodology and how it allowed deciphering the ontology of microglia and its maintenance during adulthood. We will also compare the different strategies used to perform myeloablation. Finally, we will discuss the landmark studies that used chimeric mice to characterize the roles of microglia and BMDM in several neurological disorders. This article is part of a Special Issue entitled: Neuro Inflammation edited by Helga E. de Vries and Markus Schwaninger.

Stem cell therapies for systemic lupus erythematosus: current progress and established evidence

Systemic lupus erythematosus is a multisystem autoimmune disease that, despite the advances in immunosuppressive medical therapies, remains potentially fatal in some patients, especially in treatment-refractory patients. In recent years, hematopoietic stem cells and, most recently, mesenchymal stem cells have been used to treat drug-resistant cases. Some progress was made, but there are still some issues to be resolved in the clinic.

Adult stem cell therapy for autoimmune disease

Many studies of autologous hematopoietic stem cell transplantation (HSCT) and allogeneic HSCT have been conducted for autoimmune disease in various animal models. Because of the substantial risk of morbidity and mortality associated with allogeneic bone marrow transplantation, autologous transplants justified trying this approach in patient with severe autoimmune disease who were refractory to current treatments. Remission was achieved in some of the patients and some of them relapsed. Recently, many in vitro studies have reported that mesenchymal stem cells (MSC) have immunomodulatory properties and immunosuppressive effects on MHC-mismatched lymphocytes proliferation by inhibiting naïve, memory and activated T cells, B cell, NK cells and dendritic cells. In addition, adipose tissue-derived MSC (AT-MSC) are becoming an alternative source of MSC for therapeutic applications because adipose tissues are abundant, easily accessible, easily obtainable with little patient discomfort and large amounts of AT-MSC can be easily obtained. A large body of in vitro research has shown that AT-MSC have same or similar immunomodulatory effects with bone marrow derived MSC. Drawing on this finding, the increasing numbers of researchers have turned on their attention to preclinical studies on AT-MSC. As this new path of research evolves with subsequent reports, MSC would make a significant contribution to stem cell therapy or combination therapy for ameliorating symptoms and curing autoimmune disease. By searching and studying the appropriate therapeutic gene, the therapeutic gene transfected stem cell therapy will be able to acquire the synergy effect and the combined advantage of gene therapy and stem cell therapy.

Long-term follow-up of autologous stem cell transplantation for severe paediatric systemic lupus erythematosus

This study attempts to evaluate the outcome of autologous peripheral blood hematopoietic stem cell transplantation (auto-PBHSCT) in patients with severe paediatric systemic lupus erythematosus (SLE). Five patients (n = 2 females, n = 3 males) with severe or refractory paediatric SLE received autologous peripheral blood CD34+ cell transplants between July 2005 and February 2009. The patients ranged in age from 6 to 14 years, and the course of disease extended over a period from 5 to 90 months. All of the patients received conventional therapy for 3 to 87 months. After their discharge from the hospital, the patients continued to maintain their regular follow-up visits and basic quality of life. The patients exhibited decreased immune function after the auto-PBHSCT. The CD4+ and CD19+ cells were significantly reduced. Viremia occurred in four patients 2 months after the transplantation. All of the patients went into clinical remission in 3-6 months. The severity of encephalopathy, nephritis and organ damage declined in varying degrees. The disease recurred in patient 2 at 9 months and in patient 4 at 12 months after the transplantation. Because the disease was relatively mild, we were able to administer small doses of glucocorticoids that were sufficient to control the course of the disease. Macrophage activation syndrome occurred in patient 3 at 18 months after the transplantation. At the end of the follow-up period, three of the five patients were completely off their medications. Another two patients sustained small doses of glucocorticoids. The developmental levels of these patients were comparable to those of normal children at the end of the follow-up. The quality of life improved significantly. The auto-PBHSCT is effective for severe and refractory paediatric SLE. The incidence of lethal infection and other adverse reactions is low. Long-term remission can be achieved. A milder form of the disease may have recurred after the transplantation.

Early differentiated CD138(high) MHCII+ IgG+ plasma cells express CXCR3 and localize into inflamed kidneys of lupus mice

Humoral responses are central to the development of chronic autoimmune diseases such as systemic lupus erythematosus. Indeed, autoantibody deposition is responsible for tissue damage, the kidneys being one of the main target organs. As the source of pathogenic antibodies, plasma cells are therefore critical players in this harmful scenario, both at systemic and local levels. The aim of the present study was to analyze plasma cells in NZB/W lupus mice and to get a better understanding of the mechanisms underlying their involvement in the renal inflammation process. Using various techniques (i.e. flow cytometry, quantitative PCR, ELISpot), we identified and extensively characterized three plasma cell intermediates, according to their B220/CD138/MHCII expression levels. Each of these cell subsets displays specific proliferation and antibody secretion capacities. Moreover, we evidenced that the inflammation-related CXCR3 chemokine receptor is uniquely expressed by CD138^highMHCII⁺ plasma cells, which encompass both short- and long-lived cells and mostly produce IgG (auto)antibodies. Expression of CXCR3 allows efficient chemotactic responsiveness of these cells to cognate chemokines, which production is up-regulated in the kidneys of diseased NZB/W mice. Finally, using fluorescence and electron microscopy, we demonstrated the presence of CD138⁺CXCR3⁺IgG⁺ cells in inflammatory areas in the kidneys, where they are very likely involved in the injury process. Thus, early differentiated CD138^highMHCII⁺ rather than terminally differentiated CD138^highMHCII^low plasma cells may be involved in the renal inflammatory injury in lupus, due to CXCR3 expression and IgG secretion.

Autologous haematopoietic stem cell transplantation for systemic lupus erythematosus: data from the European Group for Blood and Marrow Transplantation registry

OBJECTIVES

Patients with systemic lupus erythematosus (SLE) refractory to conventional immunosuppression suffer substantial morbidity and mortality due to active disease and treatment toxicity. Immunoablation followed by autologous stem cell transplantation (ASCT) is a novel therapeutic strategy that potentially offers new hope to these patients.

METHODS

This retrospective survey reviews the efficacy and safety of ASCT in 28 SLE patients from eight centres reported to the European Group for Blood and Marrow Transplantation (EBMT) registry between 2001 and 2008.

RESULTS

Median disease duration before ASCT was 52 (nine to 396) months, 25/28 SLE patients (89%) were female, age 29 (16-48) years. At the time of ASCT, eight (one to 11) American College of Rheumatology (ACR) diagnostic criteria for SLE were present and 17 (60%) patients had nephritis. Peripheral blood stem cells were mobilized with cyclophosphamide and granulocyte-colony stimulating factor in 93% of patients, and ex vivo CD34 stem cell selection was performed in 36%. Conditioning regimens were employed with either low (n = 10) or intermediate (18) intensities. With a median follow-up of 38 (one to 110) months after ASCT, the five-year overall survival was 81 ± 8%, disease-free survival was 29 ± 9%, relapse incidence (RI) was 56 ± 11% and non-relapse mortality was 15 ± 7%. Graft manipulation by CD34+ selection was associated with a lower RI (p = 0.001) on univariate analysis. There were five deaths within two years after ASCT: three caused by infection, one by secondary autoimmune disease and one by progressive SLE.

CONCLUSIONS

Our data further support the concept of immunoablation and ASCT to re-induce long-term clinical and serologic remissions in refractory SLE patients even in the absence of maintenance therapy. This study also suggests a beneficial effect of ex vivo graft manipulation on prevention of relapses post-transplantation in SLE.

Joint European League Against Rheumatism and European Renal Association-European Dialysis and Transplant Association (EULAR/ERA-EDTA) recommendations for the management of adult and paediatric lupus nephritis

OBJECTIVES

To develop recommendations for the management of adult and paediatric lupus nephritis (LN).

METHODS

The available evidence was systematically reviewed using the PubMed database. A modified Delphi method was used to compile questions, elicit expert opinions and reach consensus.

RESULTS

Immunosuppressive treatment should be guided by renal biopsy, and aiming for complete renal response (proteinuria <0.5 g/24 h with normal or near-normal renal function). Hydroxychloroquine is recommended for all patients with LN. Because of a more favourable efficacy/toxicity ratio, as initial treatment for patients with class III-IV(A) or (A/C) (±V) LN according to the International Society of Nephrology/Renal Pathology Society 2003 classification, mycophenolic acid (MPA) or low-dose intravenous cyclophosphamide (CY) in combination with glucocorticoids is recommended. In patients with adverse clinical or histological features, CY can be prescribed at higher doses, while azathioprine is an alternative for milder cases. For pure class V LN with nephrotic-range proteinuria, MPA in combination with oral glucocorticoids is recommended as initial treatment. In patients improving after initial treatment, subsequent immunosuppression with MPA or azathioprine is recommended for at least 3 years; in such cases, initial treatment with MPA should be followed by MPA. For MPA or CY failures, switching to the other agent, or to rituximab, is the suggested course of action. In anticipation of pregnancy, patients should be switched to appropriate medications without reducing the intensity of treatment. There is no evidence to suggest that management of LN should differ in children versus adults.

CONCLUSIONS

Recommendations for the management of LN were developed using an evidence-based approach followed by expert consensus.

Systemic Lupus Erythematosus: Recent Concepts in Genomics, Pathogenetic Mechanisms, and Therapies

Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disorder associated with multiple immunological abnormalities and a wide range of clinical manifestations. Recent progress in genetics has expanded the number of the genes associated with SLE to more than 20 in number and has contributed to improvement of understanding of the pathogenesis of the disease. This has enhanced the development of novel therapeutic targets and biomarkers for individualized and tailor-made clinical management of lupus patients. Despite this knowledge, however, it is a challenge to fully understand the genetic pathogenesis of the disease. The present paper describes the current concepts in the mechanisms, genomics, and pathogenesis of SLE and their implications for management of the disorder. The potential role of gene therapy, biological agents, intravenous immunoglobulin, anti-inflammatory cytokines, and cytokine inhibitors is discussed.

Immune mechanisms underlying the beneficial effects of autologous hematopoietic stem cell transplantation in multiple sclerosis

A recent phase I/II clinical trial drew serious attention to the therapeutic potential of autologous hematopoietic stem cell transplantation (AHSCT) in multiple sclerosis. However, questions were raised as to whether these beneficial effects should be attributed to the newly reconstituted immune system per se, or to the lymphoablative conditioning regimen-induced immunosuppression, given that T-cell depleting combinational drug therapies were used in the study. We discuss here the possibility that both AHSCT and T-cell depleting therapies may re-program alternatively the immune system, and why transplantation of CD34+ hematopoietic stem cells may offer AHSCT a possible advantage regarding long-term remission.

Current state and future directions of autologous hematopoietic stem cell transplantation in systemic lupus erythematosus

Autologous haematopoietic stem cell transplantation (AHSCT) has been proposed as a treatment modality which may arrest the autoimmune disease process and lead to sustained treatment-free remissions. Since the first consensus statement in 1997, approximately 200 autologous bone marrow or haematopoietic stem cell transplantations (HSCTs) have been reported worldwide for systemic lupus erythematosus (SLE). The current state of AHSCT in SLE was reviewed at a recent meeting of the autoimmune working party of the European Group for Blood and Marrow Transplantation. There was general agreement among experts in this field that in patients with severe SLE refractory to conventional immunosuppressive treatments, AHSCT can achieve sustained clinical remissions (ranging from 50% to 70% disease-free survival at 5 years) associated with qualitative immunological changes not seen with other forms of treatment. However, this clinical benefit is associated with an increase in short-term mortality in most studies. Improving patient selection, long-term follow-up of patients after AHSCT, optimisation of induction and maintenance treatment together with detailed analysis of the immune system are identified as key areas for future research. Optimally, AHSCT should be compared with conventional treatment in randomised controlled trials. Development of stronger transplant registries, defining a core set of clinical data and standardising biological sample collections would make future collaborations and comparison of studies more feasible.

Efficient induction of CD25- iTreg by co-immunization requires strongly antigenic epitopes for T cells

Background

We previously showed that co-immunization with a protein antigen and a DNA vaccine coding for the same antigen induces CD40^low IL-10^high tolerogenic DCs, which in turn stimulates the expansion of antigen-specific CD4⁺CD25^-Foxp3⁺ regulatory T cells (CD25^- iTreg). However, it was unclear how to choose the antigen sequence to maximize tolerogenic antigen presentation and, consequently, CD25^- iTreg induction.

Results

In the present study, we demonstrated the requirement of highly antigenic epitopes for CD25^- iTreg induction. Firstly, we showed that the induction of CD25^- iTreg by tolerogenic DC can be blocked by anti-MHC-II antibody. Next, both the number and the suppressive activity of CD25^- iTreg correlated positively with the overt antigenicity of an epitope to activate T cells. Finally, in a mouse model of dermatitis, highly antigenic epitopes derived from a flea allergen not only induced more CD25^- iTreg, but also more effectively prevented allergenic reaction to the allergen than did weakly antigenic epitopes.

Conclusions

Our data thus indicate that efficient induction of CD25^- iTreg requires highly antigenic peptide epitopes. This finding suggests that highly antigenic epitopes should be used for efficient induction of CD25^- iTreg for clinical applications such as flea allergic dermatitis.

Purified hematopoietic stem cell transplantation: the next generation of blood and immune replacement

Replacement of disease-causing stem cells with healthy ones has been achieved clinically via hematopoietic cell transplantation (HCT) for the last 40 years, as a treatment modality for a variety of cancers and immunodeficiencies with moderate, but increasing, success. This procedure has traditionally included transplantation of mixed hematopoietic populations that include hematopoietic stem cells (HSC) and other cells, such as T cells. This article explores and delineates the potential expansion of this technique to treat a variety of inherited diseases of immune function, the current barriers in HCT and pure HSC transplantation, and the up-and-coming strategies to combat these obstacles.

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.

Myeloperoxidase-specific plasma cell depletion by bortezomib protects from anti-neutrophil cytoplasmic autoantibodies-induced glomerulonephritis

Anti-neutrophil cytoplasmic autoantibodies (ANCA) cause vasculitis and necrotizing crescentic glomerulonephritis (NCGN). Steroids and cytotoxic drugs reduce mortality but can cause significant adverse events. The proteasome inhibitor bortezomib (BTZ) prevents glomerulonephritis in mouse models of lupus but its efficacy in ANCA-associated glomerulonephritis is unknown. We induced anti-MPO IgG-mediated NCGN by transplanting wild-type bone marrow (BM) into irradiated MPO-deficient mice immunized with MPO. Four weeks after BM transplantation, we treated mice with steroid/cyclophosphamide (S/CYC) or BTZ. Compared with untreated control mice, both S/CYC and BTZ significantly reduced urine abnormalities, NCGN, and infiltration of neutrophils and macrophages. Response to BTZ depended on timing of administration: BTZ abrogated NCGN if begun 3 weeks, but not 5 weeks, after BM transplantation. BTZ treatment significantly reduced total and MPO-specific plasma cells in both the spleen and bone marrow, resulting in significantly reduced anti-MPO titers. Furthermore, BTZ affected neither B cells nor total CD4 and CD8 T cells, including their naive and effector subsets. In contrast, S/CYC reduced the total number of cells in the spleen, including total and MPO-specific plasma cells and B cells. In contrast to BTZ, S/CYC did not affect total and MPO-specific plasma cells in the bone marrow. Three of 23 BTZ-treated mice died within 36 hours after BTZ administration. In summary, BTZ depletes MPO-specific plasma cells, reduces anti-MPO titers, and prevents NCGN in mice.

Purified hematopoietic stem cell transplantation: the next generation of blood and immune replacement

Replacement of disease-causing stem cells with healthy ones has been achieved clinically via hematopoietic cell transplantation (HCT) for the last 40 years, as a treatment modality for a variety of cancers and immunodeficiencies with moderate, but increasing, success. This procedure has traditionally included transplantation of mixed hematopoietic populations that include hematopoietic stem cells (HSC) and other cells, such as T cells. This article explores and delineates the potential expansion of this technique to treat a variety of inherited diseases of immune function, the current barriers in HCT and pure HSC transplantation, and the up-and-coming strategies to combat these obstacles.

Umbilical cord mesenchymal stem cell transplantation in severe and refractory systemic lupus erythematosus

OBJECTIVE

Umbilical cord (UC)-derived mesenchymal stem cells (MSCs) have shown marked therapeutic effects in a number of diseases in animal studies, based on their potential for self-renewal and differentiation. No data are available on the effectiveness of UC MSC transplantation (MSCT) in human autoimmune disease. This study was undertaken to assess the efficacy and safety of allogeneic UC MSCT in patients with severe and treatment-refractory systemic lupus erythematosus (SLE).

METHODS

We conducted a single-arm trial that involved 16 SLE patients whose disease was refractory to standard treatment or who had life-threatening visceral involvement. All of the patients gave consent and underwent UC MSCT. Clinical changes were evaluated before and after transplantation using the SLE Disease Activity Index (SLEDAI), measurement of serum antinuclear antibody (ANA), anti-double-stranded DNA (anti-dsDNA) antibody, serum complement C3 and C4, and albumin levels, and assessment of and renal function. Evaluation of potential mechanisms of MSCT effects focused on the percentage of peripheral blood Treg cells and serum levels of cytokines.

RESULTS

From April 2007 to July 2009, a total of 16 patients with active SLE were enrolled and underwent UC MSCT. The median followup time after MSCT was 8.25 months (range 3-28 months). Significant improvements in the SLEDAI score, levels of serum ANA, anti-dsDNA antibody, serum albumin, and complement C3, and renal function were observed. Clinical remission was accompanied by an increase in peripheral Treg cells and a re-established balance between Th1- and Th2-related cytokines. Significant reduction in disease activity was achieved in all patients, and there has been no recurrence to date and no treatment-related deaths.

CONCLUSION

Our findings indicate that UC MSCT results in amelioration of disease activity, serologic changes, and stabilization of proinflammatory cytokines. These data provide a foundation for conducting a randomized controlled trial of this new therapy for severe and treatment-refractory SLE.

Long-term response of juvenile idiopathic arthritis after conditioning with 8 Gy total body irradiation followed by autologous peripheral blood stem cells: case report

Investigations of HCT for refractory JIA have employed high dose immunosuppressive drugs, such as CY and ATG with or without low dose TBI. Initial disease response has been observed in approximately two-thirds of patients; however, relapse occurs in about half of the responders. The current report describes a regimen with substantially increased dose of TBI, previously shown to be associated with high rate of disease response in adult patients with refractory MS and severe SSc. We report outcome of the lead patient in this pilot study, who remains in complete remission now, five yr after HCT. This regimen should be considered for patients with JIA refractory to medical therapies, including previous low intensity regimen HCT.

Long-term remission after successful pregnancy in autologous peripheral blood stem cell transplanted system lupus erythematosus patients

Pregnancies in systemic lupus erythematosus (SLE) patients are high risk to both mother and fetus because of increased rates of complications. During the past years, we have treated many cases of SLE patients using autologous peripheral blood stem cell transplantation with good outcome after pregnancy. The rate of maternal hypertension and lupus nephritis was greatly reduced in autologous peripheral blood stem cell transplanted group (n = 11) when compared to non-transplant group (n = 39) (P < 0.05). In addition, the outcome of lupus flare activity of the mother after delivery is significantly better in transplanted group than that in non-transplanted group (P < 0.05). Here, we describe two typical cases of long duration (>6 years) of remission after successful pregnancy in refractory SLE patients post-autologous peripheral blood stem cell transplantation. Our report demonstrated that peripheral blood stem cell transplantation is safe and effective, thereby could be recommended as prior strategy in refractory SLE patients, especially for those women of child-bearing age who plan for pregnancy.

Stem cell transplantation for autoimmune diseases: what can we learn from experimental models?

Using animal models for autoimmune diseases, we have previously shown that allogeneic bone marrow transplantation (allo BMT) can be used to treat autoimmune diseases. Using cynomolgus monkeys, we have recently developed new BMT methods for the treatment of autoimmune diseases. The methods include the perfusion method (PM) for the collection of bone marrow cells (BMCs), and intra-bone marrow (IBM)-BMT for the direct injection of collected whole BMCs into the bone marrow cavity. The PM, in comparison with the conventional aspiration method, can minimize the contamination of BMCs with T cells from the peripheral blood. Therefore, without removing T cells, no graft-versus-host disease (GvHD) develops in the case of the PM. Since BMCs collected by the PM contain not only hemopoietic stem cells (HSCs) but also mesenchymal stem cells (MSCs), the injection of both cells directly into the bone marrow cavity (IBM-BMT) facilitates the engraftment of donor hemopoietic cells. In organ allografts with IBM-BMT, no graft failure occurs even if the radiation dose is reduced. In addition, IBM-BMT is applicable to regeneration therapy and various age-associated diseases such as osteoporosis, since it can efficiently recruit donor-derived normal MSCs. We have also found that IBM-BMT in conjunction with donor lymphocyte infusion can prevent GvHD, but suppress tumor growth. We believe that this strategy heralds a revolution in the field of transplantation (BMT and organ allografts) and regeneration therapy.

Autologous stem cell transplantation in autoimmune and rheumatic diseases: from the molecular background to clinical applications

Autoimmune diseases have a multifactorial origin. Because of disturbances of the immune system, autoreactive T and B cells target self-antigens, leading to permanent organ damage. Despite novel therapeutic protocols, the disease course is chronic and in many instances the outcome is lethal. The efficacy of stem cell therapy has been observed in autoimmune animal models and in autoimmune diseases related to haematological abnormalities. Although the therapy is more than 30 years old, its broad spread has been delayed by the serious side-effects due to the conditioning treatments based on oncological protocols. Evaluation of the data of patients who have undergone autologous stem cell therapy reinforced the view that protocols used for conditioning treatments, mostly causing lymphoablation, and procedures carried out in specialist centres significantly reduced mortality, with an almost optimal therapeutical efficacy. New, multicentre investigations have been launched to compare the efficacy of various protocols. In this review, we summarize certain aspects of the molecular background of autologous stem cell transplantation and also depict the response to therapy in various autoimmune and rheumatic diseases.

Regulatory T cell (Treg) subsets return in patients with refractory lupus following stem cell transplantation, and TGF-beta-producing CD8+ Treg cells are associated with immunological remission of lupus

Compared with conventional drug therapy, autologous hemopoietic stem cell transplantation (HSCT) can induce very-long-term remission in refractory lupus patients. Herein, we show that in posttransplant patients, both CD4(+)CD25(high)FoxP3(+) and an unusual CD8(+)FoxP3(+) Treg subset return to levels seen in normal subjects; accompanied by almost complete inhibition of pathogenic T cell response to critical peptide autoepitopes from histones in nucleosomes, the major lupus autoantigen from apoptotic cells. In addition to a stably sustained elevation of FoxP3, posttransplant CD8 T cells also maintained markedly higher expression levels of latency-associated peptide (LAP), CD103, PD-1, PD-L1, and CTLA-4, as compared with pretransplant CD8 T cells that were identically treated by a one-time activation and rest in short-term culture. The posttransplant CD8 regulatory T cells (Treg) have autoantigen-specific and nonspecific suppressive activity, which is contact independent and predominantly TGF-beta dependent. By contrast, the pretransplant CD8 T cells have helper activity, which is cell contact dependent. Although CD4(+)CD25(high) Treg cells return during clinical remission of conventional drug-treated lupus, the posttransplant patient's CD8 Treg cells are considerably more potent, and they are absent in drug-treated patients in whom CD4 T cell autoreactivity to nucleosomal epitopes persists even during clinical remission. Therefore, unlike conventional drug therapy, hemopoietic stem cell transplantation generates a newly differentiated population of LAP(high)CD103(high) CD8(TGF-beta) Treg cells, which repairs the Treg deficiency in human lupus to maintain patients in true immunological remission.

Reversing the Autoimmune Condition: Experience with Experimental Autoimmune Gastritis

Autoimmune diseases remain a significant health problem in our society, despite the best efforts to understand and treat these conditions. Current clinical treatments are aimed at alleviating the consequences of these diseases, with limited prospects for cure. Our studies with the experimental model of autoimmune gastritis have led us to explore potential curative strategies that can reverse the autoimmune condition. Using mouse models, we have shown that expression of the known gastric autoantigen in the thymus results in immunological tolerance and resistance to the induction of autoimmune gastritis. Also, induced tolerance in donor mice can be transferred to syngeneic recipient mice by bone marrow cells. Strategies based on these observations could lead to reversal of established disease. Transfer of ensuing knowledge to the cure of serious human autoimmune diseases is our ultimate goal.

Immunological Reconstitution after Autologous Hematopoietic Stem Cell Transplantation in Patients with Systemic Sclerosis: Relationship Between Clinical Benefits and Intensity of Immunosuppression

Objective.

To analyze the relationship between clinical benefits and immunological changes in patients with systemic sclerosis (SSc) treated with autologous hematopoietic stem cell transplantation (HSCT).

Methods.

Ten patients with SSc were treated with high-dose cyclophosphamide followed by highly purified CD34+ cells (n = 5) or unpurified grafts (n = 5). Two groups of patients were retrospectively constituted based on their clinical response (good responders, n = 7; and poor responders, n = 3). As well as clinical findings, immunological reconstitution through autologous HSCT was assessed by fluorescence-activated cell sorter analysis, quantification of signal joint T cell receptor rearrangement excision circles (sjTREC), reflecting the thymic function, andfoxp3, a key gene of regulatory T cells, mRNA levels.

Results.

Patients’ clinical and immunological findings were similar between good and poor responders, or CD34-purified and unpurified groups at inclusion. The sjTREC values were significantly suppressed at 3 months after autologous HSCT in good responders compared with poor responders (p = 0.0152). Reconstitution of CD4+CD45RO− naive T cells was delayed in good responders compared with poor responders. The phenotype of other lymphocytes, cytokine production in T cells, andfoxp3gene expression levels after autologous HSCT did not correlate with clinical response in good or poor responders. Clinical and immunological findings after autologous HSCT were similar between CD34-purified and unpurified groups.

Conclusion.

Our results suggest that immunosuppression intensity, sufficient to induce transient suppression of thymic function, is attributable to the feasible clinical response in patients with SSc treated with autologous HSCT. Appropriate monitoring of sjTREC values may predict clinical benefits in transplanted SSc patients after autologous HSCT.

Prominin-1+/CD133+ bone marrow-derived heart-resident cells suppress experimental autoimmune myocarditis

AIMS

Experimental autoimmune myocarditis (EAM) is a CD4(+) T cell-mediated mouse model of inflammatory heart disease. Tissue-resident bone marrow-derived cells adopt different cellular phenotypes depending on the local milieu. We expanded a specific population of bone marrow-derived prominin-1-expressing progenitor cells (PPC) from healthy heart tissue, analysed their plasticity, and evaluated their capacity to protect mice from EAM and heart failure.

METHODS AND RESULTS

PPC were expanded from healthy mouse hearts. Analysis of CD45.1/CD45.2 chimera mice confirmed bone marrow origin of PPC. Depending on in vitro culture conditions, PPC differentiated into macrophages, dendritic cells, or cardiomyocyte-like cells. In vivo, PPC acquired a cardiac phenotype after direct injection into healthy hearts. Intravenous injection of PPC into myosin alpha heavy chain/complete Freund's adjuvant (MyHC-alpha/CFA)-immunized BALB/c mice resulted in heart-specific homing and differentiation into the macrophage phenotype. Histology revealed reduced severity scores for PPC-treated mice compared with control animals [treated with phosphate-buffered saline (PBS) or crude bone marrow at day 21 after MyHC-alpha/CFA immunization]. Echocardiography showed preserved fractional shortening and velocity of circumferential shortening in PPC but not PBS-treated MyHC-alpha/CFA-immunized mice. In vitro and in vivo data suggested that interferon-gamma signalling on PPC was critical for nitric oxide-mediated suppression of heart-specific CD4(+) T cells. Accordingly, PPC from interferon-gamma receptor-deficient mice failed to protect MyHC-alpha/CFA-immunized mice from EAM.

CONCLUSION

Prominin-1-expressing, heart-resident, bone marrow-derived cells combine high plasticity, T cell-suppressing capacity, and anti-inflammatory in vivo effects.

Clinical experience with mixed chimerism to induce transplantation tolerance

Lymphohematopoietic chimerism was first shown to be associated with donor-specific allograft tolerance more than 60 years ago. However, early clinical experience with bone marrow transplantation soon revealed that conventional, myeloablative approaches were far too toxic and the risk of graft-versus-host disease too great to justify using this technology for the purpose of organ allograft tolerance induction in the absence of malignant disease. In this review, we discuss a step-wise approach that has been applied by several centers to establish less toxic approaches to using hematopoietic cell transplantation (HCT) for tolerance induction. These steps include (i) feasibility and efficacy data for tolerance induction in large animal models; (ii) safety data in clinical trials for patients with hematologic malignancies; and (iii) pilot trials of combined HCT and kidney transplantation for tolerance induction. Thus far, only one published trial conducted at the Massachusetts General Hospital in Boston has achieved long-term acceptance of human leukocyte antigen-mismatched kidney allografts without chronic immunosuppressive therapy. Alternative protocols have been successful in large animals, but long-term organ allograft tolerance has not been reported in patients. Thus, proof-of-principle that nonmyeloablative induction of mixed chimerism can be used intentionally to induce organ allograft tolerance has now been achieved. Directions for further research to make this approach applicable for a broader patient population are discussed.

From embryonic stem cells to blastema and MRL mice

New scientific knowledge offers fresh opportunities for regenerative medicine and tissue repair. Among various clinical options, multipotent embryonic stem cells (ESC) prepared from inner cell masses of rabbit blastocysts have been tested over many years. More recently, stem cells have been isolated from individual tissues and from umbilical cord blood. These methods seemingly offer similar rates of repair and avoid ethical complexities arising from the need for human embryos to prepare ESC. Different methods of regenerating tissues have now emerged, based on the well-known forms of organ regeneration in urodeles such as salamanders. These methods depend on the formation of a blastema, and recent studies on MRL mice have revealed that they possess similar methods of repair as in salamanders. There is also some evidence showing that this form of repair is also active in human fetuses but not in adults. Detailed knowledge of these various forms of tissue repair is now urgently needed in order to assess the benefits of each form of treatment. These matters are discussed at the end of this review where various investigations clarify the benefits and drawbacks of these varied approaches to tissue repair.