New horizons in the treatment of autoimmune diseases: immunoablation and stem cell transplantation

Association between Immunosuppressive Therapy Utilized in the Treatment of Autoimmune Disease or Transplant and Cancer Progression

Autoimmunity and cancer rates have both been on the rise in Western civilization prompting many to investigate the link between the two entities. This review will investigate the complex interactions between the activation and deactivation of the immune system and the development of malignancy. Additional focus will be placed on the main classes of immune inhibitor therapy utilized in transplant patients and in autoimmune disease including TNF-alpha, Calcineurin, mTOR, purine synthesis antagonists and IMPDH inhibitors.

Mesenchymal (Stem) Stromal Cells Based as New Therapeutic Alternative in Inflammatory Bowel Disease: Basic Mechanisms, Experimental and Clinical Evidence, and Challenges

Inflammatory bowel diseases (IBD) are an example of chronic diseases affecting 40% of the population, which involved tissue damage and an inflammatory process not satisfactorily controlled with current therapies. Data suggest that mesenchymal stem cells (MSC) may be a therapeutic option for these processes, and especially for IBD, due to their multifactorial approaches such as anti-inflammatory, anti-oxidative stress, anti-apoptotic, anti-fibrotic, regenerative, angiogenic, anti-tumor, or anti-microbial. However, MSC therapy is associated with important limitations as safety issues, handling difficulties for therapeutic purposes, and high economic cost. MSC-derived secretome products (conditioned medium or extracellular vesicles) are therefore a therapeutic option in IBD as they exhibit similar effects to their parent cells and avoid the issues of cell therapy. In this review, we proposed further studies to choose the ideal tissue source of MSC to treat IBD, the implementation of new standardized production strategies, quality controls and the integration of other technologies, such as hydrogels, which may improve the therapeutic effects of derived-MSC secretome products in IBD.

Synergistic effects of intracoronary infusion of autologous bone marrow-derived mesenchymal stem cells and revascularization procedure on improvement of cardiac function in patients with severe ischemic cardiomyopathy

Background

Ischemic cardiomyopathy (ICM) is a leading cause of cardiovascular mortality worldwide. It is defined as abnormal enlargement of the left ventricular (LV) cavity with poor LV function due to coronary artery disease. Currently available established treatments are palliative whereby blood supply is recovered to ischemic regions but fails to regenerate heart tissues. Mesenchymal stem cells (MSCs) offer a promising treatment for ICM given their regenerative and multipotent characteristics. This study aims to investigate the effect of MSCs infusion with concurrent revascularization in patients with severe ICM compared to receiving only revascularization procedure or MSCs infusion.

Methods

Twenty-seven patients with history of anterior myocardial infarction (MI) and baseline left ventricular ejection fraction (LVEF) of less than 35% were recruited into this study. Patients who are eligible for revascularization were grouped into group A (MSCs infusion with concurrent revascularization) or group B (revascularization only) while patients who were not eligible for revascularization were allocated in group C to receive intracoronary MSCs infusion. LV function was measured using echocardiography.

Results

Patients who received MSCs infusion (either with or without revascularization) demonstrated significant LVEF improvements at 3, 6 and 12 months post-infusion when compared to baseline LVEF within its own group. When comparing the groups, the magnitude of change in LVEF from baseline for third visits i.e., 12 months post-infusion was significant for patients who received MSCs infusion plus concurrent revascularization in comparison to patients who only had the revascularization procedure.

Conclusions

MSCs infusion significantly improves LV function in ICM patients. MSCs infusion plus concurrent revascularization procedure worked synergistically to improve cardiac function in patients with severe ICM.

CELL THERAPY IN INFLAMMATORY BOWEL DISEASE

In recent years, cell-based therapies have been explored in various immune-mediated inflammatory diseases, including inflammatory bowel disease (IBD). Cell therapy is the process of introducing new cells into an organism or tissue in order to treat a disease. The most studied cellular treatment in IBD was "stem cells-based therapy", which was explored according to different protocols in terms of type of donors, stem cells sources, study design and clinical endpoints. More recently, preliminary studies have also described the clinical use of "regulatory cells", which include T-reg and Tr1 cells, and "tolerogenic" dendritic cells. Finally, induced pluripotent stem cells are the subject of an intensive preclinical research program on animal models, including those related to colitis.

Successful Treatment of Catastrophic Antiphospholipid Antibody Syndrome Associated with MALT Lymphoma by Autologous Hematopoietic Stem Cell Transplantation

A 37-year-old woman with extranodal marginal-zone lymphoma was admitted with a fever, hemiplegia, and severe dyspnea after chemotherapy. Catastrophic antiphospholipid antibody syndrome (CAPS) was suspected based on the histopathological confirmation of small-pulmonary vessel occlusion, evidence of the involvement of three organs, and elevated lupus anticoagulant assay results in a short time span. The patient responded to the initial treatment. One month later, the CAPS and lymphoma relapsed, and the patient underwent autologous hematopoietic stem cell transplantation. Complete remission of the lymphoma has been successfully maintained, and the condition of the patient has remained stable for two years with no further evidence of thrombosis.

The use of hematopoietic stem cells in autoimmune diseases

Hematopoietic stem cells (HSCs) have been shown recently to hold much promise in curing autoimmune diseases. Newly diagnosed Type 1 diabetes individuals have been successfully reverted to normoglycemia by administration of autologous HSCs in association with a nonmyeloablative regimen (antithymocyte globulin + cyclophasmide). Furthermore, recent trials reported positive results by using HSCs in treatment of systemic sclerosis, multiple sclerosis and rheumatoid arthritis as well. Early data suggested that HSCs possess immunological properties that may be harnessed to alleviate the symptoms of individuals with autoimmune disorders and possibly induce remission of autoimmune diseases. Mechanistically, HSCs may facilitate the generation of regulatory T cells, may inhibit the function of autoreactive T-cell function and may reshape the immune system.

Post-transcriptional gene silencing in plants: a double-edged sword

In plants, post-transcriptional gene silencing (PTGS) protects the genome from foreign genes and restricts the expression of certain endogenous genes for proper development. Here, we review the recent progress about how the unwanted PTGS is avoided in plants. As a decision-making step of PTGS, aberrant transcripts from most endogenous coding genes are strictly sorted to the bidirectional RNA decay pathways in cytoplasm but not to the short interference RNA (siRNA)-mediated PTGS, with the exception of a few development-relevant endogenous siRNA-producing genes. We also discuss a finely balanced PTGS threshold model that plants fully take advantage of the power of PTGS without self-harm.

Umbilical cord blood-derived mesenchymal stem cells: new therapeutic weapons for idiopathic dilated cardiomyopathy?

Dilated cardiomyopathy is the most frequent etiology of non-ischemic heart failure. In a majority of cases the causal mechanism is unknown, giving rise to the term 'idiopathic' dilated cardiomyopathy (IDCM). Major pathological derangements include patchy interstitial fibrosis, degenerated cardiomyocytes, and dilatation of the cardiac chambers, but recent evidence suggests that disease progression may also have the signature of cardiac endothelial dysfunction. As we better understand the molecular basis of IDCM, novel therapeutic approaches, mainly gene transfer and cell-based therapies, are being explored. Cells with regenerative potential have been extensively tested in cardiac diseases of ischemic origin in both pre-clinical and clinical settings. However, whether cell therapy has any clinical value in IDCM patients is still being evaluated. This article is a concise summary of cell therapy studies for IDCM, with a focus on recent advances that highlight the vascular potential exhibited by umbilical cord blood-derived mesenchymal stem cells (UCBMSCs). We also provide an overview of cardiac vasculature as a key regulator of subjacent myocardial integrity and function, and discuss the potential mechanisms of UCBMSC amelioration of IDCM myocardium. Consideration of these issues shows that these cells are conceivably new therapeutic agents for this complex and elusive human disorder.

Stem cell therapy in patients with heart failure

Heart failure results from injury to the myocardium from a variety of causes, including ischemic and nonischemic etiologies. Severe heart failure carries a 50% 5-year mortality rate and is responsible for more than one-third of cardiovascular deaths in the United States.1 Heart failure progression is accompanied by activation of neurohormonal and cytokine systems as well as a series of adaptive changes within the myocardium, collectively referred to as left ventricular remodelling. The unfavorable alterations may be categorized broadly into changes that occur in the cardiac myocytes and changes that occur in the volume and composition of the extracellular matrix.2 Since remodelling in heart failure is progressive and eventually becomes detrimental, the majority of treatment strategies are aimed at stopping or reversing this process. Although medical management, cardiac resychronization therapy, and long-term or destination mechanical circulatory support have been successful in this regard, a considerable number of patients still progress to end-stage heart failure with limited therapeutic options. For these patients, stem cell therapies are being investigated as a safe treatment strategy for decreasing cardiac remodelling on top of conventional medical and device treatment.

Effects of intracoronary CD34+ stem cell transplantation in nonischemic dilated cardiomyopathy patients: 5-year follow-up

RATIONALE

CD34+ transplantation in dilated cardiomyopathy was associated with short-term improvement in left ventricular ejection fraction and exercise tolerance.

OBJECTIVE

We investigated long-term effects of intracoronary CD34+ cell transplantation in dilated cardiomyopathy and the relationship between intramyocardial cell homing and clinical response.

METHODS AND RESULTS

Of 110 dilated cardiomyopathy patients, 55 were randomized to receive CD34+ stem cell transplantation (SC group) and 55 received no cell therapy (controls). In the SC group, CD34+ cells were mobilized by granulocyte colony-stimulating factor and collected via apheresis. Patients underwent myocardial scintigraphy and cells were injected in the artery supplying segments with the greatest perfusion defect. At baseline, 2 groups did not differ in age, sex, left ventricular ejection fraction, or N-terminal B-type natriuretic peptide levels. At 5 years, stem cell therapy was associated with increased left ventricular ejection fraction (from 24.3 ± 6.5% to 30.0 ± 5.1%; P=0.02), increased 6-minute walk distance (from 344 ± 90 m to 477 ± 130 m; P<0.001), and decreased N-terminal B-type natriuretic peptide (from 2322 ± 1234 pg/mL to 1011 ± 893 pg/mL; P<0.01). Left ventricular ejection fraction improvement was more significant in patients with higher myocardial homing of injected cells. During follow-up, 27 (25%) patients died and 9 (8%) underwent heart transplantation. Of the 27 deaths, 13 were attributed to pump failure and 14 were attributed to sudden cardiac death. Total mortality was lower in the SC group (14%) than in controls (35%; P=0.01). The same was true of pump failure (5% vs. 18%; P=0.03), but not of sudden cardiac death (9% vs. 16%; P=0.39).

CONCLUSIONS

Intracoronary stem cell transplantation may be associated with improved ventricular function, exercise tolerance, and long-term survival in patients with dilated cardiomyopathy. Higher intramyocardial homing is associated with better stem cell therapy response.

Hematopoietic stem cell transplantation for systemic lupus erythematosus

Two streams of research are at the origin of the utilization of hematopoietic stem cell transplantation (HSCT) for severe autoimmune diseases (SADs). The allogeneic approach came from experimental studies on lupus mice, besides clinical results in coincidental diseases. The autologous procedure was encouraged by researches on experimental neurological and rheumatic disorders. At present the number of allogeneic HSCT performed for human SADs can be estimated to not over 100 patients, and the results are not greatly encouraging, considering the significant transplant-related mortality (TRM) and the occasional development of a new autoimmune disorder and/or relapses notwithstanding full donor chimerism. Autologous HSCT for refractory SLE has become a major target. Severe cases have been salvaged, TRM is low and diminishing, and prolonged clinical remissions are obtainable. Two types of immune resetting have been established, "re-education" and regulatory T cell (Tregs) normalization. Allogeneic HSCT for SLE seems best indicated for patients with disease complicated by an oncohematologic malignancy. Autologous HSCT is a powerful salvage therapy for otherwise intractable SLE. The duration of remission in uncertain, but a favorable response to previously inactive treatments is a generally constant feature. The comparison with new biological agents, or the combination of both, are to be ascertained.

Neurological disorders and therapeutics targeted to surmount the blood-brain barrier

We are now in an aging population, so neurological disorders, particularly the neurodegenerative diseases, are becoming more prevalent in society. As per the epidemiological studies, Europe alone suffers 35% of the burden, indicating an alarming rate of disease progression. Further, treatment for these disorders is a challenging area due to the presence of the tightly regulated blood-brain barrier and its unique ability to protect the brain from xenobiotics. Conventional therapeutics, although effective, remain critically below levels of optimum therapeutic efficacy. Hence, methods to overcome the blood-brain barrier are currently a focus of research. Nanotechnological applications are gaining paramount importance in addressing this question, and yielding some promising results. This review addresses the pathophysiology of the more common neurological disorders and novel drug candidates, along with targeted nanoparticle applications for brain delivery.

Stem cell therapy for diabetes mellitus

In this review, we present (1) a brief discussion of hematopoietic stem cell transplantation (HSCT) for severe and refractory autoimmune diseases (AIDs) from its beginning in 1996 through recently initiated prospective randomized clinical trials; (2) an update (up to July 2009) of clinical and laboratory outcomes of 23 patients with newly diagnosed type 1 diabetes mellitus (T1DM), who underwent autologous HSCT at the Bone Marrow Transplantation Unit of the Ribeirão Preto Medical School, University of São Paulo, Brazil; (3) a discussion of possible mechanisms of action of HSCT in AIDs, including preliminary laboratory data obtained from our patients; and (4) a discussion of future perspectives of stem cell therapy for T1DM and type 2 DM, including the use of stem cell sources other than adult bone marrow and the combination of cell therapy with regenerative compounds.

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.

Interstitial lung disease in systemic sclerosis

Interstitial lung disease (ILD) is a common manifestation of systemic sclerosis (SSc) and mainly encountered in patients with diffuse disease and/or anti-topoisomerase 1 antibodies. ILD develops in up to 75% of patients with SSc overall. However, SSc-ILD evolves to end-stage respiratory insufficiency in only a few patients. Initial pulmonary function tests (PFT) with measurement of carbon monoxide diffusing capacity, together with high-resolution computed tomography, allows for early diagnosis of SSc-ILD, before the occurrence of dyspnea. Unlike idiopathic ILD, SSc-ILD corresponds to non-specific interstitial pneumonia in most cases, whereas usual interstitial pneumonia is less frequently encountered. Therefore, the prognosis of SSc-ILD is better than that for idiopathic ILD. Nevertheless, ILD represents one of the two main causes of death in SSc patients. To detect SSc-ILD early, PFT must be repeated regularly, every 6 months to 1 year, depending on disease worsening. Conversely, broncho-alveolar lavage is not needed to evaluate disease activity in SSc-ILD but may be of help in diagnosing opportunistic infection. The treatment of SSc-ILD is not well established. Cyclophosphamide, which has been used for 20 years, has recently been evaluated in two prospective randomized studies that failed to demonstrate a major benefit for lung function. Open studies reported mycophenolate mofetil, azathioprine and rituximab as alternatives to cyclophosphamide. On failure of immunosuppressive agent treatment, lung transplantation can be proposed in the absence of other major organ involvement or severe gastro-esophageal reflux.

Chronic inflammatory demyelinating polyradiculoneuropathy: a role for haematopoietic stem cell transplantation?

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a clinical syndrome of a chronic progressive or relapsing and remitting, symmetrical, sensory and motor radiculoneuropathy. The immune reaction in CIDP is characterised by selective inflammation of peripheral nerves and is probably due to the interaction of cellular and humoral responses. Only three treatments for CIDP have demonstrated benefit in randomised studies, corticosteroids, plasma exchange and intravenous immunoglobulin. 25% of patients fail to respond or do not respond adequately to these treatments. Experimental data in animal models have shown that several autoimmune disorders, either congenital or acquired, can be transferred and/or treated by the transplantation of bone marrow stem cells. Haematopoietic stem cell transplantation (HSCT) has been performed with varying success in over 700 patients with autoimmune disorders throughout Europe. The experience in CIDP is very limited. This article will review current understanding of CIDP and experience of the use of HSCT in refractory CIDP.

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.

Prolongation of cardiac allograft survival by syngeneic hematopoietic stem/progenitor cell transplantation in mice

INTRODUCTION

Organ transplantation is a rapidly developing field, being the only effective treatment for end-stage organ disease. However, the associated immunosuppressant therapy has numerous direct and indirect adverse effects. Hematopoietic stem cell transplantation (HSCT), via immune reconstitution, offers an alternative method of treatment. In this study, we determined the cardiac allograft survival in mice treated with syngeneic HSCT or hematopoietic progenitor cell transplantation (HPCT).

METHODS

BALB/c and C57BL/6 mice were randomly divided into three groups. Mice in Group A (n=7) were untreated while those in Group B (n=8) and C (n=7) were treated with HPCT and HSCT, respectively. Cervical heterotopic cardiac transplantation models were established in all groups and cardiac grafts were observed throughout. Regulatory T (Treg) cell expression in peripheral blood was analyzed by flow cytometry. We recorded the cardiac allograft survival time and constructed Kaplan-Meier survival curves.

RESULTS

The number of Treg cells in Group B was significantly higher than that in Group C (P<0.05). The survival time of mice from each group differed significantly according to Kaplan-Meier/log-rank analysis (P<0.01). A total of 62.5% of the grafts in Group B showed long-term survival (>100 days); all the mice in Group A died within 9 days, compared with 59 days in Group C.

CONCLUSION

We conclude that syngeneic HSCT and HPCT can prolong cardiac allograft survival in mice. These two methods could be promising ways to induce immune tolerance in future organ transplantation.

The role of sex steroids and gonadectomy in the control of thymic involution

A major underlying cause for aging of the immune system is the structural and functional atrophy of the thymus, and associated decline in T cell genesis. This loss of naïve T cells reduces adaptive immunity to new stimuli and precipitates a peripheral bias to memory cells against prior antigens. Whilst multiple mechanisms may contribute to this process, the temporal alliance of thymic decline with puberty has implicated a causative role for sex steroids. Accordingly ablation of sex steroids induces profound thymic rejuvenation. Although the thymus retains some, albeit highly limited, function in healthy adults, this is insufficient for resurrecting the T cell pool following cytoablative treatments such as chemo- and radiation-therapy and AIDS. Increased risk of opportunistic infections and cancer relapse or appearance, are a direct consequence. Temporary sex steroid ablation may thus provide a clinically effective means to regenerate the thymus and immune system in immunodeficiency states.

[Interstitial lung disease in systemic sclerosis]

INTRODUCTION

Interstitial lung diseases (ILD) in systemic sclerosis (SSc) are mainly encountered in patients with diffuse disease although they may occur less frequently in patients with limited cutaneous disease.

BACKGROUND

In SSc early detection of ILD should be achieved by high resolution computed tomography and pulmonary function tests, including measurement of DLCO. In total up to 75% of patients with SSc develop ILD but it is progressive in only a minority of patients. Unlike idiopathic ILD, SSc associated ILD corresponds to non-specific interstitial pneumonia rather than usual interstitial pneumonia in the majority of cases. This explains the better prognosis of SSc associated ILD compared with idiopathic ILD. Nevertheless ILD represents one of the two main causes of death in SSc.

VIEWPOINT

The treatment of SSc associated ILD is not well established. Anti-fibrosing treatments have failed to demonstrate benefit and cyclophosphamide, which has been used for about 15 years in the treatment of this condition, has recently been evaluated in two prospective randomised studies which showed a significant but modest effect on respiratory function.

CONCLUSION

A subgroup of patients with rapidly progressive ILD might benefit from pulsed intravenous cyclophosphamide combined with prednisone 15 mg daily, but this remains to be confirmed.

[Haematopoietic stem cell transplantation in the treatment of autoimmune diseases]

PURPOSE

During the past ten years, more than 1000 patients suffering from severe autoimmune disease have received an autologous haematopoietic stem cell transplant. These new therapeutic have been used in systemic sclerosis (scleroderma), multiple sclerosis, rheumatoid arthritis, juvenile idiopathic arthritis and systemic lupus erythematosus.

CURRENT KNOWLEDGE AND KEY POINTS

Autologous haematopoietic stem cell transplantation has become a curative option for condition with very poor prognosis as severe systemic sclerosis, lupus erythematosus or other systemic diseases. This review summarizes the current experience in the phase I and II clinical trials in Europe and North America. We describe the main results and the limits of stem cell transplantation in systemic diseases.

FUTURE PROSPECTS AND PROJECTS

Autologous haematopoietic stem cell transplant in the treatment of autoimmune disease has evolved from a experimental concept to a clinically feasible and powerful therapy for selected patients with severe disease.

Immunoregulatory effects of allogeneic mixed chimerism induced by nonmyeloablative bone marrow transplantation on chronic inflammatory arthritis and autoimmunity in interleukin-1 receptor antagonist-deficient mice

OBJECTIVE

To investigate the immunoregulatory effects of allogeneic mixed chimerism induced by T cell-depleted, nonmyeloablative bone marrow transplantation (BMT) on chronic inflammatory arthritis and autoimmunity in mice deficient in interleukin-1 receptor antagonist (IL-1Ra).

METHODS

IL-1Ra(-/-) mice (H-2K(d)) were treated with antibody to asialoganglioside G(M1) (anti-natural killer cell), total body irradiation (500 cGy), and T cell-depleted, nonmyeloablative BMT derived from C57BL/6 mice (H-2K(b)). Engraftment and chimerism were evaluated in peripheral blood, lymph nodes, and spleen by multicolor flow cytometry. The severity of arthritis was evaluated by clinical scoring and histopathologic assessment. Levels of IgG1 and IgG2a subtypes of anti-type II collagen (anti-CII) antibodies were measured in serum samples. After T cells were stimulated with CII, ovalbumin, and phytohemagglutinin, T cell proliferative responses and levels of cytokine production (interferon-gamma [IFNgamma], tumor necrosis factor alpha [TNFalpha], interleukin-10 [IL-10], and IL-17) were assayed in culture supernatants.

RESULTS

All IL-1Ra(-/-) mice receiving BMT showed marked improvement in arthritis within 3 weeks, as well as successful induction of mixed chimerism. These mice showed higher levels of IgG1, and lower levels of IgG2a anti-CII antibodies and weaker T cell proliferative responses than did mice in the control groups (either no treatment or conditioning alone without bone marrow rescue). In mixed chimeras, the levels of IFNgamma, TNFalpha, and IL-17 produced from CII-stimulated T cells were significantly suppressed and IL-10 production was significantly higher as compared with controls.

CONCLUSION

The introduction of allogeneic mixed chimerism showed a strong immunoregulatory potential to correct established chronic inflammatory arthritis and autoimmunity originating from a dysregulated proinflammatory cytokine network.

Immunomodulatory therapy for SSc: Will high-intensity immunosuppression with stem cell rescue improve outcome?

Effective treatments for severe systemic sclerosis (SSc) have not been identified. SSc is associated with high levels of morbidity and mortality related to functional impairment and organ dysfunction. The pathogenesis of SSc, as with all autoimmune disorders, is thought to involve the interplay between genetic background and environmental exposures. Abundant evidence exists for activation of humoral and cellular immunity in SSc. These immune and inflammatory mechanisms almost certainly play a role in vascular damage and activation of pathways that lead to fibrosis. However, the types and intensities of immunomodulatory therapies employed in other connective tissue diseases have not proved as useful in patients with SSc. The question remains if increasing the intensity of immunosuppression will prove a more successful strategy. Preliminary studies of intensification of therapy to immunoablative and myeloablative levels with hematopoietic stem cell rescue have been performed and appear promising. New studies to compare these approaches with conventional immunomodulatory therapy are underway.

Autologous stem cell transplantation in the treatment of systemic sclerosis: report from the EBMT/EULAR Registry

OBJECTIVE

To analyse the durability of the responses after haematopoietic stem cell transplantation (HSCT) for severe systemic sclerosis (SSc) and determine whether the high transplant related mortality (TRM) improved with experience. This EBMT/EULAR report describes the longer outcome of patients originally described in addition to newly recruited cases.

METHODS

Only patients with SSc, treated by HSCT in European phase I-II studies from 1996 up to 2002, with more than 6 months of follow up were included. Transplant regimens were according to the international consensus statements. Repeated evaluations analysed complete, partial, or non-response and the probability of disease progression and survival after HSCT (Kaplan-Meier).

RESULTS

Given as median (range). Among 57 patients aged 40 (9.1-68.7) years the skin scores improved at 6 (n = 37 patients), 12 (n = 30), 24 (n = 19), and 36 (n = 10) months after HSCT (p<0.005). After 22.9 (4.5-81.1) months, partial (n = 32) or complete response (n = 14) was seen in 92% and non-response in 8% (n = 4) of 50 observed cases. 35% of the patients with initial partial (n = 13/32) or complete response (n = 3/14) relapsed within 10 (2.2-48.7) months after HSCT. The TRM was 8.7% (n = 5/57). Deaths related to progression accounted for 14% (n = 8/57) of the 23% (n = 13/57) total mortality rate. At 5 years, progression probability was 48% (95% CI 28 to 68) and the projected survival was 72% (95% CI 59 to 75).

CONCLUSION

This EBMT/EULAR report showed that response in two thirds of the patients after HSCT was durable with an acceptable TRM. Based on these results prospective, randomised trials are proceeding.

Alloimmune injury and rejection of human skin grafts on human peripheral blood lymphocyte-reconstituted non-obese diabetic severe combined immunodeficient beta2-microglobulin-null mice

Small animal models with the capacity to support engraftment of a functional human immune system are needed to facilitate studies of human alloimmunity. In the present investigation, non-obese diabetic (NOD) severe combined immunodeficient (scid) beta2-microglobulin-null (B2mnull) mice engrafted with human peripheral blood lymphocytes (hu-PBL-NOD-scid B2mnull mice) were used as in vivo models for studying human skin allograft rejection. Hu-PBL-NOD-scid B2mnull mice were established by injection of human spleen cells or PBLs and transplanted with full-thickness allogeneic human skin. Human cell engraftment was enhanced by injection of anti-mouse CD122 antibody. The respective contributions of human CD4+ and CD8+ cells in allograft rejection were determined using depleting antibodies. Human skin grafts on unmanipulated NOD-scid B2mnull mice uniformly survived but on chimeric hu-PBL-NOD-scid B2mnull mice exhibited severe immune-mediated injury that often progressed to complete rejection. The alloaggressive hu-PBLs did not require prior in vitro sensitization to elicit targeted effector cell activity. Extensive mononuclear cell infiltration directed towards human-origin endothelium was associated with thrombosis and fibrin necrosis. No evidence of graft-versus-host disease was detected. Either CD4+ or CD8+ T cells may mediate injury and alloimmune rejection of human skin grafts on hu-PBL-NOD-scid B2mnull mice. It is proposed that Hu-PBL-NOD-scid B2mnull mice engrafted with human skin will provide a useful model for analysis of interventions designed to modulate human allograft rejection.

[Allogeneic adoptive immunotherapy]

Recognition of the importance of immune cells present in a hematopoietic graft has resulted in a significant change in the perception of allogeneic hematopoietic transplantation. Such a transplant modality is now perceived has a very efficient form of adoptive allogeneic immunotherapy unfortunately associated with significant toxicity.

Improvement of inflammatory bowel disease after allogeneic stem-cell transplantation

Because causes of inflammatory bowel disease (IBD) remain obscure and a curative therapy is still lacking, the influence of stem-cell transplantation (SCT) on IBD is of major interest. We retrospectively analyzed the course of seven patients with Crohn's disease and four patients with idiopathic ulcerative colitis who underwent allogeneic SCT between July 1994 and August 2002 for acute and chronic myeloid leukemia and myelodysplastic syndrome. After a median follow-up of 34 months posttransplantation, 10 patients are alive. None of the patients showed IBD activity after SCT, except one patient with mild persistent symptoms of Crohn's disease early after transplant. Colonoscopy after complete discontinuation of prophylactic posttransplant immunosuppression revealed no pathologic findings. These observations imply that host immune dysregulation plays a central role in the perpetuation of IBD. It may be influenced by the implementation of a new allogeneic immune system resulting from the transplantation of hematopoietic stem cells.

The promise of hematopoietic stem cell transplantation for autoimmune diseases

Hematopoietic stem cell transplantation (HSCT) is being increasingly utilized for the treatment of a whole spectrum of severe autoimmune diseases refractory to conventional therapy. Although allogeneic HSCT has been followed by durable complete remission in a restricted number of patients with coincidental disease, the autologous procedure is generally preferred because of its lesser toxicity. Most autoimmune diseases are the consequence of a multistep process, mainly originating from the interplay of genetic, environmental, and hormonal factors. It has been postulated that if immunosuppressive regimens can eliminate or effectively reduce the level of autoreactive T and B cells, then regeneration of de novo immunity even in the autologous setting may bypass the initial breakdown of self-tolerance and ensure prolonged disease remission. As mentioned in a recent review of this field, protocol design including conditioning regimen, patient selection, stem cell source and final outcome are likely to be disease-specific. The following is a summary of the 2002 International Bone Marrow Transplantation Registry/American Society of Blood and Bone Marrow Transplantation (IBMTR/ASBMT) satellite symposium in Orlando, Florida on 24 February 2002 on 'Expanding the Promise of Hematopoietic Stem Cell Transplantation in Autoimmune Diseases'.

High-dose immune suppression and autologous hematopoietic stem cell transplantation in refractory Crohn disease

Two patients with severe Crohn disease, defined by a Crohn Disease Activity Index (CDAI) higher than 250 despite anti-tumor necrosis factor alpha (TNF-alpha), were treated by intense immune suppression and autologous hematopoietic stem cell transplantation (HSCT). Stem cells were mobilized from the peripheral blood using cyclophosphamide (2.0 g/m2) and granulocyte colony-stimulating factor (G-CSF; 5 micro g/kg/d), enriched ex vivo by CD34+ selection, and reinfused after immune conditioning with cyclophosphamide (200 mg/kg) and equine anti-thymocyte globulin (ATG; 90 mg/kg). Patients have remained in remission (CDAI < 100) for 1 year since HSCT. We conclude that further HSCT studies for severe Crohn disease appear warranted.

Refractory Evans' syndrome treated with allogeneic SCT followed by DLI. Demonstration of a graft-versus-autoimmunity effect

Evans' syndrome, a combination of autoimmune haemolytic anaemia and autoimmune (idiopathic) thrombocytopenic purpura, is generally harder to treat and more refractory than the single entities. In a male patient with refractory disease, predominantly thrombocytopenic, an allogeneic reduced intensity BMT from his human leukocyte antigen (HLA)-identical sister was followed by a dramatic platelet peak while he was still experiencing initial engraftment (presumably of autologous origin), but subsequently by progressive relapse associated with mixed chimerism. Five gradually incremental DLI achieved complete donor chimerism, which was associated not only with grade II graft-versus-host disease (GVHD), but also with complete clinical and biological remission for 2 years post-transplant. Long-term FU is necessary before claiming that allogeneic stem cell transplantation (SCT) is capable of curing an autoimmune blood disease. However, there is evidence for a graft-versus-autoimmunity effect in this case.

The myelin basic protein gene is expressed in differentiated blood cell lineages and in hemopoietic progenitors

Myelin basic proteins (MBP) are major constituents of the myelin sheath of oligodendrocytes and Schwann cells in the central nervous system and the peripheral nervous system, respectively. We previously showed that MBP-related transcripts are present in the bone marrow and the immune system. These mRNAs are transcribed from a region called 0', consisting of three exons, located upstream of the classical MBP exons; these three exons belong to the long MBP gene otherwise called "Golli-MBP." The most abundant of these mRNAs, now called HMBP (hemopoietic MBP), encompasses the sequence encoded by the region 0' plus exon 1 and part of intron 1 of the classic MBP gene. Antisera to recombinant HMBP proteins are immunoreactive with proteins of about 26-28 kDa in brain, thymus, and spleen. This report demonstrates that HMBP proteins are present in the vast majority (>95%) of thymic T cells, which express the corresponding transcripts, as do mature T cells from lymph nodes and spleen. HMBP mRNAs and proteins are also manifest in the majority of spleen B lymphocytes and in B cell lines. In addition to lymphoid cells, HMBP proteins are in all types of myeloid lineage cells, i.e., macrophages, dendritic cells, and granulocytes, as well as in megakaryocytes and erythroblasts. Finally, HMBP proteins are present in CD34+ bone marrow cells, and, furthermore, in highly proliferative cultures, these CD34+ cells express HMBP RNAs and proteins. Thus, MBP gene products are present both in the nervous system and in the entire hemopoietic system.

Treating systemic sclerosis in 2001

Systemic sclerosis (SS) is characterized by sclerosis of the dermis and internal organs and by vascular abnormalities. Although the pathophysiology of the disease has been partly elucidated, the efficacy of long-term treatments remains limited, with no significant increase in survival in prospective studies. Conventional drug treatments are disappointing in clinical practice, and in a recent prospective randomized study standard-dose D-penicillamine was not more effective than mini-dose D-penicillamine. New long-term treatments are emerging for diffuse SS, including cyclophosphamide for patients with progressive interstitial lung disease or stem cell transplantation for those with early organ involvement. The most effective treatments remain symptomatic, such as angiotensin-converting enzyme inhibitors for acute renal crisis, calcium channel antagonists for Raynaud's phenomenon, and proton pump inhibitors for the complications of gastroesophageal reflux. This review article focuses on long-term treatments that are most likely to be effective and suggests symptomatic treatment strategies tailored to specific organ involvements.

Juvenile systemic scleroderma

Systemic scleroderma in children is very rare and is considered similar to adult-onset disease. In adults, new etiopathogenetic and therapeutic approaches have emerged in recent years. For instance, it has been shown that microchimerism could play a role in disease pathogenesis and that immunoablation followed by stem cell rescue could be of potential therapeutic benefit. There is also evidence that these new approaches can be of value for childhood-onset disease.

Collection of hematopoietic stem cells from patients with autoimmune diseases

We reviewed data from 24 transplant centers in Asia, Australia, Europe, and North America to determine the outcomes of stem cell collection including methods used, cell yields, effects on disease activity, and complications in patients with autoimmune diseases. Twenty-one unprimed bone marrow harvests and 174 peripheral blood stem cell mobilizations were performed on 187 patients. Disease indications were multiple sclerosis (76 patients), rheumatoid arthritis (37 patients), scleroderma (26 patients), systemic lupus erythematosus (19 patients), juvenile chronic arthritis (13 patients), idiopathic autoimmune thrombocytopenia (8 patients), Behcet's disease (3 patients), undifferentiated vasculitis (3 patients), polychondritis (1 patient) and polymyositis (1 patient). Bone marrow harvests were used in the Peoples Republic of China and preferred worldwide for children. PBSC mobilization was the preferred technique for adult stem cell collection in America, Australia, and Europe. Methods of PBSC mobilization included G-CSF (5, 10, or 16 microg/kg/day) or cyclophosphamide (2 or 4 g/m2) with either G-CSF (5 or 10 microg/kg/day) or GM-CSF (5 microg/kg/day). Bone marrow harvests were without complications and did not affect disease activity. A combination of cyclophosphamide and G-CSF was more likely to ameliorate disease activity than G-CSF alone (P < 0.001). g-csf alone was more likely to cause disease exacerbation than the combination of cyclophosphamide and g-csf (P = 0.003). Three patients died as a result of cyclophosphamide-based stem cell collection (2.6% of patients mobilized with cyclophosphamide). When corrected for patient weight and apheresis volume, progenitor cell yields tended to vary by underlying disease, prior medication history and mobilization regimen. Trends in the approaches to, and results of, progenitor cell mobilization are suggested by this survey. While cytokine-based mobilization appears less toxic, it is more likely to result in disease reactivation. Optimization with regard to cell yields and safety are likely to be disease-specific and prospective disease-specific studies of mobilization procedures appear warranted.

Treatment of autoimmune diseases by hematopoietic stem cell transplantation

Remarkable advances have been made in bone marrow transplantation (BMT), which now has become a powerful strategy for the treatment of leukemia, aplastic anemia, congenital immunodeficiency disorders, and autoimmune diseases. Using various animal models, allogeneic BMT has been found to be useful in the treatment of autoimmune diseases. In MRL/lpr mice, which are radiosensitive (<8.5 Gy) and are an animal model for autoimmune disorders, conventional BMT resulted in only transient effects; the manifestations of the autoimmune diseases recurred 3 months after BMT. However, the combination of BMT plus bone grafts (to recruit donor stromal cells) was capable of preventing the recurrence of autoimmune diseases in MRL/lpr mice. This strategy was found to be ineffective in the treatment of MRL/lpr mice that had developed autoimmune diseases, because these mice were more sensitive to the effects of radiation after the onset of lupus nephritis due to uremic enterocolitis. We have recently discovered a safer strategy for treatment of autoimmune diseases, which includes fractionated irradiation (5.5 Gy x 2) (day -1) followed by portal venous injection (day 0) plus intravenous injection (day 5) of donor unfractionated bone marrow cells. We successfully treated autoimmune diseases in MRL/lpr mice using this strategy; 100% of MRL/lpr mice treated in this fashion survive >1 year after treatment. We identified the mechanisms underlying the components of this approach and have found that stromal cells play a crucial role in successful BMT. In this review, the conditions essential for successful allogeneic BMT are discussed.

Crohn's disease complicated by relapsed extranodal Hodgkin's lymphoma: prolonged complete remission after unmanipulated PBPC autotransplant

Crohn's disease and ulcerative colitis are inflammatory bowel diseases (IBD), which are thought to result from an inappropriate immunologic (autoimmune) response to luminal antibodies. Allogeneic stem cell transplantation (SCT) performed for coincidental diseases is able to cure both leukaemia and Crohn's disease. Autologous SCT is currently performed worldwide for severe autoimmune diseases (SADs) because of its reduced transplant-related mortality (TRM). We report the case of a 30-year-old male patient with a 10-year history of severe Crohn's disease, who developed Hodgkin's disease and received an unmanipulated peripheral blood autologous transplant. Three years after the transplant the patient is in complete treatment-free remission of both diseases.

Bone Marrow Transplantation for Non-Malignant Disease

This article reviews the experience in hematopoietic stem cell transplantation (HSCT) for non-malignant disease. HSCT has long been applied as treatment of life-threatening congenital immunodeficiency and metabolic diseases. In Section I, Dr. Parkman reviews that experience for severe combined immunodeficiency, Wiscott-Aldrich syndrome, hyper IGM syndrome, Chédiak-Higashi disease and hereditary lymphohistiocytosis. The value of HSCT in genetic metabolic diseases such as osteopetrosis, osteogenesis imperfecta and the storage diseases are reviewed. In Section II, Dr. Walters reviews the experience over the last decade with allogeneic stem cell transplantation in patients with thalassemia major and sickle cell disease. In Section III, Dr. Sullivan reviews the more recent investigations using stem cell transplantation in patients with advanced autoimmune diseases such as systemic sclerosis, systemic lupus erythematosus, multiple sclerosis and juvenile rheumatoid arthritis. The pathogenesis and outcome with conventional care of these patients, the selection criteria and current results for HSCT, and the future directions in clinical research and patient care using this modality are addressed.