Treatment of autoimmune diseases by hematopoietic stem cell transplantation

Mesenchymal stem cells to treat type 1 diabetes

What is clear is we are in the era of the stem cell and its potential in ameliorating human disease. Our perspective is generated from an in vivo model in a large animal that offers significant advantages (complete transplantation tolerance, large size and long life span). This review is an effort to meld our preclinical observations with others for the reader and to outline potential avenues to improve the present outlook for patients with diabetes. This effort exams the history or background of stem cell research in the laboratory and the clinic, types of stem cells, pluripotency or lack thereof based on a variety of pre-clinical investigations attempting endocrine pancreas recovery using stem cell transplantation. The focus is on the use of hematopoietic and mesenchymal stem cells. This review will also examine recent clinical experience following stem cell transplantation in patients with type 1 diabetes.

Stem cell-based therapies in inflammatory bowel disease: promises and pitfalls

Inflammatory bowel disease (IBD) is a chronic, often relapsing, condition that deeply impacts the quality of life for many patients. Although there have been significant advances in medical treatments, a large proportion of patients become refractory to available therapeutic options. Stem-cell therapy through hematopoietic stem cells (HSCs) or mesenchymal stem (stromal) cells (MSCs) is a promising therapeutic option for severe refractory cases especially when surgery is not feasible. In HSC transplantation, the objective is to destroy the 'autoreactive' immune cells responsible for disease chronicity, and to re-establish gut tolerance to gut microbes. In perianal Crohn's disease (CD), the objective is to deposit MSCs locally in fistulizing tracts to down-regulate the local immune response and induce wound healing. Results from upcoming and ongoing clinical trials will set the path of these novel therapeutic options that have the capability to successfully treat severe refractory Crohn's patients.

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.

Effect of nonmyeloablative unrelated fetal and neonatal murine peripheral blood mononuclear cell infusion on MRL/lpr mice

For patients with refractory systemic lupus erythematosus (SLE), current medications are insufficient to control their condition, and new treatments are necessary. We investigated the effect of fetal and neonatal murine peripheral blood (FNPB) mononuclear cells on MRL/lpr lupus-prone mice. Female MRL/lpr mice were randomized to three groups (control, radiation and infusion groups). The infusion group had significantly better results for survival rate, body weight increase, reduction of spleen index, serum anti-ds-DNA antibody, antinuclear antibodies (ANA) and creatinine (Cr), 24 h urine protein and pathological renal tissue lesions than either the control or radiation group. Graft versus host disease (GVHD) was not observed in MRL/lpr mice in the infusion group. The infusion group also had better hematogenesis reconstruction than the radiation group. Flow cytometry analysis revealed a significant increase in Th1, CD8+ T and T reg cells and a reduction in Th2, CD4+ T and Th17 cells in the peripheral blood of the radiation and infusion groups compared with the control group. Immunocytochemical assay revealed a significant increase in serum transforming growth factor (TGF)-β and a significant reduction in interleukin (IL)-17 in the radiation and infusion groups compared with the control group. Therefore, our study showed that FNPB mononuclear cell infusion has a significant role in regulating CD4+ T cells, Th1/Th2, Th17/T reg balance and their corresponding cytokines in MRL/lpr mice. The FNPB mononuclear cell infusion provided evidence in animals and suggested a potential clinical application for umbilical cord blood transplantation to treat SLE patients.

Therapy with stem cells in inflammatory bowel disease

Inflammatory bowel disease (IBD) affects a part of the young population and has a strong impact upon quality of life. The underlying etiology is not known, and the existing treatments are not curative. Furthermore, a significant percentage of patients are refractory to therapy. In recent years there have been great advances in our knowledge of stem cells and their therapeutic applications. In this context, autologous hematopoietic stem cell transplantation (HSCT) has been used in application to severe refractory Crohn’s disease (CD), with encouraging results. Allogenic HSCT would correct the genetic defects of the immune system, but is currently not accepted for the treatment of IBD because of its considerable risks. Mesenchymal stem cells (MSCs) have immune regulatory and regenerative properties, and low immunogenicity (both autologous and allogenic MSCs). Based on these properties, MSCs have been used via the systemic route in IBD with promising results, though it is still too soon to draw firm conclusions. Their local administration in perianal CD is the field where most progress has been made in recent years, with encouraging results. The next few years will be decisive for defining the role of such therapy in the management of IBD.

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.

Allogenic hematopoietic stem cell transplantation in pemphigus vulgaris: a single-center experience

Background:

Pemphigus vulgaris (PV), an autoimmune disorder characterized by blistering skin/mucus membrane lesions, is mediated by desmoglein-3 autoantibodies. We carried out a prospective clinical trial of hematopoietic stem cell transplantation (HSCT) in thymus, bone marrow (BM) and periphery to reconstitute central and peripheral arms of self-tolerance.

Materials and Methods:

Eleven (M:F=5:6) patients with mean age 33.5 years and mean duration of disease 22.8 months, having painful pruritic blisters and ulcers resistant to corticosteroids, were treated with cytokine-stimulated allogeneic HSCT (mean dose: 21.8 × 10⁸ cells/kg BW) from blood group-matched related donors. BM with mean CD34+ count 1.1% was inoculated into thymus, marrow and periphery, followed by two peripheral blood stem cell (PBSC) infusions.

Results:

Recovery began within 24 hours of HSCT and new lesions stopped after 6 months. No graft versus host disease (GvHD)/adverse effect was observed in any patient/donor. Over a mean follow-up of 8.02 years, all patients were well without recurrence/new lesions.

Conclusion:

Drug-resistant PV can be successfully and safely treated by allogeneic HSCT.

Long-term follow-up of autologous hematopoietic stem cell transplantation for severe refractory Crohn's disease

BACKGROUND

Although new therapeutic strategies have been developed to control Crohn's disease, medical treatment for refractory cases is not able to prevent extensive and/or repeat surgery. Recently, several cases have been reported of successful remission induction in Crohn's disease patients by means of hematopoietic stem cell transplantation (HSCT). Here we report our long-term (4 to 6 years) outcome in three patients.

PATIENTS

Three patients (two male, one female) with active severe Crohn's disease were planned to undergo autologous HSCT. All patients were intolerant or refractory to conventional therapies, including anti-TNFα antibodies. Patients either refused surgery or surgery was considered not to be a feasible alternative due to the extensive disease involvement of the small intestine.

METHODS

Peripheral blood stem cells were mobilized using a single infusion of cyclophosphamide 4 g/m(2), followed on day 4 by subcutaneous injections with G-CSF 5 μg/kg twice daily until leukapheresis. CD34+ cells were isolated after leukapheresis by magnetic cell sorting. In two of the three patients a second round of stem cell mobilization using G-CSF only was required, either because of low yield or because of insufficient recovery after CD34 selection. Prior to transplantation, immune ablation was achieved using cyclophosphamide 50mg/kg/day (4 days), antithymocyte globulin 30 mg/kg/day (3 days) and prednisolone 500 mg (3 days). Endoscopy, barium small bowel enteroclysis and MRI enterography were performed.

RESULTS

All three patients successfully completed stem cell mobilization, and two of them subsequently underwent conditioning and autologous HSCT with CD34+ cell selection. Treatment was well tolerated, with acceptable toxicity. Now, 5 and 6 years post-transplantation, these patients are in remission under treatment. The third patient went into remission after mobilization and therefore she decided not to undergo conditioning and HSCT transplantation. After a successful pregnancy she relapsed two years later. Since then, she suffers from refractory Crohn's disease for which we are now reconsidering conditioning and transplantation.

CONCLUSION

Autologous HSCT appears to be safe and can be an alternative strategy for Crohn's disease patients with severe and therapy resistant disease.

Hematopoietic stem cell transplantation for systemic lupus erythematosus, the antiphospholipid syndrome and bullous skin diseases

Systemic lupus erythematosus (SLE) is considered the paradigm of autoimmune diseases (AD), and the murine models are known to be curable by means of allogeneic hematopoietic stem cell transplantation (HSCT). However autologous transplantations were predominantly utilized in the clinic, starting from 1996, and by now well over 150 very severe patients have been transplanted worldwide. Transplant-related mortality (TRM) in 153 cases was 7%, with a wide center effect (from 0-2% to 13%). The disease arresting effect was dramatic even in patients on dialysis, although ASCT should not be considered a last resource, salvage therapy, but a disease- modifying intervention to be utilized in the early stages of patently aggressive disease. The autoimmune biological parameters are consistently modified, although some degree of ANA-positivity generally persists. Similar encouraging results have been obtained in the primary antiphospholipid syndrome (APS) and in bullous disorders of the skin.

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.

Cryopreservation: an optimizing factor for therapeutic potential of fetoplacental complex products

The therapeutic potential of cryopreserved fetoplacental complex cells (FPCP) has been explored for the treatment of autoimmune diseases, including autoimmune hemolytical anemia (AIHA). In this study, a murine AIHA model was utilized to investigate the application of cryopreserved fetal liver cells (cFLC), from varying gestation intervals (14 and 19 postcoital days) to correct the functional state of the lymphohemopoietic complex (LHPC). The results demonstrate that cryopreservation had little negative effect on FLC-14 corrective ability from that of nonfrozen FLC-14. Cryopreservation of FLC-19 (later gestation period) resulted in an increase in functional corrective potential over that of matched controls. Further, the increase in corrective effect of the cFLC-19 was found to be similar to that of both FLC-14 populations. In summary, these results demonstrate the potential for the use of cryopreserved FLCs as a therapeutic option for the treatment of AIHA.

High-dose total body irradiation and bone marrow cells may improve efficiency of bone marrow transplantation therapy in treating type 1 diabetes

Bone marrow transplantation (BMT) has been used to treat autoimmune diseases for many years. Insulin-dependent diabetes mellitus (IDDM), also called type 1 diabetes mellitus (T1DM), is a T cell-mediated autoimmune disease resulting from a selective destruction of pancreatic islet beta cells. Recently, T1D has been a common significant cause of morbidity and mortality. However, whether BMT can be used to treat T1DM is still controversial. During BMT procedure, recipients underwent total body irradiation (TBI) and subsequent bone marrow cells (BMCs) infusion, in which TBI kills off the most T lymphocytes and BMCs stimulates hematopoiesis and immune reconstitution. We suggest that high-dose TBI and BMCs may improve efficiency of BMT therapy in T1DM treatment.

Stem cells as potential novel therapeutic strategy for inflammatory bowel disease

Hematopoietic stem cell transplantation and mesenchymal stromal cell therapy are currently under investigation as novel therapies for inflammatory bowel diseases. Hematopoietic stem cells (HSC) are thought to repopulate the immune system and reset the immunological response to luminal antigens. Mesenchymal stromal cells (MSC) are cells that have the capacity to differentiate into wide variety of distinct cell lineages and suppress immune responses in vitro and in vivo. Recent results from animal models and early human experience in graft-versus-host disease but also Crohn's Disease suggest that ex vivo expanded MSCs may have clinically useful immunomodulatory effects.

The Wistar Bonn Kobori rat, a unique animal model for autoimmune pancreatitis with extrapancreatic exocrinopathy

The male Wistar Bonn/Kobori (WBN/Kob) rat is known to be a unique animal model for chronic pancreatitis with widely distributed fibrosis and degeneration of parenchyma because of the infiltration of lymphocytes. In this report, we show that female (but not male) rats develop dacryoadenitis at 3 months of age, and that both male and female WBN/Kob rats develop sialoadenitis, thyroiditis, sclerotic cholangitis and tubulointerstitial nephritis over 18 months of age. The infiltration of CD8+ cells and the deposits of tissue-specific IgG2b were observed in the injured pancreas and lachrymal glands. Furthermore, the number of regulatory T cells (defined as CD4+ Forkhead box P3+ cells) decreased in the periphery of both male and female WBN/Kob rats, suggesting that the onset of these diseases is attributable, at least, to the failure in the maintenance of peripheral immune tolerance. These features show clearly that WBN/Kob rats are a useful animal model for autoimmune pancreatitis and Sjøgren-like syndrome or multi-focal fibrosclerosis in humans. We also show that these autoimmune diseases can be prevented by a newly devised strategy of bone marrow transplantation (BMT) in which bone marrow cells are injected directly into the bone marrow cavity: intrabone marrow-BMT.

Hematopoietic Stem Cell Transplantation in Autoimmune Diseases: The Ahmedabad Experience

INTRODUCTION

Autoimmune disease represents a (AD) breakdown of natural tolerance against autoreactive antigens leading to a high mortality and morbidity. The reaction is usually polyclonal; T- and B-cell components of the hematopoietic system are responsible for disease progression. Allogeneic/autologous hematopoietic stem cell transplantation (HSCT) are the current modalities for treating drug-resistant AD.

PATIENTS AND METHODS

We present a single-center retrospective evaluation of allogeneic HSCT with nonmyeloablative, low-intensity conditioning in nine patients (five males, four females) with pemphigus vulgaris (PV) and 27 patients with systemic lupus erythematosus (SLE; 3 males, 24 females). The mean follow-up period was 4.24 years for PV and 4.9 years for SLE. Cytokine-mobilized HSC from unmatched related donors, with mean dose of 21.3 x 10(8) nucleated cells/kg body weight (BW; mean CD34(+) count, 6 x 10(6)/kg BW) was administered in to the thymus as well as the portal and peripheral circulations of recipients. Cyclosporine (4 +/- 1 mg/kg BW per day) and prednisolone (10 mg/kg BW per day) were administered for 6 months to protect mixed chimerism. A subset of patients with cross-gender donors were analyzed for peripheral blood chimerism at 1 month post-HSCT and every 3 months thereafter.

RESULTS

Sustained clinical remission with peripheral lymphohematopoietic chimerism of 0.7 +/- 0.3% was observed in PV, whereas SLE relapsed after mean of 7.35 months of disease-free interval associated with fall in chimerism from 5 +/- 3% to < or =0.08 +/- 0.03%.

CONCLUSION

HSCT was effective to achieve early clinical remission of PV; and in SLE relapsed after a 7.35-month disease-free interval accompanied by a fall in mixed lymphohematopoietic chimerism.

Catastrophic relapse of Evans syndrome five years after allogeneic BMT notwithstanding full donor chimerism. Terminal hemolytic-uremic syndrome

A patient with severe Evans syndrome received an allo-BMT from his HLA-identical sister on November, 2000. Full marrow and blood donor chimerism were achieved only after 5 donor lymphocyte infusions (DLI), and coincided with complete clinical remission and disappearence of auto-antibodies. Five years later, hemolytic anemia recurred with rapid increase of serum bilirubin to over 50 mg%: he responded to combined therapy, but died on day +17 from admission of an acute hemolytic uremic syndrome (HUS). All circulating blood cells, including erythrocytes, were 100% donor. Ex vivo cultured and expanded T and B cells from the peripheral blood were also 100% donor. The supernatants from B cell cultures, containing either IgM or IgG, did not react with a panel of erythrocytes. Thus in this typical autoimmune disease with a predominant B cell pathogenesis the donor immune system resulted "innocent of autoimmunity". The persistence of long-lived recipient autoreactive plasma-cell lines in survival niches, still producing autoantibodies, may be hypothesized for this and similar cases. The postulated graft-versus-autoimmunity (GVA) effect was apparently not sufficient to eradicate autoimmunity in this patient.

Regeneration of the intestinal epithelia: regulation of bone marrow-derived epithelial cell differentiation towards secretory lineage cells

The intestinal epithelia consists of four lineages of differentiated cells, all of which arise from stem cells residing in the intestinal crypt. For proper regeneration from epithelial damage, both expansion of the epithelial cell number and appropriate regulation of lineage differentiation from the remaining stem cells are thought to be required. In a series of studies, we have shown that bone-marrow derived cells could promote the regeneration of damaged epithelia in the human intestinal tract. Donor-derived epithelial cells substantially repopulated the gastrointestinal tract of bone-marrow transplant recipients during epithelial regeneration after graft-versus-host disease. Furthermore, precise analysis of epithelial cell lineages revealed that during epithelial regeneration, secretory lineage epithelial cells that originated from bone-marrow significantly increased in number. These findings may lead to a novel therapy to repair damaged intestinal epithelia using bone marrow cells, and provide an alternative therapy for refractory inflammatory bowel diseases.

Cord blood mesenchymal stem cells: Potential use in neurological disorders

Our previous studies demonstrate enhanced neural protective effects of cord blood (CB) cells in comparison to stem cells from adult marrow. To determine further whether mesenchymal stem cells (MSCs) derived from human umbilical cord blood (hUCB) possess optimal characteristics for neural therapy, we isolated populations of plastic-adherent CB MSCs. These cells generated CD34-, CD45-, CD11b-, CD3-, CD19- cells in culture and failed to produce CFU-M, CFU-GEMM, or CFU-GM hematopoietic colonies in methylcellulose. However, cultured CB MSCs possessed a remarkable ability to support proliferation as well as differentiation of hematopoietic cells in vitro. In addition, supernatants from cultured CB MSCs promoted survival of NT2 N neural cells and peripheral blood mononuclear cells (MNCs) cultured under conditions designed to induce cell stress and limit protein synthesis. After incubation in neural differentiation medium, CB MSCs expressed the neural cell-surface antigen A2B5, the neurofilament polypeptide NF200, the oligodendrocyte precursor marker 04, intermediate filament proteins characteristic of neural differentiation (nestin and vimentin), as well as the astrocyte marker glial fibrillary acidic protein (GFAP) and the neural progenitor marker TUJ-1. We examined the immunomodulatory effects of the CB MSCs after co-culture with murine splenocytes. Whereas spleen cells from normal C57Bl/6 mice exhibited a prominent immunoglobulin M (IgM) response after immunization with the T cell-dependent antigen sheep red blood cells, this response was significantly decreased after incubation with CB MSCs. These data indicate that CB MSCs possess multiple utilities that may contribute to their therapeutic potency in the treatment of neurological disorders.

Bone marrow transplantation with a reduced-intensity conditioning regimen in a patient with Wegener granulomatosis and therapy-related leukemia

We describe a patient with Wegener granulomatosis (WG) who underwent long-term cyclophosphamide treatment and thereafter developed acute myelogenous leukemia (AML). After the AML was induced into remission, the patient received an allogeneic stem cell transplant (allo-SCT) from his sibling after undergoing a reduced-intensity conditioning regimen. His clinical course shortly after allo-SCT was uneventful. No clinically apparent acute or chronic graft-versus-host disease developed. Repeated analysis of the peripheral blood lymphocytes after transplantation showed complete donor chimerism. The level of proteinase 3 antineutrophil cytoplasmic antibody (PR3-ANCA) remained undetectable until 4 months after transplantation, when it began to increase. When the level of PR3-ANCA peaked, the patient suddenly presented with fever and joint pain, which later spontaneously resolved in parallel with the declining titer of PR3-ANCA. He is now in remission for both AML and WG at 22 months after transplantation. The patient's clinical course after allo-SCT may provide us with valuable information regarding the establishment of allo-SCT as a therapeutic option for WG.

Autologous hematopoietic stem cell transplantation for autoimmune diseases

Ten years have passed since the first published consensus statement on the use of hematopoietic stem cell transplantation (HSCT) in the treatment of severe autoimmune disease (AD) appeared. During that time, around 700 patients suffering from severe AD have undergone HSCT in the frame of phase I/II clinical trials from over 20 countries including the US. The majority have received an autologous HSCT using one of a limited number of regimens, consistent with the original consensus statement. Long-term drug-free remissions, remission then relapse, no response and treatment-related mortality (TRM) were seen in all the subgroups of AD. An overall TRM of 7% was observed, with marked variation between ADs, i.e. 11% in systemic lupus erythematosus (SLE) and only 1 patient in rheumatoid arthritis (RA). Phase III prospective, comparative randomized trials are running or being planned in multiple sclerosis (MS), systemic sclerosis (SSc), SLE and RA. Basic science programs are also being undertaken to study the immunological mechanisms underlying the clinical events observed.

Autologous hematopoietic stem cell transplantation for autoimmune diseases

Experimental data and early phase I/II studies suggest that high-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (HSCT) can arrest progression of severe autoimmune diseases. We have evaluated the toxicity and disease response in 473 patients with severe autoimmune disease treated with autologous HSCT between 1995 and 2003, from 110 centers participating in the European Group for Blood and Marrow Transplantation (EBMT) autoimmune disease working party database. Survival, transplant-related mortality, treatment response and disease progression were assessed. In all, 420 patients (89%; 86+/-4% at 3 years, median follow-up 20 months) were alive, 53 (11%) had died from transplant-related mortality (N=31; 7+/-3% at 3 years) or disease progression (N=22; 9+/-4% at 3 years). Of 370 patients, 299 evaluable for response (81%) showed a treatment response, which was sustained in 213 (71% of responders). Response was associated with disease (P<0.001), was better in patients who received cyclophosphamide during mobilization (relative risk (RR)3.28 (1.57-6.83)) and was worse with increasing age (>40 years, RR0.29 (0.11-0.82)). Disease progression was associated with disease (P<0.001) and conditioning intensity (high intensity, RR1; intermediate intensity, RR1.81 (0.96-3.42)); low intensity, RR2.34 (1.074-5.11)). These data from the collective EBMT experience support the hypothesis that autologous HSCT can alter disease progression in severe autoimmune disease.

Haematopoietic stem cell transplantation in the treatment of severe autoimmune disease: results from phase I/II studies, prospective randomized trials and future directions

Around 700 patients have received an autologous haematopoietic stem cell transplant (HSCT) as treatment for a severe autoimmune disease (AD). The majority of these have been within the context of phase I/II clinical trials and following international guidelines proposed 7 years ago. In general, a positive benefit/risk ratio has led to phase III prospective randomized controlled trials in multiple sclerosis (MS), systemic sclerosis (SSc) and rheumatoid arthritis (RA) in Europe. In the US, similar trials are being planned for SSc, MS and systemic lupus erythematosus (SLE). Transplant related mortality (TRM) has fallen in all disease subgroups since the inception due to more appropriate patient selection, and so far a clear advantage of the more intense myeloablative regimens in terms of remission induction and relapse rate has not emerged. Although each AD has a different profile, over a third of patients have sustained a durable remission, often with no further need for immunosuppressive drugs. In those who relapsed, many responded to agents which pre transplant had been ineffective. The study of immune reconstitution and gene expression pre and post HSCT is being undertaken to further understand the mechanism of autoimmunity.

Hematopoietic stem and progenitor cells: clinical and preclinical regeneration of the hematolymphoid system

A vast literature exists on the biology of blood formation and regeneration under experimental and clinical conditions. The field of hematopoiesis was recently advanced by the capacity to purify to homogeneity primitive hematopoietic stem and progenitor cells. Isolation of cells at defined maturational stages has enhanced the understanding of the fundamental nature of stem cells, including how cell fate decisions are made, and this understanding is relevant to the development of other normal as well as malignant tissues. This review updates the basic biology of hematopoietic stem cells (HSC) and progenitors, the evolving use of purified HSC as grafts for clinical hematopoietic cell transplantation (HCT) including immune tolerance induction, and the application of HSC biology to other stem cell fields.

Prevention of type 1 diabetes with major histocompatibility complex-compatible and nonmarrow ablative hematopoietic stem cell transplants

Progression to hyperglycemia in young nonobese diabetic (NOD) mice is blocked by the transplantation of hematopoietic cells mismatched at the major histocompatibility complex (MHC). Because the NOD MHC class II allele, I-A(g7), is the primary disease susceptibility gene, it is logical to conclude that MHC-mismatched hematopoietic grafts prevent diabetes by replacement of this susceptibility allele on critical hematolymphoid populations. In this report, transplantation of MHC-matched purified hematopoietic stem cells (HSCs) pre-vented diabetes development in NOD mice, demonstrating that alleles of non-MHC background genes expressed on hematopoietic cells are sufficient to disrupt the autoaggressive process. Nonmarrow ablative conditioning was 100% protective, further showing that elimination of NOD hematopoiesis, including T-cells, was not required for the graft to block diabetes pathogenesis. The current standard clinical practice of hematopoietic cell transplantation uses donor/recipient pairs that are matched at the MHC. In our view, the principles established here using an MHC-matched engineered hematopoietic graft in conjunction with nonmarrow ablative conditioning to successfully block autoimmune diabetes sufficiently reduces the morbidity of the allogeneic transplantation procedure such that a similar approach can be translated to the treatment of human autoimmune disorders.

Intra-bone Marrow-Bone Marrow Transplantation: A New Strategy for Treatment of Stem Cell Disorders

We have established new bone marrow transplantation (BMT) methods for the treatment of stem cell disorders such as autoimmune diseases. The methods include the perfusion method (PM) and intra-bone marrow (IBM)-BMT. PM, in comparison with the conventional aspiration method, can minimize the contamination of bone marrow cells (BMCs) with T cells from the peripheral blood. Therefore, without removing T cells, no graft-versus-host disease develops in the case of PM. Because BMCs collected using 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. With IBM-BMT, no graft failure therefore occurs even if the radiation dose is reduced. IBM-BMT is applicable to regeneration therapy and various age-associated diseases such as osteoporosis, because it can efficiently recruit donor-derived normal MSCs into the bone marrow. We believe that this strategy heralds a revolution in the field of transplantation and regenerative therapy.

Mesenchymal stem cells in autoimmune disease

Autoimmune diseases afflict more than 3% of the U.S. population. Current therapy for mild to moderate cases is symptomatic, however advanced cases suffer high morbidity and mortality. Advanced patients have benefited from stem cell therapy in the form of bone marrow transplantation in conjunction with high-dose cytotoxic therapy. Broader application of stem cell therapy requires better understanding of how adult stem cells affect development and foster treatment of autoimmune pathologies, and of better ways to manipulate the host immune responses. While extensive research documents the role of hematopoietic stem cells (HSCs) in autoimmune disease, few studies have addressed if and how mesenchymal stem cells (MSCs) contribute to their etiopathology. Recent characterization of MSCs and their role in hematopoiesis and immune modulation suggest that their potential for cell therapy extends beyond their traditional accessory function in HSC engraftment. MSCs contribute significantly to tissue restructuring and immune functioning, in addition to facilitating durable, long-lasting stem cell engraftment. MSCs are relatively easy to obtain and expand in in vitro cultures, rendering them a prime candidate for genetic manipulations for stem cell therapy. They have the potential to differentiate into multiple lineages such as osteoblasts, adipose tissue, cartilage, tendon, and stromal cells. The role of MSCs for autoimmune disease therapy could thus be based both on immune function modulation and contribution to hematopoiesis. In this review, we examine the biology of MSCs, and their potential for cell therapy of autoimmune disease.

Haematopoietic stem cell transplantation for the treatment of systemic sclerosis and other autoimmune disorders

Systemic sclerosis (SSc) with involvement of vital organs has up to 50% 5-year mortality and no treatment is known which changes the natural history. Although components of vascular, immunological and fibrotic processes are involved, drugs such as cyclophosphamide (CY), an alkylating agent and a potent immunosuppressive, have been partially effective in uncontrolled studies. The dose of such agents is limited by the inevitable toxicity on the bone marrow, but this threshold may be superseded by first removing the patient's own haematopoietic stem cells, followed by reconstitution of the marrow after high-dose myeloablative CY or other therapy. This autologous haematopoietic stem cell transplantation (HSCT) technique has been applied to approximately 650 patients with severe autoimmune diseases worldwide, > 100 of whom had SSc. Of these, 75 are included in the Basle registry. Around 70% of patients responded with a significant (> 25%) improvement of the thickened skin and stabilisation of vital organ involvement. Approximately a third achieved a durable remission. The treatment-related mortality was 8.5%. Based on these encouraging Phase I/II study results, several multi-centre, international, prospective randomised Phase III trials are running or being planned. The preliminary data suggest that through such a jolt of heavy immunosuppression, the dysregulated autoaggressive immune system may be re-regulated. It is hypothesised that this results in fewer autoinflammatory and unwanted stimulatory signals to other systems such as vascular endothelium and fibroblasts, and these mechanisms are currently under study.

Stem cell transplantation for autoimmune disorders. Coincidental autoimmune disease in patients transplanted for conventional indications

The practice of stem cell transplantation for severe autoimmune diseases refractory to conventional therapy originated from two landmark discoveries: the excellent results of animal experiments, and serendipitous observations in human coincidental diseases. The latter include patients with an often long-standing autoimmune disease who have developed a haematological condition (aplasia, leukaemia, lymphoma) requiring stem cell transplantation (from marrow as well as from blood). Allogeneic and autologous transplants have been performed. The initial information deriving from both procedures is their feasibility, even more convincing since the patients were affected by two simultaneous severe diseases. The information derived from autologous transplants has, however, now been superseded by the considerable and increasing number of those transplants performed for primary autoimmune diseases. On the other hand, allogeneic stem cell transplantation for very severe autoimmune diseases is being cautiously explored in current protocols. Allogeneic transplants in coincidental disease have also suggested a graft-versus-autoimmunity effect, which may become relevant in conjunction with non-myeloablative, less toxic condition regimens.

Restoration of C1q levels by bone marrow transplantation attenuates autoimmune disease associated with C1q deficiency in mice

C1q deficiency in both humans and mice is strongly associated with autoimmunity. We have previously shown that bone marrow transplantation (BMT) restored C1q levels in C1q-deficient (C1qa(-/-)) mice. Here, we studied the effect of BMT on autoimmunity in C1qa(-/-) mice. Following irradiation, young C1qa(-/-) or wild-type MRL/Mp mice received bone marrow cells (BMC) from strain-matched wild-type or C1qa(-/-) animals. C1q levels increased rapidly when C1qa(-/-) mice received BMC from wild-type mice. Conversely, they decreased slowly in wild-type mice transplanted with C1qa(-/-) BMC. C1qa(-/-) animals transplanted with C1qa(-/-) BMC demonstrated accelerated disease when compared with wild-type mice given wild-type BMC. In contrast, a significant delay in the development of autoantibodies and glomerulonephritis was observed in C1qa(-/-) mice reconstituted with wild-type BMC, and the impaired clearance of apoptotic cells, previously described in C1qa(-/-) mice, was rectified. Moreover, the autoimmune disease was accelerated in wild-type mice given C1qa(-/-) BMC compared to animals transplanted with wild-type cells. These results provide supporting evidence that BMT may be a therapeutic option in the treatment of autoimmunity associated with human C1q deficiency.

High-dose immunosuppression and autologous hematopoietic stem cell rescue for severe multiple sclerosis

Multiple sclerosis is a relatively common and seriously disabling disease of autoimmune pathogenesis, for which there is currently no cure. Available therapies include immunomodulating agents and standard-dose immunosuppressants, which may be helpful but are not curative. Recently, studies in animal models have indicated that control of autoimmune disease can be obtained by high-dose immunosuppression followed by hematopoietic stem cell transplantation (rescue). Autologous transplants for severe and refractory multiple sclerosis were proposed in 1997 and have been performed ever since in selected patients and in the context of phase I/II trials. To date, more than 200 patients have been treated worldwide, and similar results were obtained in different centers: high-dose therapy suppresses inflammation in the brain to a degree superior to any other conventional therapy and seems to delay significantly clinical disease progression. There is, however, a procedure-related mortality risk of 1.5-5%, requiring careful patient selection before transplant. The treatment should be reserved for patients having high chance of response, i.e., young patients with low disability scores but rapidly progressing disease, having inflammatory rather than neurodegenerative changes in the central nervous system. The mechanism of action of transplantation is unclear. The initial concept of immune ablation by high-dose therapy and reconstitution of normal immunity from transplant-derived lymphocyte progenitors has given way to the concept of "resetting" the immune system and of bringing the disease to a lower level of activity. One could also speculate on a tissue repair effect, given the ability of human hematopoietic stem cells to migrate also into the central nervous system. The clinical effect of transplantation remains to be demonstrated in a randomized study. The Autoimmune Disease Working Party of the European Group for Blood and Marrow Transplantation has launched such a trial, comparing transplantation to the currently best available therapy, i.e., mitoxantrone, and in about 5 years we should know whether transplantation offers more than the benefit of a transient immunosuppressive effect.

Haematopoietic stem cell transplantation for autoimmune disorders: the American perspective

The hypothesis that haematopoietic stem cell transplantation (HSCT) might be useful in treating refractory autoimmune diseases (AID) was suggested by studies in animal models and by the improvement of concurrent autoimmune diseases in patients who had undergone transplantation for haematological disorders. This concept has now been tested in a substantial number of phase I/II clinical trials of autologous HSCT. These early results are promising, even in patients who have failed on multiple standard therapies for AID. Transplantation-related toxicity has decreased with growing experience in the application of this procedure, better patient selection and the modification of treatment protocols. Randomized trials currently under way or under consideration should clarify the role of HSCT in patients with autoimmune disorders.

Haematopoetic stem cell transplantation for refractory autoimmune cytopenia

This study describes the outcome of patients receiving haematopoietic stem cell transplantation (HSCT) to treat severe refractory autoimmune cytopenia. The registry of the European Group of Blood and Marrow Transplantation holds data on 36 patients receiving 38 transplants, the first transplant was autologous for 27 and allogeneic for nine patients. Patients had autoimmune haemolytic anaemia (autologous: 5; allogeneic: 2), Evans's syndrome (autologous: 2; allogeneic: 5); immune thrombocytopenia (autologous: 12), pure red cell aplasia (autologous: 4; allogeneic: 1), pure white cell aplasia (autologous: 1; allogeneic 1), or thrombotic thrombocytopenic purpura (autologous: 3). Patients had longstanding disease having failed multiple prior treatments. Among 26 evaluable patients mobilized for autologous HSCT, three died of treatment-related causes, one died of disease progression, seven were non-responders, six patients had transient responses and nine had continuous partial or complete remission. Of the seven evaluable patients receiving allogeneic HSCT, one died of treatment-related complications, one with transient response died of progressive disease and five had a continuous response. Autologous and allogeneic HSCT may induce a response in a subset of patients with autoimmune cytopenia of long duration albeit at the price of considerable toxicity.

Haematopoietic stem cell transplantation for autoimmune disease: limits and future potential

Stem cell transplantation (SCT) for autoimmune disease is handicapped by a lack of definitive clinical trials able to demonstrate an overall benefit. This deficiency will become more problematic as the impetus grows to introduce and evaluate additional technologies intended to improve the safety and efficacy of the procedure. The development of effective surrogate analyses to predict outcome by measuring resurgent autoimmune clones or by genomic- and proteomic-based technologies to detect early disease recurrence may be of value in assessing the benefits of these modifications without the need for full-scale, long-term, randomized trials. The introduction of safer allogeneic transplantation techniques may increase the effectiveness of the procedure, while work on marrow stem cell plasticity and/or fusion suggests that SCT may serve not simply to halt the autoimmune process, but also to contribute cells capable of healing or regenerating diseased organs. Finally, the introduction of therapeutic transgenes into transplanted cells may further increase the effectiveness of SCT, although the regulatory complexities of gene therapy trials will probably delay this process. All these innovations will ensure that the next decade will see major changes in the practice and purpose of SCT for autoimmune disease.

Multiple sclerosis

Autologous transplants for severe and refractory multiple sclerosis (MS) were proposed in 1997 and have been performed on about 200 selected patients worldwide. Phase I/II clinical studies have shown that high-dose immunosuppressive therapy suppresses inflammation in the CNS and may delay the progression of clinical disease. The procedure is associated with toxicity from the high-dose cytotoxic therapy and a risk of serious infections. There is a transplant-related mortality risk of 1-5%, requiring careful patient selection before transplantation. Treatment should be reserved for patients who have a significant chance of response, i.e. young patients with low disability scores but rapidly progressing disease who have inflammatory rather than neurodegenerative changes in the CNS. The long term effect of high-dose immunosuppression after transplantation on the frequency of relapse or progression of MS is unclear, but the initial concept of immune ablation by high-dose therapy and the reconstitution of normal immunity and tolerance from transplant-derived lymphocyte progenitors has given way to the concept of 'resetting' the immune system. The clinical effect of transplantation remains to be demonstrated in comparative studies.

Haematopoietic stem cell transplantation for immune thrombopenia and other refractory autoimmune cytopenias

This review summarizes data on haematopoietic stem cell transplantation (HSCT) to treat severe, refractory, haematological autoimmune cytopenia. A phase II study by the National Institutes of Health of the USA has presented data on autologous HSCT in 14 patients with immune thrombocytopenia or Evans' syndrome, with no early deaths and a response rate of 57%. The registry of the European Group for Blood and Marrow Transplantation holds data on 38 transplants, autologous for 27 and allogeneic for 9 patients. The disease entities and regimens used were more heterogeneous. The conditions encountered were autoimmune haemolytic anaemia, Evans' syndrome, immune thrombocytopenia, pure red cell aplasia, pure white cell aplasia and thrombotic thrombocytopenic purpura. Patients had long-standing disease, having failed multiple prior treatments. Among 26 evaluable patients mobilized for autologous HSCT, 3 died of treatment-related causes, 1 died of disease progression, 7 were non-responders, 6 patients had transient responses, and 9 had sustained partial or complete remission. Of the 7 evaluable patients receiving allogeneic HSCT, 1 died of treatment-related complications, 1 with a transient response died of progressive disease, and 5 showed a sustained response. Autologous and allogeneic HSCT may induce a response in a considerable proportion of patients with autoimmune cytopenia of long duration.

Nonmyeloablative Bone Marrow Transplantation of BXSB Lupus Mice Using Fully Matched Allogeneic Donor Cells from Green Fluorescent Protein Transgenic Mice

Male BXSB mice, a mouse model of systemic lupus erythematosus, were given bone marrow transplants (BMT) at 20 wk of age using MHC-matched donor cells and nonmyeloablative conditioning (550 cGy irradiation). Transplanted mice and irradiation controls were followed for a period of 20 wk. Mice transgenic for green fluorescent protein were used as donors to allow tracking of donor cells and a determination of chimerism. Radiation controls had reduced renal pathology at 10 wk posttransplant, but not at 20 wk compared with untreated mice, while nonmyeloablative BMT mice had significantly reduced pathology at both time intervals. The monocytosis characteristic of older BXSB mice was also reduced by BMT, but the treatment did not prevent production of Ab to dsDNA. A stable chimerism of 24-40% donor CD45-positive cells was achieved in spleen and bone marrow, and there was no evidence of clinical graft vs host disease. Donor cells were detected in most recipient organs, notably the thymus and renal glomeruli. The results suggest that complete depletion of mature lymphocytes or of progenitor stem cells is not required to control lupus nephritis in BXSB mice.

Comparative analysis of remyelinating potential of focal and intravenous administration of autologous bone marrow cells into the rat demyelinated spinal cord

The remyelinating potential of autologous bone marrow cells was studied after direct injection and following intravenous injection into rats with a demyelinated lesion in the spinal cord. Both focal and intravenous injections of acutely isolated mononuclear bone marrow cell fractions resulted in varying degrees of remyelination. Suspensions of bone marrow cells collected from the same rat were delivered at varied concentrations (10(2) to 10(5) for direct injection and 10(4) to 10(7) for i.v. injections). The lesions were examined histologically 3 weeks after transplantation. Light microscopic examination revealed remyelination in the dorsal funiculus with both injection protocols, but the extent of remyelination was proportional to the number of injected cells. To attain the same relative density of remyelination achieved by direct injection, intravenous administration of cells required delivery of substantially more cells (two orders of magnitude). However, the availability of autologous bone marrow cells in large number and the potential for systemically delivering cells to target lesion areas without neurosurgical intervention suggest the potential utility of intravenous cell delivery as a prospective therapeutic approach in demyelinating disease.

Stem cell transplantation for multiple sclerosis: What is the evidence?

Experimental and clinical observations have indicated that high-dose immunosuppression followed by autologous stem cell transplantation (ASCT) can induce remissions in severe, refractory, autoimmune diseases including multiple sclerosis (MS), a T cell-mediated autoimmune disorder against CNS myelin components, causing severe chronic disability. Control of the disease is unsatisfactory in most of the patients, especially those with rapidly evolving relapsing-remitting course and those with chronic progressive disease. The rationale for treating autoimmune diseases with ASCT is based on the immunosuppressive and immunomodulating effects of ASCT which may shift the immunological balance towards disease quiescence, a hypothesis supported by the results of ASCT in animal models of MS and by clinical observations in MS patients transplanted for concurrent malignancies. A number of phase I-II studies of ASCT in patients with active MS, conducted worldwide since 1995, and a comprehensive analysis of 85 patients, recently reported by the European Group for Blood and Marrow Transplantation (EBMT), have shown the feasibility of the method, a prominent anti-inflammatory effect on magnetic resonance imaging (MRI) disease, and a possible clinical benefit for active and refractory cases. The impact on MRI disease parameters appears superior with ASCT than with conventional therapies but the clinical results, in terms of stabilization of disease and prevention of disability, need to be validated in prospective, controlled trials. The procedure is also associated with a transplant-related mortality risk, of about 5% in high-risk cases, i.e., in older patients, those with high disability scores, those receiving strong myeloablative conditioning regimens and those undergoing intensive in vivo or ex vivo T cell-depletion. Therefore, it could be recommended for the treatment of a chronic, non-lethal, disease like MS only if it proved superior to standard therapies. A randomized trial is now launched by the EBMT to compare ASCT to mitoxantrone, currently regarded as one of the best available treatments, in properly selected patients having high chance of response at minimal mortality risk.

A New Concept of Stem Cell Disorders and Their New Therapy

The author previously proposed a new concept of categorizing stem cell disorders as: (1) stem cell aplasia (aplastic anemia), (2) monoclonal hematopoietic stem cell proliferative syndrome (leukemia and myelodysplastic syndrome), and (3) polyclonal hemopoietic stem cell proliferative syndrome (systemic and organ-specific autoimmune diseases). This review includes the following two stem cell disorders: mesenchymal stem cell disorders and organ-specific stem cell disorders. Age-associated diseases such as Alzheimer's disease, osteoporosis, and lung fibrosis belong to the former, whereas carcinosarcoma in the lung and adeno-endocrine cell carcinoma in the stomach belong to the latter. Recently, we have established a new method for allogeneic bone marrow transplantation using chimerism-resistant autoimmune-prone MRL/lpr mice. In this method, whole bone marrow cells containing a small number of T cells and mesenchymal stem cells are directly injected into the bone marrow cavity. MRL/lpr mice treated by injection of stem cells survived more than 2 years without showing symptoms of autoimmune disease. To apply this method to humans, we established a new method for bone marrow cell harvesting using cynomolgus monkeys. In this method, cells are harvested from the long bones using a perfusion method and are then injected directly into the bone marrow cavity of recipients. In this review, we show that this new method may become a powerful strategy for the treatment of various intractable diseases.