Autologous stem-cell transplantation in refractory autoimmune diseases after in vivo immunoablation and ex vivo depletion of mononuclear cells

Stem Cell Therapy in Lupus

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

Case Report: Lessons Learned From Subsequent Autologous and Allogeneic Hematopoietic Stem Cell Transplantations in a Pediatric Patient With Relapsing Polychondritis

Background

Autologous hematopoietic stem cell transplantation (autoHSCT) is increasingly being recognized as a treatment option for severe refractory autoimmune diseases (AD). However, efficacy is hampered by high relapse rates. In contrast, allogeneic HSCT (alloHSCT) has high potential to cure AD, but is associated with significant morbidity and mortality, and data in AD are limited. Experience with autoHSCT in relapsing polychondritis, a rare episodic inflammatory disorder characterized by destruction of cartilage, is scarce and alloHSCT has not been described before.

Case Presentation

Here, we present a case of a 9-year-old girl who was diagnosed with relapsing polychondritis, with severe airway involvement requiring a tracheostomy. The disease proved to be steroid-dependent and refractory to a wide array of disease-modifying anti-rheumatic drugs and biologicals. After an autoHSCT procedure, the disease became inactive for a short period of time, until the patient experienced a relapse after 31 days, accompanied by repopulation of effector/memory CD8⁺ T cells. Because of persistent inflammation and serious steroid toxicity, including severe osteoporosis, growth restriction, and excessive weight gain, the patient was offered an alloHSCT. She experienced transient antibody-mediated immune events post-alloHSCT, which subsided after rituximab. She ultimately developed a balanced immune reconstitution and is currently still in long-term disease remission, 8 years after alloHSCT.

Conclusion

This case adds to the few existing reports on autoHSCT in relapsing polychondritis and gives new insights in its pathogenesis, with a possible role for CD8⁺ T cells. Moreover, it is the first report of successful alloHSCT as a treatment for children with this severe autoimmune disease.

Safety and Efficacy of Mesenchymal Stromal Cells and Other Cellular Therapeutics in Rheumatic Diseases in 2022: A review of what we know so far

Although there are a number of new immunosuppressives and biologics approved for treating various autoimmune/inflammatory rheumatic diseases, there remain a substantial number of patients who have no clinical response or limited clinical response to these available treatments. Use of cellular therapies is a novel approach for the treatment of autoimmune/inflammatory rheumatic diseases with perhaps enhanced efficacy and less toxicity than current therapies. Autologous hematopoietic stem cell transplants were the first foray into cellular therapies with proven efficacy in scleroderma and multiple sclerosis. Newer yet unproven cellular therapies include allogenic mesenchymal stromal cells, shown effective in graft vs host disease and in healing of Crohn's fistulas. CAR-T cells are effective in various malignancies with possible usage in rheumatic diseases, as shown in preclinical studies in murine lupus and recently in human lupus. T regulatory cells are one of the master controllers of the immune response and are decreased in number and/or effectiveness in specific autoimmune diseases. Expansion of autologous T regulatory cells is an attractive approach to controlling autoimmunity. There are a number of other regulatory cells in the immune system including regulatory B cells, dendritic cells, macrophages, and other T cell types that are early in development. In this review, the current evidence for efficacy and mechanisms of actions of cellular therapies already in use or in clinical trials in human autoimmune diseases will be discussed including limitations of these therapies and potential side effects.

Case of paediatric relapsing polychondritis with severe airway involvement: the challenges of long-term airway and respiratory management

We describe a case of a 15-year-old girl diagnosed with relapsing polychondritis (RP) with involvement of the tracheobronchial tree, resulting in an increased difficulty in breathing, hoarseness of voice and stridor.Her case required the input of multiple specialities including ear, nose and throat, rheumatology, respiratory team and intensive care. Airway assessment and imaging showed glottic and subglottic stenosis and left bronchomalacia. Despite the use of steroids, cyclophosphamide and rituximab, her symptoms progressed and she was started on overnight non-invasive ventilation.She had further relapses of her airway RP-she was started on adalimumab and methotrexate and underwent monthly balloon dilatations which helped with her symptoms and facilitated a safe discharge home. However, she had further relapses and intensive care admissions and following further discussions, a tracheostomy was inserted. She is now stable on her tracheostomy and is off any respiratory support.

Stem Cell Therapy as a Treatment for Autoimmune Disease-Updates in Lupus, Scleroderma, and Multiple Sclerosis

PURPOSE OF REVIEW

Evidence for hematopoietic stem cell transplantation (HCT) in autoimmune disease has been building since the 1990s; however, many clinicians may not yet be aware of its applications to autoimmune disease. We review the basic tenets of HCT and evidence for autologous HCT in multiple sclerosis (MS), systemic sclerosis (SSc), and lupus with an emphasis on recent advanced phase trials.

RECENT FINDINGS

In MS, the phase 3 randomized MIST trial and the phase 2 randomized ASTIMS trial demonstrated the efficacy of autologous HCT in refractory MS over disease-modifying therapies and mitoxantrone, respectively. In SSc, the phase 3 randomized ASTIS trial and the phase 2 randomized SCOT trial demonstrated the efficacy of autologous HCT in advanced SSc compared to cyclophosphamide. The evidence for HCT in autoimmune diseases continues to grow, particularly in MS and SSc. In lupus, large, comparative trials are still needed. Across autoimmune diseases, questions that still remain to be answered include optimizing patient selection to limit TRM, the appropriate use of MAC, and the necessity for graft manipulation. Furthermore, collaboration between disease-specific and transplant physicians is imperative to expand the appropriate use of HCT in routine clinical practice.

An Overview of the Safety, Efficiency, and Signal Pathways of Stem Cell Therapy for Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that affects multiple organs and tissues. Mesenchymal stem cells (MSCs) are considered a good source for autoimmune disease and hematological disease therapy. This review will summarize the efficacy, safety, and mechanisms of MSC therapy for SLE. MSC therapy can reduce anti-dsDNA, antinuclear antigen (ANA), proteinuria, and serum creatinine in SLE patients. In animal models of SLE, MSC therapy also indicates that it could reduce anti-dsDNA, ANA, proteinuria, and serum creatinine and ameliorate renal pathology. There are no serious adverse events, treatment-related mortality, or tumor-related events in SLE patients after stem cell treatment. MSCs can inhibit inflammatory factors, such as MCP-1 and HMGB-1, and inhibit inflammation-related signaling pathways, such as the NF-κB, JAK/STAT, and Akt/GSK3β signaling pathways, to alleviate the lesions in SLE.

Long-term in vitro persistence of magnetic properties after magnetic bead-based cell separation of T cells

Magnetic‐activated cell sorting (MACS) using magnetic nanoparticles coated with specific antibodies is commonly used in immunology research. For in vitro isolation purposes, it is important to know to what extent the magnetic properties remain present in the isolated cell populations and whether it has consequences for sequential isolations. We hypothesized that only upon cell division, cells will lose their magnetic properties via dilution of the particles in/on their daughter cells. We analysed residual magnetic properties of cells that divided vs cells that did not divide after magnetic bead‐based cell separation. As a model, we isolated T cells using beads targeting the non‐modulating surface molecule CD45RO. Cells were labelled with the cell division tracking dye PKH and cultured under different conditions to induce variable degrees of cell division. We demonstrate that T cells that underwent no, or only minimal, cell divisions after MACS retained magnetic properties for up to at least 2 weeks of in vitro culture. The presence of nanoparticles was detected on their cell surface and intracellularly using Labeling Check reagent. These results have important consequences for procedures requiring repetitive isolation rounds after in vitro culture.

Mesenchymal Stem Cells: Allogeneic MSC May Be Immunosuppressive but Autologous MSC Are Dysfunctional in Lupus Patients

Mesenchymal stem cells (MSCs) have a potently immunosuppressive capacity in both innate and adaptive immune responses. Consequently, MSCs transplantation has emerged as a potential beneficial therapy for autoimmune diseases even though the mechanisms underlying the immunomodulatory activity of MSCs is incompletely understood. Transplanted MSCs from healthy individuals with no known history of autoimmune disease are immunosuppressive in systemic lupus erythematosus (SLE) patients and can ameliorate SLE disease symptoms in those same patients. In contrast, autologous MSCs from SLE patients are not immunosuppressive and do not ameliorate disease symptoms. Recent studies have shown that MSCs from SLE patients are dysfunctional in both proliferation and immunoregulation and phenotypically senescent. The senescent phenotype has been attributed to multiple genes and signaling pathways. In this review, we focus on the possible mechanisms for the defective phenotype and function of MSCs from SLE patients and summarize recent research on MSCs in autoimmune diseases.

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

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

Relapsing polychondritis: a clinical review for rheumatologists

Relapsing polychondritis (RPC) is a rare autoimmune rheumatic disorder that is traditionally classified as a systemic vasculitis. It is characterized by inflammation of cartilage, and typical presenting features include chondritis of the nasal bridge, auricular chondritis, ocular inflammation and involvement of the bronchial tree. Its rarity often leads to considerable delay in establishing a diagnosis and poses a significant management challenge to clinicians, as no conventional guidelines exist. This review summarizes the clinical features of RPC and provides guidance for rheumatologists on making the diagnosis and assessing organ involvement. The current state of RPC management is reviewed, with a focus on the use of the anti-TNF-α agents in patients with pulmonary involvement, the leading cause of mortality and morbidity in RPC.

The potential of non-myeloablative heterochronous autologous hematopoietic stem cell transplantation for extending a healthy life span

Aging is a complex multifactorial process, a prominent component being the senescence of the immune system. Consequently, immune-related diseases develop, including atherosclerosis, cancer, and life-threatening infections, which impact on health and longevity. Rejuvenating the aged immune system could mitigate these diseases, thereby contributing to longevity and health. Currently, an appealing option for rejuvenating the immune system is heterochronous autologous hematopoietic stem cell transplantation (haHSCT), where healthy autologous bone marrow/peripheral blood stem cells are collected during the youth of an individual, cryopreserved, and re-infused when he or she has reached an older age. After infusion, young hematopoietic stem cells can reconstitute the compromised immune system and improve immune function. Several studies using animal models have achieved substantial extension of the life span of animals treated with haHSCT. Therefore, haHSCT could be regarded as a potential procedure for preventing age-related immune defects and extending healthy longevity. In this review, the pros, cons, and future feasibility of this approach are discussed.

Efficacy and safety of autologous haematopoietic stem cell transplantation in systemic sclerosis: a systematic review of the literature

We aimed to assess the efficacy of autologous haematopoietic stem cell transplantation (HSCT) for skin sclerosis (SSc) and lung function in SSc. We performed a systematic literature review in the PubMed and Scopus databases from the earliest records to March 2016. We assessed study quality using the Cochrane tool for randomized studies, the Newcastle-Ottawa Scale for controlled cohort studies and an 18-item quality-appraisal checklist for case series. The primary outcome was the improvement of skin thickening using the modified Rodnan Skin Score (mRSS). The secondary outcome was efficacy on lung function, using diffusing capacity of the lungs for carbon monoxide and forced vital capacity (FVC). The safety of the procedure was evaluated. The literature search identified 431 citations. There were 38 studies involving a total of 344 patients who fulfilled our inclusion criteria. No meta-analysis was performed due to a high heterogeneity. There was a significant improvement in mRSS in the majority of the reports (P < 0·05), and the results were sustained for up to 8 years after autologous HSCT. The randomized studies and the four cohort studies each showed a slight but statistically significant improvement in FVC at 1 or 2 years. The treatment-related mortality calculated by pooling patients of 35 studies (336 patients with a follow-up up to 146 months) was 8·3% after autologous HSCT and 1% in cyclophosphamide-treated groups. Despite heterogeneity among the studies, we determined that autologous HSCT significantly improved cutaneous fibrosis and slightly improved FVC. Safety of autologous HSCT is acceptable given the severity of the disease. This systematic review was registered on PROSPERO, number CRD42016027951.

Refractory relapsing polychondritis: challenges and solutions

Relapsing polychondritis is a severe systemic immune-mediated disease characterized by an episodic and progressive inflammatory condition with progressive destruction of cartilaginous structures. This disease has for nearly a century kept secrets not yet explained. The real incidence and prevalence of this rare disease are unknown. The multiple clinical presentations and episodic nature of relapsing polychondritis cause a significant diagnosis delay. No guidelines for the management of patients with relapsing polychondritis have been validated to date. The challenges remain, both in the understanding of its pathophysiology and diagnosis, evaluation of its activity and prognosis, and its treatment. Possible solutions involve the sharing of data for relapsing polychondritis from worldwide reference centers. Thus, we would be able to evolve toward a better knowledge of its pathophysiology, the publication of new diagnosis criteria, which will include biological markers and imaging findings, the prediction of life-threatening or organ-threatening situations, and the publication of therapeutic evidence-based guidelines after performing at randomized controlled trials.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Long-term follow-up of fertility and pregnancy in autoimmune diseases after autologous haematopoietic stem cell transplantation

Issues of fertility and pregnancy require special attention in the long-term care of patients with autoimmune diseases (AD), who are candidates for haematopoietic stem cell transplantation (HSCT). In this single-centre observational study, we report fertility status and pregnancy outcomes in 15 patients (11 female and 4 male) after immunoablation with cyclophosphamide, antithymocyte globulin and autologous CD34⁺-selected HSCT for severe, refractory AD. The median follow-up after HSCT was 12 years (range 2-16 years). Impaired fertility was observed in six patients (five females and one male) before HSCT based on sexual hormone measurements. Higher age and cumulative cyclophosphamide dosage before HSCT correlated with fertility impairment. Median serum level of follicle-stimulating hormone (FSH) was significantly higher in female patients at 1 year after HSCT compared to baseline values, but premature ovarian failure developed in only one patient. Four women had five pregnancies and six healthy offsprings during follow-up, and no miscarriages were observed. The mothers were in treatment-free remissions during conception. No peripartal flare of their AD occurred. Although AD patients undergoing HSCT are at risk of developing infertility, pre-HSCT treatment and patients' age seem to have higher impact on long-term fertility status than HSCT itself. HSCT offers the opportunity to conceive during treatment-free remissions with favourable pregnancy outcomes.

Autologous blood stem cell transplantation in refractory systemic lupus erythematodes with recurrent longitudinal myelitis and cerebral infarction

Autologous hematopoietic stem cell transplantation (ASCT) has the potential to eliminate autoreactive lymphocytes and may represent a therapeutic option for patients with refractory autoimmune diseases. We describe a 19-year old woman with neuropsychiatric systemic lupus erythematodes (NPSLE) presenting with acute longitudinal myelitis and aseptic meningitis. Despite therapy with methylprednisolone and cyclophosphamide (CYC), recurrence of longitudinal myelitis and a disabling stroke-like relapse occurred. Hematopoietic stem cells were mobilized by CYC at 2 g/m2 and G-CSF. The patient was conditioned by CYC at 200 mg/kg and anti-thymocyte globulin and 3.6 = 106 CD34+ cells/kg were infused. Hematopoietic regeneration was observed on day 12 after ASCT. Currently, 18 months after ASCT, the patient is in clinical remission with no evidence for residual serological or neuroradiological activity of SLE. Although a longer follow-up will be needed to reliably assess the efficacy of ASCT in this patient, the present case demonstrates that ASCT may represent a therapeutic option for patients with severe NPSLE.

Direct transplantation of native pericytes from adipose tissue: A new perspective to stimulate healing in critical size bone defects

BACKGROUND AIMS

Fractures with a critical size bone defect (e.g., open fracture with segmental bone loss) are associated with high rates of delayed union and non-union. The prevention and treatment of these complications remain a serious issue in trauma and orthopaedic surgery. Autologous cancellous bone grafting is a well-established and widely used technique. However, it has drawbacks related to availability, increased morbidity and insufficient efficacy. Mesenchymal stromal cells can potentially be used to improve fracture healing. In particular, human fat tissue has been identified as a good source of multilineage adipose-derived stem cells, which can be differentiated into osteoblasts. The main issue is that mesenchymal stromal cells are a heterogeneous population of progenitors and lineage-committed cells harboring a broad range of regenerative properties. This heterogeneity is also mirrored in the differentiation potential of these cells. In the present study, we sought to test the possibility to enrich defined subpopulations of stem/progenitor cells for direct therapeutic application without requiring an in vitro expansion.

METHODS

We enriched a CD146+NG2+CD45- population of pericytes from freshly isolated stromal vascular fraction from mouse fat tissue and tested their osteogenic differentiation capacity in vitro and in vivo in a mouse model for critical size bone injury.

RESULTS

Our results confirm the ability of enriched CD146+NG2+CD45- cells to efficiently generate osteoblasts in vitro, to colonize cancellous bone scaffolds and to successfully contribute to regeneration of large bone defects in vivo.

CONCLUSIONS

This study represents proof of principle for the direct use of enriched populations of cells with stem/progenitor identity for therapeutic applications.

Stem cell therapies for systemic sclerosis

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

Critical airway involvement in relapsing polychondritis

Relapsing polychondritis (RP) is a rare multisystem disease characterised by progressive inflammation and destruction of cartilaginous structures. Airway involvement in RP occurs in approximately 50% of cases. We present a 70-year-old woman with a diagnosis of early adult onset asthma. She required multiple hospital admissions for recurrent episodes of acute severe dyspnoea for 1 year. These were treated as asthma. Months later she developed saddle nose deformity and hoarseness of voice. CT revealed tracheal/bronchial wall thickening and luminal narrowing. Based on these findings, RP was diagnosed. Insertion of a tracheobronchial stent was necessary due to severe tracheobronchomalacia. This intervention improved the patient's dyspnoea immediately. This case is reported to raise awareness of airway involvement in RP and discuss its current management. Early diagnosis of RP is essential to allow prompt treatment and to decrease the risk of life-threatening airway collapse.

Reversing T cell immunosenescence: why, who, and how

Immunosenescence is the term commonly used to describe the multifaceted phenomenon encompassing all changes occurring in the immune system during aging. It contributes to render older adults more prone to develop infectious disease and main age-related diseases. While age clearly imposes drastic changes in immune physiology, older adults have heterogeneous health and immune phenotypes. This confronts scientists and researcher to develop more age-specific interventions rather than simply adopting intervention regimes used in younger people and this in order to maintain immune protection in older adults. Thus, this review provides evidences of the central role played by cell-mediated immunity in the immunosenescence process and explores the means by which senescent state of the cell-mediated immune function could be identified and predicted using biomarkers. Furthermore considerations are given to recent advances made in the field of age-specific immune interventions that could contribute to maintain immune protection, to improve quality of life, and/or to promote healthy aging of the growing part of the population.

Clinical analysis of 15 patients with relapsing auricular polychondritis

Relapsing polychondritis (RP) is a rare autoimmune disorder of unknown etiology. The disease is characterized by episodic inflammation and destruction of cartilaginous and connective tissue structures, including the ear, eye, nose, larynx, trachea, bronchi, joints, skin, heart valves, and aorta. As the symptoms of RP are diverse and complex, it is easily misdiagnosed. The aim of this paper was to improve the understanding of the clinical features of RP, thereby facilitating its early diagnosis. Fifteen patients with RP were analyzed retrospectively and the relevant literature reviewed. The number of patients presenting with auricular chondritis was 13, while two presented with polyarthritis. Among them, the treatment of 2 RP patients with respiratory tract involvement failed and 1 patient died. Eleven patients with RP (73 %) were initially misdiagnosed. RP involves cartilage and connective tissue. The prognosis for patients with respiratory tract involvement is poor. RP causes episodic and progressive inflammation of cartilage throughout the body and is associated with a variety of clinical manifestations. Early diagnosis of RP depends on a thorough understanding of its clinical features.

Aging and neoteny in the B lineage

Aging and the physiologic decline of tissues and cells were once thought to be irreversible. However, recent studies suggest that various tissues, especially parts of the hematopoietic system, can be rejuvenated. Here we review potential mechanisms for this process and how they may be used to reverse age-related disorders and aging in general. We propose the novel hypothesis that altering the homeostatic process during cellular depletion can reverse aging in the hematopoietic system.

Bone marrow of NZB/W mice is the major site for plasma cells resistant to dexamethasone and cyclophosphamide: implications for the treatment of autoimmunity

Antibodies contribute to the pathogenesis of many chronic inflammatory diseases, including autoimmune disorders and allergies. They are secreted by proliferating plasmablasts, short-lived plasma cells and non-proliferating, long-lived memory plasma cells. Memory plasma cells refractory to immunosuppression are critical for the maintenance of both protective and pathogenic antibody titers. Here, we studied the response of plasma cells in spleen, bone marrow and inflamed kidneys of lupus-prone NZB/W mice to high-dose dexamethasone and/or cyclophosphamide. BrdU+, dividing plasmablasts and short-lived plasma cells in the spleen were depleted while BrdU- memory plasma cells survived. In contrast, all bone marrow plasma cells including anti-DNA secreting cells were refractory to both drugs. Unlike bone marrow and spleen, which showed a predominance of IgM-secreting plasma cells, inflamed kidneys mainly accommodated IgG-secreting plasma cells, including anti-DNA secreting cells, some of which survived the treatments. These results indicate that the bone marrow is the major site of memory plasma cells resistant to treatment with glucocorticoids and anti-proliferative drugs, and that inflamed tissues and secondary lymphoid organs can contribute to the autoreactive plasma cell memory. Therefore, new strategies targeting autoreactive plasma cell memory should be considered. This could be the key to finding a curative approach to the treatment of chronic inflammatory autoantibody-mediated diseases.

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.

Treatment of systemic sclerosis: potential role for stem cell transplantation

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

[Immunoablation followed by autologous stem cell transplantation in lupus: a clinical update]

Systemic lupus erythematosus (SLE) is a classic systemic autoimmune disease. Standard treatment consists of chronic therapy with antimalarials, glucocorticoids and immunosuppressive/cytotoxic drugs, which is associated with considerable side effects. In contrast, immunoablation of autoreactive immunologic memory followed by autologous stem cell transplantation (ASCT) has been the only regimen capable of inducing long-term remission of up to 10 years after cessation of immunosuppressive therapy, even in severely affected patients. Introduced in 1996, the procedure has since been performed in 147 patients with severe SLE refractory to standard treatment in clinical studies worldwide. Most of these patients achieved clinical long-term remission. However, SLE relapses and secondary autoimmune disorders have been reported. Transplant-related mortality occurred in 6% of the 147 cases, with a wide center effect (2-13%). Here we summarise the results published in the literature on immunoablation followed by ASCT in SLE and discuss future perspectives for optimising this therapeutic approach. It may be possible to improve the outcome and reduce the risks of treatment by identifying patients with a poor prognosis at an early stage, before irreversible organ damage has taken place.

Immuno-therapeutic potential of haematopoietic and mesenchymal stem cell transplantation in MS

In the last few years there has been extraordinary progress in the field of stem cell research. Two types of stem cells populate the bone marrow: haematopoietic stem/progenitor cells (HSC) and mesenchymal stem cells (MSC). The capacity of HSC to repopulate the blood has been known and exploited therapeutically for at least four decades. Today, haematopoietic stem cell transplantation (HSCT) holds a firm place in the therapy of some haematological malignancies, and a potential role of HSCT for treatment of severe autoimmune diseases has been explored in small-scale clinical studies. Multiple sclerosis (MS) is the noncancerous immune mediated disease for which the greatest number of transplants has been performed to date. The results of clinical studies are double-faced: on the one hand, HSCT has demonstrated powerful effects on acute inflammation, arresting the development of focal CNS lesions and clinical relapses; on the other hand, the treatment did not arrest chronic worsening of disability in most patients with secondary progressive MS, suggesting limited or no beneficial effects on the chronic processes causing progressive disability. MSC are a more recent addition to the range of experimental therapies being developed to treat MS. While interest in MSC usage was originally raised by their potential capacity to differentiate into different cell lineages, recent work showing their interesting immunological properties has led to a revised concept, envisioning their utilization for immuno-modulatory purposes. In this review we will summarize the current clinical and experimental evidence on HSC and MSC and outline some key questions warranting further investigation in this exciting research area.

Depletion of autoreactive immunologic memory followed by autologous hematopoietic stem cell transplantation in patients with refractory SLE induces long-term remission through de novo generation of a juvenile and tolerant immune system

Clinical trials have indicated that immunoablation followed by autologous hematopoietic stem cell transplantation (ASCT) has the potential to induce clinical remission in patients with refractory systemic lupus erythematosus (SLE), but the mechanisms have remained unclear. We now report the results of a single-center prospective study of long-term immune reconstitution after ASCT in 7 patients with SLE. The clinical remissions observed in these patients are accompanied by the depletion of autoreactive immunologic memory, reflected by the disappearance of pathogenic anti-double-stranded DNA (dsDNA) antibodies and protective antibodies in serum and a fundamental resetting of the adaptive immune system. The latter comprises recurrence of CD31(+)CD45RA(+)CD4(+) T cells (recent thymic emigrants) with a doubling in absolute numbers compared with age-matched healthy controls at the 3-year follow-up (P = .016), the regeneration of thymic-derived FoxP3(+) regulatory T cells, and normalization of peripheral T-cell receptor (TCR) repertoire usage. Likewise, responders exhibited normalization of the previously disturbed B-cell homeostasis with numeric recovery of the naive B-cell compartment within 1 year after ASCT. These data are the first to demonstrate that both depletion of the autoreactive immunologic memory and a profound resetting of the adaptive immune system are required to reestablish self-tolerance in SLE.

Direct assessment of thymic reactivation after autologous stem cell transplantation

Methods to quantify Th cell reconstitution after immunosuppressive therapies such as hematopoietic stem cell transplantation are becoming a key issue since persistent Th cell deficiencies may result in severe complications and adverse events. We employed here cytometric monitoring of CD31+ thymus-naive Th cells for the direct assessment of human thymic function in 10 patients undergoing autologous stem cell transplantation for severe autoimmune diseases. High frequencies of posttransplant recurring naive Th cells coexpressed CD31 and stable long-term reconstitution with elevated absolute counts of CD31+ thymus-naive Th cells that were enriched with T cell receptor excision circles was demonstrated. Cytometric monitoring of CD31+ thymus-naive Th cells enables to directly evaluate human thymic function ex vivo.

Targeting of memory

Current therapeutic options that are based on immunosuppression do not provide a cure for the treatment of chronic inflammation. Though more efficient immunosuppression and the introduction of biologicals such as antibodies targeting cytokines have improved clinical outcomes, immunosuppressive therapy has to be continued to be efficient, thus enhancing the risk of adverse events and undesired side effects. Why can immunosuppression ameliorate, even stop, but not cure chronic inflammation? Is chronic inflammation perpetuated beyond suppression by mechanisms independent of the immune system, or is it perpetuated by components of the immune system which are resistant to a block of ongoing immune reactions? One such component of the immune system is immunological memory. This article will review the role of immunological memory in chronic inflammation, as far as we understand it today, and discuss implications for the development of novel therapeutic strategies aiming at a cure for diseases involving chronic inflammation.

Immunological memory stabilizing autoreactivity

The etiopathologies of autoimmune diseases are complex. A broad variety of cell types and gene products are involved. However, clinical and experimental evidence suggests that the importance of an individual factor changes during the course of the disease. Factors and cell types that induce acute autoreactivity and initiate an autoimmune disease could be distinct from those that drive a chronic course of that disease. Autoreactive immunological memory, in particular B cell and plasma cell memory, contributes to chronicity through several mechanisms. Formation of autoreactive memory B cells leads to an increase in the numbers of autoreactive cells. In comparison to naive B cells, these memory B cells show a decreased threshold for activation. Additionally, a fraction of memory B cells express the chemokine receptor CXCR3, which supports their accumulation within chronically inflamed tissues. This may allow their escape from mechanisms for induction of peripheral tolerance. Within the inflamed tissue, inflammatory cytokines and autoantigens provide activation signals that promote plasma cell differentiation and survival. The autoantibodies produced locally by these plasma cells contribute to the severity of inflammation. Together, an autoreactive loop of autoantibody-induced inflammation is formed. Another integral part of immunological memory are long-lived plasma cells. These cells provide persistent humoral antibody memory. Though not all autoantibodies are produced by long-lived plasma cells, these cells have a special impact on immune pathology. Long-lived plasma cells are relatively resistant to existing therapies of immunosuppression and continuously secrete antibodies, without need for restimulation. Long-lived plasma cells provide titers of autoantibodies even during clinically quiescent phases and after immunosuppression. These persisting autoantibody titers, though often low and not causing acute clinical symptoms, are likely to maintain a low level of chronic inflammation and progressive tissue destruction, which reduces the threshold for another break of immunological tolerance.

[Acute mesenteric ischemia in a patient with relapsing polychondritis]

We report about a 43-year old woman with relapsing polychondritis, admitted with progressive malaise, fatigue, anorexia and profound weight loss. Two years ago a nasal chondritis with characteristic changes of the nasal profil, scleritis, laryngitis and unspecific general symptoms (fever, fatigue, signs of a systemic inflammation) developed and relapsing polychondritis was diagnosed. The patient was treated initially with azathioprine followed by methotrexate in combination with ciclosporine and glucocorticoids. During the hospitalization her condition slowly worsened, and crampy abdominal pain developed subsequently with massive tenderness, rebound and guarding. The clinically presumed diagnosis of ileus and peritonitis was radiomorphologically confirmed with signs of enteric perforation and a laparatomy was performed. A complete occlusion of the A. mesenterica superior and stenosis of the truncus coeliacus were diagnosed followed by a revascularization with an aorto-mesenteric bypass and subsequent resection of the necrotic ischemic ileum. An association with various autoimmune disorders including vasculitic syndromes is well known for relapsing polychondritis. The case demonstrated a progressive mesenteric ischemia with the acute exacerbation caused by a vasculitic mesenterial occlusion. The unusual presentation should be considered in the differential diagnosis of uncommon abdominal symptoms during the course of relapsing polychondritis.

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.

Long-lived plasma cells and their contribution to autoimmunity

The current view holds that chronic autoimmune diseases are driven by the continuous activation of autoreactive B and T lymphocytes. However, despite the use of potent immunosuppressants, the production of autoantibodies may persist and contribute to the autoimmune pathology. We recently demonstrated in autoimmune mice that both short-lived plasmablasts and long-lived plasma cells are involved in autoantibody production. While anti-proliferative immunosuppressive therapy and monoclonal anti-CD20 antibody deplete short-lived plasmablasts, long-lived plasma cells survive and continue to produce (auto)antibodies. Thus, strategies for targeting long-lived plasma cells may provide potent new treatment modalities.

The role of immune ablation and stem cell transplantation in severe SLE

High-dose immunosuppression followed by autologous hematopoietic stem cell therapy (HSCT) has the promise of long-term response after a short, intense period of immunosuppressive therapy but it is associated with an increased risk of serious short-term complications. HSCT induces major clinical responses in about 65% of patients with SLE who failed standard therapies. In some of these patients such responses are durable for at least several years, but the curative potential of this procedure in severe SLE is still unknown. Procedure-related mortality varies among studies between 5 and 12% and seems to be lower in relatively larger single center studies. Until more reliable estimates of the actual risks and long-term outcomes become available, patients with potentially life-threatening or disabling major organ involvement who are in acceptable general medical condition should be considered for autologous HSCT if they have failed a reasonable course of standard immunosuppressive therapy. To accomplish the best therapeutic and scientific results, it is necessary to treat all patients in carefully planned protocols by specialized teams of lupus specialists and transplanters. All immunoablative protocols should incorporate carefully planned studies of immune reconstitution to understand the mechanisms of cure or failure.

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.

MAINTENANCE OF SERUM ANTIBODY LEVELS

In vertebrates, serum antibodies are an essential component of innate and adaptive immunity and immunological memory. They also can contribute significantly to immunopathology. Their composition is the result of tightly regulated differentiation of B lymphocytes into antibody-secreting plasma blasts and plasma cells. The survival of antibody-secreting cells determines their contribution to the immune response in which they were generated and to long-lasting immunity, as provided by stable serum antibody levels. Short-lived plasma blasts and/or plasma cells secrete antibodies for a reactive immune response. Short-lived plasma blasts can become long-lived plasma cells, probably by competition with preexisting plasma cells for occupation of a limited number of survival niches in the body, in a process not yet fully understood. Limitation of the number of long-lived plasma cells allows the immune system to maintain a stable humoral immunological memory over long periods, to react to new pathogenic challenges, and to adapt the humoral memory in response to these antigens.

The rationale behind autologous autoimmune hematopoietic stem cell transplant conditioning regimens: concerns over the use of total-body irradiation in systemic sclerosis

Hematopoietic stem cell transplantation (HSCT) is becoming an increasingly recognized indication for treatment of autoimmune diseases and severe immune-mediated disorders. However, multicenter registry data have demonstrated higher than anticipated early toxicity, approximately 10% for autoimmune diseases in general, and 20-27% for diffuse systemic sclerosis (scleroderma). If uncorrected, this high treatment-related mortality will hinder development of stem cell therapy for immune-mediated diseases. In order to develop safer regimens, we address some pitfalls and concepts involved in design and selection of conditioning regimens for autoimmune diseases in general, and because it is associated with the highest regimen-related toxicity, scleroderma in specific.

Haemopoietic stem cell transplantation in autoimmune diseases: a European perspective

The potential of haemopoietic stem cell transplantation (HSCT) for the treatment of autoimmune and inflammatory diseases was originally supported by almost three decades of animal experiments and by the serendipitous remissions of autoimmune disease observed in patients undergoing transplantation for haematological disorders. Improved safety of both autologous and allogeneic HSCT over the last decade has been followed by increasing acceptance of HSCT as an experimental treatment for severe autoimmune diseases that are resistant to conventional treatment. International databases have collated over 700 procedures performed specifically for a variety of autoimmune diseases. Phase III clinical trials are in progress for some diseases. This review provides a comprehensive update on the efficacy and toxicity of HSCT in severe autoimmune disease. Future directions in the context of other evolving therapies are discussed.

Cell therapy for autoimmune diseases: does it have a future?

Almost all current therapeutic concepts in autoimmune diseases are based on the systemic suppression of immune functions and are not curative. The recent introduction of biologicals such as tumour necrosis factor blocking antibodies or receptors has added greater specificity to efficient management of disease by targeted suppression of rheumatic inflammation. It is evident, however, that only the elimination of the cells secreting inflammatory mediators, rather than the blockade of secreted molecules, will offer real specific therapeutic advantages in the future. Merely the elimination of such cells and also cells controlling the secreting effector cells could be curative and induce true long term remissions. We review here the state of the art and future therapeutic concepts that are based on the specific modulation of pathogenic cells that induce and sustain autoimmune inflammation. This sounds visionary, however, a variety of basic tools are at hand now. Thus, direct and specific cell therapy of rheumatic diseases will become a true alternative to conventional therapies.