Advances in hematopoietic stem cell transplantation for autoimmune diseases

Autoimmune diseases (ADs) are a collection of immunological disorders in which the immune system responds to self-antigens by producing autoantibodies or self-sensitized cells. Current treatments are unable to cure ADs, and achieving long-term drug-free remission remains a challenging task. Hematopoietic stem cell transplantation (HSCT) stands out from other therapies by specifically targeting ADs that target various cell subpopulations, demonstrating notable therapeutic benefits and resulting in sustained drug-free remission. Since different ADs have distinct mechanisms of action, the comprehensive understanding of how HSCT works in treating ADs is crucial. This review provides a detailed overview of the latest research and clinical applications of HSCT in treating ADs, offering new insights for clinicians aiming to optimize its use for ADs management.

Safety and efficacy of autologous haematopoietic stem-cell transplantation with low-dose cyclophosphamide mobilisation and reduced intensity conditioning versus standard of care in refractory Crohn's disease (ASTIClite): an open-label, multicentre, randomised controlled trial

BACKGROUND

A previous controlled trial of autologous haematopoietic stem-cell transplantation (HSCT) in patients with refractory Crohn's disease did not meet its primary endpoint and reported high toxicity. We aimed to assess the safety and efficacy of HSCT with an immune-ablative regimen of reduced intensity versus standard of care in this patient population.

METHODS

This open-label, multicentre, randomised controlled trial was conducted in nine National Health Service hospital trusts across the UK. Adults (aged 18-60 years) with active Crohn's disease on endoscopy (Simplified Endoscopic Score for Crohn's Disease [SES-CD] ulcer sub-score of ≥2) refractory to two or more classes of biological therapy, with no perianal or intra-abdominal sepsis or clinically significant comorbidity, were recruited. Participants were centrally randomly assigned (2:1) to either HSCT with a reduced dose of cyclophosphamide (intervention group) or standard care (control group). Randomisation was stratified by trial site by use of random permuted blocks of size 3 and 6. Patients in the intervention group underwent stem-cell mobilisation (cyclophosphamide 1 g/m2 with granulocyte colony-stimulating factor (G-CSF) 5 μg/kg) and stem-cell harvest (minimum 2·0 × 106 CD34+ cells per kg), before conditioning (fludarabine 125 mg/m2, cyclophosphamide 120 mg/kg, and rabbit anti-thymocyte globulin [thymoglobulin] 7·5 mg/kg in total) and subsequent stem-cell reinfusion supported by G-CSF. Patients in the control group continued any available conventional, biological, or nutritional therapy. The primary outcome was absence of endoscopic ulceration (SES-CD ulcer sub-score of 0) without surgery or death at week 48, analysed in the intention-to-treat population by central reading. This trial is registered with the ISRCTN registry, 17160440.

FINDINGS

Between Oct 18, 2018, and Nov 8, 2019, 49 patients were screened for eligibility, of whom 23 (47%) were randomly assigned: 13 (57%) to the intervention group and ten (43%) to the control group. In the intervention group, ten (77%) participants underwent HSCT and nine (69%) reached 48-week follow-up; in the control group, nine (90%) reached 48-week follow-up. The trial was halted in response to nine reported suspected unexpected serious adverse reactions in six (46%) patients in the intervention group, including renal failure due to proven thrombotic microangiopathy in three participants and one death due to pulmonary veno-occlusive disease. At week 48, absence of endoscopic ulceration without surgery or death was reported in three (43%) of seven participants in the intervention group and in none of six participants in the control group with available data. Serious adverse events were more frequent in the intervention group (38 in 13 [100%] patients) than in the control group (16 in four [40%] patients). A second patient in the intervention group died after week 48 of respiratory and renal failure.

INTERPRETATION

Although HSCT with an immune-ablative regimen of reduced intensity decreased endoscopic disease activity, significant adverse events deem this regimen unsuitable for future clinical use in patients with refractory Crohn's disease.

FUNDING

Efficacy and Mechanism Evaluation Programme, a Medical Research Council and National Institute for Health Research partnership.

Therapeutic management of fibrosis in systemic sclerosis patients - an analysis from the Swiss EUSTAR cohort

OBJECTIVES

Systemic sclerosis is a chronic autoimmune connective tissue disease leading to microvascular and fibrotic manifestations in multiple organs. Several treatment options and recommendations from different European countries are available. In this study, for which the ambit is Switzerland specifically, we aim to describe the treatment patterns of systemic sclerosis patients with fibrotic manifestations.

METHODS

Systemic sclerosis patients were selected from six Swiss tertiary centres recorded in the multicentre, prospective European Scleroderma Trials and Research (EUSTAR) registry. Patients fulfilling the 2013 ACR/EULAR systemic sclerosis classification criteria at baseline were included. To determine the differences in treatment of varying degrees of fibrosis, four groups were identified: (1) patients with a modified Rodnan skin score (mRSS) >0; (2) those with mRSS ≥7; (3) those with interstitial lung disease (SSc-ILD), diagnosed by either chest X-Ray or high-resolution computed tomography; and (4) patients fulfilling one of the additional criteria for extensive interstitial lung disease, defined as interstitial lung disease involvement of >20% in high-resolution computed tomography, dyspnea NYHA-stage 3/4, or a predicted forced vital capacity (FVC) of <70%.

RESULTS

A total of 590 patients with systemic sclerosis fulfilled the inclusion criteria. In this cohort, 421 (71.4%) had mRSS >0, of whom 195 (33.1%) had mRSS ≥7; interstitial lung disease was diagnosed in 198 of 456 (43.4%), of whom 106 (18.0 %) showed extensive interstitial lung disease. Regarding non-biologic disease-modifying medications (DMARDs), the most frequently prescribed was methotrexate, followed by hydroxychloroquine and mycophenolate mofetil. Rituximab and tocilizumab were most frequently used among the biologic DMARDs. Specifically, 148/372 (39.8%) of treated patients with skin fibrosis received methotrexate, mycophenolate mofetil or rituximab, and 80/177 (45.2%) with interstitial lung disease received cyclophosphamide, mycophenolate mofetil, tocilizumab or rituximab. Most patients received a proton-pump inhibitor, and few patients underwent hematopoietic stem cell transplantation.

CONCLUSION

Overall, in Switzerland, a wide range of medications is prescribed for systemic sclerosis patients. This includes modern, targeted treatments for which randomised controlled clinical trial have been recently reported.

Human Hematopoietic Stem/Progenitor Cells in Type One Diabetes Mellitus Treatment: Is There an Ideal Candidate?

Type 1 diabetes mellitus (T1DM) is a highly prevalent autoimmune disease causing the destruction of pancreatic islet β-cells. The resulting insulin production deficiency leads to a lifelong need for insulin re-placement therapy, systemic complications, and reduced life quality and expectancy. Cell therapy has been extensively attempted to restore insulin independence (IID), and autologous nonmyeloablative hematopoietic stem cell transplantation (AHST) has appeared to give the most promising results, but with a highly variable quote of patients achieving IID across the studies. We performed a comprehensive review of the trials involving stem cells, and in particular AHST, for the treatment of T1DM. We then pooled the patients enrolled in the different trials and looked for the patient characteristics that could be associated with the achievement of IID. We found a significantly higher probability of achieving IID in older patients (OR 1.17, 95%CI 1.06–1.33, p = 0.002) and a significantly lower probability in patients with a history of ketoacidosis (OR 0.23, 95%CI 0.06–0.78, p = 0.023). This suggests that there could be a population of patients more likely to benefit from AHST, but further data would be required to depict the profile of the ideal candidate.

Autoreactive B cell responses targeting nuclear antigens in systemic sclerosis: Implications for disease pathogenesis

A hallmark of disease pathogenesis of systemic sclerosis (SSc) is the presence of autoreactive B cell responses targeting nuclear proteins. Almost all SSc-patients harbour circulating antinuclear autoantibodies of which anti-topoisomerase 1, anti-centromere protein, anti-RNA polymerase III and anti-fibrillarin autoantibodies (ATA, ACA, ARA and AFA, respectively) are the most common and specific for SSc. In clinical practice, autoantibodies serve as diagnostic biomarkers and can aid in the identification of clinical phenotypes of the disease. However, factors driving disease progression in SSc are still poorly understood, and it is difficult to predict disease trajectories in individual patients. Moreover, treatment decisions remain rather empirical, with variable response rates in clinical trials due to patient heterogeneity. Current evidence has indicated that certain patients may benefit from B cell targeting therapies. Hence, it is important to understand the contribution of the antinuclear autoantibodies and their underlying B cell response to the disease pathogenesis of SSc.

Regulatory T cells (Tregs) and their therapeutic potential against autoimmune disorders - Advances and challenges

Autoimmune diseases are caused when immune cells act against self-protein. This biological self-non-self-discrimination phenomenon is controlled by a distinct group of lymphocytes known as regulatory T cells (Tregs), which are key inflammatory response regulators and play a pivotal role in immune tolerance and homeostasis. Treg-mediated robust immunosuppression provides self-tolerance and protection against autoimmune diseases. However, once this system fails to operate or poorly operate, it leads to an extreme situation where immune system reacts against self-antigens and destroys host organs, thus causing autoimmune diseases. Tregs can target both innate and adaptive immunity via modulating multiple immune cells such as neutrophils, monocytes, antigen-presenting cells, B cells, and T cells. This review highlights the Treg-mediated immunosuppression, role of several markers and their interplay during Treg development and differentiation, and advances in therapeutic aspects of Treg cells to reduce severity of autoimmunity-related conditions along with emphasizing limitations and challenges of their usages.

Hematopoietic Cell Transplantation for Systemic Sclerosis-A Review

Systemic sclerosis (SSc) is an autoimmune, multi-organ, connective tissue disease associated with significant morbidity and mortality. Conventional immunosuppressive therapies demonstrate limited efficacy. Autologous hematopoietic stem cell transplantation (HCT) is more efficacious but carries associated risks, including treatment-related mortality. Here, we review HCT as a treatment for SSc, its efficacy and toxicity in comparison to conventional therapies, and the proposed mechanisms of action. Furthermore, we discuss the importance of and recent developments in patient selection. Finally, we highlight the knowledge gaps and future work required to further improve patient outcomes.

Reconstitution of the immune system and clinical correlates after stem cell transplantation for systemic sclerosis

Systemic sclerosis (SSc) is a chronic autoimmune disease that includes fibrosis, diffuse vasculopathy, inflammation, and autoimmunity. Autologous hematopoietic stem cell transplantation (auto-HSCT) is considered for patients with severe and progressive SSc. In recent decades, knowledge about patient management and clinical outcomes after auto-HSCT has significantly improved. Mechanistic studies have contributed to increasing the comprehension of how profound and long-lasting are the modifications to the immune system induced by transplantation. This review revisits the immune monitoring studies after auto-HSCT for SSc patients and how they relate to clinical outcomes. This understanding is essential to further improve clinical applications of auto-HSCT and enhance patient outcomes.

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.

Autologous Haematopoietic Stem Cell Transplantation and Systemic Sclerosis: Focus on Interstitial Lung Disease

Autologous hematopoietic stem cells transplantation (AHSCT) has been employed as treatment for severe systemic sclerosis (SSc) with high risk of organ failure. In the last 25 years overall survival and treatment-related mortality have improved, in accordance with a better patient selection and mobilization and conditioning protocols. This review analyzes the evidence from the last 5 years for AHSCT-treated SSc patients, considering in particular the outcomes related to interstitial lung disease. There are increasing data supporting the use of AHSCT in selected patients with rapidly progressive SSc. However, some unmet needs remain, such as an accurate patient selection, pre-transplantation analysis to identify subclinical conditions precluding the transplantation, and the alternatives for post-transplant ILD recurrence.

Current State and Issues of Regenerative Medicine for Rheumatic Diseases

The prognosis of rheumatic diseases is generally better than that of malignant diseases. However, some cases with poor prognoses resist conventional therapies and cause irreversible functional and organ damage. In recent years, there has been much research on regenerative medicine, which uses stem cells to restore the function of missing or dysfunctional tissues and organs. The development of regenerative medicine is also being attempted in rheumatic diseases. In diseases such as systemic sclerosis (SSc), systemic lupus erythematosus (SLE), and rheumatoid arthritis, hematopoietic stem cell transplantation has been attempted to correct and reconstruct abnormalities in the immune system. Mesenchymal stem cells (MSCs) have also been tried for the treatment of refractory skin ulcers in SSc using the ability of MSCs to differentiate into vascular endothelial cells and for the treatment of systemic lupus erythematosus SLE using the immunosuppressive effect of MSCs. CD34-positive endothelial progenitor cells (EPCs), which are found in the mononuclear cell fraction of bone marrow and peripheral blood, can differentiate into vascular endothelial cells at the site of ischemia. Therefore, EPCs have been used in research on vascular regeneration therapy for patients with severe lower limb ischemia caused by rheumatic diseases such as SSc. Since the first report of induced pluripotent stem cells (iPSCs) in 2007, research on regenerative medicine using iPSCs has been actively conducted, and their application to rheumatic diseases is expected. However, there are many safety issues and bioethical issues involved in regenerative medicine research, and it is essential to resolve these issues for practical application and spread of regenerative medicine in the future. The environment surrounding regenerative medicine research is changing drastically, and the required expertise is becoming higher. This paper outlines the current status and challenges of regenerative medicine in rheumatic diseases.

Autologous stem-cell transplantation in systemic sclerosis-associated interstitial lung disease: early action in selected patients rather than escalation therapy for all

Systemic sclerosis (SSc) is a rare rheumatic disease characterised by inflammation, vasculopathy and fibrosis of skin and internal organs. A common complication and a leading cause of death in SSc is interstitial lung disease (ILD). The current armamentarium of treatments in SSc-ILD mainly includes immunosuppressive therapies and has recently been expanded with anti-fibrotic agent nintedanib. Autologous stem cell transplantation (SCT) is increasingly used in progressive diffuse cutaneous SSc. This intensive treatment has been studied in three randomised trials and demonstrated to improve survival and quality of life. In the subsets of patients with SSc-ILD, SCT resulted in stabilisation and modest improvement of lung volumes and disease extent on high resolution computed tomography, but less impact was seen on diffusion capacity. Comparison of SCT outcomes with results from SSc-ILD trials is difficult though, as lung involvement per se was not an inclusion criterion in all SCT trials. Also, baseline characteristics differed between studies. The risk of severe treatment-related complications from SCT is still considerable and patients with extensive lung disease are particularly at risk of complications during transplantation. Therefore SCT should only be provided by experienced multidisciplinary teams in carefully selected patients. Future research needs to include comprehensive pulmonary evaluation and establish whether SCT early in the disease might prevent irreversible pulmonary damage and reduce treatment-related complications. Also, more insight in mechanisms of action of SCT in the lung and predictors for response will improve the use of this treatment in SSc-ILD. In this review the role of SCT in the treatment of SSc-ILD is summarised.

Autologous hematopoietic stem cell transplantation restores the suppressive capacity of regulatory B cells in systemic sclerosis patients

OBJECTIVES

The rationale of autologous hematopoietic stem cell transplantation (AHSCT) for autoimmune diseases is that high-dose immunosuppression eradicates autoreactive T and B cells, and the infused autologous hematopoietic stem cells promote reconstitution of a naive and self-tolerant immune system. The aim of this study was to evaluate the reconstitution of different B cell subsets, both quantitatively and functionally, in systemic sclerosis (SSc) patients treated with AHSCT.

METHODS

Peripheral blood was harvested from twenty-two SSc patients before transplantation and at 30, 60, 120, 180 and 360 days post-AHSCT. Immunophenotyping of B cell subsets, B cell cytokine production, signaling pathways, and suppressive capacity of regulatory B cells (Bregs) were assessed by flow cytometry.

RESULTS

Naïve B cell frequencies increased from 60 to 360 days post-AHSCT, compared to pre-transplantation. Conversely, memory B cell frequencies decreased during the same period. Plasma cell frequencies transiently decreased at 60 days post-AHSCT. IL-10-producing Bregs CD19+CD24hiCD38hi and CD19+CD24hiCD27+ frequencies increased at 180 days. Moreover, the phosphorylation of ERK1/2 and p38MAPK proteins increased in B cells reconstituted post-AHSCT. Notably, CD19+CD24hiCD38hi Bregs recovered their ability to suppress production of Th1 cytokines by CD4+ T cells at 360 days post-AHSCT. Finally, IL-6 and TGF-β1-producing B cells decreased following AHSCT.

CONCLUSION

Taken together, these results suggest improvements in immunoregulatory and anti-fibrotic mechanisms after AHSCT for SSc, which may contribute to reestablishment of self-tolerance and clinical remission.

Curability and transferability of atopy with allogeneic hematopoietic cell transplantation

Atopy is excessive production of IgE in response to allergens. We evaluated in patients undergoing allogeneic hematopoietic cell transplantation (HCT) the following hypotheses: (1) Atopy is "curable" in atopic patients receiving HCT from a nonatopic donor (D-R+), and (2) Atopy is transferable from atopic donors to nonatopic recipients (D+R-). Atopic patients with atopic donors (D+R+) and non-atopic patients with non-atopic donors (D-R-) served as controls. We measured levels of multiallergen-specific IgE (A-IgE, atopy defined as ≥0.35 kU_A/L) in sera from 54 patients and their donors pre HCT and from the patients at ≥2 years post HCT. Only 7/12 (58%) D- R+ patients became nonatopic after HCT. Only 1/11 (9%) D+R- patients became atopic. Eleven of 13 (85%) D-R- patients remained nonatopic. Unexpectedly, 11/18 (61%) D+R+ patients became nonatopic. In conclusion, contrary to our hypothesis and previous reports, the "cure" of atopy may occur in only some D-R+ patients and the transfer of atopy may occur rarely. The "cure" may not be necessarily due to the exchange of atopic for nonatopic immune system, as the "cure" may also occur in D+R+ patients.

Involvement of the myeloid cell compartment in fibrogenesis and systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune fibrotic disease of unknown aetiology that is characterized by vascular changes in the skin and visceral organs. Autologous haematopoietic stem cell transplantation can improve skin and organ fibrosis in patients with progressive disease and a high risk of organ failure, indicating that cells originating in the bone marrow are important contributors to the pathogenesis of SSc. Animal studies also indicate a pivotal function of myeloid cells in the development of fibrosis leading to changes in the tissue architecture and dysfunction in multiple organs such as the heart, lungs, liver and kidney. In this Review, we summarize current knowledge about the function of myeloid cells in fibrogenesis that occurs in patients with SSc. Targeted therapies currently in clinical studies for SSc might affect myeloid cell-related pathways. Therefore, myeloid cells might be used as cellular biomarkers of disease through the application of high-dimensional techniques such as mass cytometry and single-cell RNA sequencing.

The role of innate immune cells in systemic sclerosis in the context of autologous hematopoietic stem cell transplantation

Systemic sclerosis (SSc) is a complex, heterogeneous autoimmune connective tissue disease. Autologous hematopoietic stem‐cell transplantation (AHSCT) has emerged as a valuable treatment option for rapidly progressive diffuse cutaneous SSc (dcSSc) patients, and thus far is the only treatment that has been shown to have a long‐term clinical benefit. AHSCT is thought to reintroduce immune homeostasis through elimination of pathogenic self‐reactive immune cells and reconstitution of a new, tolerant immune system. However, the mechanism of action underlying this reset to tolerance remains largely unknown. In this study we review the immune mechanisms underlying AHSCT for SSc, with a focus on the role of the innate immune cells, including monocytes and natural killer (NK) cells, in restoring immune balance after AHSCT.

Hematopoietic Stem Cell Transplantation for Systemic Sclerosis: Review of Current Status

Three prospective controlled clinical trials and numerous small series and case reports have confirmed that durable, drug-free remission in systemic sclerosis is possible via an autologous hematopoietic stem cell transplantation. Similar results have been seen in other autoimmune diseases. The exact mechanism by which this immune "reset" was achieved in some but not all cases remains elusive, but includes major reduction of autoreactive immune competent cells, re-establishment of T- and B cell regulatory networks and normalization of tissue niche function, particularly vascular. Some aspects regarding mobilization, conditioning and graft manipulation still remain open, but clearly a significant toxicity is associated with all effective regimens at present, and therefore patient selection remains a key issue. In the hematology/oncology arena, major efforts are being made to reduce genotoxic and other collateral toxicity induced by current mobilization and conditioning protocols, which may also translate to autoimmune disease. These include developments in rapid mobilization and antibody drug conjugate conditioning technology. If effective, such low-toxicity regimens might be applied to autoimmune disease at an earlier stage before chronicity of autoimmunity has been established, thus changing the therapeutic paradigm.

Hematopoietic stem-cell transplantation in systemic sclerosis: an update

PURPOSE OF REVIEW

To provide an overview of recently published work on autologous hematopoietic stem-cell transplantation (HSCT) in patients with systemic sclerosis (SSc).

RECENT FINDINGS

Superiority of HSCT vs. intravenous cyclophosphamide pulses was demonstrated in the randomized controlled American Scleroderma: Cyclophosphamide or Transplantation (SCOT) Trial (n = 75), supporting the results from earlier studies. In the SCOT Trial, total body irradiation was used instead of the nonmyeloablative regimens used in other trials, and considered well tolerated during a follow-up time of 4.5 years. Three small uncontrolled prospective cohorts (n = 4, 14 and 18) and one retrospective analyses (n = 18), using various nonmyeloablative regimens, also showed improvement in skin involvement and lung volumes post-HSCT. Transplant-related toxicity and mortality remain an essential issue in HSCT. High treatment-related mortality was reported in one prospective cohort (n = 18), using alemtuzumab as a conditioning agent. Furthermore, cardiac complications, either treatment or disease related, require special attention. In translational studies, trends are reported in number of regulatory T cells and diversity of T-cell receptor repertoire at baseline and post-HSCT correlating with treatment response.

SUMMARY

There is increasing evidence that patients with rapidly progressive SSc may benefit from HSCT. However, optimal patient selection, pretransplantation workup and posttransplant management, still have to be established.

Immune rebound associates with a favorable clinical response to autologous HSCT in systemic sclerosis patients

To evaluate the immunological mechanisms associated with clinical outcomes after autologous hematopoietic stem cell transplantation (AHSCT), focusing on regulatory T- (Treg) and B- (Breg) cell immune reconstitution, 31 systemic sclerosis (SSc) patients underwent simultaneous clinical and immunological evaluations over 36-month posttransplantation follow-up. Patients were retrospectively grouped into responders (n = 25) and nonresponders (n = 6), according to clinical response after AHSCT. Thymic function and B-cell neogenesis were respectively assessed by quantification of DNA excision circles generated during T- and B-cell receptor rearrangements. At the 1-year post-AHSCT evaluation of the total set of transplanted SSc patients, thymic rebound led to renewal of the immune system, with higher T-cell receptor (TCR) diversity, positive correlation between recent thymic emigrant and Treg counts, and higher expression of CTLA-4 and GITR on Tregs, when compared with pretransplant levels. In parallel, increased bone marrow output of newly generated naive B-cells, starting at 6 months after AHSCT, renovated the B-cell populations in peripheral blood. At 6 and 12 months after AHSCT, Bregs increased and produced higher interleukin-10 levels than before transplant. When the nonresponder patients were evaluated separately, Treg and Breg counts did not increase after AHSCT, and high TCR repertoire overlap between pre- and posttransplant periods indicated maintenance of underlying disease mechanisms. These data suggest that clinical improvement of SSc patients is related to increased counts of newly generated Tregs and Bregs after AHSCT as a result of coordinated thymic and bone marrow rebound.

CD34-selected versus unmanipulated autologous haematopoietic stem cell transplantation in the treatment of severe systemic sclerosis: a post hoc analysis of a phase I/II clinical trial conducted in Japan

BACKGROUND

The effectiveness of autologous haematopoietic stem cell transplantation (auto-HSCT) in treating severe systemic sclerosis (SSc) is established; however, the necessity of purified CD34+ cell grafts and the appropriate conditioning regimen remain unclear. This study aimed to compare the efficacy and safety of CD34-selected auto-HSCT with unmanipulated auto-HSCT to treat severe SSc.

METHODS

This study was a post hoc analysis of a phase I/II clinical trial conducted in Japan. Nineteen patients with severe SSc were enrolled. Peripheral blood stem cells (PBSCs) were mobilised with cyclophosphamide (4 g/m²) and filgrastim (10 μg/kg/day). Following PBSC collection by apheresis, CD34+ cells were immunologically selected in 11 patients. All patients were treated with high-dose cyclophosphamide (200 mg/kg) monotherapy as a conditioning regimen and received CD34-selected (n = 11) or unmanipulated auto-HSCT (n = 8). Changes in skin sclerosis and pulmonary function were assessed over an 8-year follow-up period. Differences in the changes, toxicity, progression-free survival (PFS) and overall survival were compared between patients who had received CD34-selected auto-HSCT and those who had received unmanipulated auto-HSCT.

RESULTS

Skin sclerosis progressively improved after transplantation over an 8-year follow-up period in both groups, and the improvement was significantly greater in the CD34-selected group than in the unmanipulated group. Forced vital capacity in the CD34-selected group continuously increased over 8 years, whereas in the unmanipulated group it returned to baseline 3 years after transplantation. Toxicity and viral infections, such as cytomegalovirus infection and herpes zoster, were more frequently found in the CD34-selected group than in the unmanipulated group. The frequency of severe adverse events, such as bacterial infections or organ toxicity, was similar between the two groups. No treatment-related deaths occurred in either treatment group. PFS of the CD34-selected group was greater than that of the unmanipulated group, and the 5-year PFS rates of the CD34-selected and unmanipulated group were 81.8% and 50% respectively.

CONCLUSIONS

CD34-selected auto-HSCT may produce favourable effects on improvement of skin sclerosis and pulmonary function compared with unmanipulated auto-HSCT. Use of CD34-selected auto-HSCT with high-dose cyclophosphamide monotherapy as a conditioning regimen may offer an excellent benefit-to-risk balance.

Autologous Hematopoietic Stem Cell Transplantation for Autoimmune Diseases: From Mechanistic Insights to Biomarkers

Phase I/II clinical trials of autologous hematopoietic stem cell transplantation (AHSCT) have led to increased safety and efficacy of this therapy for severe and refractory autoimmune diseases (AD). Recent phase III randomized studies have demonstrated that AHSCT induces long-term disease remission in most patients without any further immunosuppression, with superior efficacy when compared to conventional treatments. Immune monitoring studies have revealed the regeneration of a self-tolerant T and B cell repertoire, enhancement of immune regulatory mechanisms, and changes toward an anti-inflammatory milieu in patients that are responsive to AHSCT. However, some patients reactivate the disease after transplantation due to reasons not yet completely understood. This scenario emphasizes that additional specific immunological interventions are still required to improve or sustain therapeutic efficacy of AHSCT in patients with AD. Here, we critically review the current knowledge about the operating immune mechanisms or established mechanistic biomarkers of AHSCT for AD. In addition, we suggest recommendations for future immune monitoring studies and biobanking to allow discovery and development of biomarkers. In our view, AHSCT for AD has entered a new era and researchers of this field should work to identify robust predictive, prognostic, treatment-response biomarkers and to establish new guidelines for immune monitoring studies and combined therapeutic interventions to further improve the AHSCT protocols and their therapeutic efficacy.

Autologous Hematopoietic Stem Cell Transplantation for Treatment of Systemic Sclerosis

Systemic Sclerosis (SSc) is a complex autoimmune disease, characterized by high mortality and morbidity. The heterogeneity in terms of extent, severity, and rate of progression of skin and internal organ involvement gives rise to many difficulties in finding the optimal therapeutic interventions for SSc and, to date, no disease-modifying agents are available. In this scenario, it is not surprising that SSc was one of the first autoimmune diseases challenged with high-dose immunosuppressive treatment followed by autologous hematopoietic stem cell transplantation (AHSCT). In the last decades, AHSCT has emerged as a treatment option for refractory SSc through a reduction of the aberrant immune cells, followed by re-constitution of a new, self-tolerant immune system. After several case series and pilot studies, more recently three randomized controlled trials have shown a benefit in skin involvement, organ functions and quality of life measures in AHSCT compared to monthly cyclophosphamide. In addition, although AHSCT presents a certain risk of mortality, it has been shown that the overall survival is better, compared to the cyclophosphamide group. Current evidence suggests that SSc patients who are most likely to benefit from AHSCT are early, active, with rapidly progressing diffuse skin disease, and mild involvement of internal organs. As the studies have progressed, it has become evident the need for a more rigorous patient selection, the optimization of transplant and post-transplant procedures, and the intervention of multidisciplinary teams of specialists to increase the safety and efficacy of AHSCT in SSc.

Regulatory T Cells in Systemic Sclerosis

In recent years, accumulating evidence suggest that regulatory T cells (Tregs) are of paramount importance for the maintenance of immunological self-tolerance and immune homeostasis, even though they represent only about 5-10% of the peripheral CD4⁺ T cells in humans. Their key role is indeed supported by the spontaneous development of autoimmune diseases after Tregs depletion in mice. Moreover, there is also a growing literature that investigates possible contribution of Tregs numbers and activity in various autoimmune diseases. The contribution of Tregs in autoimmune disease has opened up a new therapeutic avenue based on restoring a healthy balance between Tregs and effector T-cells, such as Treg-based cellular transfer or low-dose IL-2 modulation. These therapies hold the promise of modulating the immune system without immunosuppression, while several issues regarding efficacy and safety need to be addressed. Systemic sclerosis (SSc) is an orphan connective tissue disease characterized by extensive immune abnormalities but also microvascular injury and fibrosis. Recently, data about the presence and function of Tregs in the pathogenesis of SSc have emerged although they remain scarce so far. First, there is a general agreement in the medical literature with regard to the decreased functional ability of circulating Tregs in SSc. Second the quantification of Tregs in patients have led to contradictory results; although the majority of the studies report reduced frequencies, there are conversely some indications suggesting that in case of disease activity circulating Tregs may increase. This paradoxical situation could be the result of a compensatory, but inefficient, amplification of Tregs in the context of inflammation. Nevertheless, these results must be tempered with regards to the heterogeneity of the studies for the phenotyping of the patients and of the most importance for Tregs definition and activity markers. Therefore, taking into account the appealing developments of Tregs roles in autoimmune diseases, together with preliminary data published in SSc, there is growing interest in deciphering Tregs in SSc, both in humans and mice models, to clarify whether the promises obtained in other autoimmune diseases may also apply to SSc.

Immunotherapy of systemic sclerosis

Systemic sclerosis (SSc) is a chronic systemic disease characterized by microvasculopathy, immune activation, and extensive collagen deposition. Microvasculopathy and immune activation occur very early in the disease process. Evidence from animal models and in vitro studies indicate that T-cells and B-cells activate fibroblasts to produce collagen. Traditional immunosuppressants, cyclophosphamide(CyP), methotrexate(MTX), and more recently mycophenolate mofetil(MMF), may prove more effective if used very early in the disease course. These drugs showed some benefit in skin (MTX, CyP, MMF) and lung function (CyP, MMF). Biologicals, such as intravenous immunoglobulin (IVIg), belimumab(Beli), tocilizumab(TCZ), abatacept(Aba), rituximab(RTX) and fresolimumab(Fresu) appear promising as they exhibited some benefit in skin (IVIg, Beli, TCZ, Aba, RTX, Fresu), hand function (IVIg), and joints (IVIg, TCZ, Aba). Autologous stem cell transplantation showed the best therapeutic efficacy on skin and internal organs, and looks very promising, as modification of transplantation immunosuppression is decreasing the early high mortality.

Systemic Sclerosis as an Indication for Autologous Hematopoietic Cell Transplantation: Position Statement from the American Society for Blood and Marrow Transplantation

Systemic sclerosis is a progressive inflammatory disease that is frequently fatal and has limited treatment options. High-dose chemotherapy with autologous hematopoietic cell transplantation (AHCT) has been evaluated as treatment for this disease in observational studies, multicenter randomized controlled clinical trials, and meta-analyses. On behalf of the American Society for Blood and Marrow Transplantation (ASBMT), a panel of experts in transplantation and rheumatology was convened to review available evidence and make a recommendation on AHCT as an indication for systemic sclerosis. Three randomized trials have compared the efficacy of AHCT with cyclophosphamide only, and all demonstrated benefit for the AHCT arm for their primary endpoint (improvement in the American Scleroderma Stem Cell versus Immune Suppression Trial, event-free survival in Autologous Stem Cell Transplantation International Scleroderma trial, and change in global rank composite score in Scleroderma: Cyclophosphamide or Transplantation trial). AHCT recipients also had better overall survival and a lower rate of disease progression. These findings have been confirmed in subsequent meta-analyses. Based on this high-quality evidence, the ASBMT recommends systemic sclerosis should be considered as a "standard of care" indication for AHCT. Close collaboration between rheumatologists and transplant clinicians is critical for optimizing patient selection and patient outcomes. Transplant centers in the United States are strongly encouraged to report patient and outcomes data to the Center for International Blood and Marrow Transplant Research on their patients receiving AHCT for this indication.

Hematopoietic stem cell therapy for autoimmune diseases - Clinical experience and mechanisms

With accumulating evidence and improved outcomes along with recognition that modern biological therapies are not universally effective, require chronic administration and have high acquisition costs, hematopoietic stem cell transplantation (HSCT) has become an emerging direction for cell therapy in autoimmune diseases (ADs). The goal of this therapy is to induce medication-free remissions by resetting the immune system into a naïve and self-tolerant state through eradication of the autoreactive immunologic memory and profound re-configuration of the immune system induced by the transplant procedure. Safety of HSCT has generally improved by implementing internal quality management and external accreditation. Inter-disciplinary guidelines for patient selection, transplant technique and supportive care along with greater center experience should optimize safe and appropriate delivery of HSCT in specific ADs. In this review, we discuss the current role and future perspectives of HSCT in AD, focusing on recent published clinical and scientific studies and recommendations in the field.

Resetting the T Cell Compartment in Autoimmune Diseases With Autologous Hematopoietic Stem Cell Transplantation: An Update

Autologous hematopoietic stem cell transplantation (aHSCT) for autoimmune diseases has been applied for two decades as a treatment for refractory patients with progressive disease. The rationale behind aHSCT is that high-dose immunosuppression eliminates autoreactive T and B cells, thereby resetting the immune system. Post-aHSCT the cytotoxic CD8⁺ T cells normalize via clonal expansion due to homeostatic proliferation within a few months. CD4⁺ T cells recover primarily via thymopoiesis resulting in complete renewal of the T cell receptor (TCR) repertoire which requires years or never normalize completely. The increase in naïve T cells inducing immune tolerance, renewal of especially the regulatory TCR repertoire, and a less pro-inflammatory functional profile of the CD4⁺ T cells seem essential for successful immune reconstitution inducing long-term remission. There is currently a knowledge gap regarding the immune response in tissue sites post-aHSCT, as well as disease-specific factors that may determine remission or relapse. Future studies on lymphocyte dynamics and function may pave the way for optimized conditioning regimens with a more individualized approach.

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.

Autologous Hematopoietic Stem Cell Transplantation for Systemic Sclerosis: A Systematic Review and Meta-Analysis

Autologous hematopoietic stem cell transplantation (AHSCT) has been proposed as a therapeutic modality for severe systemic sclerosis (SSc). We set out to systematically review and meta-analyze the efficacy and safety of AHSCT in SSc. Randomized controlled trials (RCTs) and retrospective studies comparing AHSCT with standard immunosuppressive therapy were included. Of 363 titles screened from multiple databases, 15 were extracted for further investigation, and 4 met inclusion criteria (3 RCTs and 1 retrospective analysis). The control arm was monthly cyclophosphamide in all the RCTs and the majority of patients in the retrospective analysis (69%). Compared with the control, AHSCT reduced all-cause mortality (risk ratio [RR], .5 [95% confidence interval, .33 to .75]) and improved skin thickness (modified Rodnan skin score mean difference [MD], 10.62 [95% CI, -14.21 to 7.03]), forced vital capacity (MD, 9.58 [95% CI, 3.89 to 15.18]), total lung capacity (MD, 6.36 [95% CI, 1.23 to 11.49]), and quality of life (physical 36-Item Short Form Health Survey [MD, 6.99 (95% CI, 2.79 to 11.18)]). Treatment-related mortality considerably varied between trials but was overall higher with AHSCT (RR, 9.00 [95% CI, 1.57 to 51.69]). The risk of bias for studies included in the analysis was low. Overall, AHSCT reduces the risk of all-cause mortality and has properties of a disease-modifying antirheumatic treatment in SSc. Further investigation is warranted for refining patient selection and timing of transplantation.

Autologous hematopoietic stem cell transplantation in systemic sclerosis: A reset to tolerance?

Autologous hematopoietic stem cell transplantation (ASCT) is an effective therapy for refractory autoimmune disease, in particular diffuse cutaneous systemic sclerosis (dcSSc). ASCT is the only treatment that can induce long term remission in dcSSc. However, the mechanism of action of ASCT has not yet been fully elucidated. The current hypothesis is that ASCT induces a long term 'reset' of the immune system, but there is no clear definition yet of such an immunological 'reset to tolerance', nor has it been established how to distinguish a 'reset' from long term immunosuppression. Here, we review the literature on immunological changes after ASCT in dcSSc patients to gain more insight whether changes in immunological parameters can help elucidate the mechanism of action of ASCT. We identified 12 studies. While some immunological parameters could be correlated to clinical response, heterogeneity in the studies, short follow-up time and the small sample sizes preclude firm conclusions. Importantly, most patients displayed a sustained clinical response despite the presence of auto-antibodies or higher-than-normal concentrations of cytokines and proteins associated with disease activity. This suggests that the mechanism of ASCT may not be solely immunological. Future research should focus on larger cohorts of patients and also take functional evaluation of immune cells into account in order to determine whether ASCT induces long term immunosuppression or resets the immune system to tolerance. Answering this question is key to further optimizing ASCT for dcSSc patients.

Analysis of anti-topoisomerase I antibodies in patients with systemic sclerosis before and after autologous stem cell transplantation

Objectives

To evaluate the effect of autologous stem cell transplantation (aSCTrans) on antibody (Ab) reactivity towards topo I in patients with SSc, and to see whether it may correlate with clinical outcome after aSCTrans.

Methods

Eighteen anti-topo/Scl70-positive patients with SSc in whom non-myeloablative aSCTrans had been performed were analysed. Seven patients showed good response without relapse for several years (group 1), eight primarily responded but later relapsed and three did not respond (group 2). A total of 74 sera were analysed at different time points and tested by ELISA against full length ( fl ) topo I, truncated ( tr ) topo I and a previously identified immunodominant epitope covering amino acid 489-573.

Results

Eighty-three percent had IgG Abs to topo fl and topo tr . Ab reactivity significantly decreased after aSCTrans, but remained positive in 10 of the 11 patients followed for up to 24 months. The decrease did not correlate with the clinical outcome after aSCTrans. Fifty-six percent of the patients reacted with topo489-573, and reactivity was nearly confined to group 2. There was no correlation between Ab reactivity towards topo fl or topo489-573 and the modified Rodnan Skin Score before aSCTrans or its decrease after aSCTrans.

Conclusions

Although aSCTrans is a good treatment option in patients with progressive SSc, it does not abrogate Ab reactivity towards topo I. The presence of anti-topo489-573 Abs before aSCTrans may indicate a less favourable course after aSCTrans.

Regulatory T Cells in Systemic Sclerosis: a Comprehensive Review

Systemic sclerosis (SSc) is a chronic inflammatory disease with complex pathogenesis, based on the sophisticated interplay of injury to the vascular endothelium, exaggerated tissue regeneration and fibrosis, and extensive immune abnormalities. The role of regulatory T cells (Tregs) in the development of SSc has started being studied during the last decade with new aspects being disclosed continuously, in parallel with the better understanding of Tregs physiology. There is a general agreement in the medical literature regarding the decreased functional capacity of circulating Tregs in SSc. Some patients, particularly those with active disease, may have increased numbers of circulating Tregs, representing the inhibitory response of the immune system to its inappropriate activation or occurring as a compensatory move for Tregs' decreased suppressive ability. Decreased pool of circulating Tregs can be seen in other SSc patients, with even lower Treg percentages seen in patients with long-standing disease. Skin-resident Tregs are depleted in advanced SSc but can be active and have a role in earlier disease stages. In addition to diminished suppressive ability, Tregs can contribute to SSc evolution by their microenvironment-dependent transformation to pathogenic effector T cells of Th17 or Th2 lineages with respective pro-inflammatory or pro-fibrotic activity. The current data on the effects of existing treatment modalities, including autologous stem cell transplantation, on Tregs function in SSc, is controversial, not being sufficiently elaborated.

Recent advances in managing systemic sclerosis

How the main components in systemic sclerosis—namely autoimmunity, vasculopathy, and fibrosis—fit together is still not sufficiently clear. However, vascular treatment options are well established, the body of evidence for the efficacy of immunomodulatory approaches is increasing, and now at least one hopeful substance that may directly interfere with fibrosis is being tested. Although we still wait for important breakthroughs, there is grounds for hope that better therapeutic options will be available in the near future.

Long-term immune reconstitution and T cell repertoire analysis after autologous hematopoietic stem cell transplantation in systemic sclerosis patients

The determinants of clinical responses after autologous hematopoietic stem cell transplantation (aHSCT) in systemic sclerosis (SSc) are still unraveled. We analyzed long-term immune reconstitution (IR) and T cell receptor (TCR) repertoire diversity in 10 SSc patients, with at least 6 years simultaneous clinical and immunological follow-up after aHSCT. Patients were retrospectively classified as long-term responders (A, n = 5) or non-responders (B, n = 5), using modified Rodnan’s skin score (mRSS) and forced vital capacity (FVC%). All patients had similar severe SSc before aHSCT. Number of reinjected CD34⁺ cells was higher in group B versus A (P = 0.02). Long-term mRSS fall >25% was more pronounced in group A (P = 0.004), the only to improve long-term FVC% >10% (P = 0.026). There was an overall trend toward increased of T cell reconstitution in group B versus A. B cells had a positive linear regression slope in group A (LRS = 11.1) and negative in group B (LRS = −11.6). TCR repertoire was disturbed before aHSCT and the percentage of polyclonal families significantly increased at long-term (P = 0.046), with no difference between groups. Despite improved skin score after aHSCT in all SSc patients, pretransplant B cell clonal expansion and faster post-transplant T cell IR in long-term non-responder/relapsing patients call for new therapeutic protocols guided by IR analysis to improve their outcome.

Cellular Therapies in Systemic Sclerosis: Recent Progress

Systemic sclerosis (SSc) is a rare autoimmune connective tissue disease with a high mortality and morbidity. While progress has been made in terms of identifying high-risk patients and implementing new treatment strategies, therapeutic options remain limited. In the past few decades, various cellular therapies have emerged, which have been studied in SSc and other conditions. Here, we provide a comprehensive review of currently available cellular therapies and critically assess their merit as disease-modifying treatment for SSc. Currently, hematopoietic stem cell transplantation is the only cellular therapy that has demonstrated clinical effects on the immune system, neoangiogenesis, and fibrosis. Robust mechanistic studies as well as clinical trials are essential to move the field forward.

[Autologous stem cell transplantation in systemic sclerosis]

Autologous hematopoietic stem cell transplantation (HSCT) is a very effective treatment option for patients with severe systemic sclerosis (SSc). In addition to various case series two randomized controlled trials could prove its superiority over intense cyclophosphamide pulse therapy. Nevertheless, HSCT is associated with a treatment-related mortality of approximately 10 %; therefore, further studies should be carried out to reduce the toxicity of HSCT by adaptation of the therapy regimen and the option of HSCT should be made available earlier to patients with a high risk of mortality. The mechanism of action of HSCT is still poorly understood. While profibrotic cytokines or even autoantibodies hardly appear to be influenced by the treatment, alterations to regulatory T‑cells may play a role. Further improvement of transplantation regimens as well as a better understanding of the underlying pathogenetic principles and mechanisms of action should be the aim of further studies on HSCT.

Resetting the immune response after autologous hematopoietic stem cell transplantation for autoimmune diseases

Autologous hematopoietic stem cell transplantation (AHSCT) is currently investigated as treatment for severe and refractory autoimmune diseases, such as multiple sclerosis (MS), systemic sclerosis (SSc), Crohn's disease (CD) and systemic lupus erythematosus. Randomized clinical trials in MS, SSc and CD have shown the efficacy of AHSCT to promote control of disease activity and progression, when compared to conventional treatment. The use of high dose immunosuppressive conditioning is essential to eliminate the autoimmune repertoire, and the re-infusion of autologous hematopoietic stem cells avoids long-term leucopenia by reconstitution of both immune and hematological systems. Recent studies showed that AHSCT is able to deplete the autoimmune compartment and further promote the formation of a new auto-tolerant immune repertoire, reducing the inflammatory milieu and leading to long-term clinical remission without any complementary post-graft treatment. Deep knowledge about the mechanisms of action related to AHSCT-induced remission is required for the management of possible post-AHSCT relapse and improvement of clinical protocols. This paper will review the mechanisms enrolled in the immune response resetting promoted by AHSCT in patients with autoimmune diseases.

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.

Stem cell transplantation in systemic sclerosis

PURPOSE OF REVIEW

The purpose of this review is to discuss recent published clinical and mechanistic studies on stem cell transplantation for systemic sclerosis and their implications for clinical practice.

RECENT FINDINGS

Retrospective analyses of independent cohorts of systemic sclerosis patients treated with autologous stem cell transplantation showed significant improvement of skin thickening, lung function and quality of life, but at the expense of 6-17% treatment-related mortality. Right heart catheterization was employed in one study to identify and exclude patients at risk of serious cardiopulmonary toxicity. The superior efficacy of stem cell transplantation versus intravenous pulses cyclophosphamide was demonstrated in a small randomized, controlled phase 2 trial in 19 systemic sclerosis patients and a large randomized phase 3 trial in 156 patients with severe diffuse cutaneous systemic sclerosis. The latter also showed a survival benefit of transplanted patients despite a 10% transplant-related mortality. Mechanistic studies in transplanted patients have shown major shifts in circulating natural killer cells, T and B lymphocytes immediately after stem cell transplantation, similar to those observed in other autoimmune conditions. Stem cell transplantation of systemic sclerosis patients with lung involvement resulted in demonstrable attenuation of thoracic high-resolution CT (HRCT) abnormalities and serum markers of lung fibrosis.

SUMMARY

Stem cell transplantation is an effective treatment option for patients with severe systemic sclerosis, but is associated with toxicity and treatment-related mortality. The available data suggest that patient selection and comprehensive cardiopulmonary screening are critical factors in determining outcome.

VIDEO ABSTRACT AVAILABLE

See the Supplementary Digital content 1 (http://links.lww.com/COR/A7).

Stem cells in autoimmune diseases: Implications for pathogenesis and future trends in therapy

In this review we report the recent progresses, available in the literature, concerning the biology and the potential therapeutic role of both mesenchymal stem cells (MSCs) and hematopoietic stem cells in autoimmune diseases. Mesenchymal stem cells (MSCs) are responsible for the normal turnover and maintenance of adult mesenchymal tissues and their pleiotropic nature allows them to sense and respond to an event in the local environment, be it injury or inflammation. Recently, MSCs have been shown to have immune-modulatory properties and immunosuppressive capacities, acting on different immune cells both in vitro and in vivo, in addition to an immunologically privileged phenotype. Moreover, several works suggest that MSCs are defective in autoimmune diseases. These aspects are now considered the most intriguing aspect of their biology, introducing the possibility that these cells might be used as effective therapy in autoimmune diseases. Autoimmune diseases represent a failure of normal immune regulatory processes as they are characterized by activation and expansion of immune cell subsets in response to non-pathogenic stimuli. As autoimmune diseases can be transferred, or alternatively, cured, by stem cell transplantation, a defect in the hemopoietic stem cell as a cause of autoimmune diseases may be postulated. The rationale for autologous hematopoietic stem cell transplantation (HSCT) in autoimmune diseases is the ablation of an aberrant or self-reactive immune system by chemotherapy and regeneration of a new and hopefully self-tolerant immune system from hematopoietic stem cells. In the past 15years, more than 1500 patients worldwide have received HSCT, mostly autologous, as treatment for a severe autoimmune disease and the majority were affected by multiple sclerosis, systemic sclerosis, systemic lupus erythematosus, rheumatoid arthritis, juvenile idiopathic arthritis and idiopathic cytopenic purpura.

Acute response of peripheral blood cell to autologous hematopoietic stem cell transplantation in type 1 diabetic patient

Objective

Autologous nonmyeloablative hematopoietic stem cell transplantation (AHST) was the first therapeutic approach that can improve β cell function in type 1 diabetic (T1D) patients. This study was designed to investigate the potential mechanisms involved.

Design and methods

We applied AHST to nine T1D patients diagnosed within six months and analyzed the acute responses in peripheral blood for lymphocyte subpopulation as well as for genomic expression profiling at the six-month follow-up.

Results

We found six patients obtained insulin free (IF group) and three remained insulin dependent (ID group); C-peptide production was significantly higher in IF group compared to ID group. The acute responses in lymphocytes at six-month follow-up include declined CD3⁺CD4⁺, CD3⁺CD8⁺ T cell population and recovered B cell, NK cell population in both groups but with no significant differences between the two groups; most immune-related genes and pathways were up-regulated in peripheral blood mononuclear cell (PBMC) of both groups while none of transcription factors for immune regulatory component were significantly changed; the IF group demonstrated more AHST-modified genetic events than the ID group and distinct pattern of top pathways, co-expression network as well as ‘hub’ genes (eg, TCF7 and GZMA) were associated with each group.

Conclusions

AHST could improve the islet function in newly diagnosed T1D patients and elimination of the islet specific autoreactive T cells might be one of the mechanisms involved; T1D patients responded differently to AHST possibly due to the distinct transcriptional events occurring in PBMC.

Trial Registration

ClinicalTrials.gov NCT00807651

Hematopoietic stem cell transplantation for systemic sclerosis: history and current status

PURPOSE OF REVIEW

Systemic sclerosis (SSc) remains one of the last severe autoimmune disease with a poor prognosis and modest response to immunosuppressive therapy. Mortality in severe diffuse disease with internal organ involvement is elevated. Autologous hematopoietic transplantation (HSCT) has emerged in the last decade as a promising disease-modifying treatment.

RECENT FINDINGS

In phase I/II trials, HSCT has demonstrated to induce impressive reversal of skin fibrosis, neoangiogenesis, improved functionality and quality of life, and stabilization of internal organ function. Treatment-related mortality was reduced over time by better pretransplant evaluation and by treating patients earlier in disease.

SUMMARY

Two out of three randomized trials of autologous HSCT for SSc have been concluded: the nonmyeloablative American Systemic Sclerosis Immune Suppression versus Transplant, and Autologous Stem cell Transplantation International Scleroderma. The myeloablative Scleroderma Cyclophosphamide versus Transplant instead is still recruiting patients. The soon expected results from these trials should clarify the role of autologous HSCT in the challenging management of severe SSc.