Evolution, trends, outcomes, and economics of hematopoietic stem cell transplantation in severe autoimmune diseases

Cyclophosphamide-free Mobilisation Increases Safety While Preserving the Efficacy of Autologous Haematopoietic Stem Cell Transplantation in Refractory Crohn's Disease Patients

BACKGROUND AND AIM

Autologous haematopoietic stem cell transplantation [AHSCT] is a therapeutic option for refractory Crohn's disease [CD]. However, high adverse event rates related to chemotherapy toxicity and immunosuppression limit its applicability. This study aims to evaluate AHSCT's safety and efficacy using a cyclophosphamide [Cy]-free mobilisation regimen.

METHODS

A prospective, observational study included 14 refractory CD patients undergoing AHSCT between June 2017 and October 2022. The protocol involved outpatient mobilisation with G-CSF 12-16 μg/kg/daily for 5 days, and optional Plerixafor 240 μg/d [1-2 doses] if the CD34 + cell count target was unmet. Standard conditioning with Cy and anti-thymocyte globulin was administered. Clinical, endoscopic, and radiological assessments were conducted at baseline and during follow-up.

RESULTS

All patients achieved successful outpatient mobilisation [seven patients needed Plerixafor] and underwent transplantation. Median follow-up was 106 weeks (interquartile range [IQR] 52-348). No mobilisation-related serious adverse events [SAEs] or CD worsening occurred. Clinical and endoscopic remission rates were 71% and 41.7% at 26 weeks, 64% and 25% at 52 weeks, and 71% and 16.7% at the last follow-up, respectively. The percentage of patients who restarted CD therapy for clinical relapse and/or endoscopic/radiological activity was 14% at 26 weeks, 57% at 52 weeks, and 86% at the last follow-up, respectively. Peripheral blood cell populations and antibody levels post-AHSCT were comparable to Cy-based mobilisation.

CONCLUSIONS

Cy-free mobilisation is safe and feasible in refractory CD patients undergoing AHSCT. Although relapse occurs in a significant proportion of patients, clinical and endoscopic responses are achieved upon CD-specific therapy reintroduction.

Evolving understanding of autoimmune mechanisms and new therapeutic strategies of autoimmune disorders

Autoimmune disorders are characterized by aberrant T cell and B cell reactivity to the body's own components, resulting in tissue destruction and organ dysfunction. Autoimmune diseases affect a wide range of people in many parts of the world and have become one of the major concerns in public health. In recent years, there have been substantial progress in our understanding of the epidemiology, risk factors, pathogenesis and mechanisms of autoimmune diseases. Current approved therapeutic interventions for autoimmune diseases are mainly non-specific immunomodulators and may cause broad immunosuppression that leads to serious adverse effects. To overcome the limitations of immunosuppressive drugs in treating autoimmune diseases, precise and target-specific strategies are urgently needed. To date, significant advances have been made in our understanding of the mechanisms of immune tolerance, offering a new avenue for developing antigen-specific immunotherapies for autoimmune diseases. These antigen-specific approaches have shown great potential in various preclinical animal models and recently been evaluated in clinical trials. This review describes the common epidemiology, clinical manifestation and mechanisms of autoimmune diseases, with a focus on typical autoimmune diseases including multiple sclerosis, type 1 diabetes, rheumatoid arthritis, systemic lupus erythematosus, and sjögren's syndrome. We discuss the current therapeutics developed in this field, highlight the recent advances in the use of nanomaterials and mRNA vaccine techniques to induce antigen-specific immune tolerance.

Autologous hematopoietic stem cell transplant for systemic sclerosis associated interstitial lung disease

PURPOSE OF REVIEW

Over the last 25 years, the role of autologous hematopoietic stem cell transplant (HSCT) in the treatment of diffuse cutaneous systemic sclerosis (dcSSc) has been elucidated. However, multiple critical questions remain regarding this therapy. Of particular interest is the role of HSCT in the treatment of systemic sclerosis (SSc)-associated interstitial lung disease since this is the leading cause of death in SSc.

RECENT FINDINGS

Most clinical trials and observational studies of HSCT for the treatment of dcSSc have reported pulmonary outcomes as secondary outcomes, Also, most studies have excluded patients with significant pulmonary function impairment. Despite these limitations, there is increasing evidence that suggests that HSCT leads to interstitial lung disease stabilization and possibly improvement of lung function based on pulmonary function tests and imaging.

SUMMARY

HSCT has demonstrated improved long-term outcomes compared to conventional therapies for dcSSC. Future research is needed to refine or expand patient selection, optimize conditioning regimens, and evaluate the potential role of maintenance immunosuppression. We recommend an increased focus on interstitial lung disease since this is the primary cause of death in SSc.

The Role of Chimeric Antigen Receptor T-Cell Therapy in Immune-Mediated Neurological Diseases

Despite the use of 'high efficacy' disease-modifying therapies, disease activity and clinical progression of different immune-mediated neurological diseases continue for some patients, resulting in accumulating disability, deteriorating social and mental health, and high economic cost to patients and society. Although autologous hematopoietic stem cell transplant is an effective treatment modality, it is an intensive chemotherapy-based therapy with a range of short- and long-term side-effects. Chimeric antigen receptor T-cell therapy (CAR-T) has revolutionized the treatment of B-cell and other hematological malignancies, conferring long-term remission for otherwise refractory diseases. However, the toxicity of this treatment, particularly cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome, and the complexity of production necessitate the need for a high level of specialization at treating centers. Early-phase trials of CAR-T therapies in immune-mediated B cell driven conditions, such as systemic lupus erythematosus, neuromyelitis optica spectrum disorder and myasthenia gravis, have shown dramatic clinical response with few adverse events. Based on the common physiopathology, CAR-T therapy in other immune-mediated neurological disease, including multiple sclerosis, chronic inflammatory polyradiculopathy, autoimmune encephalitis, and stiff person syndrome, might be an effective option for patients, avoiding the need for long-term immunosuppressant medications. It may prove to be a more selective immunoablative approach than autologous hematopoietic stem cell transplant, with potentially increased efficacy and lower adverse events. In this review, we present the state of the art and future directions of the use of CAR-T in such conditions. ANN NEUROL 2024;96:441-452.

Australian rheumatologists' perception of autologous haemopoietic stem cell transplantation for the treatment of systemic sclerosis: a cross-sectional survey

BACKGROUND

Autologous haemopoietic stem cell transplantation (AHSCT) is an effective treatment for systemic sclerosis (SSc); however, treatment-related toxicity remains a key issue.

AIMS

To investigate the perceptions of rheumatologists on the use of AHSCT for SSc.

METHODS

Australian rheumatologists were asked for their opinion on the role of AHSCT, the indications for treatment and the barriers to the use of AHSCT for SSc. A secondary analysis assessed what factors influenced the perception of AHSCT.

RESULTS

A total of 77.8% rheumatologists agreed or strongly agreed with the statement that AHSCT is an accepted treatment for SSc. While 65.1% agreed or strongly agreed that treatment-associated mortality was a significant barrier to referral for AHSCT, only 15.2% agreed or strongly agreed that this risk was unacceptable. Progressive lung or skin disease, or lack of response to other therapies, were considered the main referral criteria. A total of 92.0% of respondents agreed or strongly agreed that reduction of treatment toxicity would increase their likelihood to refer patients for AHSCT. Rheumatologists who were aware of the correct evidence base were more likely to consider AHSCT an acceptable treatment for SSc (4.21 ± 0.7 vs 3.64 ± 0.9, P = 0.007). Rheumatologists desire improved patient selection criteria and access to treatment.

CONCLUSION

In this national survey of rheumatologists, AHSCT is considered an accepted therapy. However, concern about toxicity remains a potential barrier to patient referral. Access, studies to refine patient selection and development of AHSCT protocols that improve safety were identified as key areas of need.

Autologous haematopoiesis stem cell transplantation (AHSCT) for treatment-refractory autoimmune diseases in children

OBJECTIVES

To evaluate the long-term effectiveness and safety of autologous haematopoiesis stem cell transplantation (AHSCT) for severe, refractory autoimmune diseases in paediatric patients.

METHODS

A single-centre study of consecutive children and adolescents with refractory autoimmune diseases undergoing AHSCT was performed. Demographics, clinical, laboratory features, pre-AHSCT medications, disease activity and functional status were captured. The primary outcome was progression-free survival, secondary outcomes included overall survival, disease-specific treatment responses, disease activity at the last follow-up and AHSCT safety.

RESULTS

The study included seven patients: two systemic sclerosis, one pansclerotic morphoea, one eosinophilic fasciitis, one juvenile dermatomyositis and two patients with systemic juvenile idiopathic arthritis; four women, three men median age at AHSCT of 10 years (7-19), median follow-up post-AHSCT of 17 years. Median progression-free survival and overall survival was 4.2 years (95% CI: 0.98 to 8.3) and 17 years (95% CI: 11.8 to 22.1), respectively. Progression-free survival rates at 1 and 2 years post-AHSCT were 100% and 77%, respectively. All children survived. All patients are in clinical remission, only four require ongoing immunotherapy.

SAFETY

Three experienced infections, including HHV6, Candida and Ralstonia sepsis; one developed a systemic inflammatory response syndrome; two new onset secondary autoimmune diseases including autoimmune haemolytic anaemia, Graves' disease and one was found to have a breast fibroadenoma. Treatment toxicity: one cyclophosphamide-associated transient renal failure and pericardial effusion, one patient with amenorrhoea/infertility.

CONCLUSIONS

AHSCT was an effective and safe approach for children and adolescents with treatment-refractory autoimmune diseases. The indication and timing of transplantation requires a careful consideration and a multidisciplinary approach.

Umbilical cord mesenchymal stem cells transplantation in patients with systemic sclerosis: a 5-year follow-up study

OBJECTIVE

To assess the long-term safety and efficacy of umbilical cord mesenchymal stem cells transplantation (UMSCT) in patients with systemic sclerosis (SSc).

METHODS

Forty-one patients with moderate to severe SSc underwent UMSCT at the Affiliated Drum Tower Hospital of Nanjing University Medical School from 2009 to 2017. In this study, we conducted a longitudinal and retrospective analysis and compared the clinical and laboratory manifestations before and after UMSCT. The main outcome of the study was overall survival. We evaluated changes in the modified Rodnan Skin Score (mRSS), as well as the changes in the pulmonary examination by using high-resolution computed tomography (HRCT) and ultrasound cardiogram (UCG). Additionally, we assessed the Health Assessment Questionnaire-Disability Index (HAQ-DI) and the severity of peripheral vascular involvement during the first year after treatment.

RESULTS

The overall 5-year survival rate was 92.7% (38 out of 41 patients). Following UMSCT, the mean mRSS significantly decreased from 18.68 (SD = 7.26, n = 41) at baseline to 13.95 (SD = 8.49, n = 41), 13.29 (SD = 7.67, n = 38), and 12.39 (SD = 8.49, n = 38) at 1, 3, and 5 years, respectively. Improvement or stability in HRCT images was observed in 72.0% of interstitial lung disease (ILD) patients. Pulmonary arterial hypertension (PAH) remained stable in 5 out of 8 patients at the 5-year follow-up. No adverse events related to UMSCT were observed in any of the patients during the follow-up period.

CONCLUSION

UMSCT may provide a safe and feasible treatment option for patients with moderate to severe SSc based on long-term follow-up data. The randomized controlled study will further confirm the clinical efficacy of UMSCT in SSc.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00962923. Key Point • UMSCT is safe and effective for SSc patients.

French protocol for the diagnosis and management of hematopoietic stem cell transplantation in autoimmune diseases

Hematopoietic stem cell transplantation (HSCT) for severe ADs was developed over the past 25years and is now validated by national and international medical societies for severe early systemic sclerosis (SSc) and relapsing-remitting multiple sclerosis (MS) and available as part of routine care in accredited center. HSCT is also recommended, with varying levels of evidence, as an alternative treatment for several ADs, when refractory to conventional therapy, including specific cases of connective tissue diseases or vasculitis, inflammatory neurological diseases, and more rarely severe refractory Crohn's disease. The aim of this document was to provide guidelines for the current indications, procedures and follow-up of HSCT in ADs. Patient safety considerations are central to guidance on patient selection and conditioning, always validated at the national MATHEC multidisciplinary team meeting (MDTM) based on recent (less than 3months) thorough patient evaluation. HSCT procedural aspects and follow-up are then carried out within appropriately experienced and Joint Accreditation Committee of International Society for Cellular Therapy and SFGM-TC accredited centres in close collaboration with the ADs specialist. These French recommendations were performed according to HAS/FAI2R standard operating procedures and coordinated by the Île-de-France MATHEC Reference Centre for Rare Systemic Autoimmune Diseases (CRMR MATHEC) within the Filière FAI2R and in association with the Filière MaRIH. The task force consisted of 3 patients and 64 clinical experts from various specialties and French centres. These data-derived and consensus-derived recommendations will help clinicians to propose HSCT for their severe ADs patients in an evidence-based way. These recommendations also give directions for future clinical research in this area. These recommendations will be updated according to newly emerging data. Of note, other cell therapies that have not yet been approved for clinical practice or are the subject of ongoing clinical research will not be addressed in this document.

Large-scale deep learning analysis to identify adult patients at risk for combined and common variable immunodeficiencies

BACKGROUND

Primary immunodeficiency (PI) is a group of heterogeneous disorders resulting from immune system defects. Over 70% of PI is undiagnosed, leading to increased mortality, co-morbidity and healthcare costs. Among PI disorders, combined immunodeficiencies (CID) are characterized by complex immune defects. Common variable immunodeficiency (CVID) is among the most common types of PI. In light of available treatments, it is critical to identify adult patients at risk for CID and CVID, before the development of serious morbidity and mortality.

METHODS

We developed a deep learning-based method (named "TabMLPNet") to analyze clinical history from nationally representative medical claims from electronic health records (Optum® data, covering all US), evaluated in the setting of identifying CID/CVID in adults. Further, we revealed the most important CID/CVID-associated antecedent phenotype combinations. Four large cohorts were generated: a total of 47,660 PI cases and (1:1 matched) controls.

RESULTS

The sensitivity/specificity of TabMLPNet modeling ranges from 0.82-0.88/0.82-0.85 across cohorts. Distinctive combinations of antecedent phenotypes associated with CID/CVID are identified, consisting of respiratory infections/conditions, genetic anomalies, cardiac defects, autoimmune diseases, blood disorders and malignancies, which can possibly be useful to systematize the identification of CID and CVID.

CONCLUSIONS

We demonstrated an accurate method in terms of CID and CVID detection evaluated on large-scale medical claims data. Our predictive scheme can potentially lead to the development of new clinical insights and expanded guidelines for identification of adult patients at risk for CID and CVID as well as be used to improve patient outcomes on population level.

Should autologous hematopoietic stem cell transplantation be offered as a first-line disease modifying therapy to patients with multiple sclerosis?

In multiple sclerosis (MS), progression independent of new focal inflammation may commence shortly after disease onset, and it is increasingly revealed that the risk of disability accrual is reduced by early use of high-efficacy disease-modifying therapies (HE-DMTs). People with aggressive MS may therefore benefit from early treatment with autologous haematopoietic stem cell transplantation (AHSCT), a procedure inducing maximal immunosuppression followed by immune reconstitution, demonstrated to be superior to DMTs in one randomized clinical trial. However, in current practice prior failure to HE-DMTs is typically required to establish the indication for AHSCT. In the present article, the available evidence on the potential role of AHSCT as first-line treatment in aggressive MS and the rationale for its early use will be summarized. Proposed definitions of aggressive MS that could help identifying MS patients eligible for early treatment with AHSCT will also be discussed.

Autologous haematopoietic stem cell transplantation for multiple sclerosis: a position paper and registry outline

Background

While substantial progress has been made in the development of disease-modifying medications for multiple sclerosis (MS), a high percentage of treated patients still show progression and persistent inflammatory activity. Autologous haematopoietic stem cell transplantation (AHSCT) aims at eliminating a pathogenic immune repertoire through intense short-term immunosuppression that enables subsequent regeneration of a new and healthy immune system to re-establish immune tolerance for a long period of time. A number of mostly open-label, uncontrolled studies conducted over the past 20 years collected about 4000 cases. They uniformly reported high efficacy of AHSCT in controlling MS inflammatory disease activity, more markedly beneficial in relapsing-remitting MS. Immunological studies provided evidence for qualitative immune resetting following AHSCT. These data and improved safety profiles of transplantation procedures spurred interest in using AHSCT as a treatment option for MS.

Objective

To develop expert consensus recommendations on AHSCT in Germany and outline a registry study project.

Methods

An open call among MS neurologists as well as among experts in stem cell transplantation in Germany started in December 2021 to join a series of virtual meetings.

Results

We provide a consensus-based opinion paper authored by 25 experts on the up-to-date optimal use of AHSCT in managing MS based on the Swiss criteria. Current data indicate that patients who are most likely to benefit from AHSCT have relapsing-remitting MS and are young, ambulatory and have high disease activity. Treatment data with AHSCT will be collected within the German REgistry Cohort of autologous haematopoietic stem CeLl trAnsplantation In MS (RECLAIM).

Conclusion

Further clinical trials, including registry-based analyses, are urgently needed to better define the patient characteristics, efficacy and safety profile of AHSCT compared with other high-efficacy therapies and to optimally position it as a treatment option in different MS disease stages.

Automating outcome analysis after stem cell transplantation: The YORT tool

Hematopoietic stem cell transplantation is a high-risk procedure. Auditing and yearly outcome reviews help keep optimal quality of care and come with increased survival, but also has significant recurring costs. When data has been entered in a standardized registry, outcome analyses can be automated, which reduces work and increases standardization of performed analyses. To achieve this, we created the Yearly Outcome Review Tool (YORT), an offline, graphical tool that gets data from a single center EBMT registry export, allows the user to define filters and groups, and performs standardized analyses for overall survival, event-free survival, engraftment, relapse rate and non-relapse mortality, complications including acute and chronic Graft vs Host Disease (GvHD), and data completeness. YORT allows users to export data as analyzed to allow you to check data and perform manual analyses. We show the use of this tool on a two-year single-center pediatric cohort, demonstrating how the results for both overall and event-free survival and engraftment can be visualized. The current work demonstrates that using registry data, standardized tools can be made to analyze this data, which allows users to perform outcome reviews for local and accreditation purposes graphically with minimal effort, and help perform detailed standardized analyses. The tool is extensible to be able to accommodate future changes in outcome review and center-specific extensions.

Hematopoietic Stem Cell: Regulation and Nutritional Intervention

Hematopoietic stem cells (HSCs) are crucial for the life maintenance of bio-organisms. However, the mechanism of HSC regulation is intricate. Studies have shown that there are various factors, either intrinsically or extrinsically, that shape the profile of HSCs. This review systematically summarizes the intrinsic factors (i.e., RNA-binding protein, modulators in epigenetics and enhancer-promotor-mediated transcription) that are reported to play a pivotal role in the function of HSCs, therapies for bone marrow transplantation, and the relationship between HSCs and autoimmune diseases. It also demonstrates the current studies on the effects of high-fat diets and nutrients (i.e., vitamins, amino acids, probiotics and prebiotics) on regulating HSCs, providing a deep insight into the future HSC research.

Improving outcomes in scleroderma: recent progress of cell-based therapies

Scleroderma is a rare, potentially fatal, clinically heterogeneous, systemic autoimmune connective tissue disorder that is characterized by progressive fibrosis of the skin and visceral organs, vasculopathy and immune dysregulation. The more severe form of the disease, diffuse cutaneous scleroderma (dcSSc), has no cure and limited treatment options. Haematopoietic stem cell transplantation has emerged as a potentially disease-modifying treatment but faces challenges such as toxicity associated with fully myeloablative conditioning and recurrence of autoimmunity. Novel cell therapies-such as mesenchymal stem cells, chimeric antigen receptor-based therapy, tolerogenic dendritic cells and facilitating cells-that may restore self-tolerance with more favourable safety and tolerability profiles are being explored for the treatment of dcSSc and other autoimmune diseases. This narrative review examines these evolving cell therapies.

Correction of T-Cell Repertoire and Autoimmune Diabetes in NOD Mice by Non-myeloablative T-Cell Depleted Allogeneic HSCT

The induction of partial tolerance toward pancreatic autoantigens in the treatment of type 1 diabetes mellitus (T1DM) can be attained by autologous hematopoietic stem cell transplantation (HSCT). However, most patients treated by autologous HSCT eventually relapse. Furthermore, allogeneic HSCT which could potentially provide a durable non-autoimmune T-cell receptor (TCR) repertoire is associated with a substantial risk for transplant-related mortality. We have previously demonstrated an effective approach for attaining engraftment without graft versus host disease (GVHD) of allogeneic T-cell depleted HSCT, following non-myeloablative conditioning, using donor-derived anti-3rd party central memory CD8 veto T cells (Tcm). In the present study, we investigated the ability of this relatively safe transplant modality to eliminate autoimmune T-cell clones in the NOD mouse model which spontaneously develop T1DM. Our results demonstrate that using this approach, marked durable chimerism is attained, without any transplant-related mortality, and with a very high rate of diabetes prevention. TCR sequencing of transplanted mice showed profound changes in the T-cell repertoire and decrease in the prevalence of specific autoimmune T-cell clones directed against pancreatic antigens. This approach could be considered as strategy to treat people destined to develop T1DM but with residual beta cell function, or as a platform for prevention of beta cell destruction after transplantation of allogenic beta cells.

Benefits and risks of haematopoietic stem cell transplantation for systemic sclerosis: A systematic review and meta-analysis

OBJECTIVES

We aimed to evaluate the efficacy and safety of haematopoietic stem cell transplantation (HSCT) in patients with systemic sclerosis.

METHODS

A systematic literature review and meta-analysis were carried out. We compared survival outcomes using the Kaplan-Meier method with patient-level data between HSCT and intravenous pulse cyclophosphamide. Additionally, the incidence rate of treatment-related deaths with HSCT was pooled using a random-effect model.

RESULTS

Of the 2091 articles screened, 22 were included: 3 randomized controlled trials and 19 observational studies. HSCT studies showed significant improvement in the skin thickness score and lung function. Despite treatment-related deaths being higher in HSCT than in intravenous pulse cyclophosphamide, the Kaplan-Meier analysis showed a high survival rate of 2 years post-transplant (log-rank, P = 0.004). The pooled frequency of transplant-related death from 700 systemic sclerosis patients was 6.30% (95% confidence interval 4.21-8.38). However, the estimated frequency of treatment-related deaths has been reducing over the last decade.

CONCLUSIONS

HSCT is an effective treatment for systemic sclerosis, but the optimal indications must be carefully determined by balancing the risks.

Hematopoietic Stem Cell Transplantation for the Treatment of Autoimmune Neurological Diseases: An Update

Over the last two decades, haematopoietic stem cell transplantation (HSCT) has been explored as a potential therapeutic strategy for autoimmune diseases refractory to conventional treatments, including neurological disorders. Although both autologous (AHSCT) and allogeneic HSCT (allo-HSCT) were investigated, AHSCT was preferentially developed due to a more favourable safety profile compared to allo-HSCT. Multiple sclerosis (MS) represents the most frequent neurological indication for AHSCT, but increasing evidence on the potential effectiveness of transplant in other autoimmune neurological diseases is emerging, although with a risk-benefit ratio overall more uncertain than in MS. In the present work, the rationale for the use of HSCT in neurological diseases and the experimental models that prompted its clinical application will be briefly covered. Case series and prospective studies exploring the use of HSCT in autoimmune diseases other than MS will be discussed, covering both frequent and rare neurological disorders such as myasthenia gravis, myopathies, and stiff-person syndrome. Finally, an updated summary of ongoing and future studies focusing on this issue will be provided.

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.

Biomarkers of demyelination and axonal damage are decreased after autologous hematopoietic stem cell transplantation for multiple sclerosis

BACKGROUND

Autologous hematopoietic stem cell transplantation (aHSCT) has seen increased use for relapsing-remitting multiple sclerosis (RRMS) in recent years. It is considered one of the most effective treatments for RRMS and has been associated with improvement in disability and prolonged remission. This suggests that the tissue-injuring disease process may have been altered by aHSCT. To assess whether this hypothesis is correct, we performed a study of three commonly used cerebrospinal fluid biomarkers of tissue damage.

METHODS

In this single center study, 63 patients treated with aHSCT at Uppsala University Hospital between January 1st 2012 and January 31st 2019 were screened for participation. A control group consisting of volunteers without neurologic disease were included as a reference. Cerebrospinal fluid concentrations of neurofilament light (NFL), myelin basic protein (MBP) and glial acidic fibrillary protein (GFAp) were determined using ELISA and a multiplex proteomics platform from Meso Scale Discovery.

RESULTS

Forty-three patients with a mean age of 31 and a median follow-up time of 3.9 years were included. Their median baseline expanded disability status scale (EDSS) score was 3.5 and the annualized relapse rate in the year preceding aHSCT was 1.6. At baseline the proportion of patients with values above the upper limit of normal was 67% for NFL, 63% for MBP and 16% for GFAp. At 5-year follow-up, the proportion of patients with values above the upper limit of normal was 12% for NFL, 12% for MBP and 25% for GFAp. The mean concentration of NFL decreased from 920 pg/mL at baseline to 270 pg/mL at 5-year follow-up (p < 0.001); MBP decreased from 1500 to 680 pg/mL (p < 0.001); whereas the mean concentration of GFAp was unchanged.

CONCLUSION

In a majority of patients, biomarkers of demyelination and axonal damage reached normal values within five years from treatment with aHSCT.

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

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

Stem Cell Therapy in Neuroimmunological Diseases and Its Potential Neuroimmunological Complications

Background: Since the 1990s, transplantations of hematopoietic and mesenchymal stem cells (HSCT and MSCT) and dendritic cell (DCT) have been investigated for the treatment of neurological autoimmune disorders (NADs). With the growing number of transplanted patients, awareness of neuroimmunolgical complications has increased. Therefore, an overview of SCT for the most common NADs and reports of secondary immunity after SCT is provided. Methods: For this narrative review, a literature search of the PubMed database was performed. A total of 86 articles reporting on different SCTs in NADs and 61 articles dealing with immune-mediated neurological complications after SCT were included. For multiple sclerosis (MS), only registered trials and phase I/II or II studies were considered, whereas all available articles on other disorders were included. The different transplantation procedures and efficacy and safety data are presented. Results: In MS patients, beneficial effects of HSCT, MSCT, and DCT with a decrease in disability and stabilization of disease activity have been reported. These effects were also shown in other NADs mainly in case reports. In seven of 132 reported patients with immune-mediated neurological complications, the outcome was fatal. Conclusions: Phase III trials are ongoing for MS, but the role of SCT in other NADs is currently limited to refractory patients due to occasional serious complications.

Non-Responsive and Refractory Coeliac Disease: Experience from the NHS England National Centre

We characterised the aetiology of non-responsive coeliac disease (NRCD) and provided contemporary mortality data in refractory coeliac disease (RCD) from our centre. We also measured urine gluten immunogenic peptides (GIPs) in patients with established RCD1 to evaluate gluten exposure in these individuals. Methods: This was a longitudinal cohort study conducted in Sheffield, UK. Between 1998 and 2019, we evaluated 285 adult (≥16 years) patients with NRCD or RCD. Patients with established RCD1 and persisting mucosal inflammation and/or ongoing symptoms provided three urine samples for GIP analysis. Results: The most common cause of NRCD across the cohort was gluten exposure (72/285; 25.3%). RCD accounted for 65/285 patients (22.8%), 54/65 patients (83.1%) had RCD1 and 11/65 patients (16.9%) had RCD2. The estimated 5-year survival was 90% for RCD1 and 58% for RCD2 (p = 0.016). A total of 36/54 (66.7%) patients with RCD1 underwent urinary GIP testing and 17/36 (47.2%) had at least one positive urinary GIP test. Conclusion: The contemporary mortality data in RCD2 remains poor; patients with suspected RCD2 should be referred to a recognised national centre for consideration of novel therapies. The high frequency of urinary GIP positivity suggests that gluten exposure may be common in RCD1; further studies with matched controls are warranted to assess this further.

Haematopoietic stem cell transplantation for severe autoimmune diseases in children: A review of current literature, registry activity and future directions on behalf of the autoimmune diseases and paediatric diseases working parties of the European Society for Blood and Marrow Transplantation

Although modern clinical management strategies have improved the outcome of paediatric patients with severe autoimmune and inflammatory diseases over recent decades, a proportion will experience ongoing or recurrent/relapsing disease activity despite multiple therapies often leading to irreversible organ damage, and compromised quality of life, growth/development and long-term survival. Autologous and allogeneic haematopoietic stem cell transplantation (HSCT) have been used successfully to induce disease control and often apparent cure of severe treatment-refractory autoimmune diseases (ADs) in children. However, transplant-related outcomes are disease-dependent and long-term outcome data are limited in respect to efficacy and safety. Moreover, balancing risks of HSCT against AD prognosis with continually evolving non-transplant options is challenging. This review appraises published literature on HSCT strategies and outcomes in individual paediatric ADs. We also provide a summary of the European Society for Blood and Marrow Transplantation (EBMT) Registry, where 343 HSCT procedures (176 autologous and 167 allogeneic) have been reported in 326 children (<18 years) for a range of AD indications. HSCT is a promising treatment modality, with potential long-term disease control or cure, but therapy-related morbidity and mortality need to be reduced. Further research is warranted to establish the position of HSCT in paediatric ADs via registries and prospective clinical studies to support evidence-based interspeciality guidelines and recommendations.

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).

Autologous Hematopoietic Stem Cell Transplantation for Multiple Sclerosis, the Ottawa Protocol

Autologous hematopoietic stem cell transplantation (aHSCT) is increasingly used to treat patients with highly active multiple sclerosis (MS) refractory to disease-modifying therapy. Briefly, cyclophosphamide and filgrastim are used to mobilize autologous hematopoietic stem cells (HSC) into the circulation. HSC are harvested by leukapheresis, purified using a CD34 immunomagnetic selection process, and cryopreserved. Busulphan, cyclophosphamide, and rabbit anti-thymocyte globulin are used to destroy the patient's autoreactive immune system, followed by infusion of the previously collected HSC, which reconstitute a naïve and self-tolerant immune system. Many MS patients experience durable remissions with no evidence of new disease activity following aHSCT. Treatment-related toxicity is rare, but potentially life-threatening complications necessitate appropriate patient selection by MS neurologists and HSCT physicians. AHSCT must be performed with a highly trained multidisciplinary team expert to minimize morbidity and mortality. We present the current aHSCT procedure for an MS indication at The Ottawa Hospital, developed from our program's 20-year experience. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Candidate selection Basic Protocol 2: Autologous hematopoietic stem cell mobilization, collection, purification, and cryopreservation Basic Protocol 3: Autologous hematopoietic stem cell transplantation Basic Protocol 4: Supportive care following recovery from aHSCT (Beyond 100 days) Basic Protocol 5: Ongoing evaluation of multiple sclerosis.

Hematopoietic stem cell transplantation and cellular therapies for autoimmune diseases: overview and future considerations from the Autoimmune Diseases Working Party (ADWP) of the European Society for Blood and Marrow Transplantation (EBMT)

Autoimmune diseases (ADs) represent a heterogenous group of complex diseases with increasing incidence in Western countries and are a major cause of morbidity. Hematopoietic stem cell transplantation (HSCT) has evolved over the last 25 years as a specific treatment for patients with severe ADs, through eradication of the pathogenic immunologic memory and profound immune renewal. HSCT for ADs is recently facing a unique developmental phase across transplant centers. This review provides a comprehensive overview of the recent evidence and developments in the area, including fundamentals of preclinical research, clinical studies in neurologic, rheumatologic and gastroenterologic diseases, which represent major indications at present, along with evidence of HSCT for rarer indications. Moreover, we describe the interwoven challenges of delivering more advanced cellular therapies, exploiting mesenchymal stem cells, regulatory T cells and potentially CAR-T cell therapies, in patients affected by ADs. Overall, we discuss past and current indications, efficacy, associated risks and benefits, and future directions of HSCT and advanced cellular therapies in the treatment of severe/refractory ADs, integrating the available literature with European Society for Blood and Marrow Transplantation (EBMT) registry data.

Autoimmune disorders associated with myelodysplastic syndromes: clinical, prognostic and therapeutic implications

Around one third of patients with myelodysplastic syndromes (MDS) suffer from concomitant autoimmune disorders (AD). However the actual burden of such an association appears to be quite heterogeneous in different studies probably due to variable criteria in selecting both MDS patients and subtypes of AD. Moreover, both the prognostic implications and the potential applications of specific therapeutic approaches in this patient subgroup are still at least partially under debate. The present review will try to shed some further light on the clinical association between MDS and AD in order to better delineate its prognostic significance and to suggest potential therapeutic algorithms available for these patients.

One and a half million hematopoietic stem cell transplants: continuous and differential improvement in worldwide access with the use of non-identical family donors

The Worldwide Network of Blood and Marrow Transplantation (WBMT) pursues the mission of promoting hematopoietic cell transplantation (HCT) for instance by evaluating activities through member societies, national registries and individual centers. In 2016, 82,718 first HCT were reported by 1,662 HCT teams in 86 of the 195 World Health Organization member states representing a global increase of 6.2% in autologous HCT and 7.0% in allogeneic HCT and bringing the total to 1,298,897 procedures. Assuming a frequency of 84,000/year, 1.5 million HCT were performed by 2019 since 1957. Slightly more autologous (53.5%) than allogeneic and more related (53.6%) than unrelated HCT were reported. A remarkable increase was noted in haploidentical related HCT for leukemias and lymphoproliferative diseases, but even more in non-malignant diseases. Transplant rates (TR; HCT/10 million population) varied according to region reaching 560.8 in North America, 438.5 in Europe, 76.7 in Latin America, 53.6 in South East Asia/Western Pacific (SEA/WPR) and 27.8 in African/East Mediterranean (AFR/EMR). Interestingly, haploidentical TR amounted to 32% in SEA/WPR and 26% in Latin America, but only 14% in Europe and EMR and 4.9% in North America of all allogeneic HCT. HCT team density (teams/10 million population) was highest in Europe (7.7) followed by North America (6.0), SEA/WPR (1.9), Latin America (1.6) and AFR/EMR (0.4). HCT are increasing steadily worldwide with narrowing gaps between regions and greater increase in allogeneic compared to autologous activity. While related HCT is rising, largely due to increase in haploidentical HCT, unrelated HCT is plateauing and cord blood HCT is in decline.

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.

Immune Reconstitution Following Autologous Hematopoietic Stem Cell Transplantation for Multiple Sclerosis: A Review on Behalf of the EBMT Autoimmune Diseases Working Party

Multiple sclerosis (MS) is a central nervous system (CNS) disorder, which is mediated by an abnormal immune response coordinated by T and B cells resulting in areas of inflammation, demyelination, and axonal loss. Disease-modifying treatments (DMTs) are available to dampen the inflammatory aggression but are ineffective in many patients. Autologous hematopoietic stem cell transplantation (HSCT) has been used as treatment in patients with a highly active disease, achieving a long-term clinical remission in most. The rationale of the intervention is to eradicate inflammatory autoreactive cells with lympho-ablative regimens and restore immune tolerance. Immunological studies have demonstrated that autologous HSCT induces a renewal of TCR repertoires, resurgence of immune regulatory cells, and depletion of proinflammatory T cell subsets, suggesting a "resetting" of immunological memory. Although our understanding of the clinical and immunological effects of autologous HSCT has progressed, further work is required to characterize the mechanisms that underlie treatment efficacy. Considering that memory B cells are disease-promoting and stem-like T cells are multipotent progenitors involved in self-regeneration of central and effector memory cells, investigating the reconstitution of B cell compartment and stem and effector subsets of immunological memory following autologous HSCT could elucidate those mechanisms. Since all subjects need to be optimally protected from vaccine-preventable diseases (including COVID-19), there is a need to ensure that vaccination in subjects undergoing HSCT is effective and safe. Additionally, the study of vaccination in HSCT-treated subjects as a means of evaluating immune responses could further distinguish broad immunosuppression from immune resetting.

Autologous Hematopoietic Stem Cell Transplantation in Multiple Sclerosis Patients: Monocentric Case Series and Systematic Review of the Literature

Multiple sclerosis (MS) is a chronic, inflammatory and immune-mediated disease of the central nervous system (CNS), commonly affecting young adults and potentially associated with life-long disability. About 14 disease-modifying treatments (DMTs) are currently approved for the treatment of MS. However, despite the use of highly effective therapies, some patients exhibit a highly active disease with an aggressive course from onset and a higher risk of long-term disability accrual. In the last few years, several retrospective studies, clinical trials, meta-analyses and systematic reviews have investigated autologous hematopoietic stem cell transplantation (AHSCT) as a possible therapeutic option in order to address this unmet clinical need. These studies demonstrated that AHSCT is a highly efficacious and relatively safe therapeutic option for the treatment of highly active MS. Particularly, over recent years, the amount of evidence has grown, with significant improvements in the development of patient selection criteria, choice of the most suitable transplant technique and clinical experience. In this paper, we present six patients who received AHSCT in our MS center and we systematically reviewed recent evidence about the long-term efficacy and safety of AHSCT and the placement of AHSCT in the rapidly evolving therapeutic armamentarium for MS.

Haematopoietic Stem Cell Transplantation Results in Extensive Remodelling of the Clonal T Cell Repertoire in Multiple Sclerosis

Autologous haematopoietic stem cell transplantation (AHSCT) is a vital therapeutic option for patients with highly active multiple sclerosis (MS). Rates of remission suggest AHSCT is the most effective form of immunotherapy in controlling the disease. Despite an evolving understanding of the biology of immune reconstitution following AHSCT, the mechanism by which AHSCT enables sustained disease remission beyond the period of lymphopenia remains to be elucidated. Auto-reactive T cells are considered central to MS pathogenesis. Here, we analyse T cell reconstitution for 36 months following AHSCT in a cohort of highly active MS patients. Through longitudinal analysis of sorted naïve and memory T cell clones, we establish that AHSCT induces profound changes in the dominant T cell landscape of both CD4+ and CD8+ memory T cell clones. Lymphopenia induced homeostatic proliferation is followed by clonal attrition; with only 19% of dominant CD4 (p <0.025) and 13% of dominant CD8 (p <0.005) clones from the pre-transplant repertoire detected at 36 months. Recovery of a thymically-derived CD4 naïve T cell repertoire occurs at 12 months and is ongoing at 36 months, however diversity of the naïve populations is not increased from baseline suggesting the principal mechanism of durable remission from MS after AHSCT relates to depletion of putative auto-reactive clones. In a cohort of MS patients expressing the MS risk allele HLA DRB1*15:01, public clones are probed as potential biomarkers of disease. AHSCT appears to induce sustained periods of disease remission with dynamic changes in the clonal T cell repertoire out to 36 months post-transplant.

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.

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.

Combining systemic and locally applied cellular therapies for the treatment of systemic sclerosis

Systemic sclerosis (SSc) is a complex autoimmune disease characterized by a functional and structural alteration of the microvascular network associated with cutaneous and visceral fibrosis lesions. Conventional therapies are based on the use of immunomodulatory molecules and symptomatic management but often prove to be insufficient, particularly for patients suffering from severe and rapidly progressive forms of the disease. In this context, cellular therapy approaches could represent a credible solution with the goal to act on the different components of the disease: the immune system, the vascular system and the extracellular matrix. The purpose of this review is to provide an overview of the cellular therapies available for the management of SSc. The first part will focus on systemically injected therapies, whose primary effect is based on immunomodulatory properties and immune system resetting, including autologous hematopoietic stem cell transplantation and intravenous injection of mesenchymal stem cells. The second part will discuss locally administered regenerative cell therapies, mainly derived from adipose tissue, developed for the management of local complications as hand and face disabilities.

Management of Endothelial Dysfunction in Systemic Sclerosis: Current and Developing Strategies

Systemic Sclerosis (SSc) is an autoimmune disease marked by dysregulation of the immune system, tissue fibrosis and dysfunction of the vasculature. Vascular damage, remodeling and inadequate endothelial repair are hallmarks of the disease. Since early stages of SSc, damage and apoptosis of endothelial cells (ECs) can lead to perivascular inflammation, oxidative stress and tissue hypoxia, resulting in multiple clinical manifestations. Raynaud's phenomenon, edematous puffy hands, digital ulcers, pulmonary artery hypertension, erectile dysfunction, scleroderma renal crisis and heart involvement severely affect quality of life and survival. Understanding pathogenic aspects and biomarkers that reflect endothelial damage in SSc is essential to guide therapeutic interventions. Treatment approaches described for SSc-associated vasculopathy include pharmacological options to improve blood flow and tissue perfusion and, more recently, cellular therapy to enhance endothelial repair, promote angiogenesis and heal injuries. This mini-review examines the current knowledge on cellular and molecular aspects of SSc vasculopathy, as well as established and developing therapeutic approaches for improving the vascular compartment.

Identification of the minimum requirements for successful haematopoietic stem cell transplantation

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

Remission is not maintained over 2 years with hematopoietic stem cell transplantation for rheumatoid arthritis: A systematic review with meta-analysis

BACKGROUND

Hematopoietic stem cell (HSC) transplantation (HSCT) is being accepted as a standard of care in various inflammatory diseases. The treatment of rheumatoid arthritis (RA) has been closely evolving with the understanding of disease pathogenesis. With the rising resistance to the traditional disease-modifying anti-rheumatic drugs and targeted biological therapy, researchers are in pursuit of other methods for disease management. Since the ultimate goal of the ideal treatment of RA is to restore immune tolerance, HSCT attracts much attention considering its reparative, paracrine, and anti-inflammatory effects. However, a systematic review of studies on HSCT in RA is lacking.

AIM

To investigate the role of HSCT in the management of RA.

METHODS

A detailed search of PubMed, Scopus, EMBASE, Cochrane, and the Web of Science databases was made to identify the relevant articles till September 2020 following Cochrane and PRISMA guidelines. We extracted data including the number of patients, source of hematopoietic stem cells, their mobilization and conditioning regimens, results, and complications from the eligible studies. Results were dichotomized into success (ACR 50/70) and failure (ACR 20) based on the improvement from baseline characteristics. The methodological quality of the included studies was also assessed. Analysis was performed using OpenMeta[Analysis] software.

RESULTS

We included 17 studies (1 randomized controlled trial, 11 prospective, and 5 retrospective studies) with 233 patients for analysis. HSCT provided a significantly beneficial overall improvement in the clinical grades of ACR criteria (Z = 11.309, P < 0.001). However, the remission was noted only till 24 mo and later on the significance of the result was lost (Z = 1.737, P = 0.082). A less than 1% treatment-related mortality was noted from the included studies. No major drug-related toxicities were noted in any of the included studies. All patients who underwent allogeneic HSCT received immunosuppression in the conditioning regimen to counteract the graft-vs-host reaction which made them vulnerable to infections. It is noted that the source of hematopoietic stem cells did not play a role in altering the functional outcome and both autologous (Z = 9.972, P < 0.001) and allogenic (Z = 6.978, P < 0.001) sources produced significant improvement in the outcome compared to the pre-operative state despite having a significant heterogeneity among the studies reporting them (I² = 99.4, P < 0.001).

CONCLUSION

Although the available literature is encouraging towards the use of HSCT in refractory cases with significant improvement from baseline till 2 years, the inclusion of HSCT into the standard of care of RA needs further exploration.

Life after Autologous Hematopoietic Stem Cell Transplantation for Systemic Sclerosis

Stem cell transplantation has been investigated as treatment for severe and progressive systemic sclerosis (SSc) for the past 25 years. To date, more than 1000 SSc patients have been transplanted worldwide. Overall and event-free survival have increased over the years, reflecting stricter patient selection criteria and better clinical management strategies. This review addresses long-term outcomes of transplanted SSc patients, considering phase I/II and randomized clinical trials, as well as observational studies and those assessing specific aspects of the disease. Clinical outcomes are discussed comparatively between studies, highlighting advances, drawbacks and controversies in the field. Areas for future development are also discussed.

Intestinal Microbiome in Hematopoietic Stem Cell Transplantation For Autoimmune Diseases: Considerations and Perspectives on Behalf of Autoimmune Diseases Working Party (ADWP) of the EBMT

Over the past decades, hematopoietic stem cell transplantation (HSCT) has been evolving as specific treatment for patients with severe and refractory autoimmune diseases (ADs), where mechanistic studies have provided evidence for a profound immune renewal facilitating the observed beneficial responses. The intestinal microbiome plays an important role in host physiology including shaping the immune repertoire. The relationships between intestinal microbiota composition and outcomes after HSCT for hematologic diseases have been identified, particularly for predicting the mortality from infectious and non-infectious causes. Furthermore, therapeutic manipulations of the gut microbiota, such as fecal microbiota transplant (FMT), have emerged as promising therapeutic approaches for restoring the functional and anatomical integrity of the intestinal microbiota post-transplantation. Although changes in the intestinal microbiome have been linked to various ADs, studies investigating the effect of intestinal dysbiosis on HSCT outcomes for ADs are scarce and require further attention. Herein, we describe some of the landmark microbiome studies in HSCT recipients and patients with chronic ADs, and discuss the challenges and opportunities of microbiome research for diagnostic and therapeutic purposes in the context of HSCT for ADs.

Real-world application of autologous hematopoietic stem cell transplantation in 507 patients with multiple sclerosis

Objective

To investigate the results of real-world application of non-myeloablative autologous HSCT for multiple sclerosis (MS).

Methods

Between July 2003 and October 2019 at a single center (Northwestern University), 414 patients with relapsing remitting MS (RRMS) and 93 patients with newly diagnosed secondary progressive MS (SPMS) underwent non-myeloablative HSCT.

Results

There was one treatment-related death (0.19%) due to hospital-acquired legionella pneumonia, and one patient developed neutropenic bacteremia (Klebsiella pneumonia) without sepsis. Overall 5-year survival was 98.8%. Post HSCT secondary autoimmune diseases (2nd ADs) were idiopathic thrombocytopenia (ITP) and hypo or hyperthyroidism. ITP was highest with alemtuzumab (14%) and 0 to 2.8% for the non-alemtuzumab regimens. After HSCT, 16 patients developed hypothyroidism (3.5%) and 15 developed hyperthyroidism / Grave’s disease (3.3%). Relapse free survival (RFS) at 5 years for RRMS and SPMS was 80.1% and 98.1%, respectively, while progression free survival (PFS) at 4 years for RRMS and SPMS was 95% versus 66%, respectively. For patients with RRMS, the EDSS significantly improved (p < 0.0001) at each follow-up from a pre-HSCT mean of 3.87 to 2.51, 2.50, 2.41, 2.33, and 2.19 at 1, 2, 3, 4, and 5 years, respectively. For SPMS, the EDSS improved significantly only at 1 year but not thereafter. For SPMS, the mean baseline EDSS of 5.09 changed post-HSCT to 4.85 (p = 0.04), 4.88 (p = 0.2), 4.92 (p = .27), 4.72 (p = 0.07), and 4.2 (p = 0.21) at 1, 2, 3, 4, 5 years, respectively.

Conclusion

In patients with RRMS, autologous non-myeloablative HSCT is an effective one-time therapy, while HSCT appears of less benefit for newly diagnosed SPMS.

Management of diffuse alveolar hemorrhage in the hematopoietic stem cell transplantation population: A systematic review

Pulmonary complications post-hematopoietic stem cell transplantation (HSCT) such as diffuse alveolar hemorrhage (DAH) can occur in 2% to 14% of HSCT patients and have a mortality greater than 80%. Diffuse alveolar hemorrhage is considered to be an inflammatory response; therefore, HSCT patients are primarily treated with different types of systemic corticosteroids with varying dosages. Other treatments currently reported in the literature in conjunction with corticosteroids include aminocaproic acid, recombinant factor VIIa (rFVIIa), and etanercept. This review highlights appropriate frontline and adjunctive treatment options for HSCT patients with DAH and outcomes for each intervention. To perform the review, the PubMed database was searched from inception through March 19, 2021, to identify potential studies using the search terms DAH and HSCT, DAH and hematopoietic cell transplant (HCT), DAH and stem cell, lung injury and HSCT, and lung injury and HCT. When applicable, references from articles identified in the search were also reviewed for inclusion. Much of the data identified were limited to retrospective cohort studies and case series. Based on the data available, the treatment approach should consist of corticosteroid therapy with a suggested methylprednisolone dose of 250 mg daily followed by a 50% taper every 3 days. Intrapulmonary administration of rFVIIa and intravenous administration of aminocaproic acid could be considered as adjunctive agents in those patients who do not promptly respond to corticosteroid therapy. Due to a lack of data specific to HSCT patients who develop DAH and the risk of infectious complications, etanercept should be avoided. Future studies should be designed as randomized controlled trials and examine the use of adjunctive therapies in the upfront setting for HSCT patients with DAH.

Haematopoietic stem cell transplantation in paediatric rheumatic disease

PURPOSE OF REVIEW

A small proportion of children affected by rheumatic diseases suffer from severe, progressive disease, resistant to conventional antirheumatic therapies and to biologic agents interfering with inflammatory cytokines, costimulatory molecules expressed on immune system cells and intracellular signalling pathways. Adding to the poor prognosis is a high risk from significant morbidity and mortality associated with long-term treatment with multiple, often combined anti-inflammatory and immunosuppressive agents. Carefully selected patients from this unfortunate group may benefit from treatment with haematopoietic stem cell transplantation.

RECENT FINDINGS

The majority of patients with severe paediatric rheumatic and autoinflammatory diseases treated with autologous and/or allogeneic haematopoietic stem cell transplantation achieved long-term remission. However, the incidence of disease relapse and transplant related morbidity and mortality is still significant.

SUMMARY

Careful patient and donor selection, timing of the transplant earlier in the course of disease rather than the 'last resort' and choosing the most suitable conditioning regimen for each individual patient are the major factors favouring successful outcome. Close co-operation between the patients, their family, and involved medical teams is essential.

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.