Mesenchymal stromal cells for systemic sclerosis treatment

International audienceSystemic sclerosis (SSc) is a rare chronic autoimmune disease characterized by vasculopathy, dysregulation of innate and adaptive immune responses, and progressive fibrosis. SSc remains an orphan disease, with high morbity and mortality in SSc patients. The mesenchymal stromal cells (MSC) demonstrate in vitro and in vivo pro-angiogenic, immuno-suppressive, and anti-fibrotic properties and appear as a promising stem cell therapy type, that may target the key pathological features of SSc disease. This review aims to summarize acquired knowledge in the field of :1) MSC definition and in vitro and in vivo functional properties, which vary according to the donor type (allogeneic or autologous), the tissue sources (bone marrow, adipose tissue or umbilical cord) or inflammatory micro-environment in the recipient; 2) preclinical studies in various SSc animal models , which showed reduction in skin and lung fibrosis after MSC infusion; 3) first clinical trials in human, with safety and early efficacy results reported in SSc patients or currently tested in several ongoing clinical trials

Differentially expressed genes in systemic sclerosis: Towards predictive medicine with new molecular tools for clinicians

International audienceSystemic sclerosis (SSc) is a rare and chronic autoimmune disease characterized by a pathogenic triad of immune dysregulation, vasculopathy, and progressive fibrosis. Clinical tools commonly used to assess patients, including the modified Rodnan skin score, difference between limited or diffuse forms of skin involvement, presence of lung, heart or kidney involvement, or of various autoantibodies, are important prognostic factors, but still fail to reflect the large heterogeneity of the disease. SSc treatment options are diverse, ranging from conventional drugs to autologous hematopoietic stem cell transplantation, and predicting response is challenging. Genome-wide technologies, such as high throughput microarray analyses and RNA sequencing, allow accurate, unbiased, and broad assessment of alterations in expression levels of multiple genes. In recent years, many studies have shown robust changes in the gene expression profiles of SSc patients compared to healthy controls, mainly in skin tissues and peripheral blood cells. The objective analysis of molecular patterns in SSc is a powerful tool that can further classify SSc patients with similar clinical phenotypes and help predict response to therapy. In this review, we describe the journey from the first discovery of differentially expressed genes to the identification of enriched pathways and intrinsic subsets identified in SSc, using machine learning algorithms. Finally, we discuss the use of these new tools to predict the efficacy of various treatments, including stem cell transplantation. We suggest that the use of RNA gene expression-based classifications according to molecular subsets may bring us one step closer to precision medicine in Systemic Sclerosis

Non-Classical HLA Determinants of the Clinical Response after Autologous Stem Cell Transplantation for Systemic Sclerosis

International audienceSystemic Sclerosis (SSc) is a chronic autoimmune disease with high morbidity and mortality. Autologous Hematopoietic Stem Cell Transplantation (AHSCT) is the best therapeutic option for rapidly progressive SSc, allowing increased survival with regression of skin and lung fibrosis. The immune determinants of the clinical response after AHSCT have yet to be well characterized. In particular, the pivotal role of the Human Leukocyte Antigen (HLA) system is not well understood, including the role of non-classical immuno-modulatory HLA-E and HLA-G molecules in developing tolerance and the role of Natural Killer cells (NK) in the immunomodulation processes. We retrospectively tested whether the genetic and/or circulating expression of the non-classical HLA-E and HLA-G loci, as well as the imputed classical HLA determinants of HLA-E expression, influence the observed clinical response to AHSCT at 12- and 24-month follow-up. In a phenotypically well-defined sample of 46 SSc patients classified as clinical responders or non-responders, we performed HLA genotyping using next-generation sequencing and circulating levels of HLA-G and quantified HLA-E soluble isoforms by ELISA. The -21HLA-B leader peptide dimorphism and the differential expression level of HLA-A and HLA-C alleles were imputed. We observed a strong trend towards better clinical response in HLA-E*01:03 or HLA-G 14bp Del allele carriers, which are known to be associated with high expression of the corresponding molecules. At 12-month post-AHSCT follow-up, higher circulating levels of soluble HLA-E were associated with higher values of modified Rodnan Skin Score (mRSS) (p = 0.0275), a proxy of disease severity. In the non-responder group, the majority of patients carried a double dose of the HLA-B Threonine leader peptide, suggesting a non-efficient inhibitory effect of the HLA-E molecules. We did not find any correlation between the soluble HLA-G levels and the observed clinical response after AHSCT. High imputed expression levels of HLA-C alleles, reflecting more efficient NK cell inhibition, correlated with low values of the mRSS 3 months after AHSCT (p = 0.0087). This first pilot analysis of HLA-E and HLA-G immuno-modulatory molecules suggests that efficient inhibition of NK cells contributes to clinical response after AHSCT for SSc. Further studies are warranted in larger patient cohorts to confirm our results

Reproducibility and utility of the 6-minute walk test in systemic sclerosis

Objective: To assess the reproducibility and the utility of the 6-minute walk test (6MWT) in systemic sclerosis (SSc). Methods: All patients with SSc who underwent at least two 6MWT within a minimum 3-month interval plus simultaneous routine clinical, biological, and functional evaluations were consecutively enrolled in this observational study over 6 years. Following American Thoracic Society guidelines, each 6MWT was repeated twice to assess the 6-minute walk distance (6MWD) reproducibility, with the highest value being reported for subsequent analysis. Results: Among 56 (38 female) included patients aged 46 +/- SD 12.7 years, with 17 +/- 10 modified Rodnan skin score (mRSS) and 1 +/- 0.8 Scleroderma Health Assessment Questionnaire (SHAQ) at first referral, 277 6MWT evaluations (5 +/- 3.9 6MWT per patient) were performed over 23 +/- 225 months followup. Meanwhile, 8 deaths (87.5% SSc-related) occurred. The mean 6MWD absolute value was 457 +/- 117 m with a 4 +/- 2.2 mean Borg dyspnea score. The 6MWD intraclass correlation coefficient was 0.996 (95% CI 0.995-0.999, p < 0.0001). In multivariate linear regression analysis, these factors were independently associated with a lower 6MWD: sex (R-2 = 0.47, p < 0.0001), mRSS (R-2 = 0.47, p = 0.008), tendon friction rub (R-2 = 0.47, p = 0.003), SHAQ (R-2 = 0.47, p = 0.02), muscle disability score (R-2 = 0.47, p = 0.03), DLCO% (R-2 = 0.47, p = 0.0008), and left ventricular ejection fraction (R-2 = 0.47, p = 0.006). The 6MWD at first referral was an independent predictor for the overall mortality (IIR 0.99, 95% CI 0.988-0.999) and the SSc-related mortality (HR 0.99, 95% CI 0.988-0.999). Conclusion: We show strong reproducibility for the 6MWD and confirm the 6MWT utility to assess the overall prognosis of patients with SSc

Regulatory B Cells Contribute to the Clinical Response After Bone Marrow-Derived Mesenchymal Stromal Cell Infusion in Patients With Systemic Sclerosis

International audiencecenter dot Initial overexpression of profibrotic factors by B cells is associated with a lack of clinical response to mesenchymal stromal cells (MSCs) in patients with severe systemic sclerosis (SSc). center dot Increase of regulatory B cells is a marker of clinical response to MSCs in SSc patients. center dot MSCs directly upregulate IL-10 production by activated B cells in vitro. Mesenchymal stromal cells (MSCs) have recently emerged as an interesting therapeutic approach for patients with progressive systemic sclerosis (SSc), a rare and life-threatening orphan autoimmune disease. Whereas MSC immunomodulatory potential is considered as a central mechanism for their clinical benefit, very few data are available on the impact of MSCs on immune cell subsets in vivo. In the current extended study of a phase I/II clinical trial exploring the injection of a single dose of allogeneic bone marrow-MSCs (alloBM-MSCs) in patients with severe SSc (NCT02213705), we performed a longitudinal in-depth characterization of circulating immune cells in 19 MSC-treated patients, including 14 responders and 5 non-responders. By a combination of flow cytometry and transcriptomic analyses, we highlighted an increase in circulating CD24(hi)CD27(pos)CD38(lo/neg) memory B cells, the main IL-10-producing regulatory B cell (Breg) subset, and an upregulation of IL10 expression in ex-vivo purified B cells, specifically in responder patients, early after the alloBM-MSC infusion. In addition, a deeper alteration of the B-cell compartment before alloBM-MSC treatment, including a higher expression of profibrotic cytokines IL6 and TGF beta by sorted B cells was associated with a non-responder clinical status. Finally, BM-MSCs were able to directly upregulate IL-10 production in activated B cells in vitro. These data suggest that cytokine-producing B cells, in particular Breg, are pivotal effectors of BM-MSC therapeutic activity in SSc. Their quantification as activity biomarkers in MSC potency assays and patient selection criteria may be considered to reach optimal clinical benefit when designing MSC-based clinical trials

Indications de l’autogreffe de cellules souches hématopoïétiques dans la polyradiculonévrite inflammatoire démyélinisante chronique : recommandations de la Société francophone de greffe de moelle et de thérapie cellulaire (SFGM-TC)

International audienceChronic Inflammatory Demyelinating Polyneuropathy (CIDP) is a chronic autoimmune disease involving the peripheral nervous system, characterized by focal and segmental demyelination accounting for neurological deficit. CIDP diagnosis is based on several criteria and requires the presence of specific clinical symptoms and of demyelinating criteria on the electroneuromyogram (ENMG) or of additional supportive criteria (spinal fluid examination with dissociation between albumin level and cellular abnormalities, nervous abnormalities on MRI or other minor abnormalities on ENMG, demyelinating features on nerve biopsy or patient improvement under so-called first-line therapy with immunodulator treatment). After failure of two successive first line immunomodulating drug therapies (corticosteroids, immunomodulating immunoglobulins, or plasma exchange), several options can be considered as second line therapies. The efficacy of autologous hematopoietic cell transplantation (AHCT) has been shown in CIDP patients. The aim of these recommendations established by a working group of experts from the "Société française de greffe de moelle osseuse et thérapie cellulaire (SFGM-TC)", the group "maladies auto-immunes et thérapie cellulaire (MATHEC)" and the "filière de santé maladies rares neuromusculaire (FILNEMUS)" is to specify the eligibility criteria for AHCT in CIPD patients, to describe the mobilization and the conditioning regimen for the AHCT procedure, as well as the patient standardized post-transplant follow-up and the management of neurological treatment throughout the all procedure

Safety and preliminary efficacy of allogeneic bone marrow-derived multipotent mesenchymal stromal cells for systemic sclerosis: a single-centre, open-label, dose-escalation, proof-of-concept, phase 1/2 study

International audienceBackground:Systemic sclerosis remains an orphan life-threatening autoimmune disease. The unique immunomodulatory, proangiogenic, and antifibrotic properties of mesenchymal stromal cells provide a strong rationale for mesenchymal stromal cell-based therapy for systemic sclerosis, and treatment with mesenchymal stromal cells has shown benefits in preclinical models of this disease. The safety of allogeneic bone marrow-derived mesenchymal stromal cell administration in patients with severe systemic sclerosis has not yet been established. We aimed to test the safety and feasibility of a single intravenous injection of intrafamilial allogeneic bone marrow-derived mesenchymal stromal cells to treat severe diffuse systemic sclerosis.Methods:We did an open-label, dose-escalation, proof-of-concept, phase 1/2 study at Saint-Louis-Hospital, Paris, France. Eligible patients were aged 18–70 years with severe diffuse systemic sclerosis, who fulfilled the 2013 American College of Rheumatology and European League Against Rheumatism systemic sclerosis criteria, had a minimum modified Rodnan skin score of 15 (range 0–51), had severe lung, heart, or kidney involvement, and had inadequate response or contraindications to conventional immunosuppressive therapy or autologous haematopoietic stem cell transplantation. Patients with severe comorbidities were excluded. The first ten recipients were to receive a single intravenous infusion of 1 × 106 bone marrow-derived mesenchymal stromal cells per kg bodyweight, and the subsequent ten recipients were to be infused with a single dose of 3 × 106 bone marrow-derived mesenchymal stromal cells per kg bodyweight. The primary endpoint was immediate tolerance during infusion and within the first 10 days after infusion, measured as the occurrence of serious adverse events (grade 3 or higher) in all infused patients. Safety was assessed in all participants during the 24-month follow-up period. This study is registered with ClinicalTrials.gov, NCT02213705.Findings:Between March 24, 2014, and Jan 6, 2020, 20 cisgender individuals (13 women and seven men) with severe diffuse systemic sclerosis were enrolled. All 20 patients were included in the primary outcome analysis. No infusion-related severe adverse events and three infusion-related adverse events occurred in the first 10 days after treatment; one patient had grade 1 flushing and another patient had grade 1 nausea and grade 2 asthenia. After ten days and up to a median follow-up of 24·1 months (IQR 20·8–24·5), 36 non-treatment-related severe adverse events in 14 (70%) patients and no treatment-related adverse event were reported.Interpretation:A single infusion of allogeneic bone marrow-derived mesenchymal stromal cells was safe in patients with severe diffuse systemic sclerosis. Future placebo-controlled trials will help to definitively ascertain the efficacy of mesenchymal stromal cell-based cell therapy from various tissue sources in larger number of patients with systemic sclerosis