Mesenchymal stromal cell therapy is associated with increased adenovirus-associated but not cytomegalovirus-associated mortality in children with severe acute graft-versus-host disease

Co-transplantation of mesenchymal stromal cell and haploidentical hematopoietic stem cell with TCR αβ depletion in children with primary immunodeficiency syndromes

BACKGROUND

Haploidentical HSCT is a good option for children with PIDs lacking an HLA-matched donor. Co-transplantation of MSCs during haploidentical HSCT in patients with PIDs may enhance engraftment, decrease the risk of GVHD, and ensure stable donor chimerism.

METHODS

Twenty-seven pediatric patients (median age, 1.4 years; range, .3-10.9) with PIDs undergoing thirty haploidentical HSCT with TCR αβ depletion and co-transplantation of MSCs were enrolled to study. Most patients (73.3%) received myeloablative conditioning consisting of treosulfan or busulfan, fludarabine, and thiotepa. The median duration of follow-up was 14.3 months (range, 1-69 months).

RESULTS

Acute GVHD occurred in 7 patients (grade I-II n = 5, grade III-IV n = 2). Chronic GVHD was observed in only one patient. Twenty-one patients (70.2%) had 100% donor chimerism in all cell lines including T-cell and B-cell lineages. Primary graft failure was observed in 7 patients (25.9%). The cumulative incidences of TRM were 20% at day 100, and 26.7% at one year and five years. Probabilities of OS were 80% at day 100, and 71.9% at 1 year and 5 years. Infants transplanted younger than 6 months of age had the highest 5-year survival rate (85.7%).

CONCLUSION

We conclude that use of TCR αβ depleted haploidentical transplantation with MSCs may ensure a rapid engraftment rate, low incidence of significant acute and chronic GVHD, and acceptable post-transplantation morbidity, especially in patients diagnosed with SCID and may be considered in children with PIDs. In younger patients (≤6 months), survival is comparable between HLA-matched graft and CD3+ TCRαβ depleted HLA-mismatched graft recipients.

Mesenchymal Stromal Cells in Pediatric Hematopoietic Cell Transplantation a Review and a Pilot Study in Children Treated With Decidua Stromal Cells for Acute Graft-versus-Host Disease

Mesenchymal stromal cells (MSCs) are rare precursors in all organs of the body. MSCs have profound anti-inflammatory effects and reduce alloreactivity in vitro and in vivo. In pediatric allogeneic hematopoietic cell transplantation (HCT), MSCs have mainly been used to treat acute graft-versus-host disease (GVHD). MSCs are commercially available for this indication in Canada, Japan, and New Zeeland. More rare indications for MSCs in pediatric patients include graft failure and chronic GVHD. MSCs from bone marrow, adipose tissue, umbilical cord, Wharton's jelly, placenta tissue, and decidua have been used, but the optimal clinical stromal cell source has not been compared in clinical trials. More experimental clinical indications using MSCs, such as sepsis, acute respiratory distress syndrome, hemorrhages, pneumo-mediastinum, and neuroinflammation have primarily been explored in animal models or adult HCT patients. MSCs have almost no if any side-effects. In this pilot study we report the outcome of six children treated with decidua stromal cells (DSCs) for steroid refractory acute GVHD. At 6 months, complete response was seen in four patients and partial response in two patients. One child with high-risk ALL died from relapse and a boy with sickle cell disease died from a cerebral hemorrhage. Five-year survival was 67% and all survivors showed a Lansky score of 100%. To conclude, MSCs from various organs are well-tolerated and have shown an encouraging outcome for acute GVHD in pediatric patients.

Current status of mesenchymal stem cell therapy for immune/inflammatory lung disorders: Gleaning insights for possible use in COVID-19

The broad immunomodulatory properties of human mesenchymal stem cells (MSCs) have allowed for wide application in regenerative medicine as well as immune/inflammatory diseases, including unmatched allogeneic use. The novel coronavirus disease COVID‐19 has unleashed a pandemic in record time accompanied by an alarming mortality rate mainly due to pulmonary injury and acute respiratory distress syndrome. Because there are no effective preventive or curative therapies currently, MSC therapy (MSCT) has emerged as a possible candidate despite the lack of preclinical data of MSCs for COVID‐19. Interestingly, MSCT preclinical data specifically on immune/inflammatory disorders of the lungs were among the earliest to be reported in 2003, with the first clinical use of MSCT for graft‐vs‐host disease reported in 2004. Since these first reports, preclinical data showing beneficial effects of MSC immunomodulation have accumulated substantially, and as a consequence, over a third of MSCT clinical trials now target immune/inflammatory diseases. There is much preclinical evidence for MSCT in noninfectious—including chronic obstructive pulmonary disease, asthma, and idiopathic pulmonary fibrosis—as well as infectious bacterial immune/inflammatory lung disorders, with data generally demonstrating therapeutic effects; however, for infectious viral pulmonary conditions, the preclinical evidence is more scarce with some inconsistent outcomes. In this article, we review the mechanistic evidence for clinical use of MSCs in pulmonary immune/inflammatory disorders, and survey the ongoing clinical trials—including for COVID‐19—of MSCT for these diseases, with some perspectives and comment on MSCT for COVID‐19.

Vascularized composite allograft rejection is delayed by infusion of IFN-γ-conditioned BMSCs through upregulating PD-L1

Mesenchymal stromal cells (MSCs) have been applied in prevention from allograft rejection based on their immunomodulatory effects. However, conflicting results have been presented among recent studies, for which one possibility being acknowledged is that the exact effect is determined by the microenvironment when MSCs are applied in vivo. Using a hind limb composite tissue allograft model, we investigate the influence of IFN-γ-preconditioning on the immunomodulatory effects of MSCs and the subsequent allograft survival. Firstly, different doses of IFN-γ were respectively used to incubate with bone marrow-derived MSCs (BMSCs). We found that IFN-γ altered the expression of PD-L1, a major suppressor gene in the immune system during allograft rejection, in a strictly dose-dependent manner in BMSCs. Ten nanograms per milliliter IFN-γ-incubated BMSCs significantly stimulated PD-L1 expression and suppressed T cell proliferation and differentiation, while 50 ng/mL IFN-γ-incubated BMSCs sharply reduced PD-L1 expression. Moreover, we observed that, in contrast to the naive BMSC transplantation group, BMSCs pre-conditioned with 10 ng/mL IFN-γ (BMSCs-IFN-γ) significantly delayed the allograft rejection in vivo. In vitro mixed lymphocyte reaction (MLR) indicated that BMSCs-IFN-γ inhibited T lymphocyte proliferation and activation via PD-L1. Moreover, BMSCs-IFN-γ did not influence the proliferation and activation of T lymphocytes when PD-L1 protein was neutralized by the PD-L1 antibody. These data collectively reveal a role of recipient ongoing immune microenviroment in BMSC-based immunesuppressive therapy. Graphical abstract ᅟ.

Remestemcel-L for the treatment of graft versus host disease

INTRODUCTION

Remestemcel-L, a third-party, off-the-shelf preparation of bone-marrow derived mesenchymal stromal cells (MSCs), has been developed for experimental use in acute graft-versus-host disease (aGvHD) and other immune-mediated conditions. Several preclinical and clinical studies have indeed suggested the potential of human mesenchymal stromal cells (MSCs) as an effective treatment for steroid-refractory aGvHD. However, an unambiguous demonstration of efficacy is still lacking. Areas covered: This review critically examines the biologic rationale supporting MSCs use in aGvHD and analyzes the results of published clinical trials in this setting, with a particular focus on the potential benefits and drawbacks of Remestemcel-L. For this purpose, a systematic literature search was performed in PubMed using the following keywords: 'mesenchymal stromal cells', 'mesenchymal progenitor cells', 'multipotent stromal cells', 'mesenchymal cells', 'MSC', 'Remestemcel-L', 'Prochymal', and 'graft-versus-host disease' or 'GvHD'. Expert commentary: Remestemcel-L represents a promising alternative to second-line immunosuppressive agents for the treatment of steroid-refractory aGvHD. Despite the safety and the favorable risk/benefit profile of this cell product, which has been demonstrated in several phase I-II studies, large and prospective randomized trials are required to confirm its efficacy in aGvHD and to define the optimal schedule of administration in terms of infusion timing, cell dose and pharmacological synergism.

Pre-Transplant Screening for Latent Adenovirus in Donors and Recipients

Human adenoviruses are frequent cause of slight self-limiting infections in immune competent subjects, while causing life-threatening and disseminated diseases in immunocompromised patients, particularly in the subjects affected by acquired immunodeficiency syndrome and in bone marrow and organ transplant recipients. Here, infections interest lungs, liver, encephalon, heart, kidney and gastro enteric tract. To date, human adenoviruses comprise 51 serotypes grouped into seven species, among which species C especially possesses the capability to persist in infected tissues. From numerous works, it emerges that in the recipient, because of loss of immune-competence, both primary infection, via the graft or from the environment, and reactivated endogenous viruses can be responsible for transplantation related adenovirus disease. The transplants management should include the evaluation of anti-adenovirus pre-transplant screening similar to that concerning cytomegalovirus. The serological screening on cytomegalovirus immunity is currently performed to prevent viral reactivation from grafts and recipient, the viral spread and dissemination to different organs and apparatus, and potentially lethal outcome.

Mesenchymal stromal cells to modulate immune reconstitution early post-hematopoietic cell transplantation

Mesenchymal stromal cells (MSCs) are multipotent progenitor cells known to modulate the immune system and to promote hematopoiesis. These dual effects make MSCs attractive for use as cellular therapy in hematopoietic cell transplantation (HCT). MSCs can be used peri-HCT or pre-engraftment to modulate immune reconstitution, promoting hematopoietic stem cell (HSC) engraftment and/or preventing graft-versus-host disease (GVHD). Pre-clinical studies have demonstrated that MSCs can potentiate HSC engraftment and prevent GVHD in a variety of animal models. Clinical trials have been small and largely non-randomized but have established safety and early evidence of efficacy, supporting the need for larger randomized trials.

Mesenchymal Stromal Cells and Viral Infection

Mesenchymal Stromal Cells (MSCs) are a subset of nonhematopoietic adult stem cells, readily isolated from various tissues and easily culture-expanded ex vivo. Intensive studies of the immune modulation and tissue regeneration over the past few years have demonstrated the great potential of MSCs for the prevention and treatment of steroid-resistant acute graft-versus-host disease (GvHD), immune-related disorders, and viral diseases. In immunocompromised individuals, the immunomodulatory activities of MSCs have raised safety concerns regarding the greater risk of primary viral infection and viral reactivation, which is a major cause of mortality after allogeneic transplantation. Moreover, high susceptibilities of MSCs to viral infections in vitro could reflect the destructive outcomes that might impair the clinical efficacy of MSCs infusion. However, the interplay between MSCs and virus is like a double-edge sword, and it also provides beneficial effects such as allowing the proliferation and function of antiviral specific effector cells instead of suppressing them, serving as an ideal tool for study of viral pathogenesis, and protecting hosts against viral challenge by using the antimicrobial activity. Here, we therefore review favorable and unfavorable consequences of MSCs and virus interaction with the highlight of safety and efficacy for applying MSCs as cell therapy.

Mesenchymal Stromal Cell Therapy in Hematology: From Laboratory to Clinic and Back Again

There is currently major interest to use mesenchymal stromal cells (MSCs) for a very diverse range of therapeutic applications. This stems mainly from the immunosuppressive qualities and differentiation capacity of these cells. In this review, we focus on cell therapy applications for MSCs in hematology. In this domain, MSCs are used for the treatment or prevention of graft-versus-host disease, support of hematopoiesis, or repair of tissue toxicities after hematopoietic cell transplantation. We critically review the accumulating clinical data and elaborate on complications that might arise from treatment with MSCs. In addition, we assume that the real clinical benefit of using MSCs for these purposes can only be estimated by a better understanding of the influence of in vitro expansion on the biological properties of these cells as well as by more harmonization of the currently used expansion protocols.

Specific subsets of mesenchymal stroma cells to treat lung disorders--finding the Holy Grail

Accumulating studies, both in animals and human clinical trials with mesenchymal stroma cells (MSC) support the hypothesis of therapeutic effects of these cells in various disorders. However, despite success in immune-mediated disorders such as Crohns' disease, lung disorders such as chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary disease (IPF) treated with MSC have so far not yielded a revolutionary effect on clinical symptoms. Promising data on immunomodulatory effects in COPD have kept nourishing the research into finding specific traits of MSC beneficial in disease. A heterogeneous population of injected cells might drown a potential therapeutic role of a specific group of MSC. Thus careful analysis of MSC regarding their molecular capabilities such as delivering specific therapeutic vesicles to the environment, or plain cytokine/chemokine fingerprinting might prove useful in augmenting therapies against lung diseases.