Human umbilical cord blood-derived stromal cells prevent graft-versus-host disease in mice following haplo-identical stem cell transplantation

Haploidentical peripheral blood stem cell transplantation combined with unrelated cord blood in hematologic malignancy patients: A report of 80 cases

The outcomes of 80 patients with hematologic malignancies who received haploidentical peripheral blood stem cell transplantation (haplo-PBSCT) combined with unrelated cord blood (UCB) from March 2017 to June 2020 were analyzed in this retrospective study. Anti-thymocyte globulin(ATG) was administered at a dose of 7.5 mg/kg. The median time for neutrophil and platelet engraftment was 13(range: 8-22) days and 14(range: 8-103) days, respectively. The 30-day cumulative incidence of neutrophil engraftment was 100%, and the 100-day cumulative incidence of platelet engraftment was 95%. All patients achieved complete haploidentical peripheral blood stem cell engraftment, and no cord blood chimerism was observed. The cumulative incidence of grades II-IV and grades III-IV acute graft-versus-host disease (aGVHD) on 100-day was 26.3%(95%CI: 17.2%–36.3%) and 5.0%(95%CI: 1.6%–11.4%), respectively. The estimated cumulative incidence of chronic GVHD (cGVHD) and moderate-severe cGVHD at 3-year was 43.3%(95%CI: 31.6%–54.4%) and 16.0%(95%CI: 8.7%–25.2%), respectively. The estimated 3-year cumulative incidence of relapse and non-relapse mortality was 18.8%(95%CI: 10.0%–29.7%) and 17.8%(95%CI: 9.9%–27.5%), respectively. The estimated 3-year probabilities of overall survival, disease-free survival, GVHD/relapse-free survival were 77.6%(95%CI: 68.3%–88.1%), 63.4%(95%CI: 52.6%–76.5%), and 55.5%(95%CI: 44.8%–68.7%), respectively. These satisfying results suggested that haplo-PBSCT combined with UCB is an alternative transplantation protocol for hematologic malignancies.

Comparison of outcomes of haploidentical donor hematopoietic stem cell transplantation supported by third-party cord blood with HLA-matched unrelated donor transplantation

Previous study indicated that co-infusion of cord blood cells may potentially improve the outcome of haploidentical donor (HID) transplantation. In this study, we analyzed the outcomes of patients who underwent HID transplantation supported by cord blood when compared with HLA-matched unrelated donor (URD) transplantation. Starting in 2015, 40 patients with hematopoietic malignancies underwent HID transplantation and 26 patients underwent URD transplantation. Hematopoietic recovery, the incidences of grade II-IV acute graft-versus-host disease (GVHD) and chronic GVHD was comparable in the two groups. At two year, the relapse risk in HID group was significantly lower than in URD group (RR 4.630; 95%CI, 1.081-19.839; p = .039). Moreover, HID group have prolonged PFS (RR 2.642; 95%CI, 1.046-6.672; p = .040). In conclusion, HID transplantation supported by cord blood results in better outcomes compared with URD transplantation and it might be a favorable alternative to a HLA-matched URD transplantation.

Human LAP+GARP+FOXP3+ regulatory T cells attenuate xenogeneic graft versus host disease

Adoptive transfer of regulatory T cells (FOXP3⁺ Tregs) has been developed as a potential curative immune therapy to prevent and treat autoimmune and graft-versus-host diseases (GVHD). A major limitation that has hindered the use of Treg immunotherapy in humans is the difficulty of consistently isolating and obtaining highly purified Tregs after ex vivo expansion. Methods: We isolated bona fide Tregs from expansion cultures based on their selective surface expression of latency-associated peptide (LAP). The TCR Vβ diversity and intracellular cytokine production of Tregs were determined by flow cytometer. The TSDR methylation was determined by epigenetic human FOXP3 qPCR Assay. Their in vitro and in vivo potency was confirmed with suppression assay and humanized xenogeneic GVHD (xGVHD) murine model, respectively. Results: LAP⁺ repurification results in >90% LAP⁺FOXP3⁺ Tregs, leaving behind FOXP3^- and FOXP3⁺ nonTregs within the LAP^- population. After 4-week expansion, the LAP⁺ Tregs were >1 billion cells, highly suppressive and anergic in vitro, >90% demethylated in the TSDR and able to maintain TCR Vβ diversity. In the xGVHD model, exogenous CD25^-PBMC administered alone results in a median survival of 32 days. The co-transfer of LAP⁺ Tregs increased median survival to 47 days, while the LAP parent (CD25⁺) and LAP^- nonTregs had median survival of 39 and 31 days, respectively. Conclusions: These preclinical data together provide evidence that LAP⁺ Tregs are highly purified with fully suppressive function for cell therapy. This population results in a more effective and safer product for immunotherapy to treat GVHD and provides the necessary preclinical data for transition into a clinical trial with LAP⁺ Tregs to prevent or treat GVHD and other autoimmune diseases.

Mesenchymal stem cells provide prophylaxis against acute graft-versus-host disease following allogeneic hematopoietic stem cell transplantation: A meta-analysis of animal models

A meta-analysis of animal models was conducted to evaluate the prophylactic effects of mesenchymal stem cells (MSCs) on acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation. A total of 50 studies involving 1848 animals were included. The pooled results showed that MSCs significantly reduced aGVHD-associated mortality (risk ratio = 0.70, 95% confidence interval 0.62 to 0.79, P = 2.73×10⁻⁹) and clinical scores (standardized mean difference = −3.60, 95% confidence interval −4.43 to −2.76, P = 3.61×10⁻¹⁷). In addition, MSCs conferred robust favorable prophylactic effects on aGVHD across recipient species, MSC doses, and administration times, but not MSC sources. Our meta-analysis showed that MSCs significantly prevented mortality and alleviated the clinical manifestations of aGVHD in animal models. These data support further clinical trials aimed at evaluating the efficacy of using MSCs to prevent aGVHD.

Isolation of mesenchymal stromal/stem cells from cryopreserved umbilical cord blood cells

Umbilical cord blood (UCB) has advantages over other tissues because it can be obtained without an invasive procedure and complex processing. We explored the availability of cryopreserved UCB cells as a source of mesenchymal stromal/stem cells (MSCs). MSCs were successfully isolated from six of 30 UCB units (median volume, 34.0 mL; median nucleated cell number, 4.4×10⁸) that were processed and cryopreserved using CP-1/human serum albumin. This isolation rate was lower than that (57%) from non-cryopreserved UCB cells. The number of nucleated cells before and after hydroxyethyl starch separation, UCB unit volume, and cell viability after thawing did not significantly differ between UCB units from which MSCs were successfully isolated and those from which they were not. When CryoSure-DEX40 was used as a cryoprotectant, MSCs were isolated from two of ten UCB units. Logistic regression analysis demonstrated that the cryopreservation method was not significantly associated with the success of MSC isolation. The isolated MSCs had a similar morphology and surface marker expression profile as bone marrow-derived MSCs and were able to differentiate into osteogenic, adipogenic, and chondrogenic cells. In summary, MSCs can be isolated from cryopreserved UCB cells. However, the cryopreservation process reduces the isolation rate; therefore, freshly donated UCB cells are preferable for the isolation of MSCs.

Umbilical cord blood graft engineering: challenges and opportunities

We are entering a very exciting era in umbilical cord blood transplantation (UCBT), where many of the associated formidable challenges may become treatable by ex vivo graft manipulation and/or adoptive immunotherapy utilizing specific cellular products. We envisage the use of double UCBT rather than single UCBT for most patients; this allows for greater ability to treat larger patients as well as to manipulate the graft. Ex vivo expansion and/or fucosylation of one cord will achieve more rapid engraftment, minimize the period of neutropenia and also give certainty that the other cord will provide long-term engraftment/immune reconstitution. The non-expanded (and future dominant) cord could be chosen for characteristics such as better HLA matching to minimize GvHD, or larger cell counts to enable part of the unit to be utilized for the development of specific cellular therapies such as the production of virus-specific T-cells or chimeric-antigen receptor T-cells which are reviewed in this study.

Isolation of mesenchymal stromal/stem cells from small-volume umbilical cord blood units that do not qualify for the banking system

The clinical application of mesenchymal stromal/stem cells (MSCs) has been extensively explored. In this study, we examined the availability of freshly donated umbilical cord blood (UCB) units that do not qualify for the Japanese banking system for transplantation because of their small volume as a source of MSCs. Forty-five UCB units were used. The median volume of each UCB unit and number of nucleated cells per unit were 40 mL and 5.39 × 10(8), respectively. MSCs were successfully isolated from 18 of 45 units (40 %). The MSC isolation rate was not affected by cell processing method or the interval between delivery and cell processing. The volume of the UCB unit and the mononuclear cell count were predictive factors of the MSC isolation rate. MSCs were effectively isolated by selecting UCB units with a volume of ≥54 mL and containing ≥1.28 × 10(8) mononuclear cells, yielding a MSC isolation rate of >70 %. UCB-derived MSCs were similar to bone marrow-derived MSCs in terms of their morphology, surface marker expression, and differentiation potential, apart from adipogenesis. Our data indicate that UCB units that are currently discarded due to inadequate volume should be reconsidered as a source of MSCs using the well-established UCB banking system.

Human umbilical cord blood-derived stromal cells: A new source of stromal cells in hematopoietic stem cell transplantation

The hematopoietic inductive microenvironment (HIM), which is composed of stromal cells, extracellular matrix and cytokines, plays a vital role in hematopoietic stem cell transplantation (HSCT). Bone marrow stromal cells (BMSCs), as the main component of HIM, have been well studied. However, the highly invasive procedure of bone marrow (BM) collection limits the clinical application of BMSCs. Human umbilical cord blood-derived stromal cells (hUCBDSCs) isolated and cultured in our laboratory have attracted much attention for their ease collection and low probability of pathophoresis. Previous research demonstrated that hUCBDSCs have numerous functions that are identical to those of BMSCs, for example, hUCBDSCs can support the growth of hematopoietic stem and progenitor cells, especially during the expansion of megakaryocyte colony-forming units (CFU-Mk), promote engraftment after hematopoietic stem cell transplantation (HSCT), exert immunosuppressive effects on xenogenic T cells in vitro and suppress acute graft-versus-host disease (aGVHD) in vivo. Although hUCBDSCs, as new stromal cells, have not been used in clinical practice, they have great practical significance because of their superiority in hematopoiesis and the regulation of immunity.

Human mesenchymal stem cells suppress donor CD4(+) T cell proliferation and reduce pathology in a humanized mouse model of acute graft-versus-host disease

Acute graft-versus-host disease (aGVHD) is a life-threatening complication following allogeneic haematopoietic stem cell transplantation (HSCT), occurring in up to 30-50% of patients who receive human leucocyte antigen (HLA)-matched sibling transplants. Current therapies for steroid refractory aGVHD are limited, with the prognosis of patients suboptimal. Mesenchymal stem or stromal cells (MSC), a heterogeneous cell population present in many tissues, display potent immunomodulatory abilities. Autologous and allogeneic ex-vivo expanded human MSC have been utilized to treat aGVHD with promising results, but the mechanisms of therapeutic action remain unclear. Here a robust humanized mouse model of aGVHD based on delivery of human peripheral blood mononuclear cells (PBMC) to non-obese diabetic (NOD)-severe combined immunodeficient (SCID) interleukin (IL)-2rγ(null) (NSG) mice was developed that allowed the exploration of the role of MSC in cell therapy. MSC therapy resulted in the reduction of liver and gut pathology and significantly increased survival. Protection was dependent upon the timing of MSC therapy, with conventional MSC proving effective only after delayed administration. In contrast, interferon (IFN)-γ-stimulated MSC were effective when delivered with PBMC. The beneficial effect of MSC therapy in this model was not due to the inhibition of donor PBMC chimerism, as CD45(+) and T cells engrafted successfully in this model. MSC therapy did not induce donor T cell anergy, FoxP3(+) T regulatory cells or cause PBMC apoptosis in this model; however, it was associated with the direct inhibition of donor CD4(+) T cell proliferation and reduction of human tumour necrosis factor-α in serum.

Umbilical cord blood-derived stromal cells regulate megakaryocytic proliferation and migration through SDF-1/PECAM-1 pathway

We have previously reported that human umbilical cord blood-derived stromal cells (hUCBDSCs) are able to enhance the expansion of CFU-Meg in vitro, particularly promote the megakaryocytic lineage recovery, and effectively protect the survival of irradiated mice. In this study, we demonstrated that hUCBDSCs secreted SDF-1 to stimulate PECAM-1 expression in HEL cells (MK cell line), and consequently promoted the proliferation and migration of HEL cells. On the other hand, SDF-1 knock down in hUCBDSCs or PECAM-1 knock down in HEL cells diminished or abrogated the above effect. In addition, SDF-1/PECAM-1 probably activated PI3K/Akt and MAPK/ERK1/2 pathways. This report for the first time defines a SDF-1/PECAM-1 signaling pathway in the proliferation and migration of MKs, which provides supportive evidence for the clinical applications of hUCBDSCs in the treatment of megakaryocytic injury.

Mesenchymal stromal cells for cell therapy: besides supporting hematopoiesis

Mesenchymal stromal cells (MSC) have attracted the attention of scientists and clinicians due to their self-renewal, capacity for multipotent differentiation, and immunomodulatory properties. Some essential problems remain to be solved before the clinical application of MSC. Platelet lysate (PL) has recently been used as a substitute for FBS in MSC amplification in vitro to achieve clinically applicable numbers of MSC. In addition to promising trials in regenerative medicine, such as in the treatment of major bone defects and myocardial infarction, MSC have shown therapeutic effect other than direct hematopoiesis support in hematopoietic reconstruction. It has been confirmed that MSC promote hematopoietic cell engraftment and immune recovery after allogeneic hematopoietic stem cell transplantation, probably through the provision of cytokines, matrix proteins, and cell-to-cell contacts. Their suppressive effects on immune cells, including T cells, B cells, NK cells and DC cells, suggest MSCs as a novel therapy for GVHD and other autoimmune disorders. These cells thus present as promising candidates for cellular therapy in the fields of regenerative medicine, allogeneic hematopoietic stem cell transplantation, and autoimmune disorders.

Amelioration of acute graft-versus-host disease by adoptive transfer of ex vivo expanded human cord blood CD4+CD25+ forkhead box protein 3+ regulatory T cells is associated with the polarization of Treg/Th17 balance in a mouse model

BACKGROUND

Human cord blood (CB) is a superior source of regulatory T cells (Tregs) compared with peripheral blood. Initial studies have shown that CB-derived Tregs can be effectively expanded ex vivo. However, in vitro suppressor activity of expanded CB-Tregs and their efficacy in the prevention of acute graft-versus-host disease (aGVHD) in vivo are poorly understood.

STUDY DESIGN AND METHODS

In vitro, human CB CD4+CD25+ T cells expanded with anti-CD3/CD28 beads plus interleukin (IL)-2 and the phenotypes, expression of cytokines, and suppression of expanded cells were analyzed after two cycles of stimulation. In vivo, the addition of human CB-Tregs was transferred in the major histocompatibility complex-mismatched aGVHD mouse model. Survival, body weight, GVHD scoring, histopathologic specimens, serum cytokines, and Th subsets were analyzed in CB-Treg-treated mice and untreated controls.

RESULTS

After being expanded ex vivo, human CB-derived Tregs with potent suppressor function could meet clinical demands. Up to 85% of mice with CB-Tregs treatment survived beyond Day 63 after bone marrow transplantation; however, all aGVHD mice died within 18 days. In the serum of the CB-Treg-treated mice, the production of transforming growth factor-β increased continuously, as opposed to IL-17, which decreased quickly. Consistent with the changes of cytokines, the percentage of mouse CD4+ forkhead box protein 3+ Tregs increased while that of Th17 cells decreased.

CONCLUSION

Ex vivo expanded human CB-Tregs significantly prevented allogeneic aGVHD in vivo by modulating various cytokine secretion and polarizing the Treg/Th17 balance toward Treg, which suggests the potential use of expanded CB-Tregs as a therapeutic approach for GVHD.

Therapeutic efficacy of cord blood-derived mesenchymal stromal cells for the prevention of acute graft-versus-host disease in a xenogenic mouse model

Human mesenchymal stromal cells (MSCs) have been successfully utilized for the treatment of refractory graft-versus-host disease (GvHD). Despite the large number of in vitro and in vivo models developed for clarifying their immunomodulatory properties, the mechanism of action of MSCs remains elusive and their efficacy controversial. Here, we tested the ability of cord blood-derived MSCs to alleviate the symptoms of GvHD induced by the injection of human peripheral blood mononuclear cells into NOD/SCID/γc(-) mice. In this in vivo xeno-GvHD model, we demonstrate that a single MSC injection is able to inhibit GvHD in terms of clinical signs and related mortality. We also show that in this model MSCs act by both immunomodulating T-cells and fostering recovery after irradiation. The translational impact of these findings could provide a reliable preclinical model for studying the efficacy, dosage, and time of administration of human MSCs for the prevention of acute GvHD.