Cord Blood Nucleated Cells Induce Delayed T Cell Alloreactivity

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Human CD4+CD25+ Cells in Combination with CD34+ Cells and Thymoglobulin to Prevent Anti-hematopoietic Stem Cell T Cell Alloreactivity

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promising role of extracellular vesicles as biomarkers of acute graft vs host disease

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t cell mediated rejection of human cd34 cells is prevented by costimulatory blockade in a xenograft model

Abstract A xenograft model of stem cell rejection was developed by co-transplantating human CD34 + and allogeneic CD3 + T cells into NOD-scid ɣ-chain null mice. T cells caused graft failure when transplanted at any CD34/CD3 ratio between 1:50 and 1:.1. Kinetics experiments showed that 2 weeks after transplantation CD34 + cells engrafted the marrow and T cells expanded in the spleen. Then, at 4 weeks only memory T cells populated both sites and rejected CD34 + cells. Blockade of T cell costimulation was tested by injecting the mice with abatacept (CTLA4-IgG1) from day –1 to +27 (group A), from day –1 to +13 (group B), or from day +14 to +28 (group C). On day +56 groups B and C had rejected the graft, whereas in group A graft failure was completely prevented, although with lower stem cell engraftment than in controls ( P  = .03). Retransplantation of group A mice with same CD34 + cells obtained a complete reconstitution of human myeloid and B cell lineages and excluded latent alloreactivity. In this first xenograft model of stem cell rejection we showed that transplantation of HLA mismatched CD34 + cells may be facilitated by treatment with abatacept and late stem cell boost

Liver Stiffness Measurement Allows Early Diagnosis of Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome in Adult Patients Who Undergo Hematopoietic Stem Cell Transplantation: Results from a Monocentric Prospective Study

ABSTRACT Veno-occlusive disease (VOD), also known as sinusoidal obstruction syndrome (SOS), is a life-threatening complication affecting patients undergoing hematopoietic stem cell transplantation (HSCT). The survival rate is higher when specific therapy is initiated early; thus, improving early, noninvasive diagnosis of VOD/SOS is an important need. In an adult population undergoing HSCT, we aimed to assess the role of liver stiffness measurement (LSM), evaluated by transient elastography (TE), for diagnosing VOD/SOS. Between April 2016 and March 2018, 78 consecutive adult patients with indications for allogeneic HSCT were prospectively included. LSM was performed before HSCT and at days +9/10, +15/17, and +22/24 post-HSCT. New European Society for Blood and Marrow Transplantation criteria were used to establish VOD/SOS diagnosis. Four patients developed VOD/SOS (5.1%) during the study period, with a median time of +17 days post-HSCT. A sudden increase in LSM compared with previously assessed values and pre-HSCT values, was seen in all patients who developed VOD/SOS. LSM increases occurred from 2 to 12 days before clinical SOS/VOD appearance. The VOD/SOS diagnostic performance of increased LSM over pre-HSCT assessment showed an area under the receiver operating characteristic curve of 0.997 (sensitivity 75%; specificity 98.7%). LSM gradually decreased following successful VOD/SOS-specific treatment. Interestingly, LSM values did not increase significantly in patients experiencing hepatobiliary complications (according to the Common Terminology Criteria) other than VOD/SOS. LSM by TE can be considered a promising method to perform an early, preclinical diagnosis and follow-up of VOD/SOS

Term amniotic membrane is a high throughput source for multipotent mesenchymal stem cells with the ability to differentiate into endothelial cells in vitro

BACKGROUND: Term Amniotic membrane (AM) is a very attractive source of Mesenchymal Stem Cells (MSCs) due to the fact that this fetal tissue is usually discarded without ethical conflicts, leading to high efficiency in MSC recovery with no intrusive procedures. Here we confirmed that term AM, as previously reported in the literature, is an abundant source of hMSCs; in particular we further investigated the AM differentiation potential by assessing whether these cells may also be committed to the angiogenic fate. In agreement with the recommendation of the International Society for Cellular Therapy, the mesenchymal cells herein investigated were named Amniotic Membrane-human Mesenchymal Stromal Cells (AM-hMSC). RESULTS: The recovery of hMSCs and their in vitro expansion potential were greater in amniotic membrane than in bone marrow stroma. At flow cytometry analysis AM-hMSCs showed an immunophenotypical profile, i.e., positive for CD105, CD73, CD29, CD44, CD166 and negative for CD14, CD34, CD45, consistent with that reported for bone marrow-derived MSCs. In addition, amniotic membrane-isolated cells underwent in vitro osteogenic (von Kossa stain), adipogenic (Oil Red-O stain), chondrogenic (collagen type II immunohistochemichal detection) and myogenic (RT-PCR MyoD and Myogenin expression as well as desmin immunohistochemical detection) differentiation. In angiogenic experiments, a spontaneous differentiation into endothelial cells was detected by in vitro matrigel assay and this behaviour has been enhanced through Vascular Endothelial Growth Factor (VEGF) induction. According to these findings, VEGF receptor 1 and 2 (FLT-1 and KDR) were basally expressed in AM-hMSCs and the expression of endothelial-specific markers like FLT-1 KDR, ICAM-1 increased after exposure to VEGF together with the occurrence of CD34 and von Willebrand Factor positive cells. CONCLUSION: The current study suggests that AM-hMSCs may emerge as a remarkable tool for the cell therapy of multiple diseased tissues. AM-hMSCs may potentially assist both bone and cartilage repair, nevertheless, due to their angiogenic potential, they may also pave the way for novel approaches in the development of tissue-engineered vascular grafts which are useful when vascularization of ischemic tissues is required

Intrabone transplant provides full stemness of cord blood stem cells with fast hematopoietic recovery and low GVHD rate: results from a prospective study

Umbilical Cord Blood (UCB) represents a valid option for patients with hematopoietic malignancies lacking an HLA matched donor. To overcome the limitation of the low stem cell dose of UCB, the intrabone (IB) route has been proposed. We report the results of a prospective study on a poor-prognosis cohort of 23 patients receiving intrabone single UCB transplant (Clinicaltrials.gov NCT00886522). Cumulative incidence of hematological recovery at day 90 was 82 ± 9% (ANC > 0.5 × 109/L) and 70 ± 10% (platelet > 50 × 109/L) and correlated with CD34 + cells in the graft. NRM was 20 ±  9%. No severe aGVHD and only one extensive cGVHD occurred, with fast immune reconstitution. To test the hypothesis that the direct IB injection could affect the expression of stem cells regulatory pathways, CD34 + cells from BM aspirates at day + 10, + 20, + 30, processed in hypoxic conditions mimicking the BM-microenvironment (7%pO2), were studied for the expression of c-Mpl, Notch1 and CXCR4. We found that the expression of c-Mpl in CD34 + cells at day + 10 significantly correlated with hematological recovery. In conclusion, IB-UCB transplant success is associated with low incidence of GVHD and high-speed platelet recovery; intrabone route may preserve full hematopoietic stemness by direct delivery of UCB stem cells into the hypoxic HSC niche

Pre-transplant CD69+ extracellular vesicles are negatively correlated with active ATLG serum levels and associate with the onset of GVHD in allogeneic HSCT patients

Graft versus host disease (GVHD) is a major complication of allogeneic hematopoietic stem cell transplantation (HSCT). Rabbit anti-T lymphocyte globulin (ATLG) in addition to calcineurin inhibitors and antimetabolites is a suitable strategy to prevent GVHD in several transplant settings. Randomized studies already demonstrated its efficacy in terms of GVHD prevention, although the effect on relapse remains the major concern for a wider use. Tailoring of ATLG dose on host characteristics is expected to minimize its side effects (immunological reconstitution, relapse, and infections). Here, day -6 to day +15 pharmacokinetics of active ATLG serum level was first assayed in an explorative cohort of 23 patients by testing the ability of the polyclonal serum to bind antigens on human leukocytes. Significantly lower levels of serum active ATLG were found in the patients who developed GVHD (ATLG_AUC(CD45): 241.52 +/- 152.16 vs. 766.63 +/- 283.52 (mu g*day)/ml, p = 1.46e(-5)). Consistent results were obtained when the ATLG binding capacity was assessed on CD3+ and CD3+/CD4+ T lymphocytes (ATLG_AUC(CD3): 335.83 +/- 208.15 vs. 903.54 +/- 378.78 (mu g*day)/ml, p = 1.92e(-4); ATLG_AUC(CD4): 317.75 +/- 170.70 vs. 910.54 +/- 353.35 (mu g*day)/ml, p = 3.78e(-5). Concomitantly, at pre-infusion time points, increased concentrations of CD69+ extracellular vesicles (EVs) were found in patients who developed GVHD (mean fold 9.01 +/- 1.33; p = 2.12e(-5)). Consistent results were obtained in a validation cohort of 12 additional ATLG-treated HSCT patients. Serum CD69+ EVs were mainly represented in the nano (i.e. 100 nm in diameter) EV compartment and expressed the leukocyte marker CD45, the EV markers CD9 and CD63, and CD103, a marker of tissue-resident memory T cells. The latter are expected to set up a host pro-inflammatory cell compartment that can survive in the recipient for years after conditioning regimen and contribute to GVHD pathogenesis. In summary, high levels of CD69+ EVs are significantly correlated with an increased risk of GVHD, and they may be proposed as a tool to tailor ATLG dose for personalized GVHD prevention