Deciphering Natural Killer Cell Cytotoxicity Against Medulloblastoma in vitro and in vivo: Implications for Immunotherapy.

Purpose: Medulloblastoma (MB) is the most prevalent paediatric brain tumour. Despite improvements in patient survival with current treatment strategies, the quality of life of these patients remains poor owing to the sequelae and relapse risk. An alternative, or, in addition to the current standard treatment, could be considered immunotherapy, such as Natural Killer cells (NK). NK cells are cytotoxic innate lymphoid cells that play a major role in cancer immunosurveillance. To date, the mechanism of cytotoxicity of NK cells, especially regarding the steps of adhesion, conjugation, cytotoxic granule polarisation in the cell contact area, perforin and granzyme release in two and three dimensions, and therapeutic efficacy in vivo have not been precisely described. Materials and Methods: Each step of NK cytotoxicity against the three MB cell lines was explored using confocal microscopy for conjugation, Elispot for degranulation, flow cytometry, and luminescence assays for target cell necrosis and lysis and mediators released by cytokine array, and then confirmed in a 3D spheroid model. Medulloblastoma-xenografted mice were treated with NK cells. Their persistence was evaluated by flow cytometry, and their efficacy in tumour growth and survival was determined. In addition, their effects on the tumour transcriptome were evaluated. Results: NK cells showed variable affinities for conjugation with MB target cells depending on their subgroup and cytokine activation. Chemokines secreted during NK and MB cell co-culture are mainly associated with angiogenesis and immune cell recruitment. NK cell cytotoxicity induces MB cell death in both 2D and 3D co-culture models. NK cells initiated an inflammatory response in a human MB murine model by modulating the MB cell transcriptome. Conclusion: Our study confirmed that NK cells possess both in vitro and in vivo cytotoxic activity against MB cells and are of interest for the development of immunotherapy.

[Organizational and budgetary impacts of the implementation of CAR-T cell therapies in a French academic hospital]. / Impacts organisationnels et budgétaires de la mise en place des thérapies CAR-T cells au sein d'un centre hospitalier académique français.

Belonging to the family of advanced therapy medicinal products, CAR-T cells have changed the management of hematological malignancies. These treatments are known to involve many actors in a complex process. The quotation of hospital stays associated with this therapeutic strategy is also unusual since there is currently no specific quotation. From November 2021 to May 2022, a study was conducted at the Nancy University Hospital to evaluate the organizational impact of CAR-T cell therapy on hospital actors and the budgetary impact of stays in care centers. Through this study, we have shown significant and variable organizational impacts: from 3.12% of an additional full-time equivalent for an administrative manager to 41.5% for a clinical research associate. These times, when compared to the hourly rates of the actors, generated high costs: 6582.81 € per patient, i.e. 15.60% of the total cost of hospitalization. Taking into account the current refund of hospital stays and the costs calculated above, the balance of an average hospital stay is a deficit of 674.10 € [±10,224.79] with a median of 1334.97 €. This study highlighted the workload generated by the management of these new therapies, as well as the fragile balance of financing hospital stays. To date, it seems necessary and even essential to adapt the quotations of the acts dedicated to CAR-T cells activity and to provide adequate funding through an adapted pricing system.

A French single-center experience on allogeneic stem cell transplant cryopreservation during severe acute respiratory syndrome coronavirus 2 pandemic.

BACKGROUND AIMS: Allogeneic hematopoietic stem cell transplantation (allo-SCT) is a curative treatment for chemo-resistant hematological malignancies. Because of transport restriction imposed by the coronavirus disease 2019 pandemic, regulatory bodies and societies recommended graft cryopreservation before recipient conditioning. However, the freezing and thawing processes, including washing steps, might impair CD34+ cell recovery and viability, thereby impacting the recipient engraftment. Over 1 year (between March 2020 and May 2021), we aimed to analyze the results of frozen/thawed peripheral blood stem cell allografts in terms of stem cell quality and clinical outcomes. METHODS: Transplant quality was evaluated by comparing total nucleated cells (TNCs), CD34+ cells and colony-forming unit-granulocyte/macrophage (CFU-GM)/kg numbers as well as TNC and CD34+ cell viabilities before and after thawing. Intrinsic biological parameters such as granulocyte, platelet and CD34+ cell concentrations were analyzed, as they might be responsible for a quality loss. The impact of the CD34+ cell richness of the graft on TNC and CD34 yields was evaluated by designing three groups of transplants based on their CD34 /kg value at collection: >8 × 10 6/kg, between 6 and 8 × 106/kg and <6 × 106/kg. The consequences of cryopreservation were compared in the fresh and thawed group by evaluating the main transplant outcomes. RESULTS: Over 1 year, 76 recipients were included in the study; 57 patients received a thawed and 19 patients a fresh allo-SCT. None received allo-SCT from a severe acute respiratory syndrome coronavirus 2-positive donor. The freezing of 57 transplants led to the storage of 309 bags, for a mean storage time (between freezing and thawing) of 14 days. For the fresh transplant group, only 41 bags were stored for potential future donor lymphocyte infusions. Regarding the graft characteristics at collection, median number of cryopreserved TNC and CD34+ cells/kg were greater than those for fresh infusions. After thawing, median yields were 74.0%, 69.0% and 48.0% for TNC, CD34+ cells and CFU-GM, respectively. The median TNC dose/kg obtained after thawing was 5.8 × 108, with a median viability of 76%. The median CD34+ cells/kg was 5 × 106, with a median viability of 87%. In the fresh transplant group, the median TNC/kg was 5.9 × 108/kg, and the median CD34+ cells/kg and CFU-GM/kg were 6 × 106/kg and 276.5 × 104/kg, respectively. Sixty-one percent of the thawed transplants were out of specifications regarding the CD34+ cells/ kg requested cell dose (6 × 106/kg) and 85% of them would have had this dose if their hematopoietic stem cell transplant had been infused fresh. Regarding fresh grafts, 15.8% contained less than 6 × 106 CD34+ cells /kg and came from peripheral blood stem cells that did not reach 6 × 106 CD34+ cells /kg at collection. Regarding the factor that impaired CD34 and TNC yield after thawing, no significant impact of the granulocyte count, the platelet count or the CD34+ cells concentration/µL was observed. However, grafts containing more than 8 × 10 6/kg at collection showed a significantly lower TNC and CD34 yield. CONCLUSIONS: Transplant outcomes (engraftment, graft-versus-host disease, infections, relapse or death) were not significantly different between the two groups.

Systematic Review on CAR-T Cell Clinical Trials Up to 2022: Academic Center Input.

The development of Chimeric Antigen Receptor T cells therapy initiated by the United States and China is still currently led by these two countries with a high number of clinical trials, with Europe lagging in launching its first trials. In this systematic review, we wanted to establish an overview of the production of CAR-T cells in clinical trials around the world, and to understand the causes of this delay in Europe. We particularly focused on the academic centers that are at the heart of research and development of this therapy. We counted 1087 CAR-T cells clinical trials on ClinicalTrials.gov (Research registry ID: reviewregistry1542) on the date of 25 January 2023. We performed a global analysis, before analyzing the 58 European trials, 34 of which sponsored by academic centers. Collaboration between an academic and an industrial player seems to be necessary for the successful development and application for marketing authorization of a CAR-T cell, and this collaboration is still cruelly lacking in European trials, unlike in the leading countries. Europe, still far behind the two leading countries, is trying to establish measures to lighten the regulations surrounding ATMPs and to encourage, through the addition of fundings, clinical trials involving these treatments.

Wharton's jelly-derived stromal cells and their cell therapy applications in allogeneic haematopoietic stem cell transplantation.

For decades, mesenchymal stromal cells (MSCs) have been of great interest in the fields of regenerative medicine, tissue engineering and immunomodulation. Their tremendous potential makes it desirable to cryopreserve and bank MSCs to increase their accessibility and availability. Postnatally derived MSCs seem to be of particular interest because they are harvested after delivery without ethical controversy, they have the capacity to expand at a higher rate than adult-derived MSCs, in which expansion decreases with ageing, and they have demonstrated immunological and haematological supportive properties similar to those of adult-derived MSCs. In this review, we focus on MSCs obtained from Wharton's jelly (the mucous connective tissue of the umbilical cord between the amniotic epithelium and the umbilical vessels). Wharton's jelly MSCs (WJ-MSCs) are a good candidate for cellular therapy in haematology, with accumulating data supporting their potential to sustain haematopoietic stem cell engraftment and to modulate alloreactivity such as Graft Versus Host Disease (GVHD). We first present an overview of their in-vitro properties and the results of preclinical murine models confirming the suitability of WJ-MSCs for cellular therapy in haematology. Next, we focus on clinical trials and discuss tolerance, efficacy and infusion protocols reported in haematology for GVHD and engraftment.

Umbilical cord blood transplants facilitated by the French cord blood banks network. On behalf of the Agency of Biomedicine, Eurocord and the French society of bone marrow transplant and cell therapy (SFGM-TC).

The public French Cord Blood Banks Network was established in 1999 with the objective of standardizing the practices governing umbilical cord blood (UCB) banking in France. The Network adopted a strategy to optimize its inventory and improve the quality of its banked units based on a quality improvement process using outcome data regularly provided by Eurocord. This study aimed to describe the results, over 10 years, of UCBT facilitated by a national network that used the same criteria of UCB collection and banking and to assess how modifications of banking criteria and unit selection might influence transplant outcomes. Nine hundred and ninety-nine units (593 single-unit and 203 double-unit grafts) were released by the Network to transplant 796 patients with malignant (83%) and non-malignant (17%) diseases. Median cell dose exceeded 3.5 × 107 TNC/kg in 86%. There was a trend to select units more recently collected and with higher cell dose. Neutrophil engraftment was 88.2% (85.7-90.7) and 79.3% (72.6-86.5) respectively for malignant and non-malignant diseases with a trend to faster recovery with higher cell doses. The respective 3-year transplant-related mortality were 31.1% (27.5-35.1) and 34.3% (27.0-43.5). OS was 49% ± 4 in malignant and 62% ± 4 in non-malignant disorders. In multivariate analysis, cell dose was the only unit-related factor associated with outcomes. Our results reflect the benefit on clinical outcomes of the strategy adopted by the Network to bank units with higher cell counts.

Natural Killer cells and monoclonal antibodies: Two partners for successful antibody dependent cytotoxicity against tumor cells.

Monoclonal antibodies targeting tumors are one of the most important discoveries in the field of cancer. Although several effective antibodies have been developed, a relapse may occur. One of their mechanisms of action is Antibody Dependent Cell Cytotoxicity (ADCC), by engaging the Fc γ receptor CD16 expressing Natural Killer cells, innate lymphoid cells involved in cancer immunosurveillance and able to kill tumor cells. A lack of NK cells observed in many cancers may therefore be a cause of the low efficacy of antibodies observed in some clinical situations. Here we review clear evidences of the essential partnership between NK cells and antibodies showed in vitro, in vivo, and in clinical trials in different indications, describe the hurdles and ways to enhance ADCC and the evolution of monoclonal antibody therapy. NK cell adoptive immunotherapy combined with monoclonal antibodies may overcome the resistance to the treatment and enhance their efficacy.

Mesenchymal stromal cells for sepsis and septic shock: Lessons for treatment of COVID-19.

Sepsis is defined as life-threatening organ dysfunction caused by a deregulated immune host response to infection. The emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has highlighted this multifactorial and complex syndrome. The absence of specific treatment neither against SARS-CoV-2 nor against acute respiratory distress syndrome (ARDS), the most serious stage of this infection, has emphasized the need to find alternative treatments. Several therapeutics are currently being tested, including mesenchymal stromal cells. These cells, already used in preclinical models of ARDS, sepsis, and septic shock and also in a few clinical trials, appear well-tolerated and promising, but many questions remain unanswered.

Mesenchymal Stem/Stromal Cell Production Compliant with Good Manufacturing Practice: Comparison between Bone Marrow, the Gold Standard Adult Source, and Wharton's Jelly, an Extraembryonic Source.

Many clinical trials report mesenchymal stem/stromal cells (MSCs) efficacy in various indications. Therefore, standardization of MSC production becomes necessary. MSC properties are impacted by tissue origin, especially if they are from extraembryonic tissue or adult sources. For this reason, we evaluated the impact of MSC tissue origin on production. METHODS: Three productions of MSC from Wharton's Jelly (WJ) or from bone marrow (BM) were performed according to good manufacturing practice. The identity (phenotype, differentiation, and clonogenic capacities), safety (karyotype, telomerase activity, sterility, and donor qualification), and functionality (viability, mixed lymphocyte reaction) of each cell batch were analyzed. RESULTS: Slight differences between MSC sources were observed for phenotype, telomerase activity, and clonogenic capacities. CONCLUSION: Both sources have made it possible to quickly and easily obtain clinical grade MSC. However, as availability of the source is thought to be essential, WJ seems more advantageous than BM.

Bone marrow vs Wharton's jelly mesenchymal stem cells in experimental sepsis: a comparative study.

BACKGROUND: The use of mesenchymal stem cells (MSCs) is being extensively studied in clinical trials in the setting of various diseases including diabetes, stroke, and progressive multiple sclerosis. The unique immunomodulatory properties of MSCs also point them as a possible therapeutic tool during sepsis and septic shock, a devastating syndrome associated with 30-35% mortality. However, MSCs are not equal regarding their activity, depending on their tissue origin. Here, we aimed at comparing the in vivo properties of MSCs according to their tissue source (bone marrow (BM) versus Wharton's jelly (WJ)) in a murine cecal ligation and puncture (CLP) model of sepsis that mimics a human peritonitis. We hypothesized that MSC properties may vary depending on their tissue source in the setting of sepsis. METHODS: CLP, adult, male, C57BL/6 mice were randomized in 3 groups receiving respectively 0.25 × 106 BM-MSCs, 0.25 × 106 WJ-MSCs, or 150 µL phosphate-buffered saline (PBS) intravenously 24 h after the CLP procedure. RESULTS: We observed that both types of MSCs regulated leukocyte trafficking and reduced organ dysfunction, while only WJ-MSCs were able to improve bacterial clearance and survival. CONCLUSION: This study highlights the importance to determine the most appropriate source of MSCs for a given therapeutic indication and suggests a better profile for WJ-MSCs during sepsis.

Clinical-grade mesenchymal stem cells derived from umbilical cord improve septic shock in pigs.

BACKGROUND: Septic shock is the leading cause of death in intensive care units. The pathophysiological complexity of this syndrome contributes to an absence of specific treatment. Several preclinical studies in murine models of septic shock have shown improvements to organ injury and survival after administration of mesenchymal stem cells (MSCs). To better mimic a clinical approach in humans, we investigated the impact of randomized controlled double-blind administration of clinical-grade umbilical cord-derived MSCs to a relevant pig model of septic shock. METHODS: Septic shock was induced by fecal peritonitis in 12 male domestic pigs. Animals were resuscitated by an experienced intensivist including fluid administration and vasopressors. Four hours after the induction of peritonitis, pigs were randomized to receive intravenous injection of thawed umbilical cord-derived MSCs (UCMSC) (1 × 106 UCMSCs/kg diluted in 75 mL hydroxyethyl starch (HES), (n = 6) or placebo (HES alone, n = 6). Researchers were double-blinded to the treatment administered. Hemodynamic parameters were continuously recorded. Gas exchange, acid-base status, organ function, and plasma cytokine concentrations were assessed at regular intervals until 24 h after the onset of peritonitis when animals were sacrificed under anesthesia. RESULTS: Peritonitis induced profound hypotension, hyperlactatemia, and multiple organ failure. These disorders were significantly attenuated when animals were treated with UCMSCs. In particular, cardiovascular failure was attenuated, as attested by a better mean arterial pressure and reduced lactatemia, despite lower norepinephrine requirements. As such, UCMSCs improved survival in this very severe model (60% survival vs. 0% at 24 h). CONCLUSION: UCMSCs administration is beneficial in this pig model of polymicrobial septic shock.

Adenovirus-specific T-lymphocyte efficacy in the presence of methylprednisolone: An in vitro study.

Virus-specific T-cell (VST) infusion becomes a promising alternative treatment for refractory viral infections after hematopoietic stem cell transplantation (HSCT). However, VSTs are often infused during an immunosuppressive treatment course, especially corticosteroids, which are a first-line curative treatment of graft-versus-host disease (GVHD). We were interested in whether corticosteroids could affect adenovirus (ADV)-VST functions. After interferon (IFN)-γ based immunomagnetic selection, ADV-VSTs were in vitro expanded according to three different culture conditions: without methylprednisolone (MP; n = 7), with a final concentration of MP 1 µg/mL (n = 7) or MP 2 µg/mL (n = 7) during 28 ± 11 days. Efficacy and alloreactivity of expanded ADV-VSTs was controlled in vitro. MP transitorily inhibited ADV-VST early expansion. No impairment of specific IFN-γ secretion capacity and cytotoxicity of ADV-VSTs was observed in the presence of MP. However, specific proliferation and alloreactivity of ADV-VSTs were decreased in the presence of MP. Altogether, these results and the preliminary encouraging clinical experiences of co-administration of MP 1 mg/kg and ADV-VSTs will contribute to safe and efficient use of anti-viral immunotherapy.

Modification of NK cell subset repartition and functions in granulocyte colony-stimulating factor-mobilized leukapheresis after expansion with IL-15.

The ability of natural killer (NK) cells to kill tumor cells without antigen recognition makes them appealing as an adoptive immunotherapy. However, NK cells are not routinely used in the context of leukemic relapse after hematopoietic stem cell transplantation. Patients who experience relapse can be treated with donor lymphocyte infusions (DLI) based on small-cell fractions frozen at the time of transplantation. Since peripheral blood stem cells (PBSCs) are increasingly used as a stem cell source and as a source of cells for DLI, we aimed to evaluate the impact of G-SCF mobilization on NK cell phenotype, subset repartition, and functionality. Immunomagnetically isolated NK cells from healthy donor blood, donor PBSCs, and patient PBSCs were expanded for 14 days with IL-15. The expansion capacity, phenotype, and functions (cytokine secretion and cytotoxicity) of NK cell subsets based on CD56 and CD16 expression were then evaluated. Mobilized sources showed a significant decrease of CD56brightCD16+ NK cells (28 versus 74%), whereas a significant increase (64 versus 15%) of CD56brightCD16- NK cells was observed in comparison with peripheral blood. Patient-mobilized NK cells showed a significantly decreased cytotoxicity, and antibody-dependent cell cytototoxicity (ADCC) was also observed to a lesser extent in NK cells from healthy donor PBSC. G-CSF-mobilized NK cell TNF-α and IFN-γ secretion was impaired at day 0 compared to healthy donors but was progressively restored after culture. In conclusion, expansion of NK cells from G-CSF-mobilized sources may progressively improve their functionality.

Concise Review: Mesenchymal Stromal/Stem Cells: A New Treatment for Sepsis and Septic Shock?

Sepsis and septic shock are the leading cause of admission and mortality in non-coronary intensive care units. Currently, however, no specific treatments are available for this syndrome. Due to the failure of conventional treatments in recent years, research is focusing on innovative therapeutic agents, including cell therapy. One particular type of cell, mesenchymal stromal/stem cells (MSCs), has raised hopes for the treatment of sepsis. Indeed, their immunomodulatory properties, antimicrobial activity and capacity of protection against organ failure confer MSCs with a major advantage to treat the immune and inflammatory dysfunctions associated with sepsis and septic shock. After a brief description of the pathophysiology of sepsis and septic shock, the latest advances in the use of MSCs to treat sepsis will be presented. Stem Cells 2017;35:2331-2339.

Umbilical cord-derived mesenchymal stromal cells: predictive obstetric factors for cell proliferation and chondrogenic differentiation.

BACKGROUND: The umbilical cord is becoming a notable alternative to bone marrow (BM) as a source of mesenchymal stromal cells (MSC). Although age-dependent variations in BM-MSC are well described, less data are available for MSC isolated from Wharton's jelly (WJ-MSC). We initiated a study to identify whether obstetric factors influenced MSC properties. We aimed to evaluate the correlation between a large number of obstetric factors collected during pregnancy and until peripartum (related to the mother, the labor and delivery, and the newborn) with WJ-MSC proliferation and chondrogenic differentiation parameters. METHODS: Correlations were made between 27 obstetric factors and 8 biological indicators including doubling time at passage (P)1 and P2, the percentage of proteoglycans and collagens, and the relative transcriptional expression of Sox-9, aggrecans, and total type 2 collagen (Coll2T). RESULTS: Amongst the obstetric factors considered, birth weight, the number of amenorrhea weeks, placental weight, normal pregnancy, and the absence of preeclampsia were identified as relevant factors for cell expansion, using multivariate linear regression analysis. Since all the above parameters are related to term, we concluded that WJ-MSC from healthy, full-term infants exhibit greater proliferation capacity. As for chondrogenesis, we also observed that obstetric factors influencing proliferation seemed beneficial, with no negative impact on MSC differentiation. CONCLUSIONS: Awareness of obstetric factors influencing the proliferation and/or differentiation of WJ-MSC will make it possible to define criteria for collecting optimal umbilical cords with the aim of decreasing the variability of WJ-MSC batches produced for clinical use in cell and tissue engineering.

Curative or pre-emptive adenovirus-specific T cell transfer from matched unrelated or third party haploidentical donors after HSCT, including UCB transplantations: a successful phase I/II multicenter clinical trial.

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (HSCT), the most widely used potentially curable cellular immunotherapeutic approach in the treatment of hematological malignancies, is limited by life-threatening complications: graft versus host disease (GVHD) and infections especially viral infections refractory to antiviral drugs. Adoptive transfer of virus-specific T cells is becoming an alternative treatment for infections following HSCT. We report here the results of a phase I/II multicenter study which includes a series of adenovirus-specific T cell (ADV-VST) infusion either from the HSCT donor or from a third party haploidentical donor for patients transplanted with umbilical cord blood (UCB). METHODS: Fourteen patients were eligible and 11 patients received infusions of ADV-VST generated by interferon (IFN)-γ-based immunomagnetic isolation from a leukapheresis from their original donor (42.9%) or a third party haploidentical donor (57.1%). One patient resolved ADV infection before infusion, and ADV-VST could not reach release or infusion criteria for two patients. Two patients received cellular immunotherapy alone without antiviral drugs as a pre-emptive treatment. RESULTS: One patient with adenovirus infection and ten with adenovirus disease were infused with ADV-VST (mean 5.83 ± 8.23 × 103 CD3+IFN-γ+ cells/kg) up to 9 months after transplantation. The 11 patients showed in vivo expansion of specific T cells up to 60 days post-infusion, associated with adenovirus load clearance in ten of the patients (91%). Neither de novo GVHD nor side effects were observed during the first month post-infusion, but GVHD reactivations occurred in three patients, irrespective of the type of leukapheresis donor. For two of these patients, GVHD reactivation was controlled by immunosuppressive treatment. Four patients died during follow-up, one due to refractory ADV disease. CONCLUSIONS: Adoptive transfer of rapidly isolated ADV-VST is an effective therapeutic option for achieving in vivo expansion of specific T cells and clearance of viral load, even as a pre-emptive treatment. Our study highlights that third party haploidentical donors are of great interest for ADV-VST generation in the context of UCB transplantation. (N° Clinical trial.gov: NCT02851576, retrospectively registered).

Mesenchymal Stem Cells Derived from Human Bone Marrow and Adipose Tissue Maintain Their Immunosuppressive Properties After Chondrogenic Differentiation: Role of HLA-G.

Mesenchymal stem cells (MSC) have emerged as alternative sources of stem cells for regenerative medicine because of their multipotency and strong immune-regulatory properties. Also, human leukocyte antigen G (HLA-G) is an important mediator of MSC-mediated immunomodulation. However, it is unclear whether MSC retain their immune-privileged potential after differentiation. As promising candidates for cartilage tissue engineering, the immunogenic and immunomodulatory properties of chondro-differentiated MSC (chondro-MSC) require in-depth exploration. In the present study, we used the alginate/hyaluronic acid (Alg/HA) hydrogel scaffold and induced both bone marrow- and adipose tissue-derived MSC into chondrocytes in three-dimensional condition. Then, MSC before and after chondrocyte differentiation were treated or not with interferon γ and tumor necrosis factor α mimicking inflammatory conditions and were compared side by side using flow cytometry, mixed lymphocyte reaction, and immunostaining assays. Results showed that chondro-MSC were hypoimmunogenic and could exert immunosuppression on HLA-mismatched peripheral blood mononuclear cells as well as undifferentiated MSC did. This alloproliferation inhibition mediated by MSC or chondro-MSC was dose dependent. Meanwhile, chondro-MSC exerted inhibition on natural killer cell-mediated cytolysis. Also, we showed that HLA-G expression was upregulated in chondro-MSC under hypoxia context and could be boosted in allogenic settings. Besides, the Alg/HA hydrogel scaffold was hypoimmunogenic and its addition for supporting MSC chondrocyte differentiation did not modify the immune properties of MSC. Finally, considering their chondro-regenerative potential and their retained immunosuppressive capacity, MSC constitute promising allogenic sources of stem cells for cartilage repair.

Adenovirus-specific T-cell Subsets in Human Peripheral Blood and After IFN-γ Immunomagnetic Selection.

Adoptive antiviral cellular immunotherapy by infusion of virus-specific T cells (VSTs) is becoming an alternative treatment for viral infection after hematopoietic stem cell transplantation. The T memory stem cell (TSCM) subset was recently described as exhibiting self-renewal and multipotency properties which are required for sustained efficacy in vivo. We wondered if such a crucial subset for immunotherapy was present in VSTs. We identified, by flow cytometry, TSCM in adenovirus (ADV)-specific interferon (IFN)-γ+ T cells before and after IFN-γ-based immunomagnetic selection, and analyzed the distribution of the main T-cell subsets in VSTs: naive T cells (TN), TSCM, T central memory cells (TCM), T effector memory cell (TEM), and effector T cells (TEFF). In this study all of the different T-cell subsets were observed in the blood sample from healthy donor ADV-VSTs, both before and after IFN-γ-based immunomagnetic selection. As the IFN-γ-based immunomagnetic selection system sorts mainly the most differentiated T-cell subsets, we observed that TEM was always the major T-cell subset of ADV-specific T cells after immunomagnetic isolation and especially after expansion in vitro. Comparing T-cell subpopulation profiles before and after in vitro expansion, we observed that in vitro cell culture with interleukin-2 resulted in a significant expansion of TN-like, TCM, TEM, and TEFF subsets in CD4IFN-γ T cells and of TCM and TEM subsets only in CD8IFN-γ T cells. We demonstrated the presence of all T-cell subsets in IFN-γ VSTs including the TSCM subpopulation, although this was weakly selected by the IFN-γ-based immunomagnetic selection system.

Adoptive Immunotherapies After Allogeneic Hematopoietic Stem Cell Transplantation in Patients With Hematologic Malignancies.

Hematopoietic stem cell transplantation (HSCT) is the only curative therapy for patients with chemotherapy-resistant hematologic malignancies that are usually fatal in absence of treatment. Hematopoietic stem cell transplantation is associated with significant early and late morbidity and mortality. Graft-versus-host disease, infections, and relapse are the most important causes of mortality after HSCT. Until now, these complications have been managed mainly with pharmacological drugs, but in some situations, this approach clearly shows its limit. As such, there is a significant need for novel therapies for the treatment of complications after allogeneic HSCT. In this review, the currently available adoptive immunotherapies offering an alternative in case of treatment failure of HSCT complications will be described. The results of the main clinical trials based on immune cell infusion will be discussed and the strategies aiming at maximizing cytotoxic T-lymphocyte, regulatory T-cell, natural killer cell, cytokine-induced killer cell, and γδ T-cell efficacies in the context of immunotherapy approaches after allogeneic HSCT in patients with hematologic malignancies will be gathered.