Congenital sideroblastic anaemias (CSA) are a rare group of disorders characterized by the presen... more Congenital sideroblastic anaemias (CSA) are a rare group of disorders characterized by the presence of pathologic iron deposits within the mitochondria of erythroid precursors (ring sideroblasts) in the bone marrow due to heterogenous germline mutations leading to defects in mitochondrial heme synthesis, iron-sulfur (Fe-S) cluster biogenesis, or protein synthesis. Patients present with anaemia and relative reticulocytopenia, and systemic iron overload secondary to chronic ineffective erythropoiesis, leading to end-organ damage. The disease is heterogenous underlying the genetic variability and the variable response to treatment. Although a number of CSA patients have received a bone marrow transplant, the outcomes and toxicities are not known. This status makes it very difficult to understand the role of BMT in the management of CSA. A search in the EBMT database identified 28 patients receiving a HSCT for CSA between 1998 to 2018 by 24 participating centres. The median year of tran...
Haematopoietic stem cell transplantation is increasingly used as consolidation therapy in severe ... more Haematopoietic stem cell transplantation is increasingly used as consolidation therapy in severe haematological diseases. In the post-transplantation period, the immunity of haematopoietic stem cell transplantation recipients is impaired due to toxicity of the pre-haematopoietic stem cell transplantation treatment (chemo- and/or radiotherapy), the conditioning regimen with a reset of the immune system, and – in case of allogeneic haematopoietic stem cell transplantation – the use of immunosuppressive drugs and potentially graft-versus-host-disease. This leads to a considerably increased risk of infections, with high morbidity and mortality. Therefore, prevention of infections, i.a. by revaccination, is of major importance to improve outcomes. We present the Belgian guidelines for vaccination after haematopoietic stem cell transplantation, based on available data in the literature and international guidelines, taking into account the availability of vaccines and - if applicable - the...
IntroductionSystemic sclerosis (SSc) is a chronic, autoimmune connective tissue disease associate... more IntroductionSystemic sclerosis (SSc) is a chronic, autoimmune connective tissue disease associated with high morbidity and mortality, especially in diffuse cutaneous SSc (dcSSc). Currently, there are several treatments available in early dcSSc that aim to change the disease course, including immunosuppressive agents and autologous haematopoietic stem cell transplantation (HSCT). HSCT has been adopted in international guidelines and is offered in current clinical care. However, optimal timing and patient selection for HSCT are still unclear. In particular, it is unclear whether HSCT should be positioned as upfront therapy or rescue treatment for patients refractory to immunosuppressive therapy. We hypothesise that upfront HSCT is superior and results in lower toxicity and lower long-term medical costs. Therefore, we propose this randomised trial aiming to determine the optimal treatment strategy for early dcSSc by comparing two strategies used in standard care: (1) upfront autologous...
ABSTRACT Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative trea... more ABSTRACT Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment option in both adult and pediatric patients with malignant and non-malignant hematological diseases. Chimerism analysis, which determines the donor or recipient origin of hematopoietic cells in HSCT recipients, is an essential aspect of post-HSCT follow-up.Objectives: To review the current literature and develop Belgian consensus guidelines for the use of chimerism analysis in the standard of care after allogeneic HSCT.Methods: Non-systematic review of the literature in consultancy with the members of the BHS transplantation committee.Results: Clinical application with regards to prediction of graft failure or relapse as well as cell source are reviewed. A consensus guideline on the use of chimerism analysis after HSCT is presented.Conclusion: Monitoring of the dynamics or kinetics of a patient’s chimerism status by serial analysis at fixed time points, as well as on suspicion of relapse or graft failure, is needed to monitor engraftment levels, as well as disease control and possible relapse.
More patients with chronic hepatitis B and C infection are being exposed to immune checkpoint inh... more More patients with chronic hepatitis B and C infection are being exposed to immune checkpoint inhibitors (ICIs), but the safety and efficacy of ICIs in patients with chronic viral hepatitis are still poorly described. To explore this interaction, we identified eight studies of cancer patients with viral hepatitis treated with one or more ICIs, formally assessed tumor responses and safety by grading liver dysfunction. ICIs appear to be relatively safe in HBV/HCV-infected patients, and hepatitis related to viral reactivation is rare. In some patients, viral load regressed during ICI treatment, so immune checkpoints may play a role in viral clearance. HBV/HCV do not appear to be a contraindication to ICIs, although careful clinical and biochemical follow-up is recommended and, whenever necessary, antiviral therapy commenced.
Patient characteristics Bone marrow (BM) and/or peripheral blood (PB) samples from 29 pedAML pati... more Patient characteristics Bone marrow (BM) and/or peripheral blood (PB) samples from 29 pedAML patients were evaluated for TARP expression (Table S2). Patients were selected based on sample availability (>50x10 cells) and CD34 expression (≥1%). Patients were treated according to the DB-AML01 protocol (n=9), NOPHO-DBH AML2012 protocol (n=15) or treated otherwise (n=5). In addition, samples were collected from healthy subjects. Pediatric normal bone marrow (NBM, n=13, 12-18 yr.) was collected from posterior iliac crest during scoliosis surgery. Cord blood (CB, n=15) was obtained after full-term vaginal deliveries. Mobilized peripheral blood stem cells (mPBSCs) were collected from apheresis of adult donors pre-allotransplant (n=4). All healthy subjects and patients and/or their guardians gave informed consent. Approval was issued by the ethical committee in accordance with the declaration of Helsinki (EC2015-1443 and EC2019-0294).
Introduction: Therapy-related myeloid neoplasms (t-MNs) account for about 10 to 20% of all cases ... more Introduction: Therapy-related myeloid neoplasms (t-MNs) account for about 10 to 20% of all cases of AML and MDS. Allogenic hematopoietic cell transplantation (allo-HCT) is considered as the only curative treatment in this high-risk setting. Given the rise of long-term cancer survivors, an increasing number of patients are expected to become transplant candidates. Physicians are concerned about the frailty and the risk of recurrence of primary cancer. In this retrospective registry-based study, we focused on patients with t-MN secondary to breast cancer radio- and/or chemotherapy, and collected information about the outcomes and complications after allo-HCT. Methods and results: In the EBMT registry we identified 252 female adult patients who underwent an allo-HCT between 2006 and 2016 for t-MN secondary to breast cancer treatment. Median age at transplantation was 57 years, and the median time from the breast cancer diagnosis to t-MN diagnosis and subsequent allo-HCT were 3.7 and 4....
Human thymic CD8αα+ CD10+ PD-1+ αβ T cells selected through early agonist selection have been pro... more Human thymic CD8αα+ CD10+ PD-1+ αβ T cells selected through early agonist selection have been proposed as the putative thymic precursors of the human CD8αα+ intestinal intraepithelial lymphocytes (IELs). However, the progeny of these thymic precursor cells in human blood or tissues has not yet been characterized. Here, we studied the phenotypical and transcriptional differentiation of the thymic IEL precursor (IELp) lineage upon in vitro exposure to cytokines prominent in the peripheral tissues such as interleukin-15 (IL-15) and the inflammatory cytokines interleukin-12 (IL-12) and interleukin-18 (IL-18). We showed that only the CD1a− fraction of the CD10+ PD-1+ IELp population was able to proliferate with IL-15, suggesting that this subset had acquired functionality. These cells downregulated PD-1 expression and completely lost CD10 expression, whereas other surface markers such as CD95 and CXCR3 remained highly expressed. RNA-seq analysis of the IL-15-cultured cells clearly showed...
γδ and αβ T cells have unique roles in immunity and both originate in the thymus from T‐lineage c... more γδ and αβ T cells have unique roles in immunity and both originate in the thymus from T‐lineage committed precursors through distinct but unclear mechanisms. Here, we show that Notch1 activation is more stringently required for human γδ development compared to αβ‐lineage differentiation and performed paired mRNA and miRNA profiling across 11 discrete developmental stages of human T cell development in an effort to identify the potential Notch1 downstream mechanism. Our data suggest that the miR‐17–92 cluster is a Notch1 target in immature thymocytes and that miR‐17 can restrict BCL11B expression in these Notch‐dependent T cell precursors. We show that enforced miR‐17 expression promotes human γδ T cell development and, consistently, that BCL11B is absolutely required for αβ but less for γδ T cell development. This study suggests that human γδ T cell development is mediated by a stage‐specific Notch‐driven negative feedback loop through which miR‐17 temporally restricts BCL11B expression and provides functional insights into the developmental role of the disease‐associated genes BCL11B and the miR‐17–92 cluster in a human context.
Chimeric antigen receptor (CAR)-T-cell therapy is an innovative form of adoptive cell therapy tha... more Chimeric antigen receptor (CAR)-T-cell therapy is an innovative form of adoptive cell therapy that has revolutionized the treatment of certain hematological malignancies, including B-cell non-Hodgkin lymphoma (NHL) and B-cell acute lymphoblastic leukemia (ALL). The treatment is currently also being studied in other B-cell neoplasms, including multiple myeloma (MM) and chronic lymphocytic leukemia (CLL). CD19 and B-cell maturation antigen (BCMA) have been the most popular target antigens for CAR-T-cell immunotherapy of these malignancies. This review will discuss the efficacy and toxicity data from the pivotal clinical studies of CD19- and BCMA-targeted CAR-T-cell therapies in relapsed/refractory B-cell malignancies (NHL, ALL, CLL) and MM, respectively.
Recent approval of chimeric antigen receptor (CAR) T cell therapy by the European Medicines Agenc... more Recent approval of chimeric antigen receptor (CAR) T cell therapy by the European Medicines Agency (EMA)/Federal and Drug Administration (FDA) and the remarkable results of CAR T clinical trials illustrate the curative potential of this therapy. While CARs against a multitude of different antigens are being developed and tested (pre)clinically, there is still a need for optimization. The use of single-chain variable fragments (scFvs) as targeting moieties hampers the quick generation of functional CARs and could potentially limit the efficacy. Instead, nanobodies may largely circumvent these difficulties. We used an available nanobody library generated after immunization of llamas against Cluster of Differentiation (CD) 20 through DNA vaccination or against the ectodomain of CD33 using soluble protein. The nanobody specific sequences were amplified by PCR and cloned by Gibson Assembly into a retroviral vector containing two different second-generation CAR constructs. After transduct...
TPS3093 Background: Chimeric Antigen Receptor (CAR)-T therapy has potentially serious limitations... more TPS3093 Background: Chimeric Antigen Receptor (CAR)-T therapy has potentially serious limitations related to target antigen loss, toxicity due to pre-conditioning regimen, and lack of activity in many tumor types. To overcome these limitations, we have developed a novel CAR-T, called NKR-2, incorporating the full-length human natural killer receptor NKG2D fused with the human CD3 zeta signaling domain. When expressed in T-cells, the naturally-expressed DAP10 provides co-stimulatory signals to NKR-2 to produce cytokines and selectively target tumor cells upon recognition of up to 8 different stress-induced NKG2D ligands expressed in many solid and hematologic malignancies. In preclinical studies, NKR-2 demonstrated long-term anti-tumor activity towards a breadth of tumor indications, in the absence of pre-conditioning, whilst simultaneously targeting tumor cells and cells from the local tumor neo-vasculature and suppressive immune environment. In our recently completed First-in-Human...
Congenital sideroblastic anaemias (CSA) are a rare group of disorders characterized by the presen... more Congenital sideroblastic anaemias (CSA) are a rare group of disorders characterized by the presence of pathologic iron deposits within the mitochondria of erythroid precursors (ring sideroblasts) in the bone marrow due to heterogenous germline mutations leading to defects in mitochondrial heme synthesis, iron-sulfur (Fe-S) cluster biogenesis, or protein synthesis. Patients present with anaemia and relative reticulocytopenia, and systemic iron overload secondary to chronic ineffective erythropoiesis, leading to end-organ damage. The disease is heterogenous underlying the genetic variability and the variable response to treatment. Although a number of CSA patients have received a bone marrow transplant, the outcomes and toxicities are not known. This status makes it very difficult to understand the role of BMT in the management of CSA. A search in the EBMT database identified 28 patients receiving a HSCT for CSA between 1998 to 2018 by 24 participating centres. The median year of tran...
Haematopoietic stem cell transplantation is increasingly used as consolidation therapy in severe ... more Haematopoietic stem cell transplantation is increasingly used as consolidation therapy in severe haematological diseases. In the post-transplantation period, the immunity of haematopoietic stem cell transplantation recipients is impaired due to toxicity of the pre-haematopoietic stem cell transplantation treatment (chemo- and/or radiotherapy), the conditioning regimen with a reset of the immune system, and – in case of allogeneic haematopoietic stem cell transplantation – the use of immunosuppressive drugs and potentially graft-versus-host-disease. This leads to a considerably increased risk of infections, with high morbidity and mortality. Therefore, prevention of infections, i.a. by revaccination, is of major importance to improve outcomes. We present the Belgian guidelines for vaccination after haematopoietic stem cell transplantation, based on available data in the literature and international guidelines, taking into account the availability of vaccines and - if applicable - the...
IntroductionSystemic sclerosis (SSc) is a chronic, autoimmune connective tissue disease associate... more IntroductionSystemic sclerosis (SSc) is a chronic, autoimmune connective tissue disease associated with high morbidity and mortality, especially in diffuse cutaneous SSc (dcSSc). Currently, there are several treatments available in early dcSSc that aim to change the disease course, including immunosuppressive agents and autologous haematopoietic stem cell transplantation (HSCT). HSCT has been adopted in international guidelines and is offered in current clinical care. However, optimal timing and patient selection for HSCT are still unclear. In particular, it is unclear whether HSCT should be positioned as upfront therapy or rescue treatment for patients refractory to immunosuppressive therapy. We hypothesise that upfront HSCT is superior and results in lower toxicity and lower long-term medical costs. Therefore, we propose this randomised trial aiming to determine the optimal treatment strategy for early dcSSc by comparing two strategies used in standard care: (1) upfront autologous...
ABSTRACT Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative trea... more ABSTRACT Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment option in both adult and pediatric patients with malignant and non-malignant hematological diseases. Chimerism analysis, which determines the donor or recipient origin of hematopoietic cells in HSCT recipients, is an essential aspect of post-HSCT follow-up.Objectives: To review the current literature and develop Belgian consensus guidelines for the use of chimerism analysis in the standard of care after allogeneic HSCT.Methods: Non-systematic review of the literature in consultancy with the members of the BHS transplantation committee.Results: Clinical application with regards to prediction of graft failure or relapse as well as cell source are reviewed. A consensus guideline on the use of chimerism analysis after HSCT is presented.Conclusion: Monitoring of the dynamics or kinetics of a patient’s chimerism status by serial analysis at fixed time points, as well as on suspicion of relapse or graft failure, is needed to monitor engraftment levels, as well as disease control and possible relapse.
More patients with chronic hepatitis B and C infection are being exposed to immune checkpoint inh... more More patients with chronic hepatitis B and C infection are being exposed to immune checkpoint inhibitors (ICIs), but the safety and efficacy of ICIs in patients with chronic viral hepatitis are still poorly described. To explore this interaction, we identified eight studies of cancer patients with viral hepatitis treated with one or more ICIs, formally assessed tumor responses and safety by grading liver dysfunction. ICIs appear to be relatively safe in HBV/HCV-infected patients, and hepatitis related to viral reactivation is rare. In some patients, viral load regressed during ICI treatment, so immune checkpoints may play a role in viral clearance. HBV/HCV do not appear to be a contraindication to ICIs, although careful clinical and biochemical follow-up is recommended and, whenever necessary, antiviral therapy commenced.
Patient characteristics Bone marrow (BM) and/or peripheral blood (PB) samples from 29 pedAML pati... more Patient characteristics Bone marrow (BM) and/or peripheral blood (PB) samples from 29 pedAML patients were evaluated for TARP expression (Table S2). Patients were selected based on sample availability (>50x10 cells) and CD34 expression (≥1%). Patients were treated according to the DB-AML01 protocol (n=9), NOPHO-DBH AML2012 protocol (n=15) or treated otherwise (n=5). In addition, samples were collected from healthy subjects. Pediatric normal bone marrow (NBM, n=13, 12-18 yr.) was collected from posterior iliac crest during scoliosis surgery. Cord blood (CB, n=15) was obtained after full-term vaginal deliveries. Mobilized peripheral blood stem cells (mPBSCs) were collected from apheresis of adult donors pre-allotransplant (n=4). All healthy subjects and patients and/or their guardians gave informed consent. Approval was issued by the ethical committee in accordance with the declaration of Helsinki (EC2015-1443 and EC2019-0294).
Introduction: Therapy-related myeloid neoplasms (t-MNs) account for about 10 to 20% of all cases ... more Introduction: Therapy-related myeloid neoplasms (t-MNs) account for about 10 to 20% of all cases of AML and MDS. Allogenic hematopoietic cell transplantation (allo-HCT) is considered as the only curative treatment in this high-risk setting. Given the rise of long-term cancer survivors, an increasing number of patients are expected to become transplant candidates. Physicians are concerned about the frailty and the risk of recurrence of primary cancer. In this retrospective registry-based study, we focused on patients with t-MN secondary to breast cancer radio- and/or chemotherapy, and collected information about the outcomes and complications after allo-HCT. Methods and results: In the EBMT registry we identified 252 female adult patients who underwent an allo-HCT between 2006 and 2016 for t-MN secondary to breast cancer treatment. Median age at transplantation was 57 years, and the median time from the breast cancer diagnosis to t-MN diagnosis and subsequent allo-HCT were 3.7 and 4....
Human thymic CD8αα+ CD10+ PD-1+ αβ T cells selected through early agonist selection have been pro... more Human thymic CD8αα+ CD10+ PD-1+ αβ T cells selected through early agonist selection have been proposed as the putative thymic precursors of the human CD8αα+ intestinal intraepithelial lymphocytes (IELs). However, the progeny of these thymic precursor cells in human blood or tissues has not yet been characterized. Here, we studied the phenotypical and transcriptional differentiation of the thymic IEL precursor (IELp) lineage upon in vitro exposure to cytokines prominent in the peripheral tissues such as interleukin-15 (IL-15) and the inflammatory cytokines interleukin-12 (IL-12) and interleukin-18 (IL-18). We showed that only the CD1a− fraction of the CD10+ PD-1+ IELp population was able to proliferate with IL-15, suggesting that this subset had acquired functionality. These cells downregulated PD-1 expression and completely lost CD10 expression, whereas other surface markers such as CD95 and CXCR3 remained highly expressed. RNA-seq analysis of the IL-15-cultured cells clearly showed...
γδ and αβ T cells have unique roles in immunity and both originate in the thymus from T‐lineage c... more γδ and αβ T cells have unique roles in immunity and both originate in the thymus from T‐lineage committed precursors through distinct but unclear mechanisms. Here, we show that Notch1 activation is more stringently required for human γδ development compared to αβ‐lineage differentiation and performed paired mRNA and miRNA profiling across 11 discrete developmental stages of human T cell development in an effort to identify the potential Notch1 downstream mechanism. Our data suggest that the miR‐17–92 cluster is a Notch1 target in immature thymocytes and that miR‐17 can restrict BCL11B expression in these Notch‐dependent T cell precursors. We show that enforced miR‐17 expression promotes human γδ T cell development and, consistently, that BCL11B is absolutely required for αβ but less for γδ T cell development. This study suggests that human γδ T cell development is mediated by a stage‐specific Notch‐driven negative feedback loop through which miR‐17 temporally restricts BCL11B expression and provides functional insights into the developmental role of the disease‐associated genes BCL11B and the miR‐17–92 cluster in a human context.
Chimeric antigen receptor (CAR)-T-cell therapy is an innovative form of adoptive cell therapy tha... more Chimeric antigen receptor (CAR)-T-cell therapy is an innovative form of adoptive cell therapy that has revolutionized the treatment of certain hematological malignancies, including B-cell non-Hodgkin lymphoma (NHL) and B-cell acute lymphoblastic leukemia (ALL). The treatment is currently also being studied in other B-cell neoplasms, including multiple myeloma (MM) and chronic lymphocytic leukemia (CLL). CD19 and B-cell maturation antigen (BCMA) have been the most popular target antigens for CAR-T-cell immunotherapy of these malignancies. This review will discuss the efficacy and toxicity data from the pivotal clinical studies of CD19- and BCMA-targeted CAR-T-cell therapies in relapsed/refractory B-cell malignancies (NHL, ALL, CLL) and MM, respectively.
Recent approval of chimeric antigen receptor (CAR) T cell therapy by the European Medicines Agenc... more Recent approval of chimeric antigen receptor (CAR) T cell therapy by the European Medicines Agency (EMA)/Federal and Drug Administration (FDA) and the remarkable results of CAR T clinical trials illustrate the curative potential of this therapy. While CARs against a multitude of different antigens are being developed and tested (pre)clinically, there is still a need for optimization. The use of single-chain variable fragments (scFvs) as targeting moieties hampers the quick generation of functional CARs and could potentially limit the efficacy. Instead, nanobodies may largely circumvent these difficulties. We used an available nanobody library generated after immunization of llamas against Cluster of Differentiation (CD) 20 through DNA vaccination or against the ectodomain of CD33 using soluble protein. The nanobody specific sequences were amplified by PCR and cloned by Gibson Assembly into a retroviral vector containing two different second-generation CAR constructs. After transduct...
TPS3093 Background: Chimeric Antigen Receptor (CAR)-T therapy has potentially serious limitations... more TPS3093 Background: Chimeric Antigen Receptor (CAR)-T therapy has potentially serious limitations related to target antigen loss, toxicity due to pre-conditioning regimen, and lack of activity in many tumor types. To overcome these limitations, we have developed a novel CAR-T, called NKR-2, incorporating the full-length human natural killer receptor NKG2D fused with the human CD3 zeta signaling domain. When expressed in T-cells, the naturally-expressed DAP10 provides co-stimulatory signals to NKR-2 to produce cytokines and selectively target tumor cells upon recognition of up to 8 different stress-induced NKG2D ligands expressed in many solid and hematologic malignancies. In preclinical studies, NKR-2 demonstrated long-term anti-tumor activity towards a breadth of tumor indications, in the absence of pre-conditioning, whilst simultaneously targeting tumor cells and cells from the local tumor neo-vasculature and suppressive immune environment. In our recently completed First-in-Human...
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