Tolerance Induction Protocols Research Articles

VCA supercooling in a swine partial hindlimb model

Vascularized composite allotransplantations are complex procedures with substantial functional impact on patients. Extended preservation of VCAs is of major importance in advancing this field. It would result in improved donor-recipient matching as well as the potential for ex vivo manipulation with gene and cell therapies. Moreover, it would make logistically feasible immune tolerance induction protocols through mixed chimerism. Supercooling techniques have shown promising results in multi-day liver preservation. It consists of reaching sub-zero temperatures while preventing ice formation within the graft by using various cryoprotective agents. By drastically decreasing the cell metabolism and need for oxygen and nutrients, supercooling allows extended preservation and recovery with lower ischemia–reperfusion injuries. This study is the first to demonstrate the supercooling of a large animal model of VCA. Porcine hindlimbs underwent 48 h of preservation at − 5 °C followed by recovery and normothermic machine perfusion assessment, with no issues in ice formation and favorable levels of injury markers. Our findings provide valuable preliminary results, suggesting a promising future for extended VCA preservation.

Biodistribution and Safety of Human Multi-Chimeric Cells After Systemic Intraosseous and Intravenous Administration in the Experimental Mouse Model.

Cellular therapies provide promising options for inducing tolerance in transplantation of solid organs, bone marrow, and vascularized composite allografts. However, novel tolerance-inducing protocols remain limited, despite extensive research. We previously introduced and characterized a human multi-chimeric cell (HMCC) line, created through ex vivo fusion of human umbilical cord blood (UCB) cells derived from three unrelated donors. In this study, we assessed in vivo biodistribution and safety of HMCCs in the NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ NOD scid gamma (NSG) mouse model. Twenty-four NSG mice were randomly assigned to four groups (n = 6/group) and received intraosseous (IO.) or intravenous (IV.) injections of 0.6 × 106 donor UCB cells or fused HMCC: Group 1-UCB (IO.), Group 2-UCB (IV.), Group 3-HMCC (IO.), and Group 4-HMCC (IV.). Hematopoietic phenotype maintenance and presence of human leukocyte antigens (HLA), class I antigens, in the selected lymphoid and nonlymphoid organs were assessed by flow cytometry. Weekly evaluation and magnetic resonance imaging (MRI) assessed HMCC safety. Comparative analysis of delivery routes revealed significant differences in HLA class I percentages for IO.: 1.83% ± 0.79%, versus IV. delivery: 0.04% ± 0.01%, P < 0.01, and hematopoietic stem cell marker percentages of CD3 (IO.: 1.41% ± 0.04%, vs. IV.: 0.07% ± 0.01%, P < 0.05) and CD4 (IO.: 2.74% ± 0.31%, vs. IV.: 0.59% ± 0.11%, P < 0.01). Biodistribution analysis after IO. delivery confirmed HMCC presence in lymphoid organs and negligible presence in nonlymphoid organs, except for lung (IO.: 0.19% ± 0.06%, vs. IV.: 6.33% ± 0.56%, P < 0.0001). No evidence of tumorigenesis was observed by MRI at 90 days following IO. and IV. administration of HMCC. This study confirmed biodistribution and safety of HMCC therapy in the NSG mouse model, both following IO. and IV. administration. However, IO. delivery route confirmed higher efficacy of engraftment and safety profile, introducing HMCCs as a novel cell-based therapeutic approach with promising clinical applications in solid organ, bone marrow, and vascularized composite allotransplantation transplantation.

Evaluation of Methods to Obtain Peripheral Blood Mononuclear Cells From Deceased Donors for Tolerance-Induction Protocols.

Regulatory cell therapies have shown promise in tolerance-induction protocols in living donor organ transplantation. These protocols should be pursued in deceased donor transplantation. Donor peripheral mononuclear cells (PBMCs) are an optimal source of donor antigens for the induction of donor-specific regulatory cells. During the development of a regulatory cell tolerance-induction protocol with organs from deceased donors, we compared 3 methods of obtaining PBMCs from deceased donors focusing on cell yield, viability, and contamination of unwanted cell types. PBMC procurement methods: 1. During organ procurement at the time of cold perfusion, blood was collected from the vena cava and placed into a 10-liter blood collection bag, and thereafter transported to Karolinska University Hospital, where leukapheresis was performed (BCL). 2. Blood was collected via the vena cava into blood donation bags before cold perfusion. The bags underwent buffy coat separation and thereafter automated leukocyte isolation system (BCS). 3. To collect PBMCs, leukapheresis was performed via a central dialysis catheter on deceased donors in the intensive care unit (ICU) prior to the organ procurement procedure (LEU).All 3 methods to obtain PBMC from deceased donors were safe and did not affect the procurement of organs. BCL contained around 50% of NK cells in lymphocytes population. LEU had a highest yield of donor PBMC among 3 groups. LEU had the lower amount of granulocyte contamination, compared to BCS and BCL. Based on these results, we choose LEU as the preferred method to obtain donor PBMC in the development of our tolerance-induction protocol.

CPA toxicity screening of cryoprotective solutions in rat hearts

In clinical practice, donor hearts are transported on ice prior to transplant and discarded if cold ischemia time exceeds ∼5 h. Methods to extend these preservation times are critically needed, and ideally, this storage time would extend indefinitely, enabling improved donor-to-patient matching, organ utilization, and immune tolerance induction protocols. Previously, we demonstrated successful vitrification and rewarming of whole rat hearts without ice formation by perfusion-loading a cryoprotective agent (CPA) solution prior to vitrification. However, these hearts did not recover any beating even in controls with CPA loading/unloading alone, which points to the chemical toxicity of the cryoprotective solution (VS55 in Euro-Collins carrier solution) as the likely culprit. To address this, we compared the toxicity of another established CPA cocktail (VEG) to VS55 using ex situ rat heart perfusion. The CPA exposure time was 150 min, and the normothermic assessment time was 60 min. Using Celsior as the carrier, we observed partial recovery of function (atria-only beating) for both VS55 and VEG. Upon further analysis, we found that the VEG CPA cocktail resulted in 50 % lower LDH release than VS55 (N = 4, p = 0.017), suggesting VEG has lower toxicity than VS55. Celsior was a better carrier solution than alternatives such as UW, as CPA + Celsior-treated hearts spent less time in cardiac arrest (N = 4, p = 0.029). While we showed substantial improvement in cardiac function after exposure to vitrifiable concentrations of CPA by improving both the CPA and carrier solution formulation, further improvements will be required before we achieve healthy cryopreserved organs for transplant.

CTH1/TH2 repolarization in induction of immune tolerance to non-steroidal anti-inflammatory drugs during the management of sickle cell disease vaso-occlusive crisis

Respiratory manifestations related to the intake of non-steroidal anti-inflammatory drugs (NSAIDs) during the treatment of the painful vaso-occlusive crisis of sickle cell disease are either a type I hypersensitivity mechanism of the Gell and Coombs classification, or a pharmacological mechanism of NSAIDs. The use of NSAIDs is essential in the Abidjan school because of the absence of therapeutic alternatives in the management of the inflammatory crisis of this disease. The induction of tolerance to NSAIDs initiated by the authors has had clear clinical success. The basic biological reasons for this tolerance were evaluated in this study. A group of 11 sickle cell patients aged 12 to 39 years in whom post-NSAID respiratory manifestations disappeared for at least 6 months following a short tolerance induction protocol with ibuprofen, was assayed by ELISA for TNFα, INFg (Th1 cytokines), IL-4 (Th2 cytokine), IL-10, TGF-β (immunosuppressive cytokines) and total IgE, before induction or pre-induction (D-1) and at day one (D1), D2- 3, one month (M1), and M6 after induction. A repolarization of the Th1/Th2 balance was noted during the post induction period. The high concentration of IL-4 observed at D-1 gradually decreased in favor of the cytokines TNFα, INFg. The decrease in cytokine IL-4 with the level of total IgE was accompanied by the increase of IL-10 and TGF-β demonstrating the regulatory role of these cytokines in the control of allergic diseases. In conclusion, the induction of immuno-tolerance to NSAIDs through a short protocol is well supported by immune regulation. The medium-term effects are real, unlike the results of allergen desensitization or specific immunotherapy. However, this protocol could be used in certain circumstances such as in the case of intolerance to trimethoprim-sulfamethoxazole, used as the treatment of choice for the prevention of opportunistic diseases in people living with human immunodeficiency virus.

Helical TomoTherapy Total Lymphoid Irradiation and Hematopoietic Cell Transplantation for Kidney Transplant Tolerance in Rhesus Macaques.

Development of a post-transplant kidney transplant tolerance induction protocol involving a novel total lymphoid irradiation (TLI) conditioning method in a rhesus macaque model is described. We examined the feasibility of acheiving tolerance to MHC 1-haplotype matched kidney transplants by establishing a mixed chimeric state with infusion of donor hematopoietic cells (HC) using TomoTherapy TLI. The chimeric state was hypothesized to permit the elimination of all immunosuppressive (IS) medications while preserving allograft function long-term without development of graft-versus-host-disease (GVHD) or rejection. An experimental group of 11 renal transplant recipients received the tolerance induction protocol and outcomes were compared to a control group (n = 7) that received the same conditioning but without donor HC infusion. Development of mixed chimerism and operational tolerance was accomplished in two recipients in the experimental group. Both recipients were withdrawn from all IS and continued to maintain normal renal allograft function for 4 years without rejection or GVHD. None of the animals in the control group achieved tolerance when IS was eliminated. This novel experimental model demonstrated the feasibility for inducing of long-term operational tolerance when mixed chimerism is achieved using a TLI post-transplant conditioning protocol in 1-haplotype matched non-human primate recipients of combined kidney and HC transplantation.

Oral tolerance induction protocol to egg white – A report of three pediatric cases

Food allergies are the main cause of anaphylaxis in children. Cow’s milk and egg white are the most common agents and elimination diets are considered the current strategy for their management. Many children can tolerate increasing amounts of the known allergen, and thus, oral tolerance induction protocols seem to be a promising approach. The authors present a protocol drawn up in a pediatric allergic diseases’ outpatient clinic, at a level II hospital, with the aim of egg white oral tolerance induction. During the protocol there is an increase in the amount of egg white offered to children, at the end, tolerance is tested with the ingestion of an entire egg. The protocol was performed in three children with anaphylaxis to egg white. Two children completed the protocol successfully. Oral tolerance to egg white allows a less restrictive diet and improves the quality of life of the patients and their caregivers.

215.9: Achievement of Persistent Mixed Chimerism in Recipients of Matched and Mismatched Living Donor Kidney Transplants in a Tolerance Induction Protocol

Purpose: The induction of tolerance to kidney transplants after development of specific unresponsiveness of recipient immune cells to donor alloantigens allows elimination of maintenance immunosuppressive (IS) drugs while preventing graft loss due to rejection. We have previously reported successful induction of mixed chimerism and tolerance in recipients of fully HLA-matched living donor kidney and hematopoietic cell (HCT) transplants. This work continues in HLA-mismatched transplants, wherein achieving persistent mixed chimerism is more challenging. Methods: Living donors underwent hematopoietic stem cell mobilization and leukopheresis 6 weeks before kidney donation. The recipient conditioning regimen for the HCT consisted of 10 doses of total lymphoid irradiation (TLI) and 5 doses of anti-thymocyte globulin (ATG) following kidney transplant, with HCT on day 11. The HCT consisted of CD34+ hematopoietic progenitor cells and CD3+ cells. Twenty-nine patients received fully HLA-matched living donor transplants. Twenty-five patients received HLA-mismatched (1-haplotype matched) living donor transplants with an escalating dose of CD3+ cells to enhance HCT engraftment. Six patients recently received HLA-mismatched living donor transplants with substitution of a dose of total body irradiation (TBI) for the final dose of TLI. Results: Of the 29 fully HLA-matched living donor transplants, complete IS drug withdrawal was achieved in 24, all of whom had at least 6 months of persistent mixed chimerism. Of the 24, 17 are alive, well and have been off IS drugs from 4 to 14 years without evidence of rejection. Two off IS drugs died due to cardiovascular events at 2 and 3 years. Two returned to IS drugs after loss of chimerism at 1 year followed by acute rejection at 4 years off IS drugs, and 3 after relapse of kidney disease at 1, 5 and 6 years off IS drugs. In the 25 1-haplotype matched living donor transplants, mixed whole blood chimerism persisted in 10 (mean 20% chimerism) at the end of the 1st year posttransplant while immunosuppression was reduced to tacrolimus monotherapy. Chimerism was lost during the 2nd year in the 5 who were withdrawn from monotherapy; they returned to IS drug(s). Mixed chimerism without rejection has persisted in 3 maintained on IS monotherapy, for up to 5 years. The recent addition of a dose of TBI markedly increased levels and stability of mixed chimerism during the 1st year posttransplant. Conclusions: The loss of chimerism during withdrawal of IS drug monotherapy in the HLA-mismatched transplants may have been due to the low level of whole blood chimerism, a contrast to the HLA-matched. A very low single dose of TBI added to the TLI/ATG conditioning regimen increased early chimerism. The stability of high levels of mixed chimerism after complete IS drug withdrawal during the 2nd year posttransplant is the subject of continuing investigation.

245.2: Evaluation of Methods to Obtain Peripheral Blood Mononuclear Cells From Deceased Donors Adjacent to Organ Procurement for Tolerance-Induction Protocols

Regulatory cell therapies have shown promise in tolerance-induction protocols in living donor organ transplantation. These protocols should be pursed in deceased-donor transplantation. Donor peripheral mononuclear cells (PBMCs) are an optimal source of donor antigens for the induction of donor-specific regulatory cells that are more effective than antigen non-specific regulatory cells. During the development of a regulatory cell tolerance induction protocol with organs from deceased donors, we compared three methods of obtaining PBMCs from deceased donors focusing on: cell yield, viability, and contamination of unwanted cell types. PBMC procurement methods: During organ procurement at the time of cold perfusion, blood was collected from the vena cava and placed into a 10-liter blood collection bag, and thereafter transported to Karolinska University Hospital, where leukapheresis was performed (BCL) n=7. Blood was collected via the vena cava into blood donation bags before cold perfusion. The bags underwent buffy coat separation and thereafter automated leukocyte isolation using SEPAX (BCS) n=2.To collect PBMCs, leukapheresis was performed via a central dialysis catheter on deceased donors in the ICU prior to the organ procurement procedure (LEU) n=9. Our results show that all methods were safe in relation to the intended organ procurement procedure. LEU is a feasible method to obtain PBMC from deceased donors. LEU tend to have higher yield of donor PBMC/kg compared to BCS and BCL and acceptable level of granulocyte contamination compared to BCS. Further investigations including the quality of the cell products that was manufactured with PBMCs from these methods will be needed to determine which approach is the most suitable for tolerance induction protocols.

Immune tolerance induced by hematopoietic stem cell infusion after HLA identical sibling kidney transplantation.

After the first attempt to induce operational tolerance, it has taken decades to implement it in clinical practice. Recipients with Human leukocyte antigen (HLA) identical sibling donors were enrolled. Hematopoietic stem cells (HSCs) infusion was done after HLA identical sibling kidney transplantation (KTx). Three cases included were followed up for over 8 years. The perioperative conditioning protocol included anti-CD20, rabbit anti-thymocyte globulin (ATG), total lymphoid irradiation (TLI), and cyclophosphamide. Infusion of CD3+ cells and CD34+ cells was conducted. The withdrawal of immunosuppression was determined by mixed lymphocyte reaction (MLR) and graft biopsy. Case 1 and Case 2 showed persistent chimerism, while chimerism was not detected in Case 3. All three recipients showed a low-level response to donor-specific stimulation. Case 1 and Case 3 met the withdrawal rules at 16 and 32 months after transplantation, respectively. Graft function was stable, and no rejection signs were observed in routine biopsies until 94 and 61 months after transplantation. Case 2 was diagnosed with graft-versus-host disease (GVHD) 9 months after transplantation and recovered after an enhanced immunosuppression therapy. Steroids were withdrawn after 1 year, and 0.5 mg tacrolimus twice a day is currently the only immunosuppression at 8 years and 8 months. In conclusion, our clinical experience indicated the efficacy of non-myeloablative conditioning protocol for tolerance induction in HLA identical patients. Complete chimerism might be a risk factor for GVHD.

Life-threatening anaphylaxis in children with cow's milk allergy during oral immunotherapy and after treatment failure.

BackgroundOral immunotherapy (OIT) is a promising therapeutic approach for children with persistent IgE‐mediated cow's milk allergy (CMA) but data are still limited.ObjectiveTo analyze the prevalence of life‐threatening anaphylaxis in children with persistent CMA undergoing OIT and to evaluate potential risk factors.MethodsThis is a retrospective cohort study among children with persistent CMA undergoing OIT over a 20‐year period, following a specific Oral Tolerance Induction protocol. Adverse reactions during the whole period and data on long‐term outcome were registered. Descriptive and nondescriptive statistics were used to describe data.ResultsThree hundred forty‐two children were evaluated. During OIT, 12 children (3.5%) presented severe anaphylactic reactions that needed an adrenaline injection. None required intubation, intensive care unit (ICU) admission, or showed a fatal outcome. Five of them abandoned OIT, five reached unrestricted diet and the others are still undergoing OIT. As far as outcome is concerned, 51.2% reached an unrestricted diet; 13.5% are at the build‐up stage; and 28.0% (97 patients) stopped the OIT. Among these 96 children, 6.3% experienced a severe reaction induced by accidental ingestion of milk with two fatal outcomes.ConclusionsThe risk of life‐threatening reactions was nearly two times lower (3.5% vs. 6.3%) among patients assuming milk during OIT than in those who stopped the protocol. A trend in favor of more severe reactions, requiring ICU admission, or fatal, was shown in patients who stopped OIT.

Antigen-specific immunotherapy with apitopes suppresses generation of FVIII inhibitor antibodies in HLA-transgenic mice

AbstractHemophilia A (HA) is a blood clotting disorder that is caused by various genetic deficiencies in the factor VIII (FVIII)-encoding F8 gene. Patients receiving FVIII-replacement therapy are at risk for developing neutralizing antibodies (FVIII inhibitors), rendering the FVIII-replacement therapy ineffective. Immunological tolerance toward FVIII can be achieved through immune tolerance induction protocols in some patients, but this is a lengthy and costly desensitization program. Long-term eradication of inhibitors in patients with HA could be achieved by antigen-specific immunotherapy targeting CD4+ T-cells, because formation of FVIII inhibitors is T-cell dependent. Here, we report a peptide-based antigen-specific immunotherapy that is designed to specifically reestablish immune tolerance to FVIII through the development of antigen-processing-independent epitopes (apitopes). We identified 2 FVIII immunodominant peptides in immunized HLA-DRA*0101/DRB1*1501 transgenic (HLA-DR2tg) mice that were optimized for tolerogenicity. These modified peptide analogs were initially screened for recognition using FVIII-specific T-cell hybridoma clones from FVIII-immunized HLA-DR2tg mice. The FVIII apitopes were promiscuous and bound common human HLA-DRB1* allelic variants. The combination of these 2 FVIII apitopes (ATX-F8-117), administered according to a dose-escalation protocol, promoted T-cell tolerance toward FVIII in HLA-DR2tg mice. Furthermore, treatment with ATX-F8-117 significantly reduced FVIII inhibitor formation. ATX-F8-117 regulates anti-FVIII T-cell and B-cell responses, specifically the generation of FVIII inhibitors, revealing peptide-based antigen-specific immunotherapy as a promising approach to suppress and treat inhibitor formation in susceptible patients with HA.

Costs and management of patients with hemophilia A in France: the Hemraude study

The Hemraude study was conducted to describe the profile of patients with HA, disease management, and economic burden in a collective perspective. This retrospective study was conducted using the French administrative healthcare claims database SNIIRAM/SNDS. Male patients treated for hemophilia A with a long-term illness (ALD) status or invalidity were included in the study between January 1, 2016 and December 31, 2017. Patients were classified in six treatment groups: no treatment, on-demand FVIII, prophylactic FVIII, FVIII in immune tolerance induction (ITI) protocol, on-demand bypassing agents, and prophylactic bypassing agents. Patients treated with FVIII in ITI protocol and those treated with bypassing agents are deemed to have developed inhibitors. HA patients were compared to a control population without coagulation disorder and matched (ratio 1:3) on age and sex. A total of 4172 patients were included in the analysis, aged on average 35.2years, 5.3% had HIV infection, and 8.8% had hepatitis B or C. In 2017, half of the patients received no treatment for HA, 46.7% were treated with FVIII (25% on demand, 20.6% with prophylaxis, and 1.1% ITI), 1.5% with bypassing agents. Patients treated with prophylactic treatments, either inhibitor or non-inhibitor, were less likely to be hospitalized for severe bleeding compared to patients receiving on-demand treatments. The average annual costs for HA management per patient were 72,209.60 €. The highest costs were observed in patients treated with FVIII in ITI protocol and those receiving prophylactic bypassing agents. Direct costs of HA treatments for HA may be very high especially in the small percentage of patients developing inhibitors or treated with ITI protocol.

A new rapid titration protocol for lamotrigine that reduces the risk of skin rash.

ObjectiveLamotrigine is one of the most widely used antiepileptic drugs, but it has a critical issue of a skin rash if the starting dose is too high or the escalation rate is too rapid. We investigated the efficacy and safety of a novel and rapid titration protocol for lamotrigine that takes only 11 days to reach a daily dose of 200 mg.MethodsWe prospectively enrolled 33 adult patients (age 18‐85) who were diagnosed with epilepsy and started lamotrigine administration for the first time at a single tertiary hospital. Our new protocol starts with a subthreshold dose of the drug and then administers a stepwise‐incremental dose until reaching the full therapeutic dose within 11 days.ResultsOf 29 patients analyzed, only two (6.9%) experienced idiosyncratic skin rash before the first follow‐up visit at 2 weeks (±3 days). In addition, a therapeutic concentration was reached in more than 75% of studied patients after 2 weeks of lamotrigine administration.SignificanceThese findings demonstrate the value of the novel tolerance induction protocol for lamotrigine, which could widen the available application of lamotrigine in various situations. However, this study is a preliminary study limited by a small number of patients and its nonrandomized and open‐label design, so the current protocol needs more rigorous clinical evaluations before the application to the real clinical setting.

Strategies for Liver Transplantation Tolerance.

Liver transplant (LT) recipients require life-long immunosuppression (IS) therapy to preserve allograft function. The risks of chronic IS include an increased frequency of malignancy, infection, renal impairment, and other systemic toxicities. Despite advances in IS, long-term LT outcomes have not been improved over the past three decades. Standard-of-care (SoC) therapy can, in rare cases, lead to development of operational tolerance that permits safe withdrawal of maintenance IS. However, successful IS withdrawal cannot be reliably predicted and, in current prospective studies, is attempted several years after the transplant procedure, after considerable exposure to the cumulative burden of maintenance therapy. A recent pilot clinical trial in liver tolerance induction demonstrated that peri-transplant immunomodulation, using a regulatory T-cell (Treg) approach, can reduce donor-specific alloreactivity and allow early IS withdrawal. Herein we review protocols for active tolerance induction in liver transplantation, with a focus on identifying tolerogenic cell populations, as well as barriers to tolerance. In addition, we propose the use of novel IS agents to promote immunomodulatory mechanisms favoring tolerance. With numerous IS withdrawal trials underway, improved monitoring and use of novel immunomodulatory strategies will help provide the necessary knowledge to establish an active liver tolerance induction protocol for widespread use.

A Simplified, Real-World Approach to Safely Inducing Bite-Proof Tolerance in Peanut-Allergic Preschool-Aged Children and Babies

When babies and toddlers are identified as peanut-allergic, especially after identification through LEAP-based recommendations, these children should not necessarily wait until age four-years to attempt induction of tolerance. We sought to safely induce tolerance in these young children by adapting tolerance-inducing protocols to our clinical practice.

Suppression of liver transplant rejection by anti-donor MHC antibodies via depletion of donor immunogenic dendritic cells.

BackgroundWe previously found two distinct passenger dendritic cell (DC) subsets in the rat liver that played a central role in the liver transplant rejection. In addition, a tolerance-inducing protocol, donor-specific transfusion (DST), triggered systemic polytopical production of depleting alloantibodies to donor class I MHC (MHCI) antigen (DST-antibodies).MethodsWe examined the role of DST-antibodies in the trafficking of graft DC subsets and the alloresponses in a rat model. We also examined an anti-donor class II MHC (MHCII) antibody that recognizes donor DCs more selectively.ResultsPreoperative transfer of DST-antibodies or DST pretreatment eliminated all passenger leukocytes, including both DC subsets and depleted the sessile DCs in the graft to ~20% of control. The CD172a+CD11b/c+ immunogenic subset was almost abolished. The intrahost direct or semi-direct allorecognition pathway was successfully blocked, leading to a significant suppression of the CD8+ T-cell response in the recipient lymphoid organs and the graft with delayed graft rejection. Anti-donor MHCII antibody had similar effects without temporary graft damage. Although DST pretreatment had a priming effect on the proliferative response of recipient regulatory T cells, DST-primed sera and the anti-donor MHCII antibody did not.ConclusionDST-antibodies and anti-donor MHCII antibodies could suppress the CD8+ T-cell-mediated liver transplant rejection by depleting donor immunogenic DCs, blocking the direct or semi-direct pathways of allorecognition. Donor MHCII-specific antibodies may be applicable as a selective suppressant of anti-donor immunity for clinical liver transplantation without the cellular damage of donor MHCII– graft cells and recipient cells.

PRO75 Health Care Management of Hemophilia a in France: The Hemraude Study

Management of hemophilia A (HA) combine two main approaches: a preventative one where medicines are used to prevent bleeding and joint and muscle damage and an on-demand treatment, where medicines aim to treat prolonged bleeding. One objective of the HEMRAUDE study was to describe patients with HA and HA care practices in real life in France. A retrospective analysis of all HA male patients figuring in the National French healthcare claims database SNDS between January 1, 2016 and December 31, 2017 was conducted. Using treatment algorithm and expert review of patient’s files, patients were classified in 6 treatment groups: no treatment, on-demand FVIII, FVIII immune tolerance induction (ITI) protocol, FVIII prophylaxis, on-demand bypassing agents, and bypassing agent prophylaxis. Patterns of treatment were described including drug utilization, physician and paramedics services, hospitalizations. Overall, 4,172 patients (all degree of severity) were included in the analysis, aged on average 35.2 years, 34.1% were less than 18 years old. Based on a treatment algorithm, 2.8% had FVIII inhibitors in 2017. Half of the patients (51.6%) did not receive any treatment for HA over this year, 25% were treated on demand, and 20.6 % had long-term prophylaxis (30.3% under 18 y). Only 1.6% were treated with by-passant agents either on demand or in prophylaxis. Overall, 8.2% have received at least once strong opioids over the year and 5.0% desmopressin. Only one half of the patients have visited a specialist over the year (55.8%). Finally, 26.7% of patients were hospitalized at least once and 19.8% had to go to the emergency room. A wide-range integrated care management of HA was observed in 2017 in real-life. Few patients have developed FVIII inhibitors. A rather small percentage of patients including children received prophylaxis which may call into question the HA guidelines follow-up in France.

Tolerance induction with donor hematopoietic stem cell infusion in kidney transplantation: a single-center experience in China with a 10-year follow-up.

BackgroundImmunosuppressive therapy after life-saving kidney transplantation increases the risk of infection, cardiovascular diseases, metabolic diseases, and cancer. To date, four centers (three in the USA and one in South Korea) have reported clinical tolerance trials in kidney transplantation. We performed the first Chinese clinical trial in which kidney transplantation was combined with donor hematopoietic stem cell (DHSC) infusion to induce tolerance. This study summarizes the 10-year follow-up results.MethodsFrom 2009 to 2017, 11 donor/recipient pairs underwent living-related kidney transplantation combined with DHSC infusion. Two of the pairs were human leukocyte antigen (HLA)-matched, and nine were HLA-mismatched. DHSCs were mobilized using granulocyte colony-stimulating factor (G-CSF) and harvested 1 day before transplantation. The recipients received consecutive total lymphoid irradiation (TLI) for 3 days before kidney transplantation. The induction drug was anti-thymocyte globulin (ATG). DHSCs were infused on days 2, 4, and 6 post surgery. All patients were followed-up until Dec 2019. Routine laboratory examinations, chimerism, biopsies, and mixed lymphocyte reactions were performed.ResultsOne HLA-matched recipient had 30–50% chimerism, while the other patients had less than 1% chimerism. Recipients had donor-specific hyporesponsiveness (DSH) while sustaining normal reactivity to non-donors in mixed lymphocyte reactions. All recipients were followed up for 717–3,918 days. One recipient lost allograft function, and 10 recipients had stable renal function. None of the 11 recipients developed myelosuppression or graft-versus-host disease (GVHD) post transplantation. Our protocol did not increase the risk of infection. Allograft biopsy confirmed that one patient had mild rejection with Banff grade IA, while the other ten recipients did not develop rejection. Five patients were able to reduce the dose of their immunosuppressive therapy.ConclusionsOur immune tolerance induction protocol, which used DHSC infusion and TLI, achieved low dose immunosuppression with long-term stable kidney allograft survival in Chinese patients.

Cutaneous leukocyte lineages in tolerant large animal and immunosuppressed clinical vascularized composite allograft recipients.

Vascularized composite allografts (VCAs) can restore fully functional anatomic units in patients with limb amputations or severe facial tissue loss. However, acute rejection of the skin is frequently observed and underscores the importance of developing tolerance induction protocols. In this study, we have characterized the skin immune system in VCAs. We demonstrate infiltration of recipient leukocytes, regardless of rejection status, and in tolerant mixed hematopoietic chimeras, the co-existence of these cells with donor leukocytes in the absence of rejection. Here we characterize the dermal T cell and epidermal Langerhans cell components of the skin immune system in our porcine model of VCA tolerance, and the kinetics of cutaneous chimerism in both of these populations in VCAs transplanted to tolerant and nontolerant recipients, as well as in host skin. Furthermore, in biopsies from the first patient to receive a hand transplant in our program, we demonstrate the presence of recipient T cells in the skin of the transplanted limb in the absence of clinical or histological evidence of rejection.