Browsing by Subject "HLA Antigens"
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Item Open Access A novel reduced-intensity conditioning regimen for unrelated umbilical cord blood transplantation in children with nonmalignant diseases.(Biology of blood and marrow transplantation : journal of the American Society for Blood and Marrow Transplantation, 2014-03) Parikh, Suhag H; Mendizabal, Adam; Benjamin, Cara L; Komanduri, Krishna V; Antony, Jeyaraj; Petrovic, Aleksandra; Hale, Gregory; Driscoll, Timothy A; Martin, Paul L; Page, Kristin M; Flickinger, Ketti; Moffet, Jerelyn; Niedzwiecki, Donna; Kurtzberg, Joanne; Szabolcs, PaulReduced-intensity conditioning (RIC) regimens have the potential to decrease transplantation-related morbidity and mortality. However, engraftment failure has been prohibitively high after RIC unrelated umbilical cord blood transplantation (UCBT) in chemotherapy-naïve children with nonmalignant diseases (NMD). Twenty-two children with a median age of 2.8 years, many with severe comorbidities and prior viral infections, were enrolled in a novel RIC protocol consisting of hydroxyurea, alemtuzumab, fludarabine, melphalan, and thiotepa followed by single UCBT. Patients underwent transplantation for inherited metabolic disorders (n = 8), primary immunodeficiencies (n = 9), hemoglobinopathies (n = 4) and Diamond Blackfan anemia (n = 1). Most umbilical cord blood (UCB) units were HLA-mismatched with median infused total nucleated cell dose of 7.9 × 10(7)/kg. No serious organ toxicities were attributable to the regimen. The cumulative incidence of neutrophil engraftment was 86.4% (95% confidence interval [CI], 65% to 100%) in a median of 20 days, with the majority sustaining > 95% donor chimerism at 1 year. Cumulative incidence of acute graft-versus-host disease (GVHD) grades II to IV and III to IV by day 180 was 27.3% (95% CI, 8.7% to 45.9%) and 13.6% (95 CI, 0% to 27.6%), respectively. Cumulative incidence of extensive chronic GVHD was 9.1% (95% CI, 0% to 20.8%). The primary causes of death were viral infections (n = 3), acute GVHD (n = 1) and transfusion reaction (n = 1). One-year overall and event-free survivals were 77.3% (95% CI, 53.7% to 89.8%) and 68.2% (95% CI, 44.6% to 83.4%) with 31 months median follow-up. This is the first RIC protocol demonstrating durable UCB engraftment in children with NMD. Future risk-based modifications of this regimen could decrease the incidence of viral infections. (www.clinicaltrials.gov/NCT00744692).Item Open Access Allo-Specific Humoral Responses: New Methods for Screening Donor-Specific Antibody and Characterization of HLA-Specific Memory B Cells.(Frontiers in immunology, 2021-01) Song, Shengli; Manook, Miriam; Kwun, Jean; Jackson, Annette M; Knechtle, Stuart J; Kelsoe, GarnettAntibody-mediated allograft rejection (AMR) causes more kidney transplant failure than any other single cause. AMR is mediated by antibodies recognizing antigens expressed by the graft, and antibodies generated against major histocompatibility complex (MHC) mismatches are especially problematic. Most research directed towards the management of clinical AMR has focused on identifying and characterizing circulating donor-specific HLA antibody (DSA) and optimizing therapies that reduce B-cell activation and/or block antibody secretion by inhibiting plasmacyte survival. Here we describe a novel set of reagents and techniques to allow more specific measurements of MHC sensitization across different animal transplant models. Additionally, we have used these approaches to isolate and clone individual HLA-specific B cells from patients sensitized by pregnancy or transplantation. We have identified and characterized the phenotypes of individual HLA-specific B cells, determined the V(D)J rearrangements of their paired H and L chains, and generated recombinant antibodies to determine affinity and specificity. Knowledge of the BCR genes of individual HLA-specific B cells will allow identification of clonally related B cells by high-throughput sequence analysis of peripheral blood mononuclear cells and permit us to re-construct the origins of HLA-specific B cells and follow their somatic evolution by mutation and selection.Item Open Access Allogeneic Umbilical Cord Blood Infusion for Adults with Ischemic Stroke: Clinical Outcomes from a Phase I Safety Study.(Stem cells translational medicine, 2018-07) Laskowitz, Daniel T; Bennett, Ellen R; Durham, Rebecca J; Volpi, John J; Wiese, Jonathan R; Frankel, Michael; Shpall, Elizabeth; Wilson, Jeffry M; Troy, Jesse; Kurtzberg, JoanneStroke is a major cause of death and long-term disability, affecting one in six people worldwide. The only currently available approved pharmacological treatment for ischemic stroke is tissue plasminogen activator; however, relatively few patients are eligible for this therapy. We hypothesized that intravenous (IV) infusion of banked unrelated allogeneic umbilical cord blood (UCB) would improve functional outcomes in patients with ischemic stroke. To investigate this, we conducted a phase I open-label trial to assess the safety and feasibility of a single IV infusion of non-human leukocyte antigen (HLA) matched, ABO matched, unrelated allogeneic UCB into adult stroke patients. Ten participants with acute middle cerebral artery ischemic stroke were enrolled. UCB units were matched for blood group antigens and race but not HLA, and infused 3-9 days post-stroke. The adverse event (AE) profile over a 12 month postinfusion period indicated that the treatment was well-tolerated in these stroke patients, with no serious AEs directly related to the study product. Study participants were also assessed using neurological and functional evaluations, including the modified Rankin Score (mRS) and National Institute of Health Stroke Scale (NIHSS). At 3 months post-treatment, all participants had improved by at least one grade in mRS (mean 2.8 ± 0.9) and by at least 4 points in NIHSS (mean 5.9 ± 1.4), relative to baseline. Together, these data suggest that a single i.v. dose of allogeneic non-HLA matched human UCB cells is safe in adults with ischemic stroke, and support the conduct of a randomized, placebo-controlled phase 2 study. Stem Cells Translational Medicine 2018;7:521-529.Item Open Access Development of New Donor-Specific and Human Leukocyte Antigen Antibodies After Transfusion in Adult Lung Transplantation.(Journal of cardiothoracic and vascular anesthesia, 2023-09) Stoker, Alexander; Hicks, Anne; Wright, Mary Cooter; Ali, Azfar; Klapper, Jacob; Poisson, Jessica; Zaffiri, Lorenzo; Chen, Dongfeng; Hartwig, Matthew; Ghadimi, Kamrouz; Welsby, Ian; Bottiger, BrandiObjectives
The development of new human leukocyte antigens (HLAs) and donor-specific antibodies (DSAs) in patients are associated with worse outcomes following lung transplantation. The authors aimed to examine the relationship between blood product transfusion in the first 72 hours after lung transplantation and the development of HLA antibodies, including DSAs.Design
A retrospective observational study.Setting
At a single academic tertiary center.Participants
Adult lung transplant recipients who underwent transplantation between September 2014 and June 2019.Interventions
None.Measurements and main results
A total of 380 patients were included in this study, and 87 (23%) developed de novo donor-specific antibodies in the first year after transplantation. Eighty-five patients (22%) developed new HLA antibodies that were not donor-specific, and 208 patients (55%) did not develop new HLA antibodies in the first year after transplantation. Factors associated with increased HLA and DSA development included donor pulmonary infection, non-infectious indication for transplant, increased recipient body mass index, and a preoperative calculated panel reactive antibody value above 0. Multivariate analysis identified platelet transfusion associated with an increased risk of de novo HLA antibody development compared to the negative group (odds ratio [OR; 95% CI] 1.18 [1.02-1.36]; p = 0.025). Cryoprecipitate transfusion was associated with de novo DSA development compared to the negative group (OR [95% CI] 2.21 [1.32-3.69] for 1 v 0 units; p = 0.002).Conclusions
Increased perioperative transfusion of platelets and cryoprecipitate are associated with de novo HLA and DSA development, respectively, in lung transplant recipients during the first year after transplantation.Item Open Access Effect of HLA-matching recipients to donor noninherited maternal antigens on outcomes after mismatched umbilical cord blood transplantation for hematologic malignancy.(Biology of blood and marrow transplantation : journal of the American Society for Blood and Marrow Transplantation, 2012-12) Rocha, Vanderson; Spellman, Stephen; Zhang, Mei-Jie; Ruggeri, Annalisa; Purtill, Duncan; Brady, Colleen; Baxter-Lowe, Lee Ann; Baudoux, Etienne; Bergamaschi, Paola; Chow, Robert; Freed, Brian; Koegler, Gesine; Kurtzberg, Joanne; Larghero, Jerome; Lecchi, Lucilla; Nagler, Arnon; Navarrette, Cristina; Prasad, Vinod; Pouthier, Fabienne; Price, Thomas; Ratanatharathorn, Voravit; van Rood, Jon J; Horowitz, Mary M; Gluckman, Eliane; Eapen, Mary; Eurocord-European Blood and Marrow Transplant Group and the Center for International Blood and Marrow Transplant ResearchTransplantation-related mortality (TRM) is high after HLA-mismatched umbilical cord blood (UCB) transplantation (UCBT). In utero, exposure to noninherited maternal antigen (NIMA) is recognized by the fetus, which induces T regulator cells to that haplotype. It is plausible that UCBTs in which recipients are matched to donor NIMAs may alleviate some of the excess mortality associated with this treatment. To explore this concept, we used marginal matched-pair Cox regression analysis to compare outcomes in 48 NIMA-matched UCBTs (ie, the NIMA of the donor UCB unit matched to the patient) and in 116 non-NIMA-matched UCBTs. All patients had a hematologic malignancy and received a single UCB unit. Cases and controls were matched on age, disease, disease status, transplantation-conditioning regimen, HLA match, and infused cell dose. TRM was lower after NIMA-matched UCBTs compared with NIMA-mismatched UCBTs (relative risk, 0.48; P = .05; 18% versus 32% at 5 years posttransplantation). Consequently, overall survival was higher after NIMA-matched UCBT. The 5-year probability of overall survival was 55% after NIMA-matched UCBTs versus 38% after NIMA-mismatched UCBTs (P = .04). When faced with the choice of multiple HLA-mismatched UCB units containing adequate cell doses, selecting an NIMA-matched UCB unit may improve survival after mismatched UCBT.Item Open Access Extensive haplotype diversity in African American mothers and their cord blood units.(Tissue antigens, 2013-01) Tu, B; Leahy, N; Yang, R; Cha, N; Kariyawasam, K; Hou, L; Xiao, Y; Masaberg, C; Pulse-Earle, D; Maiers, M; Ng, J; Kurtzberg, J; Hurley, CKHLA-A, -B, -C, -DRB1, -DQB1 assignments were obtained for 374 pairs of African American mothers and their umbilical cord blood units (CBU) by DNA sequencing. An algorithm developed by the National Marrow Donor Program was used to assign 1122 haplotypes by segregation. Seventy percent of the haplotypes carried assignments at all five loci. In the remainder, alleles at various loci, most often DQB1 in 48% of the haplotypes with a missing assignment, could not be assigned due to sharing of both alleles by mother and CBU. There were 652 haplotypes carrying a unique combination of alleles at the five loci; the majority (74%) were singletons. Novel B∼C and DRB1~DQB1 associations were observed. The results show the genetic diversity in this population and provide validation for a publically available tool for pedigree analysis. Our observations underscore the need for procurement of increased numbers of units in the national cord blood inventory in order to identify matching donors for all patients requiring hematopoietic stem cell transplantation.Item Open Access Hematopoietic cell transplantation with cord blood for cure of HIV infections.(Biology of blood and marrow transplantation : journal of the American Society for Blood and Marrow Transplantation, 2013-03) Petz, Lawrence D; Redei, Istvan; Bryson, Yvonne; Regan, Donna; Kurtzberg, Joanne; Shpall, Elizabeth; Gutman, Jonathan; Querol, Sergio; Clark, Pamela; Tonai, Richard; Santos, Sarah; Bravo, Aide; Spellman, Stephen; Gragert, Loren; Rossi, John; Li, Shirley; Li, Haitang; Senitzer, David; Zaia, John; Rosenthal, Joseph; Forman, Stephen; Chow, RobertHematopoietic cell transplantation (HCT) using CCR5-Δ32/Δ32 stem cells from an adult donor has resulted in the only known cure of human immunodeficiency virus (HIV) infection. However, it is not feasible to repeat this procedure except rarely because of the low incidence of the CCR5-Δ32 allele, the availability of only a small number of potential donors for most patients, and the need for a very close human leukocyte antigen (HLA) match between adult donors and recipients. In contrast, cord blood (CB) transplantations require significantly less stringent HLA matching. Therefore, our hypothesis is that cure of HIV infections by HCT can be accomplished much more readily using umbilical CB stem cells obtained from a modestly sized inventory of cryopreserved CCR5-Δ32/Δ32 CB units. To test this hypothesis, we developed a screening program for CB units and are developing an inventory of CCR5-Δ32/Δ32 cryopreserved units available for HCT. Three hundred such units are projected to provide for white pediatric patients a 73.6% probability of finding an adequately HLA matched unit with a cell dose of ≥2.5 × 10(7) total nucleated cells (TNCs)/kg and a 27.9% probability for white adults. With a cell dose of ≥1 × 10(7) TNCs/kg, the corresponding projected probabilities are 85.6% and 82.1%. The projected probabilities are lower for ethnic minorities. Impetus for using CB HCT was provided by a transplantation of an adult with acute myelogenous leukemia who was not HIV infected. The HCT was performed with a CCR5-Δ32/Δ32 CB unit, and posttransplantation in vitro studies indicated that the patient's peripheral blood mononuclear cells were resistant to HIV infection.Item Open Access Human Leukocyte Antigen Sensitization in Solid Organ Transplantation: A Primer on Terminology, Testing, and Clinical Significance for the Apheresis Practitioner.(Therapeutic apheresis and dialysis : official peer-reviewed journal of the International Society for Apheresis, the Japanese Society for Apheresis, the Japanese Society for Dialysis Therapy, 2017-10) Abbes, Sarah; Metjian, Ara; Gray, Alice; Martinu, Tereza; Snyder, Laurie; Chen, Dong-Feng; Ellis, Matthew; Arepally, Gowthami M; Onwuemene, OluwatoyosiThe human leukocyte antigen (HLA) system is an important immunologic barrier that must be considered for successful solid organ transplantation. Formation of donor-specific HLA antibodies in solid organ transplantation is an important cause of allograft injury and may contribute to recipient morbidity and mortality. Therapeutic plasma exchange is often requested to lower HLA antibody levels prior to or after transplantation and for management of HLA antibodies in the context of organ rejection. In this review, we summarize the current terminology, laboratory testing, and clinical significance of HLA sensitization in the solid organ transplant population. Furthermore, to illustrate applications of HLA testing in clinical practice, we summarize our own lung and kidney institutional protocols for managing HLA antibodies in the peri-transplant setting.Item Open Access Indications for and outcomes of therapeutic plasma exchange after cardiac transplantation: A single center retrospective study.(Journal of clinical apheresis, 2018-08) Onwuemene, Oluwatoyosi A; Grambow, Steven C; Patel, Chetan B; Mentz, Robert J; Milano, Carmelo A; Rogers, Joseph G; Metjian, Ara D; Arepally, Gowthami M; Ortel, Thomas LINTRODUCTION:Limited data are available describing indications for and outcomes of therapeutic plasma exchange (TPE) in cardiac transplantation. METHODS:In a retrospective study of patients who underwent cardiac transplantation at Duke University Medical Center from 2010 to 2014, we reviewed 3 TPE treatment patterns: a Single TPE procedure within 24 h of transplant; Multiple TPE procedures initiated within 24 h of transplant; and 1 or more TPE procedures beginning >24 h post-transplant. Primary and secondary outcomes were overall survival (OS) and TPE survival (TS), respectively. RESULTS:Of 313 patients meeting study criteria, 109 (35%) underwent TPE. TPE was initiated in 82 patients within 24 h, 40 (37%) receiving a single procedure (Single TPE), and 42 (38%) multiple procedures (Multiple TPE). Twenty-seven (25%) began TPE >24 h after transplant (Delayed TPE). The most common TPE indication was elevated/positive panel reactive or human leukocyte antigen antibodies (32%). With a median follow-up of 49 months, the non-TPE treated and Single TPE cohorts had similar OS (HR 1.08 [CI, 0.54, 2.14], P = .84), while the Multiple and Delayed TPE cohorts had worse OS (HR 2.62 [CI, 1.53, 4.49] and HR 1.98 [CI, 1.02, 3.83], respectively). The Multiple and Delayed TPE cohorts also had worse TS (HR 2.59 [CI, 1.31, 5.14] and HR 3.18 [CI, 1.56, 6.50], respectively). Infection rates did not differ between groups but was independently associated with OS (HR 2.31 [CI, 1.50, 3.54]). CONCLUSIONS:TPE is an important therapeutic modality in cardiac transplant patients. Prospective studies are needed to better define TPE's different roles in this patient population.Item Open Access Lung Transplantation and the Era of the Sensitized Patient.(Frontiers in immunology, 2021-01) Young, Katherine A; Ali, Hakim A; Beermann, Kristi J; Reynolds, John M; Snyder, Laurie DLong term outcomes in lung transplant are limited by the development of chronic lung allograft dysfunction (CLAD). Within the past several decades, antibody-mediated rejection (AMR) has been recognized as a risk factor for CLAD. The presence of HLA antibodies in lung transplant candidates, "sensitized patients" may predispose patients to AMR, CLAD, and higher mortality after transplant. This review will discuss issues surrounding the sensitized patient, including mechanisms of sensitization, implications within lung transplant, and management strategies.Item Open Access Relationship of race/ethnicity and survival after single umbilical cord blood transplantation for adults and children with leukemia and myelodysplastic syndromes.(Biology of blood and marrow transplantation : journal of the American Society for Blood and Marrow Transplantation, 2012-06) Ballen, Karen K; Klein, John P; Pedersen, Tanya L; Bhatla, Deepika; Duerst, Reggie; Kurtzberg, Joanne; Lazarus, Hillard M; LeMaistre, Charles F; McCarthy, Phillip; Mehta, Paulette; Palmer, Jeanne; Setterholm, Michelle; Wingard, John R; Joffe, Steven; Parsons, Susan K; Switzer, Galen E; Lee, Stephanie J; Rizzo, J Douglas; Majhail, Navneet SThe relationship of race/ethnicity with outcomes of umbilical cord blood transplantation (UCBT) is not well known. We analyzed the association between race/ethnicity and outcomes of unrelated single UCBT for leukemia and myelodysplastic syndromes. Our retrospective cohort study consisted of 885 adults and children (612 whites, 145 blacks, and 128 Hispanics) who received unrelated single UCBT for leukemia and myelodysplastic syndromes between 1995 and 2006 and were reported to the Center for International Blood and Marrow Transplant Research. A 5-6/6 HLA-matched unit with a total nucleated cell count infused of ≥2.5 × 10(7)/kg was given to 40% white and 42% Hispanic, but only 21% black patients. Overall survival at 2 years was 44% for whites, 34% for blacks, and 46% for Hispanics (P = .008). In multivariate analysis adjusting for patient, disease, and treatment factors (including HLA match and cell dose), blacks had inferior overall survival (relative risk of death, 1.31; P = .02), whereas overall survival of Hispanics was similar (relative risk, 1.03; P = .81) to that of whites. For all patients, younger age, early-stage disease, use of units with higher cell dose, and performance status ≥80 were independent predictors of improved survival. Black patients and white patients infused with well-matched cords had comparable survival; similarly, black and white patients receiving units with adequate cell dose had similar survival. These results suggest that blacks have inferior survival to whites after single UCBT, but outcomes are improved when units with a higher cell dose are used.Item Open Access Sensitization and Desensitization in Vascularized Composite Allotransplantation.(Frontiers in immunology, 2021-01) Moris, Dimitrios; Cendales, Linda CVascularized composite allotransplantation (VCA) is a field under research and has emerged as an alternative option for the repair of severe disfiguring defects that result from severe tissue loss in a selected group of patients. Lifelong immunosuppressive therapy, immunosuppression associated complications, and the effects of the host immune response in the graft are major concerns in this type of quality-of-life transplant. The initial management of extensive soft tissue injury can lead to the development of anti-HLA antibodies through injury-related factors, transfusion and cadaveric grafting. The role of antibody-mediated rejection, donor-specific antibody (DSA) formation and graft rejection in the context of VCA still remain poorly understood. The most common antigenic target of preexisting alloantibodies are MHC mismatches, though recognition of ABO incompatible antigens, minor histocompatibility complexes and endothelial cells has also been shown to contribute to rejection. Mechanistically, alloantibody-mediated tissue damage occurs primarily through complement fixation as well as through antibody-dependent cellular toxicity. If DSA exist, activation of complement and coagulation cascades can result in vascular thrombosis and infarction and thus rejection and graft loss. Both preexisting DSA but especially de-novo DSA are currently considered as main contributors to late allograft injury and graft failure. Desensitization protocols are currently being developed for VCA, mainly including removal of alloantibodies whereas treatment of established antibody-mediated rejection is achieved through high dose intravenous immunoglobulins. The long-term efficacy of such therapies in sensitized VCA recipients is currently unknown. The current evidence base for sensitizing events and outcomes in reconstructive transplantation is limited. However, current data show that VCA transplantation has been performed in the setting of HLA-sensitization.Item Open Access Sensitization in transplantation: Assessment of risk (STAR) 2019 Working Group Meeting Report.(American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons, 2020-10) Tambur, Anat R; Campbell, Patricia; Chong, Anita S; Feng, Sandy; Ford, Mandy L; Gebel, Howard; Gill, Ronald G; Kelsoe, Garnett; Kosmoliaptsis, Vasilis; Mannon, Roslyn B; Mengel, Michael; Reed, Elaine F; Valenzuela, Nicole M; Wiebe, Chris; Dijke, I Esme; Sullivan, Harold C; Nickerson, PeterThe purpose of the STAR 2019 Working Group was to build on findings from the initial STAR report to further clarify the expectations, limitations, perceptions, and utility of alloimmune assays that are currently in use or in development for risk assessment in the setting of organ transplantation. The goal was to determine the precision and clinical feasibility/utility of such assays in evaluating both memory and primary alloimmune risks. The process included a critical review of biologically driven, state-of-the-art, clinical diagnostics literature by experts in the field and an open public forum in a face-to-face meeting to promote broader engagement of the American Society of Transplantation and American Society of Histocompatibility and Immunogenetics membership. This report summarizes the literature review and the workshop discussions. Specifically, it highlights (1) available assays to evaluate the attributes of HLA antibodies and their utility both as clinical diagnostics and as research tools to evaluate the effector mechanisms driving rejection; (2) potential assays to assess the presence of alloimmune T and B cell memory; and (3) progress in the development of HLA molecular mismatch computational scores as a potential prognostic biomarker for primary alloimmunity and its application in research trial design.Item Open Access Sickle cell disease: an international survey of results of HLA-identical sibling hematopoietic stem cell transplantation.(Blood, 2017-03) Gluckman, Eliane; Cappelli, Barbara; Bernaudin, Francoise; Labopin, Myriam; Volt, Fernanda; Carreras, Jeanette; Pinto Simões, Belinda; Ferster, Alina; Dupont, Sophie; de la Fuente, Josu; Dalle, Jean-Hugues; Zecca, Marco; Walters, Mark C; Krishnamurti, Lakshmanan; Bhatia, Monica; Leung, Kathryn; Yanik, Gregory; Kurtzberg, Joanne; Dhedin, Nathalie; Kuentz, Mathieu; Michel, Gerard; Apperley, Jane; Lutz, Patrick; Neven, Bénédicte; Bertrand, Yves; Vannier, Jean Pierre; Ayas, Mouhab; Cavazzana, Marina; Matthes-Martin, Susanne; Rocha, Vanderson; Elayoubi, Hanadi; Kenzey, Chantal; Bader, Peter; Locatelli, Franco; Ruggeri, Annalisa; Eapen, Mary; Eurocord, the Pediatric Working Party of the European Society for Blood and Marrow Transplantation, and the Center for International Blood and Marrow Transplant ResearchDespite advances in supportive therapy to prevent complications of sickle cell disease (SCD), access to care is not universal. Hematopoietic cell transplantation is, to date, the only curative therapy for SCD, but its application is limited by availability of a suitable HLA-matched donor and lack of awareness of the benefits of transplant. Included in this study are 1000 recipients of HLA-identical sibling transplants performed between 1986 and 2013 and reported to the European Society for Blood and Marrow Transplantation, Eurocord, and the Center for International Blood and Marrow Transplant Research. The primary endpoint was event-free survival, defined as being alive without graft failure; risk factors were studied using a Cox regression models. The median age at transplantation was 9 years, and the median follow-up was longer than 5 years. Most patients received a myeloablative conditioning regimen (n = 873; 87%); the remainder received reduced-intensity conditioning regimens (n = 125; 13%). Bone marrow was the predominant stem cell source (n = 839; 84%); peripheral blood and cord blood progenitors were used in 73 (7%) and 88 (9%) patients, respectively. The 5-year event-free survival and overall survival were 91.4% (95% confidence interval, 89.6%-93.3%) and 92.9% (95% confidence interval, 91.1%-94.6%), respectively. Event-free survival was lower with increasing age at transplantation (hazard ratio [HR], 1.09; P < .001) and higher for transplantations performed after 2006 (HR, 0.95; P = .013). Twenty-three patients experienced graft failure, and 70 patients (7%) died, with the most common cause of death being infection. The excellent outcome of a cohort transplanted over the course of 3 decades confirms the role of HLA-identical sibling transplantation for children and adults with SCD.Item Open Access The immune checkpoint molecule, VTCN1/B7-H4, guides differentiation and suppresses proinflammatory responses and MHC class I expression in an embryonic stem cell-derived model of human trophoblast.(Frontiers in endocrinology, 2023-01) Zhou, Jie; Tian, Yuchen; Qu, Ying; Williams, Madyson; Yuan, Ye; Karvas, Rowan M; Sheridan, Megan A; Schulz, Laura C; Ezashi, Toshihiko; Roberts, Michael R; Schust, Danny JThe placenta acts as a protective barrier to pathogens and other harmful substances present in the maternal circulation throughout pregnancy. Disruption of placental development can lead to complications of pregnancy such as preeclampsia, intrauterine growth retardation and preterm birth. In previous work, we have shown that expression of the immune checkpoint regulator, B7-H4/VTCN1, is increased upon differentiation of human embryonic stem cells (hESC) to an in vitro model of primitive trophoblast (TB), that VTCN1/B7-H4 is expressed in first trimester but not term human placenta and that primitive trophoblast may be uniquely susceptible to certain pathogens. Here we report on the role of VTCN1 in trophoblast lineage development and anti-viral responses and the effects of changes in these processes on major histocompatibility complex (MHC) class I expression and peripheral NK cell phenotypes.