Human Leukocyte Antigen Matching Research Articles

A Multicenter, Open Label, Phase 3 Study of Tabelecleucel for Solid Organ Transplant Subjects with Epstein-Barr Virus-Driven Post-Transplant Lymphoproliferative Disorder (EBV+PTLD) after Failure of Rituximab or Rituximab and Chemotherapy (ALLELE)

Background In immunocompromised individuals where T-cell function is impaired, EBV-transformed B-cells can proliferate resulting in lymphoproliferative disorders or lymphoma (EBV+LPD). EBV+LPD following solid organ transplant (SOT) is known as EBV+ post-transplant lymphoproliferative disorder (EBV+PTLD). Treatments for EBV+PTLD following SOT include reduction in immunosuppression and off-label rituximab ± multi-agent chemotherapy (CT). Limitations of current EBV+PTLD treatments include lack of response, relapse, potential for graft rejection, short- and long-term toxicity and high mortality, highlighting a clear unmet medical. Tabelecleucel (tab-cel) is an off-the-shelf allogeneic EBV-specific T cell immunotherapy generated from healthy donors that is selected for each patient (pt) from a library of T cells using the most appropriate human leukocyte antigen (HLA) restriction to address the patient's disease. Tab-cel has been evaluated in several clinical studies; One published interim analysis showed that in ALLELE-eligible patients with EBV+PTLD following SOT, the objective response rate (ORR) was 83% (5/6 patients) (Prockop et al, ASH 2017). Here we describe the design of an ongoing study of tab-cel for SOT subjects with EBV+PTLD after failure of rituximab ± CT. Study Design and Methods ALLELE is a multicenter, open-label, single arm, phase 3 study evaluating the clinical benefit of tab-cel in pts with EBV+PTLD following SOT (n=33) after failure of (1) rituximab monotherapy or (2) rituximab plus CT (NCT03394365). Key inclusion criteria are a diagnosis of locally assessed, biopsy-proven EBV+PTLD and failure of rituximab or rituximab plus concurrent/sequential CT. Exclusion criteria include untreated or in-progress treatment of central nervous system PTLD and suspected or confirmed grade >2 graft-vs-host disease. Tab-cel is partially matched to each patient from a library that is HLA-characterized using 1 EBV HLA restriction allele and at least 1 other matched HLA allele. Tab-cel is administered in cycles lasting 5 weeks (35 days). During each cycle, subjects receive intravenous (IV) tab-cel at a dose of 2 × 106 cells/kg on days 1, 8, and 15, followed by observation through day 35. Response per clinical and radiographic assessment are evaluated at the end of each cycle by the investigator and independent review using modified Lugano Classification criteria. Up to 2 different HLA restrictions are allowed per protocol. Treatment is continued until maximal response, unacceptable toxicity, initiation of non-protocol therapy, or failure of the maximum allowable HLA restrictions. After treatment is completed or discontinued, subjects are assessed every 3 months, up to 24 months and every 6 months thereafter up to 5 years for survival status. The primary endpoint of the study is overall response rate (ORR) following the administration of tab-cel.

Critical evaluation of a possible role of HLA epitope matching in kidney transplantation.

Human leukocyte antigen (HLA) matching is one of the cornerstones of organ allocation in deceased-donor kidney transplantation. Increased numbers of HLA allele mismatches are associated with a higher risk of immunological rejection, de novo donor-specific HLA antibody development and graft failure. HLA epitopes are defined as the specific portions of HLA molecules to which antibodies and T-cell receptors bind with their paratopes. The same epitope can be present on different HLA alleles. Therefore, HLA matching at the epitope instead of allele level theoretically offers a more precise assessment of donor-recipient HLA compatibility and may more effectively prevent sensitization against foreign tissue. In this review, we describe the different options proposed to define clinically relevant HLA epitopes and critically discuss the potential role of HLA epitope matching in kidney transplantation.

Umbilical Cord Blood Units Cryopreserved in the Public Cord Blood Bank: A Breakthrough in iPSC Haplobanking?

The use of induced pluripotent stem cells (iPSCs) is an emerging therapeutic option for precision medicine. Cord blood (CB) cells with lower immunogenicity, fewer genomic changes, and persistent epigenetic memory might be ideal candidates for iPSC production. Based on the human leukocyte antigen (HLA) distribution of cord blood units (CBUs) in the public CB bank, we estimated the coverage of the Korean population with HLA-homozygous iPSCs to repurpose cryopreserved CBUs. We analyzed a total of 27,904 Korean CBUs donated to the public CB bank. Low-to-intermediate resolution typing was performed for HLA-A, -B, and -DRB1 alleles, and individuals possessing homozygous HLA haplotypes were identified by direct counting. Moreover, the matching probabilities for zero-mismatch transplantation were calculated for 27,904 CBUs and 50,000,000 potential Korean patients. Among the preserved CBUs, 15 HLA-A, 40 HLA-B, and 13 HLA-DRB1 alleles as well as 48 homozygous HLA-A-B-DRB1 haplotypes were identified at serological equivalents (2 digits). The 48 identified homozygous haplotypes cumulatively matched 78.18% of the 27,904 Korean CB donors as zero HLA-mismatch iPSC sources. Among the combinations of 1,699 haplotypes with frequencies greater than 0.001%, assuming a population of 50 million, those 48 haplotypes can provide a match for 78.37% of potential Korean recipients. A practicable number of HLA-A, -B, and -DRB1 homozygous iPSC lines derived from CBUs may be an efficient option in allogeneic iPSC therapy because this type of haplobanking may provide cell lines with optimal HLA matching for up to three-quarters of the Korean population.

Renal Transplant Outcomes in Spousal and Living-Related Donors in Malaysia

Studies have shown that a compatible human leukocyte antigen (HLA) match can confer a favourable effect on graft outcomes. We examined the outcomes of HLA matching in renal transplant donors in Malaysia. A total of 140 patients who had compatible ABO blood type with negative T-cell lymphocytotoxicity crossmatch were included in the study and 25% of them were spousal transplant donors. No remarkable differences in acute rejection rate, graft survival, patient survival and serum creatinine level were observed between the spousal and living-related donor groups. The spousal donor group had a higher degree of HLA mismatch than the living-related donor group. HLA-A mismatch was associated with increased rejection risk at 6 months (odds ratio [OR], 2.75; P = 0.04), 1 year (OR, 2.54; P = 0.03) and 3 years (OR, 3.69; P = 0.001). It was also observed in the deleterious effects of HLA-B and HLA-DQ loci when the number of antigen mismatches increased. The risk was 7 times higher in patients with ≥1 mismatch at HLA-A, HLA-B and HLA-DR loci than those who did not have a mismatch at these loci at 6 months (P = 0.01), 1 year (P = 0.03) and 3 years (P = 0.003). A good match for HLA-A, HLA-B, HLA-DR and HLA-DQ can prevent acute rejection risk in renal transplant patients. Consequently, spousal donor transplants could be a safe intervention in renal patients.

Karyomapping in preimplantation genetic testing for β-thalassemia combined with HLA matching: a systematic summary.

To investigate the validity, accuracy, and clinical outcomes of Karyomapping in preimplantation genetic testing (PGT) for β-thalassemia combined with human leukocyte antigen (HLA) matching. A total of 128 cycles from January 2014 to December 2017 were identified, and 1205 embryos were biopsied. The case group included 88 cycles using Karyomapping for PGT-HLA, compared with 40 cycles using polymerase chain reaction-short tandem repeat (PCR-STR) as the control group. There were significant differences in the HLA matching rate (21.34 vs. 14.37%), the matched transferable embryo rate (9.79 vs. 14.07%), the clinical pregnancy rate (65.08 vs. 41.86%), and the spontaneous miscarriage rate (2.44 vs. 22.22%) between the case and control groups. In the case group, nearly 1/3 (33.37%) of the embryos showed aneuploidy. According to the results of single nucleotide polymorphism (SNP) haplotype analysis, the recombination rates of HBB (hemoglobin subunit beta) and HLA were 11.46% and 5.61% respectively. HLA gene recombination was mostly distributed between HLA-A and HLA-B and the downstream region of HLA-DQB1. In addition, STR analysis could be considered in the case of copy-neutral loss of heterozygosity (LOH) in the region where the HLA gene is located. Karyomapping contributes to accurate selection of matched embryos, along with aneuploidy screening. However, STRs assist identification in cases of LOH in the target region.

Proceedings From the Clinical and Scientific Innovations in Oral and Maxillofacial Surgery Conference 2019

Proceedings From the Clinical and Scientific Innovations in Oral and Maxillofacial Surgery Conference 2019

Single-Molecule Sequencing: A New Approach for Preimplantation Testing and Noninvasive Prenatal Diagnosis Confirmation of Fetal Genotype

We investigated the potential of next-generation sequencing (NGS) as an alternative method for preimplantation genetic testing of monogenic disease (PGT-M) with human leukocyte antigen (HLA) matching and for noninvasive prenatal diagnosis follow-up. The case involved parents who were carriers of the Fanconi anemia complementation group G (FANCG) 260delG mutation. After clinical PGT using conventional short tandem repeat and mutation analysis, two euploid disease-free embryos were transferred, resulting in a twin pregnancy. Using the original embryo whole genome amplification products from 10 embryos, NGS confirmed the genotypes of the eight nontransferred embryos for both mutation status and HLA combination. NGS also confirmed that the two transferred embryos, which resulted in a twin pregnancy, were euploid, Fanconi disease free, and HLA matched to their sick sibling. At 15 weeks' gestation, noninvasive prenatal diagnosis of the maternal cell-free DNA determined fetal fractions of 14% and 6.6% for twins 1 and 2, respectively. The maternal plasma FANCG 260delG mutation ratio was measured at 46.2%, consistent with the presence of a carrier fetus and a normal fetus. These findings provide proof of concept that NGS has clinical utility as a safe and effective PGT-M method for embryo genotyping as well as more complex direct HLA matching. In addition, NGS can be used to confirm the original PGT-M and HLA matching embryo results in early pregnancy without the need for invasive prenatal diagnosis.

Knockout of beta-2 microglobulin reduces stem cell-induced immune rejection and enhances ischaemic hindlimb repair via exosome/miR-24/Bim pathway.

Generating universal human umbilical mesenchymal stem cells (UMSCs) without immune rejection is desirable for clinical application. Here we developed an innovative strategy using CRISPR/Cas9 to generate B2M‐UMSCs in which human leucocyte antigen (HLA) light chain β2‐microglobulin (B2M) was deleted. The therapeutic potential of B2M‐UMSCs was examined in a mouse ischaemic hindlimb model. We show that B2M‐UMSCs facilitated perfusion recovery and enhanced running capability, without inducing immune rejection. The beneficial effect was mediated by exosomes. Mechanistically, microRNA (miR) sequencing identified miR‐24 as a major component of the exosomes originating from B2M‐UMSCs. We identified Bim as a potential target of miR‐24 through bioinformatics analysis, which was further confirmed by loss‐of‐function and gain‐of‐function approaches. Taken together, our data revealed that knockout of B2M is a convenient and efficient strategy to prevent UMSCs‐induced immune rejection, and it provides a universal clinical‐scale cell source for tissue repair and regeneration without the need for HLA matching in the future.

Results of Unrelated Donor Hematopoietic Stem Cell Transplantation for Sickle Cell Disease in Europe on Behalf of Paediatric Diseases (PDWP) and Inborn Errors Working Parties (IEWP) of the EBMT

Introduction: Allogeneic hematopoietic stem cell transplantation (HSCT) is, to date, the only curative treatment for sickle cell disease (SCD). Because a human leukocyte antigen (HLA) matched sibling donor is not always available, alternative stem cell sources such as unrelated or haploidentical related donors have been explored. The likelihood of finding a 10/10 (HLA-A, B, C, DRB1 and DQB1) matched donor varies among ethnic groups, with the lowest probability among individuals of African descent. To date, few series of SCD patients transplanted with an unrelated donor (UD) have been reported, but the high rates of rejection and chronic graft versus host disease (cGvHD) have limited its widespread application. Patients and methods: We report the results of a retrospective, registry based, survey on 70 UD HSCT performed in patients (pts) with SCD from UD in 22 European Society for Blood and Marrow Transplantation (EBMT) centers between 2005 and 2017. Data were collected from the EBMT database and missing information was updated by the centers. Median follow up was 38 (range 2-154) months. Most pts were HbSS (n=54; 78%), had positive serology for CMV (80%), and a Karnofsky score >80% (98%). Eighteen pts had a major ABO incompatibility. Recurrent vaso-occlusive crisis (n=58), cerebral vasculopathy (n=23) and acute chest syndrome (n=24) were the main indications for HSCT. Red blood cell (RBC) transfusions pre-HSCT were reported in 97% of pts of whom 53% received more than 20 transfusions; 14% of the transfused pts had RBC alloantibodies. Hydroxyurea pre-HSCT was used in 65% of pts. Median age at HSCT was 9.6 years (range 2-43) with 87% of pts being ≤ 16 years. Stem cell source was bone marrow (BM) in 55 pts (79%) and peripheral blood (PBSC) in 15 (21%). The median number of infused TNC /kg was 3.6 x 108 for BM and 7.1 x 108 for PBSC; the median number of infused CD34/kg was 4.4 x 106 for BM and 8.3 x 106 for PBSC. HLA matching at high resolution typing was 10/10 (HLA-A, B, C, DRB1 and DQB1) in 31, 9/10 in 17 and 8/10 in 4 of the patient-donor pairs; intermediate resolution typing was available for 10 (10/10 or 9/10) and the HLA information was missing for the remaining 8 patient-donor pairs. The most frequent conditioning regimens were fludarabine-thiotepa-treosulfan (64%) and busulfan- cyclophosphamide (12%). GvHD prophylaxis was cyclosporine plus methotrexate in 59%. Anti-thymocyte globulin was used in 90% and alemtuzumab in 9% of pts. Results: The cumulative incidence (CI) of neutrophil engraftment at 60 days was 93% (95% CI 76-100), with median time to engraftment of 18 days; platelet engraftment at 180 days was 90% (95% CI 83-98) with a median time of 20 days. Ten pts had graft failure (5 primary and 5 secondary) of whom 6 had a second transplant and were all alive at last FU (median 9.5 months after second HSCT). The CI of grade II-IV aGVHD at 100 days was 23% (95% CI 15-36), and 8 pts (11%) had grade III-IV. Acute GVHD was more frequent in patients who received PBSC (PBSC 42.9%, BM 18.2%, p=0.062). Three-year CI of cGVHD was 23% (95% CI 15-36), 7 pts (10%) had limited and 9 (13%) extensive cGvHD. Three-year overall survival (OS) was 90±4%; three-year event free survival (EFS) (considering death and graft failure as events) was 76±6%; HLA matching between donor and recipient was the most important factor for OS and EFS. Considering only pts-donor pairs with high resolution HLA typing available (n=52), 3-year OS was 96±4% in 10/10 group compared to 77±11% in 9/10 plus 8/10 group (p 0.065), 3-year EFS was 85±7% vs 62±12% (p 0.040), respectively. No significant differences between the groups were observed in CI of neutrophil engraftment, aGVHD and cGVHD. Conclusion: UD HSCT is a valid option for SCD patients who lack an HLA-identical sibling donor. Nevertheless, efforts are still needed to improve outcomes after UD HSCT. Our results indicate that using a 10/10 HLA matched UD improves both OS and EFS compared to donors with 1 or more mismatches; so, when such a matched unrelated donor is not found, using an haplo relative or an unrelated cord blood as donor source should be evaluated. A prospective trial is in preparation to evaluate the use of haploidentical donors for HSCT in SCD (EudraCT number: 2018-002652-33). Disclosures No relevant conflicts of interest to declare.

Human Leukocyte Antigen Matched Unrelated Donors for Patients with Sickle Cell Disease According to Geographic Origin: Results of International Donor Searches

Background: Hematopoietic stem cell transplantation (HSCT), the only available curative therapy for sickle cell disease (SCD), remains hampered by the lack of histocompatible stem cell donors. Most patients will not have a suitable human leukocyte antigen(HLA) matched sibling donor. In addition, SCD affects ethnic groups that are underrepresented in stem cell donor registries worldwide. Objective: to assess the probability of having a potential allelic HLA matched unrelated donor(MUD) for HLA-A,B and DRB1 loci (6/6) in international donor registries for patients with SCD. Methods: 185 patients with SCD were included, 116 from Brazil, of whom 23 underwent HSCT, and 69 patients who underwent HSCT in centers reporting to the European Society for Blood and Marrow Transplantation (EBMT). All patients had HLA typing available at intermediate or high resolution. For intermediate resolution, using the National Marrow Donor Program (NMDP) code, we assigned alleles based on allele frequencies.We performed HLA haplotype estimation using the HaploStats website, which describes HLA haplotype frequency from the NMDP registry for the following ethnic groups: Caucasian, African-American, Asian, Hispanic and Native American. Because Hispanic is not a primary ethnicity, we did not consider this group in our analyses. Based on haplotype frequency of each ethnic group, we defined the most likely ethnicity for each estimated haplotype; those with frequency >1:1000 in all ethnic groups were named common. Unrelated donor search was done using the World Marrow Donor Association (WMDA) algorithm, which is based on haplotype matching. A potential allelic donor was defined as a full match high resolution 6/6 donor. Because it is described that testing at least 5 potential allelic donors simultaneously increases the chances of having a real donor, we assessed the probability of finding at least 1 and at least 5 potential allelic donors. Patients who received HSCT from MUD were excluded from donor searches (n=10).Comparisons of probabilities of having potential allelic donors between Brazilian and EBMT cohorts were performed by chi-square. Results: In the Brazilian cohort, from 181 HLA haplotypes, 45% were classified as African-American, 18% common, 12% Caucasian, 9% Amerindian and 16% could not be classified. In the EBMT cohort, from 116 HLA haplotypes, 70% were classified as African-American, 8% common, 6% Caucasian, 3% Amerindian and 13% were not classified. Although Brazilians showed greater genetic admixture, chances of finding at least one potential allelic MUD were 47% in both groups (p-value not significant) and chances of having at least 5 potential allelic MUD were 24% for Brazilians and 15% for EBMT (p-value not significant). Overall, most potential allelic MUD were found in the NMDP registry, followed by the Brazilian registry (REDOME) and by the German registry (ZKMD); for the Brazilian cohort, most potential allelic MUD were found in REDOME. Discussion: Migration from Africa to Brazil started at the colonial period, and interethnic admixture have been occurring since then, explaining the higher diversity observed in the Brazilian cohort. Despite differences in ethnic composition, chances of having at least one potential allelic MUD are identical, probably because carrying at least one African or Amerindian haplotype decreases the chances of a full HLA matching. Although we demonstrated higher probabilities of finding a potential allelic MUD in SCD than previous studies, the chances are still low, therefore further strategies are required to increase donor representativeness for SCD. In this setting, alternative sources, such as haploidentical HSCT and cord blood, should be considered. Also, our study might help to predict the probabilities of finding a MUD for patients with SCD. This is important because given that HSCT in SCD has better results if performed at earlier age, knowing which patients are less likely to find a MUD might influence therapy management. Disclosures No relevant conflicts of interest to declare.

The Impact of Identifying the Syndromic and Genetic Diagnoses on Hematopoietic Stem Cell Transplantation Outcome in Patients with Inherited Bone Marrow Failure Syndromes

Background: Over the last decade major progress has been made in developing new diagnostic methods and in phenotypic and molecular classification of inherited bone marrow failure syndromes (IBMFSs). Nevertheless, data from the Canadian Inherited Marrow Failure Registry (CIMFR) indicates that 28% of patients with inherited bone marrow failure syndromes (IBMFS) cannot be assigned a specific syndromic diagnosis. These unclassified IBMFS (UIBMFS) cases may represent either novel syndromes or atypical presentations of previously described disorders. Hematopoietic stem cell transplantation (HSCT) is the only curative option for bone marrow failure and malignant myeloid transformation in IBMFSs. However, it is unknown whether the application of this treatment to UIBMFS patients without an ability to modify the procedure according to the underlying genetic and syndromic diagnosis affects outcome. To our knowledge, there are no published transplant data on cohorts of patients with UIBMFSs. The aims of this study were to evaluate the outcome and prognostic factors of HSCT in a cohort of patients with UIBMFSs and to determine whether the knowledge of the syndromic/genetic diagnosis before HSCT has an impact on transplant outcome. Methods: Patients were enrolled on the CIMFR if they were diagnosed with a specific IBMFSs (e.g. Fanconi anemia), and/or they had bone marrow failure and either a family history of bone marrow, or physical malformations or a diagnosis before the age of one year. Patients were considered as having an UIBMFS if they fulfilled the above criteria, but could not be assigned a specific syndromic diagnosis since they did not meet the diagnostic criteria for any known IBMFS. HSCT data were extracted from the CIMFR database and analyzed. Descriptive statistics were used to compare between groups. Cox proportional hazards model was used for univariate analysis to identify risk factors for worse overall survival post HSCT in patients with UIBMFSs. Results: Among the patients enrolled in the CIMFR, 22 with UIBMFSs and 68 with classified IBMFSs (CIBMFSs) underwent HSCT between January 2001 and December 31, 2017. Transplanted patients with UIBMFSs were hematologically characterized by multilineage cytopenia (n=13), single-lineage cytopenia (n=1), myelodysplastic syndrome (MDS) (n=5) or acute myeloid leukemia (AML) (n=3). Patients with CIBMFSs had Fanconi anemia (n=30), dyskeratosis congenita (n=7), Shwachman-Diamond syndrome (n=9), Kostmann syndrome (n=6), Diamond-Blackfan anemia (n=4) or others (n= 11). Median age at diagnosis of patients with UIBMFSs was 4.18 years (range; 0 to 32.0 years) and median age at HSCT for UIBMFSs was 5.74 years (range; 0.17-66.67 years). Median time between diagnosis of UIBMFS and HSCT was 0.48 years (range; 0.12 - 34.67), this was significantly shorter than that of CIBMFS (1.77 years, range; 0.17 - 15 years, P=0.014). Six patients (27.3%) of UIBMFS and 9 patients (19.7%) with CIBMFS underwent HSCT for MDS-RCEB or AML (P=0.15). The overall 5-year survival of UIBMFS patients was significantly inferior to that of CIBMFS patients: 56±11.4% vs. 76±5.5%, respectively (P=0.047). 5-year overall survival of patients with UIBMFSs was significantly worse among those whose stem cell source was cord blood (15±13.3%) vs. those who received other stem cell sources (91±8.7%, P=0.04), while stem cell source did not affect prognosis of patients with CIBMFSs. Engraftment failure among UIBMFS patients who received cord blood was significantly higher than engraftment failure among those who received bone marrow (55.6% vs. 9.1%, P=0.024). No other factors reached statistical significance when the impact of stem cell source on overall survival was analyzed, including transfusion load, transplant indications, intensity of conditioning regimens, related/non-related donor, degree of human leukocyte antigen (HLA) matching or identifying a diagnosis after HSCT. Conclusion: Identifying the syndromic diagnosis of IBMFSs is critically important when considering HSCT. The worse HSCT outcome of UIBMFSs in this study might be related to an inability to tailor the transplant approach to the patient specific phenotype and genotype. Our data suggest that cord blood should be avoided as a stem cell source in patients with UIBMFSs. Disclosures No relevant conflicts of interest to declare.

Plasma Biomarker Predicts Lethal Acute Graft Versus Host Disease and Non-Relapse Mortality in Japanese Patients

Introduction Allogeneic hematopoietic stem cell transplantation (aHSCT) is a curative treatment option for hematopoietic malignancies. In addition to relapse mortality, non-relapse mortality (NRM) such as severe graft-versus-host disease(GVHD) is a major cause of aHSCT. Pre-transplant clinical risk factors for acute GVHD include the degree of human leukocyte antigen (HLA) match between donor and recipient, recipient age, donor type, and conditioning regimen intensity. Although GVHD prophylaxis is usually decided by these risk factors, excessive immunosuppression induces opportunistic infection. Laboratory test cannot predict the risk of NRM or severe GVHD after aHSCT prior to the onset of GVHD symptoms; however, 2-biomarker (ST2 and REG3α) algorithm, namely MAGIC algorithm, may predict severe GVHD as has been shown recently (Hartwell et al. JCI Insight 2017). We retrospectively analyzed these 2 biomarkers in our patients to try whether the 2-biomarker algorithm is available to identify high risk of lethal GVHD and non-relapse mortality in Japanese patients. Patients and Methods We retrospectively analyzed consecutive 47 patients who received aHSCT for hematologic malignancies at Kansai Medical University Hospital from January 1, 2010 until April 30, 2016.Overall survival (OS), non-relapse mortality, cause of death, and GVHD clinical staging were investigated. Non-relapse deaths were considered related to GVHD if the patient died from either GVHD itself or from an infection that developed while receiving systemic steroids (at least 10 mg prednisone daily or equivalent) for the treatment of GVHD. Bloodsamples were obtained 7 days after transplantation. ST2 and REG3α concentrations were analyzed by ELISA, and were used for the 2-biomarker algorithm (Hartwell et al. JCI Insight 2017). Results Of the 47 patients (male 24, female 23), median age was 52 years (range, 22-69 years). Eleven patients received PBSCT, 27 patients received bone marrow transplantation, and 9 patients received cord blood transplantation. Of 27 patients who received bone marrow transplantation, 3 patients were transplanted allografts from HLA mismatched donor. Twenty-seven patients underwent reduced intensity conditioning regimen. The median survival time and 1-year OS rate were 375 days (range, 7-3236 days) and 53.2 %, respectively.The overall cumulative incidences of 6-month NRM was 23.4%. The incidence of grade II-IV and III-IV acute GVHD were 17.0%, and 13.2%, respectively. Twelve patients were identified as high risk (HR), and 35 patients were identified as low risk (LR) by the MAGIC algorithm. OS was 33.3% in HR and 71.4% in LR (p<0.05). Six-month cumulative incidence of NRM in HR patients was significantly higher than that of LR (58.3% vs. 11.4%, p<0.001) (Figure), whereas the relapse rate did not differ between risk groups. Four and three patients died from GVHD in HR and LR patients, respectively (33.3% vs. 8.6%, p<0.05). Severe gastrointestinal GVHD was greater in HR patients (18.7 % vs. 8.6%). Conclusion The biomarker algorithm based on blood sample taken 7 day after aHSCT can identify HR patients of lethal GVHD and NRM in Japanese patients as well. Figure Disclosures Ito: Celgene: Honoraria; Bristol-Myers Squibb: Honoraria, Research Funding.

Application of NGS-based SNP haplotyping for preimplantation genetic diagnosis for beta-thalassemia and HLA matching

To assess the value of next-generation sequencing (NGS)-based single nucleotide polymorphism (SNP) haplotyping for preimplantation genetic diagnosis (PGD) for beta-thalassemia coupled with human leukocyte antigen (HLA) matching. Three couples were recruited. Couple 1 both carried a β (IVS-2-654) variation and had previously given birth to a son with β thalassemia major. Couple 2 respectively carried (cd41-42) and β (IVS-2-654) but had no history of pregnancy. Couple 3 respectively carried β (CD17) and β (IVS-2-654), and had a daughter carrying β (CD17). For couple 1, NGS-SNP typing identified two embryos not only unaffected with thalassemia but also with matched HLA. One blastocyst was transferred and resulted in successful pregnancy. A healthy baby was born at 39th week of gestation. Its umbilical blood was used to treat the sick brother through hemopoietic stem cell transplantation. For couple 2, seven blastocysts were obtained. Second transplantation has resulted in successful pregnancy. Prenatal diagnosis was consistent with PGD. For couple 3, two blastocysts not only unaffected with thalassemia but also with no pathogenic copy number variations were obtained. Transfer of one blastocyte resulted in successful pregnancy, and prenatal diagnosis was consistent with PGD. NGS-based SNP typing is an useful tool for selecting embryos unaffected with beta-thalassemia and matched HLA through PGD.

Non-HLA donor-recipient mismatches in kidney transplantation-A stone left unturned.

In kidney transplantation, short-term allograft survival has improved due to improvements in acute rejection episodes without corresponding improvements in long-term survival. Although current organ allocation algorithms take into account human leukocyte antigen (HLA) matching to reduce antidonor alloimmune responses, it is likely that genomic variation at non-HLA loci (ie, non-HLA donor-recipient [D-R] pair mismatches) play a role in the "non-self" responses and ultimately affect long-term allograft survival. Existing data from both animal models and human studies suggest an association between non-HLA D-R mismatches and kidney allograft outcomes. In this minireview, we examine existing and emerging data and discuss putative mechanisms on the role of non-HLA D-R mismatches on long-term allograft outcomes in kidney transplantation.

The utility of cognitive changes in identifying those with acute graft vs. host disease following allogeneic hematopoietic cell transplant

Objectives: Acute graft versus host disease (aGVHD) is a common complication of allogeneic hematopoietic cell transplant (HCT) and is associated with morbidity and mortality. Identifying those at risk for developing aGVHD is crucial for early intervention. The current study assessed whether scores on a brief cognitive screening measure could identify those that develop aGVHD by 100 days post-HCT.Methods: Participants were 37 patients undergoing allogeneic HCT, assessed prior to transplant, and at 30- and 100-days post-HCT. Of those completing all evaluations, patients were divided into those who did (n = 14) and did not (n = 16) develop aGVHD by day 100 post-HCT. At 100 days post-transplant, groups did not differ on relevant demographic factors, disease, conditioning regimen, relatedness of donor, stem cell source, steroid use, total body irradiation use, human leukocyte antigens (HLA) match, or frequency of infection.Results: At 100 days post-HCT, those with aGVHD performed significantly worse on a working memory measure than those without aGvHD. The presence of aGVHD at day 100 increased significantly with every one standard deviation decrease in working memory from baseline to 30 days post-HCT (odds ratio = 3.08; 95% CI: 1.00–9.36). These findings were observed despite a small sample size and statistically controlling for multiple analyses.Conclusions: While this study is exploratory in nature, and has a small sample size, findings suggest that early detection of working memory declines could coincide with, or signal the development of, aGVHD. Potential etiologies are discussed. Implementing early cognitive screening within the first 30 days post-HCT may be useful in identifying patients at risk for aGVHD.

HLA-matched platelet transfusions are effective only in refractory patients with positive HLA antibody screening.

Recipients of platelet transfusions with 1-hour corrected count increments (1hCCIs) of 7.5 or less on two subsequent platelet transfusions with random platelets may benefit from human leukocyte antigen (HLA)-matched platelet concentrates. We aimed to quantify the efficacy of HLA-matched platelets concentrates expressed in 1hCCIs. We performed a cohort study among consecutive refractory patients who received HLA-matched platelet concentrates in the Netherlands between 1994 and 2017. We performed mixed-model linear regression comparing 1hCCIs after HLA split-antigen-matched transfusions with 1hCCIs after HLA-mismatched transfusions, adjusted for within-patient correlations. A donor-to-patient match was categorized as a split-match if all donor HLA-A and -B antigens were present in the patient as well; that is, donor and patient were HLA identical or compatible. Subgroup analyses were performed for patients with positive or negative HLA antibody screens. Finally, the additional effect of ABO mismatches on 1hCCIs was investigated. The 1hCCI after an HLA-matched transfusion was 14.09 (95% reference interval, 1.13-29.89). This was 1.94 (95% confidence interval [CI], 0.74-3.15) higher than 1hCCI after HLA-mismatched transfusions. In patients with negative HLA antibody screening tests, HLA matching did not affect 1hCCIs. Conditional on HLA matching, 1hCCIs decreased by 3.70 (95% CI, -5.22 to -2.18) with major ABO mismatches. Matched platelet concentrates yielded maximal 1hCCIs, whereas mismatched transfusions still resulted in adequate increments. There is no indication for HLA-matched platelets in patients with negative antibody screens.

Human Leukocyte Antigen and Red Blood Cells Impact Umbilical Cord Blood CD34+ Cell Viability after Thawing.

Hematopoietic progenitor cell (HPC) transplantation is a treatment option for malignant and nonmalignant diseases. Umbilical cord blood (UCB) is an important HPC source, mainly for pediatric patients. It has been demonstrated that human leukocyte antigen (HLA) matching and cell dose are the most important features impacting clinical outcomes. However, UCB matching is performed using low resolution HLA typing and it has been demonstrated that the unnoticed mismatches negatively impact the transplant. Since we found differences in CD34+ viability after thawing of UCB units matched for two different patients (p = 0.05), we presumed a possible association between CD34+ cell viability and HLA. We performed a multivariate linear model (n = 67), comprising pre-cryopreservation variables and high resolution HLA genotypes separately. We found that pre-cryopreservation red blood cells (RBC), granulocytes, and viable CD34+ cell count significantly impacted CD34+ viability after thawing, along with HLA-B or -C (R2 = 0.95, p = 0.01; R2 = 0.56, p = 0.007, respectively). Although HLA-B*40:02 may have a negative impact on CD34+ cell viability, RBC depletion significantly improves it.

First Asian, Single-Center Experience of Blastocyst Preimplantation Genetic Diagnosis with Human Leukocyte Antigen Matching in Thailand for the Prevention of Thalassemia and Subsequent Curative Hematopoietic Stem Cell Transplantation of Ten Affected Siblings

First Asian, Single-Center Experience of Blastocyst Preimplantation Genetic Diagnosis with Human Leukocyte Antigen Matching in Thailand for the Prevention of Thalassemia and Subsequent Curative Hematopoietic Stem Cell Transplantation of Ten Affected Siblings

Tissue typing for kidney transplantation for the general nephrologist.

Tissue typing is the process by which an individual's human leukocyte antigens (HLA) are determined. In transplantation, this vital process allows the immunologic or rejection risk of a donor-recipient pairing to be assessed through reviewing their HLA matching and whether any anti-HLA antibodies present in recipient serum are donor specific. Tissue typing has increased in sophistication over time which has allowed a deeper appreciation of the antigenically important parts of HLA and increased the complexity of determining immunologic risk.

Current status of umbilical cord blood transplantation in children

The first umbilical cord blood (UCB) transplantation was performed 30years ago. UCB transplantation (UCBT) is now widely used in children with malignant and non-malignant disorders who lack a matched family donor. UCBT affords a lower incidence of graft-versus-host disease compared to alternative stem cell sources, but also presents a slower immune recovery and a high risk of infections if serotherapy is not omitted or targeted within the conditioning regimen. The selection of UCB units with high cell content and good human leucocyte antigen match is essential to improve the outcome. Techniques, such as double UCBT, ex vivo stem cell expansion and intra-bone injection of UCB, have improved cord blood engraftment, but clinical benefit remains to be demonstrated. Cell therapies derived from UCB are under evaluation as potential novel strategies to reduce relapse and viral infections following transplantation. In recent years, improvements within haploidentical transplantation have reduced the overall use of UCBT as an alternative stem cell source; however, each may have its relative merits and disadvantages and tailored use of these alternative stem cell sources may be the optimal approach.