Off-the-Shelf Partial HLA Matching SARS-CoV-2 Antigen Specific T Cell Therapy: A New Possibility for COVID-19 Treatment

BackgroundImmunological characteristics of COVID-19 show pathological hyperinflammation associated with lymphopenia and dysfunctional T cell responses. These features provide a rationale for restoring functional T cell immunity in COVID-19 patients by adoptive transfer of SARS-CoV-2 specific T cells.MethodsTo generate SARS-CoV-2 specific T cells, we isolated peripheral blood mononuclear cells from 7 COVID-19 recovered and 13 unexposed donors. Consequently, we stimulated cells with SARS-CoV-2 peptide mixtures covering spike, membrane and nucleocapsid proteins. Then, we culture expanded cells with IL-2 for 21 days. We assessed immunophenotypes, cytokine profiles, antigen specificity of the final cell products.ResultsOur results show that SARS-CoV-2 specific T cells could be expanded in both COVID-19 recovered and unexposed groups. Immunophenotypes were similar in both groups showing CD4+ T cell dominance, but CD8+ and CD3+CD56+ T cells were also present. Antigen specificity was determined by ELISPOT, intracellular cytokine assay, and cytotoxicity assays. One out of 14 individuals who were previously unexposed to SARS-CoV-2 failed to show antigen specificity. Moreover, ex-vivo expanded SARS-CoV-2 specific T cells mainly consisted of central and effector memory subsets with reduced alloreactivity against HLA-unmatched cells suggesting the possibility for the development of third-party partial HLA-matching products.DiscussionIn conclusion, our findings show that SARS-CoV-2 specific T cell can be readily expanded from both COVID-19 and unexposed individuals and can therefore be manufactured as a biopharmaceutical product to treat severe COVID-19 patients.One Sentence SummaryEx-vivo expanded SARS-CoV-2 antigen specific T cells developed as third-party partial HLA-matching products may be a promising approach for treating severe COVID-19 patients that do not respond to previous treatment options.

A Historical Cohort in Kidney Transplantation: 55-Year Follow-Up of 72 HLA-Identical, Donor-Recipient Pairs

The impact of HLA matching on graft survival has been well characterized in renal transplantation, with a higher degree of matching associated with superior graft survival. Additionally, living donor grafts are known to confer superior survival compared to those from deceased donors. The purpose of this study is to report our multi-decade institutional experience and outcomes for patients who received HLA-identical living donor grafts, which represent the most favorable scenario in kidney transplantation. We conducted a retrospective analysis of these graft recipients performed at a Duke University Medical Center between the years of 1965 and 2002. The recipients demonstrated excellent graft and patient survival outcomes, superior to a contemporary cohort, with median patient and graft survival of 24.2 and 30.9 years, respectively, among Duke recipients vs. 16.1 and 16.0 years in a cohort derived from national data. This study offers a broad perspective on the importance of HLA matching and graft type, and demonstrates a historical best-case-scenario in renal transplantation.

Review of Unrelated Donor Cord Blood Transplantation in Children over the Past 3 Decades

Four decades ago, Hal Broxmeyer demonstrated that umbilical cord blood (CB) contained hematopoietic stem cells (HSC) and hypothesized that CB could be used as a source of donor HSC for rescue of myeloablated bone marrow. In 1988, Gluckman et al reported the first successful cord blood transplant (CBT) of a child with Fanconi Anemia using matched sibling CB. This patient survives and 35 years later still has durable hematopoiesis from the CB donor graft. In 1991, Rubinstein et al established an unrelated donor (UD) CB bank and in 1993 the first UD CBT was using a unit from this bank. Since that time, >40,000 CBTs have been performed worldwide. We hypothesized that changes in cord blood banking (increased size, diversity, and quality of banked units enabling selection of units with higher cell doses and closer HLA matching) and in transplantation (less use of steroids, availability of newer therapies for prophylaxis and treatment of graft versus host disease [GVHD], improved antifungal and antiviral detection and therapeutics) have improved outcomes of CBT today. To address this hypothesis, we performed a retrospective study combining data from Eurocord and Duke University in a large cohort of children transplanted with a single UD CB unit (CBU) from 1993-2019. Standard transplant outcomes (overall survival [OS], disease free survival [DFS], acute and chronic GVHD, treatment related mortality [TRM], and relapse) and changes in outcomes over 3 time periods (1:<2005, n=1297; 2:2005-2010, n=1735; and 3:>2010, n=1802) were studied. Relative contributions of cell dose and HLA matching to transplant outcomes over time were assessed. A total of 4834 patients (4015 from Eurocord and 819 from Duke) were analyzed. The majority of patients, (59%, n=2839) had malignant diagnoses including 1422 with ALL, 887 with AML and 167 with MDS. Of the 1995 with non-malignant diagnoses, 761 had inborn errors of metabolism, 644 had primary immunodeficiency, 325 had a bone marrow failure syndrome and 206 had a histiocytic disorder. Half of the patients had positive serologies for CMV prior to transplant. The median age of the cohort fell from 5.2 to 3.25 years over time. In patients with malignancies, use of total body irradiation decreased over time. The median total nucleated cell (TNC) and CD34+ cell doses administered were 8.07x10e7 and 6.17x10e5 cells/kg and increased over time. HLA matching and transplantation of patients in earlier disease states also increased over time, p<0.001 for both. The probability of 5-year OS in the entire cohort was 53.48% and improved over time: 42%; 57.4%; and 60.4%, in periods 1,2,3 respectively (p<0.0001). OS improved with closer HLA matching, higher cell dose, myeloablative conditioning, and negative pre-transplant CMV serologies. For patients with malignancies, DFS increased and TRM and acute GVHD decreased over time. In contrast, leukemic relapse did not change throughout the years. OS was higher in patients with inborn errors of metabolism and also improved over time with 57.8% surviving before 2005, 69.4% from 2005-2010, and 71% after 2010 (p=0.0141). Similar results were seen in the cohort with immune deficiencies. In the entire cohort, the median time to neutrophil engraftment decreased from 25 days (period 1) to 19 days (period 3). In multivariate analysis for engraftment, a higher TNC dose (p=0.001) up to but not beyond the median cell dose (8.07x10e7 cells/kg), total body irradiation, and the use of ATG improved engraftment. Acute GVHD decreased from 35% before 2005 to 27.1% after 2010 (p=0.0556) while the incidence of chronic GvHD was stable. The use of ATG reduced the risk of acute GVHD and closer HLA matching reduced the risk of both acute and chronic GVHD. In this population of patients receiving high cell doses, outcomes were predominantly influenced by HLA matching and increasing cell dose did not abrogate HLA mismatching. In conclusion, we analyzed the largest cohort of pediatric patients undergoing CBT over the past 3 decades. OS, DFS and engraftment have improved over time accompanied by decreases in TRM and acute GVHD. Relapse and chronic GVHD were stable and remain low. These improvements are explained by the increased availability of high quality banked CBUs enabling selection of closer HLA matching and units with higher cell doses. The numbers of CBTs have decreased in the past decade, but these results support the ongoing use of CBT in children lacking matched related or unrelated donors. Figure 1 Figure 1. Disclosures Kurtzberg: Neurogene: Consultancy; CryoCell: Patents & Royalties: Duke licensed IP, and data and regulatory packages for manufacturing and use of cord blood and cord tissue MSCs in the treatment of patients with hypoxic ischemic encephalopathy, cerebral palsy, autism, acute ischemic stroke, COVID-ARDS, and COVID-MIS-C. ; Sinocell: Patents & Royalties: Duke licensed IP, data, and regulatory packages for use of autologous and sibling cord blood to treat children with cerebral palsy.; Celularity: Current holder of stock options in a privately-held company. Troy: SinoCell: Patents & Royalties; CryoCell: Patents & Royalties; Bristol Myers Squibb: Research Funding; Synthetic Biologics: Honoraria; Gamida Cell: Consultancy; The EMMES Corporation: Consultancy; The Community Data Roundtable: Consultancy; AegisCN: Consultancy.

Effectiveness of matching human leukocyte antigens (HLA) in corneal transplantation: a systematic review protocol

Background Corneal transplantation is the most frequently performed transplantation in the UK. Despite this, the therapeutic value of matching human leukocyte antigen (HLA) subtypes for transplanted corneas remains controversial. Ocular immune privilege was originally deemed to render matching unnecessary; however, more recently, matching has demonstrated improved outcomes including graft success, amongst others. This systematic review aims to evaluate the effectiveness of major and minor antigen matching on graft outcomes in corneal transplantation. Methods Standard systematic review methodology will be used to identify, select and extract data from observational studies and clinical trials assessing the effects of HLA matching on corneal graft outcomes. Bibliographic databases (Cochrane Library, EMBASE, MEDLINE, Web of Science, Scopus), clinical trial registers, abstract and conference proceedings, in addition to dissertation, thesis and grey literature will be searched. Neither date of publication nor language will be restricted, and non-English articles will be translated where necessary. The primary outcome will be to assess corneal graft success for different degrees of HLA matching/mismatching. The precise end outcome measure varies amongst studies and includes graft rejection, immunoreaction, failure and survival. Therefore, data will be extracted across all relevant outcome parameters and grouped for subsequent statistical tests. Risk of bias assessment will be completed, appropriate to each study design. Study selection, data extraction and risk of bias assessment will be independently completed by two reviewers. Data will be tabulated, and a narrative synthesis presented. Meta-analysis will be performed where there is sufficient homogeneity between studies to warrant its effective completion. Subgroup and sensitivity analysis will be undertaken if appropriate. Discussion Many studies have investigated the effectiveness of HLA matching for corneal transplantation. A systematic review is needed to collate and analyse this evidence. Findings of this systematic review may form the basis of evidence-based recommendations on pre-operative HLA typing and matching of corneal grafts for transplantation. Systematic review registration PROSPERO reference CRD42020198882

Maternal-Fetal HLA Compatibility in Uncomplicated and Preeclamptic Naturally Conceived Pregnancies

IntroductionIn pregnancy, the mother and fetus differ in HLA antigens, and yet the maternal immune system generally tolerates the fetus. KIR receptors expressed by maternal uterine NK cells at the maternal-fetal interface directly interact with HLA-C on extravillous trophoblast cells for optimal placental development. In this study, we aimed to determine whether there is a preferential selection for HLA compatibility and specific KIR/HLA-C combinations in uncomplicated and preeclamptic naturally conceived pregnancies compared to what would be expected by chance.MethodsGenotyping for maternal and fetal HLA-A, -B, -C, -DR, and -DQ, and maternal KIR was performed for 451 uncomplicated pregnancies and 77 pregnancies complicated with preeclampsia. The number of HLA antigen (mis)matches between mother and fetus was calculated and compared to expected values obtained by randomization of the HLA haplotype, inherited from the father, over the existing maternal haplotype of the fetuses. A similar methodology was executed for analysis of the KIR/HLA-C data (n=309).ResultsIn uncomplicated pregnancies, the degree of maternal-fetal HLA matching was not different than expected-by-chance values. In preeclamptic pregnancies, the degree of maternal-fetal HLA matching was different in observed compared to expected-by-chance values (p=0.012). More specifically, the degree of maternal-fetal matching of HLA-C was higher in the actual preeclamptic pregnancies than was expected-by-chance (p=0.007). Preeclamptic pregnancies showed an overall tendency towards higher maternal-fetal HLA compatibility, for total HLA matches (p=0.021), HLA class I (p=0.038) and HLA-C (p=0.025) compared to uncomplicated pregnancies.ConclusionThe data suggest that there is no preferential selection of maternal-fetal HLA compatibility in uncomplicated pregnancies. In contrast, increased total HLA, HLA class I and, especially, HLA-C compatibility is associated with preeclampsia, suggestive for a role of HLA mismatches in immune regulation leading to uncomplicated pregnancy.

Non-Tumorigenic Pluripotent Reparative Muse Cells Provide a New Therapeutic Approach for Neurologic Diseases

Muse cells are non-tumorigenic endogenous reparative pluripotent cells with high therapeutic potential. They are identified as cells positive for the pluripotent surface marker SSEA-3 in the bone marrow, peripheral blood, and connective tissue. Muse cells also express other pluripotent stem cell markers, are able to differentiate into cells representative of all three germ layers, self-renew from a single cell, and are stress tolerant. They express receptors for sphingosine-1-phosphate (S1P), which is actively produced by damaged cells, allowing circulating cells to selectively home to damaged tissue. Muse cells spontaneously differentiate on-site into multiple tissue-constituent cells with few errors and replace damaged/apoptotic cells with functional cells, thereby contributing to tissue repair. Intravenous injection of exogenous Muse cells to increase the number of circulating Muse cells enhances their reparative activity. Muse cells also have a specific immunomodulatory system, represented by HLA-G expression, allowing them to be directly administered without HLA-matching or immunosuppressant treatment. Owing to these unique characteristics, clinical trials using intravenously administered donor-Muse cells have been conducted for myocardial infarction, stroke, epidermolysis bullosa, spinal cord injury, perinatal hypoxic ischemic encephalopathy, and amyotrophic lateral sclerosis. Muse cells have the potential to break through the limitations of current cell therapies for neurologic diseases, including amyotrophic lateral sclerosis. Muse cells provide a new therapeutic strategy that requires no HLA-matching or immunosuppressant treatment for administering donor-derived cells, no gene introduction or differentiation induction for cell preparation, and no surgery for delivering the cells to patients.

Race as a Factor in Donor Selection and Survival of Children with Hematologic Malignancies Undergoing Hematopoietic Stem Cell Transplant in Florida

Background Previous studies have explored post-hematopoietic cell transplant (HCT) outcomes by race in adults; however, pediatric data addressing this topic are scarce. Procedure This retrospective registry study included 238 White (W) and 57 Black (B) children with hematologic malignancies (HM) receiving first allogeneic HCT between 2010 and 2019 in one of five Florida pediatric HCT centers. Results We found no differences between W and B children by transplant characteristics, other than donor type. There was a significant difference in use of HLA-mismatched donors (HLA-MMD) (53% W, 71% B, p=0.01). When comparing HLA-MMD use to fully HLA-matched donors, B had RR of 1.47 [95% CI 0.7-3] of receiving a mismatched unrelated donor (MMUD), RR of 2.34 [95% CI 1.2-4.4] of receiving a mismatched related donor (MMRD), and a RR of 1.9 [95% CI 0.99-3.6] of receiving a mismatched cord blood donor (MMCBD) HCT, respectively. There was no significant difference in the incidence of aGVHD (48% W, 35% B), p=0.1 or cGVHD (19% W 28% B, p=0.1), or primary cause of death. Overall 24-month survival was 61% [95% CI 54-68%] for W, and 60% [95% CI 38-68] for B children, log-rank p=0.72. While HLA matching improved survival in W children, the number of B children receiving HLA-matched HCT was too small to identify the impact of HLA matching on survival. Conclusions In this contemporary cohort of children with HM we found that B children were more likely to receive HLA-MMD transplants, but this did not adversely affect survival or GVHD rates.