Impact of HLA in cord blood transplantation outcomes

HLA peptide-binding pocket diversity modulates immunological complications after cord blood transplant in acute leukaemia

Pocket motifs and their amino acid positions of HLA molecules are known to govern antigen presentation to effector cells. Our objective was to analyse their influence on the risk of graft-versus-host disease (GVHD) and relapse after umbilical cord blood transplant (UCBT). The transplant characteristics of 849 patients with acute leukaemia were obtained from the Eurocord/EBMT database. Higher acute (a) GVHD was associated with homozygosity of UCB HLA-C amino acid positions 77 and 80 (NN/KK) (p = 0.008). Severe aGVHD was associated with HLA-A pocket B YSAVMENVHY motif (p = 0.002) and NN and RR genotypes of the HLA-C amino acid positions 77 and 156 (p = 0.006 and p = 0.002). Such risk was also increased in case of recipient and UCB mismatches in P4 (p < 0.0001) and P9 (p = 0.003) pockets of HLA-DQB1 alleles. For chronic GVHD, the pocket B YYAVMEISNY motif of the HLA-B*15:01 allele and the absence of mismatch between recipient and UCB in the P6 pocket of HLA-DRB1 were associated with a lower risk (p = 0.0007 and p = 0.0004). In relapse, both UCB pocket B YFAVMENVHY belonging to HLA-A*32:01 and recipient pocket B YDSVGENYQY motif of the HLA-C*07:01 allele were associated with higher risk (p = 0.0026 and p = 0.015). We provide clues on HLA-mediated cellular interactions and their role in the development of GVHD and relapse.

The impact of pre-transplant anti-HLA antibodies in transplants from HLA-identical sibling donors: A multicenter study

Few studies have performed comparative analysis of the outcome of hematopoietic stem cell transplantation from HLA-identical sibling donors (ISD-HSCT) in patients with or without anti-HLA Abs. In this study we retrospectively collected data from a multicenter study to analyze the distribution and impact of the pre-existing anti-HLA Abs in ISD-HSCT. Among 402 recipients, 111 were positive for anti-HLA Abs. Gender, time from diagnosis to transplantation and distribution of primary disease might be risk factors for the occurrence of anti-HLA Abs. We found that patients with anti-HLA Abs had delayed neutrophil engraftment and were more vulnerable to experience Cytomegalovirus (CMV) reactivation. The presence of anti-HLA Abs was proved to be an independent risk factor for neutrophil engraftment (HR 1.42 95% CI 1.13-1.80, p = 0.003) and CMV reactivation (HR 2.03 95% CI 1.19-3.46, p = 0.009). We found that anti-HLA Abs have a negative impact on the prognosis in the early period after transplantation from sibling donors and anti-HLA Abs was also an independent risk factor for the overall survival (OS) at 180 days (HR 2.32, 95% CI 1.03-5.27, p = 0.042) among female recipients. In conclusion, anti-HLA Abs have a negative impact on the prognosis early after ISD-HSCT.

Mitigation of acute radiation syndrome (ARS) with human umbilical cord blood

PURPOSE

The growing concern over potential unintended nuclear accidents or malicious activities involving nuclear/radiological devices cannot be overstated. Exposure to whole-body doses of radiation can result in acute radiation syndrome (ARS), colloquially known as "radiation sickness," which can severely damage various organ systems. Long-term health consequences, such as cancer and cardiovascular disease, can develop many years post-exposure. Identifying effective medical countermeasures and devising a strategic medical plan represents an urgent, unmet need. Various clinical studies have investigated the therapeutic use of umbilical cord blood (UCB) for a range of illnesses, including ARS. The objective of this review is to thoroughly discuss ARS and its sub-syndromes, and to highlight recent findings regarding the use of UCB for radiation injury. UCB, a rich source of stem cells, boasts numerous advantages over other stem cell sources, like bone marrow, owing to its ease of collection and relatively low risk of severe graft-versus-host disease. Preclinical studies suggest that treatment with UCB, and often UCB-derived mesenchymal stromal cells (MSCs), results in improved survival, accelerated hematopoietic recovery, reduced gastrointestinal tract damage, and mitigation of radiation-induced pneumonitis and pulmonary fibrosis. Interestingly, recent evidence suggests that UCB-derived exosomes and their microRNAs (miRNAs) might assist in treating radiation-induced damage, largely by inhibiting fibrotic pathways.

CONCLUSION

UCB holds substantial potential as a radiation countermeasure, and future research should focus on establishing treatment parameters for ARS victims.

Multipotent fetal stem cells in reproductive biology research

Due to the limited accessibility of the in vivo situation, the scarcity of the human tissue, legal constraints, and ethical considerations, the underlying molecular mechanisms of disorders, such as preeclampsia, the pathological consequences of fetomaternal microchimerism, or infertility, are still not fully understood. And although substantial progress has already been made, the therapeutic strategies for reproductive system diseases are still facing limitations. In the recent years, it became more and more evident that stem cells are powerful tools for basic research in human reproduction and stem cell-based approaches moved into the center of endeavors to establish new clinical concepts. Multipotent fetal stem cells derived from the amniotic fluid, amniotic membrane, chorion leave, Wharton´s jelly, or placenta came to the fore because they are easy to acquire, are not associated with ethical concerns or covered by strict legal restrictions, and can be banked for autologous utilization later in life. Compared to adult stem cells, they exhibit a significantly higher differentiation potential and are much easier to propagate in vitro. Compared to pluripotent stem cells, they harbor less mutations, are not tumorigenic, and exhibit low immunogenicity. Studies on multipotent fetal stem cells can be invaluable to gain knowledge on the development of dysfunctional fetal cell types, to characterize the fetal stem cells migrating into the body of a pregnant woman in the context of fetomaternal microchimerism, and to obtain a more comprehensive picture of germ cell development in the course of in vitro differentiation experiments. The in vivo transplantation of fetal stem cells or their paracrine factors can mediate therapeutic effects in preeclampsia and can restore reproductive organ functions. Together with the use of fetal stem cell-derived gametes, such strategies could once help individuals, who do not develop functional gametes, to conceive genetically related children. Although there is still a long way to go, these developments regarding the usage of multipotent fetal stem cells in the clinic should continuously be accompanied by a wide and detailed ethical discussion.

Umbilical Cord Blood Transplantation: Connecting Its Origin to Its Future

Transplantation of umbilical cord blood (UCB) is an attractive alternative source of hematopoietic stem cells (HSCs). The unique properties of cord blood and its distinct immune tolerance and engraftment kinetics compared to bone marrow (BM) and peripheral blood progenitor cells, permit a wider disparity in human leukocyte antigen levels between a cord blood donor and recipient after an unrelated umbilical cord blood transplant (UCBT). In addition, it is readily available and has a lowered risk of graft-versus-host disease (GvHD), with similar long-term clinical outcomes, compared to BM transplants. However, the relatively low number of cells administered by UCB units, as well as the associated delayed engraftment and immune reconstitution, pose limitations to the wide application of UCBT. Research into several aspects of UCBT has been evaluated, including the ex vivo expansion of cord blood HSCs and the process of fucosylation to enhance engraftment. Additionally, UCB has also been used in the treatment of several neurodegenerative and cardiovascular disorders with varying degrees of success. In this article, we will discuss the biology, clinical indications, and benefits of UCBT in pediatric and adult populations. We will also discuss future directions for the use of cord blood.

Haematopoietic stem cell transplantation for severe autoimmune diseases in children: A review of current literature, registry activity and future directions on behalf of the autoimmune diseases and paediatric diseases working parties of the European Society for Blood and Marrow Transplantation

Although modern clinical management strategies have improved the outcome of paediatric patients with severe autoimmune and inflammatory diseases over recent decades, a proportion will experience ongoing or recurrent/relapsing disease activity despite multiple therapies often leading to irreversible organ damage, and compromised quality of life, growth/development and long-term survival. Autologous and allogeneic haematopoietic stem cell transplantation (HSCT) have been used successfully to induce disease control and often apparent cure of severe treatment-refractory autoimmune diseases (ADs) in children. However, transplant-related outcomes are disease-dependent and long-term outcome data are limited in respect to efficacy and safety. Moreover, balancing risks of HSCT against AD prognosis with continually evolving non-transplant options is challenging. This review appraises published literature on HSCT strategies and outcomes in individual paediatric ADs. We also provide a summary of the European Society for Blood and Marrow Transplantation (EBMT) Registry, where 343 HSCT procedures (176 autologous and 167 allogeneic) have been reported in 326 children (<18 years) for a range of AD indications. HSCT is a promising treatment modality, with potential long-term disease control or cure, but therapy-related morbidity and mortality need to be reduced. Further research is warranted to establish the position of HSCT in paediatric ADs via registries and prospective clinical studies to support evidence-based interspeciality guidelines and recommendations.

Sequential Transplantation of Haploidentical Stem Cell and Unrelated Cord Blood With Using ATG/PTCY Increases Survival of Relapsed/Refractory Hematologic Malignancies

Allogeneic haploidentical HSCT (haplo-HSCT) and unrelated umbilical cord blood transplantation(UCBT)are used in patients lacking HLA-identical sibling or unrelated donors. With myeloablative condition and GVHD prophylaxis of using low-dose ATG and post-transplantation cyclophosphamide (PTCY), we conducted a prospective clinical trial. Of eligible 122 patients from February 2015 to December 2019 in the study, 113 patients were involved. Forty-eight patients were in the group of sequential haplo-cord transplantation (haplo-cord HSCT), and 65 patients were in the group of single UCBT. The primary endpoint of 2-year disease-free survival (DFS) was no statistical difference between groups (64.1 vs. 56.5%), p>0.05. The analysis of subgroup patients with relapsed/refractory showed haplo-cord HSCT was associated with better OS (HR 0.348, 95% CI, 0.175–0.691; p=0.0025), DFS (HR 0.402, 95% CI, 0.208–0.779; p=0.0069), and GRFS (HR 0.235, 95% CI, 0.120–0.457, p<0.0001) compared to the single cord group. The 2-year’s probability in OS, DFS, and GRFS was 64.9 vs. 31.6%, 64.5 vs. 31.6%, and 60.8 vs. 15.0% in the haplo-cord group and single cord group, respectively. III-IV acute GVHD 8.3 vs. 6.2%, chronic GVHD 25.8 vs. 13.7%, and extensive chronic GVHD 5.3 vs. 1.8% were shown in corresponding group, p>0.05. The patients engrafted persistently with UCB showed better survival outcomes. Our sequential Haplo-cord HSCT with ATG/PTCY improved the survival of patients and might be an alternative transplantation approach for patients with relapsed/refractory hematologic malignancies.

Umbilical cord blood transplants facilitated by the French cord blood banks network. On behalf of the Agency of Biomedicine, Eurocord and the French society of bone marrow transplant and cell therapy (SFGM-TC)

The public French Cord Blood Banks Network was established in 1999 with the objective of standardizing the practices governing umbilical cord blood (UCB) banking in France. The Network adopted a strategy to optimize its inventory and improve the quality of its banked units based on a quality improvement process using outcome data regularly provided by Eurocord. This study aimed to describe the results, over 10 years, of UCBT facilitated by a national network that used the same criteria of UCB collection and banking and to assess how modifications of banking criteria and unit selection might influence transplant outcomes. Nine hundred and ninety-nine units (593 single-unit and 203 double-unit grafts) were released by the Network to transplant 796 patients with malignant (83%) and non-malignant (17%) diseases. Median cell dose exceeded 3.5 × 107 TNC/kg in 86%. There was a trend to select units more recently collected and with higher cell dose. Neutrophil engraftment was 88.2% (85.7-90.7) and 79.3% (72.6-86.5) respectively for malignant and non-malignant diseases with a trend to faster recovery with higher cell doses. The respective 3-year transplant-related mortality were 31.1% (27.5-35.1) and 34.3% (27.0-43.5). OS was 49% ± 4 in malignant and 62% ± 4 in non-malignant disorders. In multivariate analysis, cell dose was the only unit-related factor associated with outcomes. Our results reflect the benefit on clinical outcomes of the strategy adopted by the Network to bank units with higher cell counts.

Cord-Blood-Derived Professional Antigen-Presenting Cells: Functions and Applications in Current and Prospective Cell Therapies

Human umbilical cord blood (UCB) represents a valuable source of hematopoietic stem cells, particularly for patients lacking a matching donor. UCB provides practical advantages, including a lower risk of graft-versus-host-disease and permissive human leukocyte antigen mismatching. These advantageous properties have so far been applied for stem cell, mesenchymal stromal cell, and chimeric antigen receptor T cell therapies. However, UCB-derived professional antigen-presenting cells are increasingly being utilized in the context of immune tolerance and regenerative therapy. Here, we review the cell-specific characteristics as well as recent advancements in UCB-based cell therapies focusing on dendritic cells, monocytes, B lymphocytes, innate lymphoid cells, and macrophages.

Reduced-intensity single-unit unrelated cord blood transplant with optional immune boost for nonmalignant disorders

Children with many inherited nonmalignant disorders can be cured or their condition alleviated by hematopoietic stem cell transplantation (HSCT). Umbilical cord blood (UCB) units are a rapidly available stem cell source and offer great flexibility in HLA matching, allowing nearly uniform access to HSCT. Although reduced-intensity conditioning (RIC) regimens promise decreased treatment-related morbidity and mortality, graft failure and infections have limited their use in chemotherapy-naive patients. We prospectively evaluated a novel RIC regimen of alemtuzumab, hydroxyurea, fludarabine, melphalan, and thiotepa with a single-unit UCB graft in 44 consecutive patients with inborn errors of metabolism, immunity, or hematopoiesis. In addition, 5% of the UCB graft was re-cryopreserved and reserved for cord donor leukocyte infusion (cDLI) posttransplant. All patients engrafted at a median of 15 days posttransplant, and chimerism was >90% donor in the majority of patients at 1-year posttransplant with only 1 secondary graft failure. The incidence of grade II to IV graft-versus-host disease (GVHD) was 27% (95% confidence interval [CI], 17-43) with no extensive chronic GVHD. Overall survival was 95% (95% CI, 83-99) and 85% (95% CI, 64-93) at 1 and 5 years posttransplant, respectively. No significant end-organ toxicities were observed. The use of cDLI did not affect GVHD and showed signals of efficacy for infection control or donor chimerism. This RIC transplant regimen using single-unit UCB graft resulted in outstanding survival and remarkably low rates of graft failure. Implementation of the protocol not requiring pharmacokinetic monitoring would be feasible and applicable worldwide for children with inherited disorders of metabolism, immunity, or hematopoiesis. This trial was registered at www.clinicaltrials.gov as #NCT01962415.

Analysis of HLA haplotype and clinical factors during hematopoietic stem cell transplantation

BACKGROUND

The human leukocyte antigen (HLA) haplotype of the recipient in hematopoietic stem cell transplantation (HSCT) is a key factor in its success or failure. We analyzed the relationship between HLA haplotype frequency and associated clinical factors in HSCT patients.

METHODS

Patients who underwent allogeneic HSCT between 2000 and 2019 at our institution were enrolled in this study. The HSCT composition was 77 bone marrow transplantations (BMT), 38 peripheral blood stem cell transplantations (PBSCT), and 36 cord blood transplantations (CBT). Patients were classified into three groups according to their donor HLA haplotype frequency in the Japan Population: group A, top 1-10 haplotypes; group B, top 11-100 haplotypes; and group C, haplotype 101-. We then compared various items including clinical biomarkers with the HLA haplotype frequency.

RESULTS

A significant negative correlation was identified between older persons and length of survival. There are also significant correlations between survival and levels of immunoglobulin G, D-dimer, and C-reactive protein, as well as the platelet-large cell ratio before transplantation. A total of 96, 30, and 25 patients were classified into groups A, B, and C, respectively. The HSCT match rate was significantly higher in group A patients than in those of groups B and C. In contrast, the death rate, D-dimer level, and length of time for engraftment were significantly higher in group B and C patients than in those of group A.

CONCLUSION

An assessment of transplant-related complications is important in improving the performance of HSCT. The present data suggest that a special therapeutic strategy is necessary for HSCT using low-frequency HLA haplotypes.

Cord blood maternal microchimerism following unrelated cord blood transplantation

Cord blood transplantation (CBT) is associated with low risk of leukemia relapse. Mechanisms underlying antileukemia benefit of CBT are not well understood, however a previous study strongly but indirectly implicated cells from the mother of the cord blood (CB) donor. A fetus acquires a small number of maternal cells referred to as maternal microchimerism (MMc) and MMc is sometimes detectable in CB. From a series of 95 patients who underwent double or single CBT at our center, we obtained or generated HLA-genotyping of CB mothers in 68. We employed a technique of highly sensitive HLA-specific quantitative-PCR assays targeting polymorphisms unique to the CB mother to assay CB-MMc in patients post-CBT. After additional exclusion criteria, CB-MMc was evaluated at multiple timepoints in 36 patients (529 specimens). CB-MMc was present in 7 (19.4%) patients in bone marrow, peripheral blood, innate and adaptive immune cell subsets, and was detected up to 1-year post-CBT. Statistical trends to lower relapse, mortality, and treatment failure were observed for patients with vs. without CB-MMc post-CBT. Our study provides proof-of-concept that maternal cells of the CB graft can be tracked in recipients post-CBT, and underscore the importance of further investigating CB-MMc in sustained remission from leukemia following CBT.

Guidelines for Cord Blood Unit Selection

Optimal cord blood (CB) unit selection is critical to maximize the likelihood of successful engraftment and survival after CB transplantation (CBT). However, unit selection can be complex because multiple characteristics must be considered including unit cell dose, donor-recipient human leukocyte antigen (HLA) match, and unit quality. This review provides evidence-based and experience-based comprehensive guidelines for CB unit selection. Topics addressed include the use of both the TNC and the CD34⁺ cell dose, as well as the CD34⁺ cell to TNC content ratio to evaluate unit progenitor cell content and engraftment potential, the acceptable TNC and CD34⁺ cell dose criteria that define an adequate single-unit graft, and the indication and acceptable cell dose criteria for double-unit grafts. The acceptable criteria for 6-loci (HLA-A, -B antigen, -DRB1 allele) and 8-allele (HLA-A, -B, -C, -DRB1) donor-recipient HLA match, the evaluation of patients with donor-specific HLA antibodies, and the multiple determinants of unit quality are also reviewed in detail. Finally, a practical step-by-step guide to CB searches and the principles that guide ultimate graft selection are outlined.

Post transplant cyclophosphamide based haplo-identical transplant versus umbilical cord blood transplant; a meta-analysis

OBJECTIVES

Both haplo-identical transplant (haplo) and umbilical cord transplant (UC) are valuable graft options for patients without available matched relative. Previous studies showed inconsistent outcomes comparing Post transplant Cyclophosphamide based haplo (PTCy-haplo) and UC; therefore, we attempt to compare the studies by mean of meta-analysis.

METHODS

We searched for titles of articles in MEDLINE (PubMed), Cochrane library, EMBASE database and Google scholar that compared transplantation with PTCy-haplo versus UC. We conducted a random-effect meta-analysis of seven studies involving a total of 3434 participants and reported the pooled odd ratios (OR) of acute graft-versus-host disease (aGVHD), chronic graft-versus-host disease (cGVHD), relapse and overall survival (OS) between PTCy-haplo and UC groups.

RESULTS

We found a significantly decreased risk of aGVHD and relapse in the PTCy-haplo group compared to the UC group with a pooled OR of 0.78, 95% Confidence Interval (CI) 0.67-0.92, I2=0%, and 0.74, 95% CI 0.57-0.97, I2=23.9% respectively. We also found a significantly increased rate of cGVHD and OS with a pooled OR of 1.41, 95% CI 1.02-1.95, I2=56.8%, and 1.77, 95% CI 1.1-2.87, I2=82.5%, respectively.

CONCLUSION

Our meta-analysis of clinical trials demonstrated superior outcome from PTCy-haplo group compared to the UC group in terms of decreased rate of aGVHD and relapse as well as the increased rate of OS but inferior in terms of increased cGVHD risk compared to UC transplant.

Umbilical Cord Blood Transplants: Current Status and Evolving Therapies

Hematopoietic cell transplants using stem cells from umbilical cord blood are used worldwide for the treatment of malignant and non-malignant disorders. Transplant procedures from this stem cell source have shown promising outcomes in successfully treating various hematologic, immunologic, malignant, and inherited metabolic disorders. Rapid availability of these stem cells is an important advantage over other unrelated donor transplants, especially in situations where waiting can adversely affect the prognosis. The umbilical cord blood is rich in CD34+ stem cells, though with a limited cell dose and usually takes longer to engraft. Limitations around this have been addressed by in vivo and ex vivo expansion techniques as well as enhanced engraftment kinetics. Development of adoptive immunotherapy using other components of umbilical cord blood such as regulatory T cells, virus-specific T cells, and natural killer cells has further transformed the field and enhanced the utility of umbilical cord blood unit.

Evaluation of Cord Blood Total Nucleated and CD34+ Cell Content, Cell Dose, and 8-Allele HLA Match by Patient Ancestry

How cord blood (CB) CD34⁺ cell content and dose and 8-allele HLA match vary by patient ancestry is unknown. We analyzed cell content, dose, and high-resolution HLA-match of units selected for CB transplantation (CBT) by recipient ancestry. Of 544 units (286 infused, 258 next-best backups) chosen for 144 racially diverse adult patients (median weight, 81 kg), the median total nucleated cell (TNC) and CD34⁺cell ⁺contents were higher for Europeans than for non-Europeans: 216 × 10⁷versus 197 × 10⁷ (P = .002) and 160 × 10⁵ versus 132 × 10⁵ (P = .007), respectively. There were marked cell content disparities among ancestry groups, with units selected for Africans having the lowest TNC (189 × 10⁷) and CD34⁺ cell (122 × 10⁵) contents. Units for non-Europeans were also more HLA-mismatched (P = .017). When only the 286 transplanted units were analyzed, the adverse effect of reduced cell content was exacerbated by the higher weights in some groups. For example, northwestern Europeans (high patient weight, high unit cell content) had the best-dosed units, and Africans (high weight, low unit cell content) had the lowest. In Asians, low cell content was partially compensated for by lower weight. Marked differences in 8-allele HLA-match distribution were also observed by ancestry group; for example, 23% of units for northwestern Europeans were 3/8 to 4/8 HLA-matched, compared with 40% for southern Europeans, 46% for white Hispanics, and 51% for Africans. During the study period, 20 additional patients (17 non-Europeans; median weight, 98 kg) did not undergo CBT owing to the lack of a suitable graft. CB extends transplantation access to most patients, but racial disparities exist in cell content, dose, and HLA match.

HLA-A, -B, -C, -DRB1, and -DQB1 allele and haplotype frequencies: An analysis of umbilical cord blood units at the Barcelona Cord Blood Bank

Allele-level HLA compatibility in cord blood transplantation has been associated with better transplant outcomes and is recommended as a selection criterion. It is also a crucial aspect for other therapeutic applications involving cord blood-derived cells. Determination of high-resolution HLA frequencies is an important step towards improving the quality of cord blood banks. We analyzed HLA-A, -B, -C, -DRB1, and -DQB1 allele frequencies in 5458 high-quality cord blood units from the Barcelona Cord Blood Bank and identified 275 class I and 121 class II HLA alleles. A*02:01, B*44:03, C*07:01, DRB1*07:01 and DQB1*03:01 were the most frequent alleles at each locus. We detected 26 novel alleles and were able to determine the presence or absence of some null alleles, including C*04:09N, in a large number of units. We also analyzed maternal HLA typing information for 1877 units to determine real haplotype frequencies and linkage disequilibrium. A*29:02-B*44:03-C*16:01-DRB1*07:01-DQB1*02:02 was the most frequent HLA haplotype and the DRB1-DQB1 gene pair contained the two-locus haplotypes with the strongest linkage disequilibrium values. Four of the 11 unique haplotypes identified in the HLA-homozygous cord blood units were the top-ranking haplotypes identified and were present in 18% of the cohort. This is the first study to report on HLA allele and haplotype frequencies for umbilical cord blood units from the Barcelona Cord Blood Bank and the largest study to date involving two fields of HLA resolution typing of Spanish registry data.

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.

Association of HLA-DQA1 gene polymorphisms with the risk of children primary nephrotic syndrome in Chinese population

BACKGROUND

The association between gene polymorphisms and the risk of primary nephrotic syndrome (PNS) is uncovering recently. This study aims to investigate the relationship between single nucleotide polymorphisms (SNPs) on HLA-DQA1 gene and the risk of PNS.

METHODS

In this study, we genotyped eight single nucleotide polymorphisms (SNPs) in the HLA-DQA1 gene in 501 PNS patients and 532 healthy people in Chinese population. Then we analyzed associations of these SNPs with the clinical features in primary nephrotic syndrome of children in Chinese population.

RESULTS

Significant associations with PNS were found on missense SNP rs1129740 (GG vs AA, odds ratio (OR) = 1.987, 95% confidence interval (CI) = 1.468-2.652, P = 0.00177049) and rs1047992 (AA vs GG, OR = 1.857, 95% CI = 1.325-2.391, P = 1.1073E-10) of the HLA-DQA1 gene.

CONCLUSIONS

This work suggests SNPs of HLA-DQA1 are risk factors for PNS in Chinese population, which implies roles of immune response in the pathogenesis of PNS.

B Regulatory Cells: Players in Pregnancy and Early Life

Pregnancy and early infancy represent two very particular immunological states. During pregnancy, the haploidentical fetus and the pregnant women develop tolerance mechanisms to avoid rejection; then, just after birth, the neonatal immune system must modulate the transition from the virtually sterile but haploidentical uterus to a world full of antigens and the rapid microbial colonization of the mucosa. B regulatory (Breg) cells are a recently discovered B cell subset thought to play a pivotal role in different conditions such as chronic infections, autoimmunity, cancer, and transplantation among others in addition to pregnancy. This review focuses on the role of Breg cells in pregnancy and early infancy, two special stages of life in which recent studies have positioned Breg cells as important players.

Luminex® xMAP® technology is an effective strategy for high-definition human leukocyte antigen typing of cord blood units prior to listing

INTRODUCTION

Allele-level donor-recipient match at HLA-A, HLA-B, HLA-C and HLA-DRB1 loci impacts the outcome after cord blood transplantation for hematologic malignancies and modifies the strategy of donor selection. High definition of both class I and II HLA loci at time of listing is a way to improve the attractiveness of cord blood bank inventories, reducing the time for donor search and procurement and simplifying donor choice, in particular, for patients of non-European heritage.

METHODS

In 2014, Luminex^® xMAP^® technology was introduced in our laboratory practice and was applied to cord blood units typing. In this study, we evaluated the impact of this strategy in comparison with the platform in use until 2013, relying on LiPA reverse polymerase chain reaction-sequence-specific oligonucleotide (revPCR-SSO) plus polymerase chain reaction-sequence-specific primer (PCR-SSP).

RESULTS

In 2014, the time for testing was shorter (141 vs 181 days on average), the number of test repetitions was lower (in particular for HLA-A locus, p = 0.026), and the cost reduced (240.7 vs 395.6 euros per unit on average) compared to 2013, demonstrating that Luminex xMAP technology is superior to the previous approach.

CONCLUSION

Luminex xMAP platform has useful application in cord blood banking programs, to achieve high-definition HLA typing of cord blood units at the time of banking in a quick, accurate, and cost-effective manner.

Curative or pre-emptive adenovirus-specific T cell transfer from matched unrelated or third party haploidentical donors after HSCT, including UCB transplantations: a successful phase I/II multicenter clinical trial

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (HSCT), the most widely used potentially curable cellular immunotherapeutic approach in the treatment of hematological malignancies, is limited by life-threatening complications: graft versus host disease (GVHD) and infections especially viral infections refractory to antiviral drugs. Adoptive transfer of virus-specific T cells is becoming an alternative treatment for infections following HSCT. We report here the results of a phase I/II multicenter study which includes a series of adenovirus-specific T cell (ADV-VST) infusion either from the HSCT donor or from a third party haploidentical donor for patients transplanted with umbilical cord blood (UCB).

METHODS

Fourteen patients were eligible and 11 patients received infusions of ADV-VST generated by interferon (IFN)-γ-based immunomagnetic isolation from a leukapheresis from their original donor (42.9%) or a third party haploidentical donor (57.1%). One patient resolved ADV infection before infusion, and ADV-VST could not reach release or infusion criteria for two patients. Two patients received cellular immunotherapy alone without antiviral drugs as a pre-emptive treatment.

RESULTS

One patient with adenovirus infection and ten with adenovirus disease were infused with ADV-VST (mean 5.83 ± 8.23 × 10³ CD3+IFN-γ+ cells/kg) up to 9 months after transplantation. The 11 patients showed in vivo expansion of specific T cells up to 60 days post-infusion, associated with adenovirus load clearance in ten of the patients (91%). Neither de novo GVHD nor side effects were observed during the first month post-infusion, but GVHD reactivations occurred in three patients, irrespective of the type of leukapheresis donor. For two of these patients, GVHD reactivation was controlled by immunosuppressive treatment. Four patients died during follow-up, one due to refractory ADV disease.

CONCLUSIONS

Adoptive transfer of rapidly isolated ADV-VST is an effective therapeutic option for achieving in vivo expansion of specific T cells and clearance of viral load, even as a pre-emptive treatment. Our study highlights that third party haploidentical donors are of great interest for ADV-VST generation in the context of UCB transplantation. (N° Clinical trial.gov: NCT02851576, retrospectively registered).

Maternal microchimerism is prevalent in cord blood in memory T cells and other cell subsets, and persists post-transplant

Among reported advantages of umbilical cord blood (CB) in transplantation is lower leukemia relapse probability. Underlying cellular mechanisms of graft-vs.-leukemia (GVL) are thought to include a prominent role for T cells. Cells of the CB's mother, maternal microchimerism (MMc), were recently strongly, but indirectly, implicated in this GVL benefit. We assayed MMc directly and hypothesized benefit accrues from CB maternal T cells. MMc was quantified in 51 CBs and, within memory T, naïve T, B, NK cells, and monocytes in 27 CBs. Polymorphism-specific quantitative-PCR assays targeted maternal genotypes non-shared with CBs. Overall MMc was common and often at substantial levels. It was present in 52.9% of CB and in 33.3-55.6% of tested subsets. Remarkably, MMc quantities were greater in memory T cells than other subsets (p < 0.001). Expressed as genome equivalents (gEq) per 10⁵ total gEq tested (gEq/10⁵), memory T cell MMc averaged 850.2 gEq/10⁵, while other subset mean quantities were 13.8-30.1 gEq/10⁵. After adjustment for proportionality in CB, MMc remained 6-17 times greater in memory T, and 3-9 times greater in naïve T, vs. non-T-cell subsets. Further, CB-origin MMc was detected in vivo in a patient up to 6 mo post-transplantation, including among T cells. Overall, results revealed levels and phenotypes of CB MMc with potential relevance to CB transplantation and, more broadly, to offspring health.

Characterization of the Highly Prevalent Regulatory CD24hiCD38hi B-Cell Population in Human Cord Blood

The newborn's immune system must transition from a sterile haploidentical uterus to the world full of antigens. Regulatory B-cells (Breg; broadly defined as CD19⁺CD24^hiCD38^hi) are tolerance promoters in the adult immune system. They can inhibit IFN-γ and IL-17 production by T-cells and are essential in different conditions, including pregnancy. Breg have still not been well characterized in umbilical cord blood, where we hypothesize that they are pivotal in the achievement of tolerance. We studied CD19⁺CD24^hiCD38^hi Breg in healthy umbilical cord blood (hUCB) compared to healthy peripheral adult blood (hAPB). Total numbers of Breg were increased in hUCB compared to hAPB (34.39 vs. 9.49%; p = 0.0002), especially in the marginal zone-like B-cell subset, in which the most marked difference could be observed between hUCB and hAPB (60.80 vs. 4.94%; p = 0.1). CD24^hiCD38^hi subset in hUCB produced IL-10 and inhibited T-cell IFN-γ [1.63 vs. 0.95 stimulation ratio (SR); p = 0.004] and IL-4 (1.63 vs. 1.44 SR; p = 0.39) production. Phenotypically, hUCB Breg cells presented IgM^hiIgD^hiCD5⁺CD10⁺CD27^- markers, similar to those described in hAPB Breg cells, but they showed increased IgM concentration and decreased expression of CD22 and CD73 markers. Our work characterized the frequency, phenotype, and function of Breg in hUCB, which may contribute to understanding of immune tolerance during pregnancy, paving the way to a new approach to immune-related diseases in the fetus and the newborn.

Impact of total body irradiation on successful neutrophil engraftment in unrelated bone marrow or cord blood transplantation

Total body irradiation (TBI) has been thought to promote donor cell engraftment in allogeneic hematopoietic cell transplantation (HCT) from alternative donors. However, recent progress in HCT strategies may affect the clinical significance of TBI on neutrophil engraftment. With the use of a Japanese transplant registry database, we analyzed 3933 adult recipients (>15 y.o.) who underwent HCT between 2006 and 2013 from an 8/8 HLA-matched unrelated bone marrow donor (MUD, n = 1367), an HLA-mismatched unrelated bone marrow donor (MMUD, n = 1102), or unrelated cord blood (CBT, n = 1464). Conditioning regimens were divided into five groups: High-TBI-(>8Gy), Low-TBI- (≤8Gy), and no-TBI-myeloablative conditioning (MAC), and Low-TBI- and no-TBI-reduced-intensity conditioning (RIC). In both MUD and MMUD, neutrophil engraftment rate was >90% in each of the five conditioning groups, and TBI was not associated with prompt neutrophil engraftment in multivariate analyses. Conversely, in CBT, TBI regimens had a higher rate of day-30 neutrophil engraftment than no-TBI-regimens: 78% in High-TBI-MAC, 83% in Low-TBI-MAC, and 76% in Low-TBI-RIC versus 65% in No-TBI-MAC, and 68% in No-TBI-RIC (P < .001). Multivariate analyses in CBT demonstrated that TBI-regimens were significantly associated with a higher rate of neutrophil engraftment. Subsequently focusing on CBT patients alone, TBI-regimens were significantly associated with a higher rate of neutrophil engraftment in patients who received CBT with a 4/6 or less HLA allele-match, or who had anti-HLA antibodies. In summary, TBI-regimens had no impact on neutrophil engraftment in the current practice of unrelated bone marrow transplantation. However, in CBT, TBI is still necessary to enhance engraftment.