The novel HLA-DPB1*05:01:20 allele, identified by Sanger dideoxy nucleotide sequencing in a Chinese individual

HLA-DPB1*05:01:20 differs from HLA-DPB1*05:01:01:01 by one nucleotide in exon 3.

Cytomegalovirus Reactivations in Allogeneic Hematopoietic Stem Cell Transplantation from HLA-Matched and Haploidentical Donors with Post-Transplantation Cyclophosphamide

Cytomegalovirus (CMV) reactivations cause significant morbidity in allogeneic hematopoietic stem cell transplantation (HSCT) recipients. Graft-versus-host disease (GVHD) prophylaxis with post-transplantation cyclophosphamide (PTCy) is associated with an increased risk of CMV infections. Data are limited comparing HSCT with PTCy performed from matched sibling donors (MSDs), matched unrelated donors (MUDs), and haploidentical (Haplo) donors. In the present study, we aimed to characterize CMV reactivation and recurrence in patients with hematologic malignancies undergoing HSCT from MSD, MUD, and Haplo donors using PTCy as GVHD prophylaxis in the pre-letermovir era. We also analyzed risk factors of CMV reactivation, including GVHD as a time-dependent variable, on the incidence and mortality associated with CMV infections. We analyzed CMV reactivation in patients undergoing HSCT from 160 MSDs, 124 MUDs, and 82 Haplo donors from a single institution. Uniform GVHD prophylaxis with PTCy, sirolimus, and mycophenolate mofetil was given irrespective of donor type. Overall, 46% of patients had at least 1 CMV reactivation. The 1-year cumulative incidence of CMV infection was 39% for MSD, 44% for MUD, and 62% for Haplo donors (P < .001), with 96% of reactivations occurring before day +100. Multivariate analysis identified factors associated with the first CMV reactivation, including Haplo donor, positive recipient CMV serology, older patient age, and grade II-IV acute GVHD. The 1-year cumulative incidence of second reactivation from HSCT was 13%. Recipient CMV seropositivity, older patient age, and grade II-IV acute GVHD, but not type of donor, were identified as adverse factors for second CMV reactivation in multivariate analysis. The 1-year cumulative incidence of a third reactivation post HSCT was 4.4%. Ten cases of CMV disease were recorded, with no attributable deaths. Nevertheless, the risk for nonrelapse mortality was greater for patients who experienced CMV reactivation in multivariate time-dependent Cox model analysis. CMV reactivation is frequent in HSCT with PTCy in patients not receiving letermovir prophylaxis. Identified risk factors include the use of a Haplo donor, recipient CMV seropositivity, and grade II-IV acute GVHD. The prevalence of recurrent CMV reactivations is a noteworthy issue, especially after acute GVHD, warranting trials of secondary prophylaxis strategies.

A pig kidney supporting human physiology

Because of the global shortage of donor kidneys, xenotransplantation emerges as a potential solution for individuals with kidney failure who face challenges in securing a suitable donor kidney. A study featured in this month's issue of Kidney International assesses the kidney physiology of a porcine kidney transplanted into a brain-dead human with kidney failure, demonstrating life-sustaining physiological function for 7 days. Together with preclinical nonhuman primate studies, decedent models provide complementary data for development of clinical kidney xenotransplantation.

Peripheral blood stem cell transplantation using HLA-haploidentical donor with post-transplant cyclophosphamide versus HLA-matched sibling donor for lymphoma

Data comparing HLA-haploidentical donors and HLA-matched sibling donors (MSDs) in peripheral blood stem cell transplantation (PBSCT) for lymphoma are scarce. We retrospectively analyzed 465 patients with lymphoma aged 16 years or older who underwent PBSCT using haploidentical donors with post-transplant cyclophosphamide (PTCy-haplo) (n = 166) or MSDs with calcineurin inhibitor-based graft-versus-host disease (GVHD) prophylaxis (n = 299). Two-year overall survival (OS), progression-free survival (PFS), and GVHD-free, relapse-free survival (GRFS) in the PTCy-haplo and MSD groups were 49.2% versus 51.9% (P = 0.64), 38.0% versus 39.9% (P = 0.97), and 27.7% versus 18.5% (P = 0.006), respectively. In multivariable analyses, PTCy-haplo recipients had slower neutrophil recovery (hazard ratio [HR], 0.62; P < 0.001) and platelet recovery (HR, 0.54; P < 0.001), lower risk of chronic GVHD (HR, 0.64; P = 0.038) and extensive chronic GVHD (HR, 0.45; P = 0.008), and better GRFS (HR, 0.66; P = 0.003) than MSD transplant recipients. OS, PFS, relapse or progression, and non-relapse mortality were similar between the groups. The difference might be mainly due to PTCy use rather than donor type; however, the results suggested that PTCy-haplo could be a possible option as an alternative to conventional MSD transplantation for lymphoma in PBSCT.

Characterisation of the novel HLA-C*15:274 allele using short and long-read sequencing technologies

The novel HLA-C*15:274 allele, first described in a potential bone marrow donor from Brazil.

Characterisation of the novel HLA-C*08:275 allele, first identified in a Brazilian individual

The novel HLA-C*08:275 allele, first described in a potential bone marrow donor from Brazil.

Donor genetic determinant of thymopoiesis, rs2204985, and stem cell transplantation outcome in a multipopulation cohort

BACKGROUND

A genetic polymorphism, rs2204985, has been reported to be associated with the diversity of T-cell antigen receptor repertoire and TREC levels, reflecting the function of the thymus. As the thymus function can be assumed to be an important factor regulating the outcome of stem cell transplantation (SCT), it was of great interest that rs2204985 showed a genetic association to disease-free and overall survival in a German SCT donor cohort. Tools to predict the outcome of SCT more accurately would help in risk assessment and patient safety.

OBJECTIVE

To evaluate the general validity of the original genetic association found in the German cohort, we determined genetic associations between rs2204985 and the outcome of SCT in 1,473 SCT donors from four different populations.

STUDY DESIGN

Genetic associations between rs2204985 genotype AA versus AG/GG and overall survival (OS) and disease-free survival (DFS) in 1,473 adult, allogeneic SCT from Finland, the United Kingdom, Spain, and Poland were performed using the Kaplan-Meier analysis and log-rank tests. We adjusted the survival models with covariates using Cox regression.

RESULTS

In unrelated SCT donors (N = 425), the OS of genotype AA versus AG/GG had a trend for a similar association (p = 0.049, log-rank test) as previously reported in the German cohort. The trend did not remain significant in the Cox regression analysis with covariates. No other associations were found.

CONCLUSION

Weak support for the genetic association between rs2204985, previously also associated with thymus function, and the outcome of SCT could be found in a cohort from four populations.

PIRCHE application major versions 3 and 4 lead to equivalent T cell epitope mismatch scores in solid organ and stem cell transplantation modules

PIRCHE scores in organ and stem cell transplantation have been shown to correlate with increased risk of donor-specific HLA antibodies and graft-versus-host disease, respectively. With advancements of the PIRCHE application server, it is critical to compare the predicted scores with previous versions. This manuscript compares the newly introduced PIRCHE version 4.2 with its predecessor version 3.3, which was widely used in retrospective studies, using a virtual cohort of 10,000 transplant pairs. In the stem cell transplantation module, both versions yield identical results in 100% of the test population. In the solid organ module, 97% of the test population has identical PIRCHE scores. The deviating cases (3%) were attributed to refinements in the PIRCHE algorithm's specification. Furthermore, the magnitude of the difference is likely to be below the detection limit for clinical effects, confirming the equivalence in PIRCHE scores between versions 3.3 and 4.2.

Donor age has no relevant role in biomechanical properties of allografts used in anterior cruciate ligament (ACL) reconstruction: A systematic review

PURPOSE

Surgeons generally consider the donor age as a factor that negatively influences the quality of allograft used in anterior cruciate ligament (ACL) reconstruction, however, the available evidence does not clearly support this statement. The purpose of the study was to investigate if donor age influences the biomechanical properties of allografts used in ACL reconstruction.

METHODS

A comprehensive literature search was conducted for all relevant articles using MEDLINE (PubMed), Scopus, and Cochrane Collaboration Library, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Studies including the analysis of the correlation between biomechanical properties of the allografts and donor age were selected. The role of donor age was labelled as 'none' if absent, 'higher' or 'lower' if the properties were higher or lower in older specimens with respect to younger. The correlation was defined as 'weak' or 'strong' according to each study definition.

RESULTS

No conflicting role of donor age was reported for modulus of elasticity, load to failure, strain, stiffness and displacement. The only parameters where the significant results were consistent were the tensile strength and the stress (low or moderate correlations). When considering the tested samples with a donor's age <65 years, a significant role of age was reported in only four out of 13 groups of graft tested (patellar tendon, fascia lata, anterior tibialis tendon and posterior tibialis tendon).

CONCLUSION

The current literature did not allow to state that the donor age negatively influences the biomechanical properties of allografts, making it impossible to identify a clear age cut-off value to exclude them from ACL reconstruction procedures.

LEVEL OF EVIDENCE

Level IV, systematic review.

Effect of Donor Age and Liver Steatosis on Potential of Decellularized Liver Matrices to be used as a Platform for iPSC-Hepatocyte Culture

Decellularization of discarded whole livers and their recellularization with patient-specific induced pluripotent stem cells (iPSCs) to develop a functional organ is a promising approach to increasing the donor pool. The effect of extracellular matrix (ECM) of marginal livers on iPSC-hepatocyte differentiation and function has not been shown. To test the effect of donor liver ECM age and steatosis, young and old, as well as no, low, and high steatosis livers, are decellularized. All livers are decellularized successfully. High steatosis livers have fat remaining on the ECM after decellularization. Old donor liver ECM induces lower marker expression in early differentiation stages, compared to young liver ECM, while this difference is closed at later stages and do not affect iPSC-hepatocyte function significantly. High steatosis levels of liver ECM lead to higher albumin mRNA expression and secretion while at later stages of differentiation expression of major cytochrome (CYP) 450 enzymes is highest in low steatosis liver ECM. Both primary human hepatocytes and iPSC-hepatocytes show an increase in fat metabolism marker expression with increasing steatosis levels most likely induced by excess fat remaining on the ECM. Overall, removal of excess fat from liver ECM may be needed for inducing proper hepatic function after recellularization.

Characterisation of the novel HLA-B*35:593 allele using short and long-read sequencing technologies

The novel HLA-B*35:593 allele, first described in a potential bone marrow donor from Brazil.

Semilunar valve growth and function 10 years after infant heart transplantation: Predicting long-term outcomes of partial heart transplants

INTRODUCTION

Partial heart transplants are a new type of pediatric transplant that replace defective heart valves with the parts of matched donor hearts containing the necessary valves. Short-term outcomes of partial heart transplants are excellent, but long-term outcomes are unknown. In order to predict the long-term outcomes of partial heart transplants, we evaluated long-term growth and function of semilunar heart valves transplanted in infancy as part of a heart transplant.

METHODS

All children who underwent infant heart transplantation at a single center from 1997 to 2014 were included in this study. Children in whom echocardiograms after heart transplantation and after 10 years were not available for review were excluded. The echocardiograms were reviewed by two authors to analyze semilunar valve annulus diameters, Z-scores, peak valve gradients, and valve regurgitation. Statistical difference was determined using two-tailed, paired sample t-tests with Bonferroni correction for multiple comparisons.

RESULTS

Data from 15 patients were analyzed. The aortic valve annulus averaged 1.3 cm (range 0.7-1.8 cm) immediately after transplantation and grew to an average of 1.7 cm (range 1.4-2.3 cm) after 10 years (p < .001). After 10 years, the aortic valve peak gradient avereraged 5.1 mmHg (range 2.1-15.5 mmHg) and none of the valves had more than trivial regurgitation. The pulmonary valve annulus averaged 1.5 cm (range 1.1-2.5 cm) immediately after transplantation and grew to an average of 2.1 cm (range 1.0-2.9 cm) after 10 years (p < .001). After 10 years, the pulmonary valve peak gradient averaged 4.3 mmHg (range 1.1-13.8 mmHg), and 7% of valves had moderate regurgitation.

DISCUSSION

Semilunar heart valves transplanted in infancy as part of a heart transplant demonstrate statistically significant growth and excellent function after 10 years. This predicts excellent long-term outcomes of partial heart transplants.

Donation after circulatory death improves probability of heart transplantation in waitlisted candidates and results in post-transplant outcomes similar to those achieved with brain-dead donors

OBJECTIVE

To quantitate the impact of heart donation after circulatory death (DCD) donor utilization on both waitlist and post-transplant outcomes in the United States.

METHODS

The United Network for Organ Sharing database was queried to identify all adult waitlisted and transplanted candidates between October 18, 2018, and December 31, 2022. Waitlisted candidates were stratified according to whether they had been approved for donation after brain death (DBD) offers only or also approved for DCD offers. The cumulative incidence of transplantation was compared between the 2 cohorts. In a post-transplant analysis, 1-year post-transplant survival was compared between unmatched and propensity-score-matched cohorts of DBD and DCD recipients.

RESULTS

A total of 14,803 candidates were waitlisted, including 12,287 approved for DBD donors only and 2516 approved for DCD donors. Overall, DCD approval was associated with an increased sub-hazard ratio (HR) for transplantation and a lower sub-HR for delisting owing to death/deterioration after risk adjustment. In a subgroup analysis, candidates with blood type B and status 4 designation received the greatest benefit from DCD approval. A total of 12,238 recipients underwent transplantation, 11,636 with DBD hearts and 602 with DCD hearts. Median waitlist times were significantly shorter for status 3 and status 4 recipients receiving DCD hearts. One-year post-transplant survival was comparable between unmatched and propensity score-matched cohorts of DBD and DCD recipients.

CONCLUSIONS

The use of DCD hearts confers a higher probability of transplantation and a lower incidence of death/deterioration while on the waitlist, particularly among certain subpopulations such as status 4 candidates. Importantly, the use of DCD donors results in similar post-transplant survival as DBD donors.

Quality assurance in corneal transplants: Donor cornea assessment and oversight

The cornea is the most frequently transplanted human tissue, and corneal transplantation represents the most successful allogeneic transplant worldwide. In order to obtain good surgical outcome and visual rehabilitation and to ensure the safety of the recipient, accurate screening of donors and donor tissues is necessary throughout the process. This mitigates the risks of transmission to the recipient, including infectious diseases and environmental contaminants, and ensures high optical and functional quality of the tissues. The process can be divided into 3 stages: (1) donor evaluation and selection before tissue harvest performed by the retrieval team, (2) tissue analysis during the storage phase conducted by the eye bank technicians after the retrieval, and, (3) tissue quality checks undertaken by the surgeons in the operating room before transplantation. Although process improvements over the years have greatly enhanced safety, quality, and outcome of the corneal transplants, a lack of standardization between centers during certain phases of the process still remains, and may impact on the quality and number of transplanted corneas. Here we detail the donor screening process for the retrieval teams, eye bank operators. and ophthalmic surgeons and examine the limitations associated with each of these stages.

Remuneration of donors for cell and gene therapies: an update on the principles and perspective of the World Marrow Donor Association

The cell and gene therapy (CGT) sector has witnessed significant advancement over the past decade, the inception of advanced therapy medicinal products (ATMPs) being one of the most transformational. ATMPs treat serious medical conditions, in some cases providing curative therapy for seriously ill patients. There is interest in pivoting the ATMP development from autologous based treatments to allogenic, to offer faster and greater patient access that should ultimately reduce treatment costs. Consequently, starting material from allogenic donors is required, igniting ethical issues associated with financial gains and donor remuneration within CGT. The World Marrow Donor Association (WMDA) established the Cellular Therapy Committee to identify the role WMDA can play in safeguarding donors and patients in the CGT field. Here we review key ethical principles in relation to donating cellular material for the CGT field. We present the updated statement from WMDA on donor remuneration, which supports non-remuneration as the best way to ensure the safety and well-being of donors and patients alike. This is in line with the fundamental objective of the WMDA to maintain the health and safety of volunteer donors while ensuring high-quality stem cell products are available for all patients. We acknowledge that the CGT field is evolving at a rapid pace and there will be a need to review this position as new practices and applications come to pass.

Quantifying the Effect of Consent for High-Kidney Donor Profile Index Deceased Donor Transplants in the United States

Key Points

Background

Despite known benefits of kidney transplantation, including transplantation from donors with increased risk factors, many waitlisted candidates die before transplantation. Consent to receive donor kidneys with lower expected survival (e.g., Kidney Donor Profile Index [KDPI] >85%) is typically obtained at waitlist placement. The presumed benefit of consent to receive high-KDPI donor kidneys is higher likelihood and timeliness of donor offers for transplantation. However, the specific effect of consent on access to transplantation is unclear. Our aims were to evaluate the characteristics of candidates consenting to high-KDPI donor kidneys and the likelihood of receiving a deceased donor transplant over time on the basis of consent.

Methods

We used national Scientific Registry of Transplant Recipients data between 2015 and 2022 (n=213,364). We evaluated the likelihood of consent using multivariable logistic models and time to deceased donor transplant with cumulative incidence plots accounting for competing risks and multivariable Cox models.

Results

Overall, high-KDPI consent was 41%, which was higher among candidates who were older, were Black or Hispanic, had higher body mass index, had diabetes, had vascular disease, and had 12–48 months prelisting dialysis time, with significant center-level variation. High-KDPI consent was associated with higher rates of deceased donor transplant (adjusted hazard ratio=1.15; 95% confidence interval, 1.13 to 1.17) with no difference in likelihood of deceased donor transplant from donors with KDPI <85%. The effect of high-KDPI consent on higher rates of deceased donor transplantation was higher among candidates older than 60 years and candidates with diabetes and variable on the basis of center characteristics.

Conclusions

There is significant variation of consent for high-KDPI donor kidneys and higher likelihood of transplantation associated with consent.

Technique of corneal allogenic ring segment preparation using femtosecond laser: preclinical study on human corneal grafts

PURPOSE

To describe a new technique for preparing corneal allogenic ring segments (CAIRSs) using femtosecond laser technology.

SETTING

Hospital Foundation Adolphe de Rothschild-Noémie de Rothschild institute, Paris, France.

DESIGN

Preclinical study conducted on human corneal grafts.

METHODS

The corneal grafts were mounted on an artificial chamber pressurizer (ACP) with preset constant pressure, and the FSL was used to create a circular annulus with specific dimensions. The resulting CAIRSs were analyzed for their thickness and width after air drying.

RESULTS

A total of 25 CAIRSs were prepared using the FSL. The mean width and thickness of the CAIRSs were 803 ± 77 μm and 83 ± 16 μm, respectively. Statistical analysis revealed no significant differences in width among the various quadrants of each CAIRS or between different CAIRSs. Significantly thicker CAIRSs were obtained with a higher ACP pressure.

CONCLUSIONS

The technique of CAIRS preparation using FSL technology and controlled artificial anterior chamber pressure demonstrated reproducibility and precision. This approach holds the potential for customizing and personalizing CAIRSs based on individual corneal characteristics.

The novel HLA-B*15:659 allele, identified by Sanger dideoxy nucleotide sequencing in a Chinese individual

HLA-B*15:659 differs from HLA-B*15:02:01:01 by one nucleotide in exon 2.

Biomechanical Correlations Between the Cornea and the Optic Nerve Head

Purpose

A thin cornea is a potent risk factor for glaucoma. The underlying mechanisms remain unexplained. It has been postulated that central corneal thickness (CCT) may be a surrogate for biomechanical parameters of the posterior eye. In this study, we aimed to explore correlations of biomechanical responses between the cornea and the optic nerve head (ONH) and the peripapillary sclera (PPS) to elevated intraocular pressure (IOP), the primary risk factor of glaucoma.

Methods

Inflation tests were performed in nine pairs of human donor globes. One eye of each pair was randomly assigned for cornea or posterior eye inflation. IOP was raised from 5 to 30 millimeters of mercury (mmHg) at 0.5 mmHg steps in the whole globe and the cornea or the ONH/PPS was imaged using a 50 MHz ultrasound probe. Correlation-based ultrasound speckle tracking was used to calculate tissue displacements and strains. Associations of radial, tangential, and shear strains at 30 mmHg between the cornea and the ONH or PPS were evaluated.

Results

Corneal shear strain was significantly correlated with ONH shear strain (R = 0.857, P = 0.003) and PPS shear strain (R = 0.724, P = 0.028). CCT was not correlated with any strains in the cornea, ONH, or PPS.

Conclusions

Our results suggested that an eye that experiences a larger shear strain in the cornea would likely experience a larger shear strain in its ONH and PPS at IOP elevations. The strong correlation between the cornea's and the ONH's shear response to IOP provides new insights and suggests a plausible explanation of the cornea's connection to glaucoma risk.

T-cell receptor sequencing reveals selected donor-reactive CD8+ T cell clones resist antithymocyte globulin depletion after kidney transplantation

High frequencies of donor-reactive memory T cells in the periphery of transplant candidates prior to transplantation are linked to the development of posttransplant acute rejection episodes and reduced allograft function. Rabbit antithymocyte globulin (rATG) effectively depletes naïve CD4+ and CD8+ T cells for >6 months posttransplant, but rATG's effects on human donor-reactive T cells have not been carefully determined. To address this, we performed T cell receptor β-chain sequencing on peripheral blood mononuclear cells aliquots collected pretransplant and serially posttransplant in 7 kidney transplant recipients who received rATG as induction therapy. We tracked the evolution of the donor-reactive CD4+ and CD8+ T cell repertoires and identified stimulated pretransplant, CTV-(surface dye)-labeled, peripheral blood mononuclear cells from each patient with donor cells or third-party cells. Our analyses showed that while rATG depleted CD4+ T cells in all tested subjects, a subset of donor-reactive CD8+ T cells that were present at high frequencies pretransplant, consistent with expanded memory cells, resisted rATG depletion, underwent posttransplant expansion and were functional. Together, our data support the conclusion that a subset of human memory CD8+ T cells specifically reactive to donor antigens expand in vivo despite induction therapy with rATG and thus have the potential to mediate allograft damage.