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The major histocompatibility complex (MHC) encodes a range of immune response genes, including the human leukocyte antigens (HLAs) in humans. These molecules bind peptide antigens and present them on the cell surface for T cell recognition. The repertoires of peptides presented by HLA molecules are termed immunopeptidomes. The highly polymorphic nature of the genres that encode the HLA molecules confers allotype-specific differences in the sequences of bound ligands. Allotype-specific ligand preferences are often defined by peptide-binding motifs. Individuals express up to six classical class I HLA allotypes, which likely present peptides displaying different binding motifs. Such complex datasets make the deconvolution of immunopeptidomic data into allotype-specific contributions and further dissection of binding-specificities challenging. Herein, we developed MHCpLogics as an interactive machine learning-based tool for mining peptide-binding sequence motifs and visualization of immunopeptidome data across complex datasets. We showcase the functionalities of MHCpLogics by analyzing both in-house and published mono- and multi-allelic immunopeptidomics data. The visualization modalities of MHCpLogics allow users to inspect clustered sequences down to individual peptide components and to examine broader sequence patterns within multiple immunopeptidome datasets. MHCpLogics can deconvolute large immunopeptidome datasets enabling the interrogation of clusters for the segregation of allotype-specific peptide sequence motifs, identification of sub-peptidome motifs, and the exportation of clustered peptide sequence lists. The tool facilitates rapid inspection of immunopeptidomes as a resource for the immunology and vaccine communities. MHCpLogics is a standalone application available via an executable installation at: https://github.com/PurcellLab/MHCpLogics. [ABSTRACT FROM AUTHOR]

Celiac disease (CD) is thought to affect around 1% of people in the United Kingdom, but only approximately 30% are diagnosed. The aim of this work was to assess the cost-effectiveness of strategies for identifying adults and children with CD in terms of who to test and which tests to use. A decision tree and Markov model were used to describe testing strategies and model long-term consequences of CD. The analysis compared a selection of pre-test probabilities of CD above which patients should be screened, as well as the use of different serological tests, with or without genetic testing. Value of information analysis was used to prioritize parameters for future research. Using serological testing alone in adults, immunoglobulin A (IgA) tissue transglutaminase (tTG) at a 1% pre-test probability (equivalent to population screening) was most cost-effective. If combining serological testing with genetic testing, human leukocyte antigen combined with IgA tTG at a 5% pre-test probability was most cost-effective. In children, the most cost-effective strategy was a 10% pre-test probability with human leukocyte antigen plus IgA tTG. Value of information analysis highlighted the probability of late diagnosis of CD and the accuracy of serological tests as important parameters. The analysis also suggested prioritizing research in adult women over adult men or children. For adults, these cost-effectiveness results suggest UK National Screening Committee Criteria for population-based screening for CD should be explored. Substantial uncertainty in the results indicate a high value in conducting further research. • Celiac Disease (CD) is thought to affect around 1% of people in the United Kingdom, but only approximately 30% are diagnosed. • This cost-effectiveness analysis has compared strategies for identifying CD and found that, using serological testing alone in adults, population screening using immunoglobulin A (IgA) tissue transglutaminase (tTG) was most cost-effective. If combining serological testing with genetic testing, human leukocyte antigen combined with IgA tTG at a 5% pre-test probability was most cost-effective. In children, the most cost-effective strategy was a 10% pre-test probability with human leukocyte antigen plus IgA tTG. Value of information analysis highlighted the probability of late diagnosis of CD and the accuracy of serological tests as important parameters. The analysis also suggested prioritizing research in adult women over adult men or children. • For adults, these cost-effectiveness results suggest UK National Screening Committee Criteria for population-based screening for CD should be explored. Substantial uncertainty in the results indicate a high value in conducting further research. [ABSTRACT FROM AUTHOR]

Primary graft dysfunction (PGD) is a leading cause of early morbidity and mortality following heart transplantation (HT). We sought to determine the association between pretransplant human leukocyte antigen (HLA) sensitization, as measured using the calculated panel reactive antibody (cPRA) value, and the risk of PGD. Consecutive adult HT recipients (n = 596) from 1/2015 to 12/2019 at 2 US centers were included. Severity of PGD was based on the 2014 International Society for Heart and Lung Transplantation consensus statement. For each recipient, unacceptable HLA antigens were obtained and locus-specific cPRA (cPRA-LS) and pre-HT donor-specific antibodies (DSA) were assessed. Univariable logistic modeling showed that peak cPRA-LS for all loci and HLA-A was associated with increased severity of PGD as an ordinal variable (all loci: OR 1.78, 95% CI: 1.01-1.14, p = 0.025, HLA-A: OR 1.14, 95% CI: 1.03-1.26, p = 0.011). Multivariable analysis showed peak cPRA-LS for HLA-A, recipient beta-blocker use, total ischemic time, donor age, prior cardiac surgery, and United Network for Organ Sharing status 1 or 2 were associated with increased severity of PGD. The presence of DSA to HLA-B was associated with trend toward increased risk of mild-to-moderate PGD (OR 2.56, 95% CI: 0.99-6.63, p = 0.053), but DSA to other HLA loci was not associated with PGD. Sensitization for all HLA loci, and specifically HLA-A, is associated with an increased severity of PGD. These factors should be included in pre-HT risk stratification to minimize the risk of PGD. [ABSTRACT FROM AUTHOR]

Coronaviruses are highly transmissible and pathogenic viruses for humans and animals. The vast quantity of information collected about SARS-CoV-2 during the pandemic helped to unveil details of the mechanisms behind the infection, which are still largely elusive. Recent research demonstrated that different class I/II human leukocyte antigen (HLA) alleles might define an individual susceptibility to SARS-CoV-2 spreading, contributing to the differences in the distribution of the infection through different populations; additional studies suggested that the homolog of the HLA in cats, the feline leukocyte antigen (FLA), plays a pivotal role in the transmission of viruses. With these premises, this study aimed to exploit a bioinformatic approach for the prediction of the transmissibility potential of two distinct feline coronaviruses (FCoVs) in domestic cats (feline enteric coronavirus (FeCV) and feline infectious peritonitis virus (FIPV)) using SARS-CoV-2 as the reference model. We performed an epitope mapping of nonapeptides deriving from SARS-CoV-2, FeCV, and FIPV glycoproteins and predicted their affinities for different alleles included in the three main loci in class I FLAs (E, H, and K). The predicted complexes with the most promising affinities were then subjected to molecular docking and molecular dynamics simulations to provide insights into the stability and binding energies in the cleft. Results showed the FLA proteins encoded by alleles in the FLA-I H (H*00501 and H*00401) and E (E*01001 and E*00701) loci are largely responsive to several epitopes deriving from replicase and spike proteins of the analyzed coronaviruses. The analysis of the most affine epitope sequences resulting from the prediction can stimulate the development of anti-FCoV immunomodulatory strategies based on peptide drugs. [ABSTRACT FROM AUTHOR]

Background and Objective: Prior Epstein–Barr virus (EBV) infection is associated with an increased risk of pediatric-onset multiple sclerosis (POMS) and adult-onset multiple sclerosis (MS). It has been challenging to elucidate the biological mechanisms underlying this association. We examined the interactions between candidate human leukocyte antigen (HLA) and non-HLA variants and childhood EBV infection as it may provide mechanistic insights into EBV-associated MS. Methods: Cases and controls were enrolled in the Environmental and Genetic Risk Factors for Pediatric MS study of the US Network of Pediatric MS Centers. Participants were categorized as seropositive and seronegative for EBV-viral capsid antigen (VCA). The association between prior EBV infection and having POMS was estimated with logistic regression. Interactions between EBV serostatus, major HLA MS risk factors, and non-HLA POMS risk variants associated with response to EBV infection were also evaluated with logistic regression. Models were adjusted for sex, age, genetic ancestry, and the mother's education. Additive interactions were calculated using relative risk due to interaction (RERI) and attributable proportions (APs). Results: A total of 473 POMS cases and 702 controls contributed to the analyses. Anti-VCA seropositivity was significantly higher in POMS cases compared to controls (94.6% vs 60.7%, p < 0.001). There was evidence for additive interaction between childhood EBV infection and the presence of the HLA-DRB1*15 allele (RERI = 10.25, 95% confidence interval (CI) = 3.78 to 16.72; AP = 0.61, 95% CI = 0.47 to 0.75). There was evidence for multiplicative interaction (p < 0.05) between childhood EBV infection and the presence of DRB1*15 alleles (odds ratio (OR) = 3.43, 95% CI = 1.06 to 11.07). Among the pediatric MS variants also associated with EBV infection, we detected evidence for additive interaction (p = 0.02) between prior EBV infection and the presence of the GG genotype in risk variant (rs2255214) within CD86 (AP = 0.30, 95% CI = 0.03 to 0.58). Conclusion: We report evidence for interactions between childhood EBV infection and DRB1*15 and the GG genotype of CD86 POMS risk variant. Our results suggest an important role of antigen-presenting cells (APCs) in EBV-associated POMS risk. [ABSTRACT FROM AUTHOR]

T cell is vital in the adaptive immune system, which relays on T-cell receptor (TCR) to recognize and defend against infection and tumors. T cells are mainly divided into well-known CD4+ and CD8+ T cells, which can recognize short peptide antigens presented by major histocompatibility complex (MHC) class II and MHC class I respectively in humoral and cell-mediated immunity. Due to the Human Leukocyte Antigen (HLA) diversity and restriction with peptides complexation, TCRs are quite diverse and complicated. To better elucidate the TCR in humans, the present study shows the difference between the TCR repertoire in CD4+ and CD8+ T cells from 30 healthy donors. The result showed count, clonality, diversity, frequency, and VDJ usage in CD4+ and CD8+ TCR-β repertoire is different, but CDR3 length is not. The Common Clone Cluster result showed that CD4+ and CD8+ TCR repertoires are connected separately between the bodies, which is odd considering the HLA diversity. More knowledge about TCR makes more opportunities for immunotherapy. The TCR repertoire is still a myth for discovery. [ABSTRACT FROM AUTHOR]

Exagamglogene autotemcel (Casgevy™) is a genetically modified autologous CD34+ cell enriched population. It contains human haematopoietic stem and progenitor cells edited ex vivo by CRISPR/Cas9 (a DNA double strand break-inducing nuclease system) to differentiate into erythroid cells that produce high levels of foetal hemoglobin. Developed by Vertex Pharmaceuticals and CRISPR Therapeutics, exagamglogene autotemcel received its first approval on 16 November 2023 in the UK for the treatment of transfusion-dependent β-thalassemia (TDT) in patients aged ≥ 12 years for whom haematopoietic stem cell (HSC) transplantation is appropriate and a human leukocyte antigen matched related HSC donor is not available. On the same day, it was also approved in the UK for the treatment of sickle cell disease (SCD) in patients aged ≥ 12 years with recurrent vasoocclusive crises (VOCs) who have the βS/βS, βS/β+ or βS/β0 genotype for whom HSC transplantation is appropriate and a human leukocyte antigen matched related HSC donor is not available. Subsequently, exagamglogene autotemcel was approved in the USA on 8 December 2023 for the treatment of SCD in patients aged ≥ 12 years with recurrent VOCs and received a positive opinion in the EU on 14 December 2023 for the treatment of TDT and SCD. A regulatory assessment of exagamglogene autotemcel is currently underway for the treatment of TDT in the USA. This article summarizes the milestones in the development of exagamglogene autotemcel leading to these first approvals. [ABSTRACT FROM AUTHOR]

The brain is not immune privileged, leading to new challenges for cell therapies. While cell therapies for stroke have been shown to enhance recovery in animal studies, their move into clinical reality needs to be reassessed from an immunological perspective. A major hurdle in allogeneic cell transplantation is the low immunocompatibility due to human leukocyte antigen (HLA) mismatches. Finding an HLA match for unrelated individuals is 1 in 100 000, and hundreds of homozygous cell lines are needed for most of the population. Modifying HLAs and related genes in cell grafts has improved immune compatibility in animal studies, setting the stage for human trials. HLA engineering offers a means to bypass the host immune response and reduce cells required for the HLA spectrum. However, these cell sources introduce safety challenges, addressed with genetic safety mechanisms. Stem cell therapy is an emerging treatment paradigm for stroke patients with remaining neurological deficits. While allogeneic cell transplants overcome the manufacturing constraints of autologous grafts, they can be rejected by the recipient's immune system, which identifies foreign cells through the human leukocyte antigen (HLA) system. The heterogeneity of HLA molecules in the human population would require a very high number of cell lines, which may still be inadequate for patients with rare genetic HLAs. Here, we outline key progress in genetic HLA engineering in pluripotent stem and derived cells to evade the host's immune system, reducing the number of allogeneic cell lines required, and examine safety measures explored in both preclinical studies and upcoming clinical trials. [ABSTRACT FROM AUTHOR]

Adoptive cell therapy using virus‐specific T cells (VST) is a strategy for treating common opportunistic viral infections after transplantation, particularly when these infections do not resolve through antiviral drug therapy. The availability of third‐party healthy donors allows for the immediate use of cells for allogeneic therapy in cases where patients lack an appropriate donor. Here, we present the creation of a cell donor registry of human leukocyte antigen (HLA)‐typed blood donors, REDOCEL, a strategic initiative to ensure the availability of compatible cells for donation when needed. Currently, the registry consists of 597 healthy donors with a median age of 29 years, 54% of whom are women. The most represented blood groups were A positive and O positive, with 36.52% and 34.51%, respectively. Also, donors were screened for cytomegalovirus (CMV) and Epstein–Barr virus (EBV). Almost 65% of donors were CMV‐seropositive, while less than 5% were EBV‐seronegative. Of the CMV‐seropositive donors, 98% were also EBV‐seropositive. High‐resolution HLA‐A, ‐B, ‐C, ‐DRB1 and ‐DQB1 allele and haplotype frequencies were determined in the registry. Prevalent HLA alleles and haplotypes were well represented to ensure donor‐recipient HLA‐matching, including alleles reported to present viral immunodominant epitopes. Since the functional establishment of REDOCEL, in May 2019, 87 effective donations have been collected, and the effective availability of donors with the first call has been greater than 75%. Thus, almost 89% of patients receiving an effective donation had available at least 5/10 HLA‐matched cell donors (HLA‐A, ‐B, ‐C, ‐DRB1, and ‐DQB1). To summarize, based on our experience, a cell donor registry from previously HLA‐typed blood donors is a useful tool for facilitating access to VST therapy. [ABSTRACT FROM AUTHOR]

Immune alterations in end-stage renal patients receiving hemodialysis are complex and predispose patients to infections. Anticoagulation may also play an immunomodulatory role in addition to the accumulation of uremic toxins and the effects of the dialysis procedure. Accordingly, it has been recently shown that the infection rate increases in patients under regional citrate anticoagulation (RCA) compared with systemic heparin anticoagulation (SHA). We hypothesized that RCA affects the immune status of hemodialysis patients by targeting monocytes. In a cohort of 38 end-stage renal patients undergoing hemodialysis, we demonstrated that whole blood monocytes of patients receiving RCA—but not SHA—failed to upregulate surface activation markers, like human leukocyte antigen class II (HLA-DR), after stressful insults, indicating a state of deactivation during and immediately after dialysis. Additionally, RNA sequencing (RNA-seq) data and gene set enrichment analysis of pre-dialysis monocytes evidenced a great and complex difference between the groups given that, in the RCA group, monocytes displayed a dramatic transcriptional change with increased expression of genes related to the cell cycle regulation, cellular metabolism, and cytokine signaling, compatible with the reprogramming of the immune response. Transcriptomic changes in pre-dialysis monocytes signalize the lasting nature of the RCA-related effects, suggesting that monocytes are affected even beyond the dialysis session. Furthermore, these findings demonstrate that RCA—but not SHA—impairs the response of monocytes to activation stimuli and alters the immune status of these patients with potential clinical implications. [ABSTRACT FROM AUTHOR]

The advent of biologic drugs has revolutionized the treatment of Inflammatory Bowel Disease, increasing rates of response and mucosal healing in comparison to conventional therapies by allowing the treatment of corticosteroid-refractory cases and reducing corticosteroid-related side effects. However, biologic therapies (anti-TNFα inhibitors, anti-α4β7 integrin and anti-IL12/23) are still burdened by rates of response that hover around 40% (in biologic-naïve patients) or lower (for biologic-experienced patients). Moreover, knowledge of the mechanisms underlying drug resistance or loss of response is still scarce. Several cellular and molecular determinants are implied in therapeutic failure; genetic predispositions, in the form of single nucleotide polymorphisms in the sequence of cytokines or Human Leukocyte Antigen, or an altered expression of cytokines and other molecules involved in the inflammation cascade, play the most important role. Accessory mechanisms include gut microbiota dysregulation. In this narrative review of the current and most recent literature, we shed light on the mentioned determinants of therapeutic failure in order to pave the way for a more personalized approach that could help avoid unnecessary treatments and toxicities. [ABSTRACT FROM AUTHOR]

Tebentafusp demonstrated a superior overall survival (OS) benefit [hazard ratio (HR) 0.51] compared to investigator's choice (82% pembrolizumab) in a randomized, phase III trial (IMCgp100-202; N = 378) in untreated metastatic uveal melanoma (mUM). The 1-year OS rates for tebentafusp and pembrolizumab were 73% and 59%, respectively. In the single-arm GEM1402 (N = 52), the 1-year OS rate for nivolumab plus ipilimumab (N+I) in mUM was 52%. Due to limitations in conducting randomized trials in mUM, we compared OS on tebentafusp or pembrolizumab (IMCgp100-202) to N+I (GEM1402) in untreated mUM using propensity scoring methods. Analyses were adjusted using propensity score-based inverse probability of treatment weighting (IPTW), balancing age, sex, baseline lactate dehydrogenase (LDH), baseline alkaline phosphatase, disease location, Eastern Cooperative Oncology Group status, and time from primary diagnosis to metastasis. OS was assessed using IPT-weighted Kaplan–Meier and Cox proportional hazard models. Sensitivity analyses using alternative missing data and weights methods were conducted. The primary IPTW analysis included 240 of 252 patients randomized to tebentafusp from IMCgp100-202 and 45 of 52 N+I-treated patients from GEM-1402. Key baseline covariates, including LDH, were generally well balanced before weighting. The IPTW-adjusted OS favored tebentafusp, HR 0.52 [95% confidence interval (CI) 0.35-0.78]; 1-year OS was 73% for tebentafusp versus 50% for N+I. Sensitivity analyses showed consistent superior OS for tebentafusp with all IPTW HRs ≤0.61. IPTW analysis of pembrolizumab versus N+I showed no significant difference in OS (HR 0.72; 95% CI 0.50-1.06). Tebentafusp was previously shown to provide an OS benefit compared to checkpoint inhibitors or chemotherapy in untreated mUM. Propensity score analysis demonstrated a similar OS benefit for tebentafusp compared with N+I. These data further support tebentafusp as the standard of care in previously untreated human leukocyte antigen (HLA)-A∗02:01+ adult patients with mUM. • No randomized comparison of tebentafusp with combination N+I in mUM has been reported. • This propensity score analysis demonstrated an OS benefit for tebentafusp over N+I in first-line mUM. • The HR of 0.52 (95% CI 0.35-0.78) favored tebentafusp. • No significant difference in OS was observed between single-agent pembrolizumab and combination N+I. • This further supports the use of tebentafusp as first-line treatment of choice for HLA-A∗02:01+ adult patients with mUM. [ABSTRACT FROM AUTHOR]

Kidney transplantation, the gold-standard therapeutic approach for patients with end-stage kidney disease, offers improvement in patient survival and quality of life. However, broad sensitization against human leukocyte antigens often resulting in a positive crossmatch against the patient's living donor or the majority of potential deceased donors in the allocation system represents a major obstacle due to a high risk for antibody-mediated rejection, delayed graft function and allograft loss. Kidney-paired donation and desensitization protocols have been established to overcome this obstacle, with limited success. Imlifidase, a novel immunoglobulin G (IgG)-degrading enzyme derived from Streptococcus pyogenes and recombinantly produced in Escherichia coli , is a promising agent for recipients with a positive crossmatch against their organ donor with high specificity towards IgG, rapid action and high efficacy in early pre-clinical and clinical studies. However, the rebound of IgG after a few days can lead to antibody-mediated rejection, making the administration of potent immunosuppressive regimens in the early post-transplant phase necessary. There is currently no comparative study evaluating the efficiency of imlifidase therapy compared with conventional desensitization protocols along with the lack of randomized control trials, indicating the clear need for future large-scale clinical studies in this field. Besides providing a practical framework for the clinical use of the agent, our aim in this article is to evaluate the underlying mechanism of action, efficiency and safety of imlifidase therapy in immunologically high-risk kidney transplant recipients. [ABSTRACT FROM AUTHOR]

Pustular skin diseases, with pustular psoriasis (PP) being the prototype, are immune-mediated diseases characterized by the presence of multiple pustules, resulting from neutrophil accumulation in the layer of epidermis. Sterile skin pustular eruption, like PP, is also observed in 20–30% of patients with adult-onset immunodeficiency syndrome (AOID) and anti-interferon γ autoantibodies (IFN-γ), leading to challenges in classification and diagnosis. While the mechanism underlying this similar phenotype remains unknown, genetic factors in relation to the immune system are suspected of playing an important role. Here, the association between human leukocyte antigen (HLA) genes, which play essential roles in antigen presentation, contributing to immune response, and the presence of skin pustules in AOID and PP was revealed. HLA genotyping of 41 patients from multiple centers in Thailand who presented with multiple sterile skin pustules (17 AOID patients and 24 PP patients) was conducted using a next-generation-sequencing-based approach. In comparison to healthy controls, HLA-B*13:01 (OR = 3.825, 95%CI: 2.08–7.035), C*03:04 (OR = 3.665, 95%CI: 2.102–6.39), and DQB1*05:02 (OR = 2.134, 95%CI: 1.326–3.434) were significantly associated with the group of aforementioned conditions having sterile cutaneous pustules, suggesting a common genetic-related mechanism. We found that DPB1*05:01 (OR = 3.851, p = 0.008) and DRB1*15:02 (OR = 3.195, p = 0.033) have a significant association with pustular reaction in AOID patients, with PP patients used as a control. A variant in the DRB1 gene, rs17885482 (OR = 9.073, p = 0.005), was observed to be a risk factor for PP when using AOID patients who had pustular reactions as a control group. DPB1*05:01 and DRB1*15:02 alleles, as well as the rs17885482 variant in the DRB1 gene, were proposed as novel biomarkers to differentiate PP and AOID patients who first present with multiple sterile skin pustules without known documented underlying conditions. [ABSTRACT FROM AUTHOR]

Introduction. In Colombia, only 24% of patients on the waiting list received a renal transplant, most of them from cadaveric donors. HLA A-B-DR is considered for organ allocation, but recent evidence suggests that HLA A-B is not associated with transplant outcomes. The objective of this study was to evaluate the relevance of HLA A-B-DR on graft survival in kidney transplant recipients. Methods. Retrospective cohort study that included 1337 kidney transplant recipients with a cadaveric donor in Colombiana de Trasplantes from 2008 to 2023. A Propensity Score Matching (PSM) was applied to adjust the covariates in comparison groups for compatibility, and the relationship of HLA A-B-DR with kidney graft survival was evaluated using the log rank test and Cox regression. Results. There were 38.7% female patients, with median age of 47 years, and BMI 23.8 kg/m2. After adjusting the covariates with PSM for the comparison groups, HLA A-B matching was not significantly related to graft loss, with HR of 0.99 (95% CI 0.71-1.37) and 0.75 (95% CI 0.55-1.02), respectively. Only HLA DR matching was significant for graft loss with an HR of 0.67 (95% CI 0.46-0.98). Conclusions. This study suggests that HLA A-B matching does not significantly influence graft loss, whereas HLA DR matching does improve graft survival in renal transplantation with a cadaveric donor. [ABSTRACT FROM AUTHOR]

Analyzing HLA polymorphism in lung transplantation (LTx) is important, given its impact on LTx recipient survival and graft function. Accordingly, we conducted a retrospective study to examine the influence of HLA mismatch and donor-specific antibodies (DSA) on short-term outcomes and early-phase post-LTx complications. HLA antigen or eplet mismatch in LTx patients at Tohoku University Hospital from 2018 to 2023 was determined, and DSA was measured on admission for surgery to identify preformed DSA and at weeks 4 to 12 post-LTx for de novo DSA, respectively. The participants were 45 LTx recipients, HLA-A/B/DR antigen mismatch (5-6 of 6) being identified in 57%, HLA-A/B/Cw/DR/DQ mismatch (8-10 of 10) in 57%, and HLA eplet mismatch (>61) in 46%. The prevalence of preformed DSA was 24%, and persistence (uncleared) was 16%. The incidence of de novo DSA was 16% after LTx. During the study,16 recipients experienced grade 3 primary graft dysfunction (PGD), 8 developed acute rejection, and 5 died. No HLA-related variables were significantly associated with post-LTx mortality and were not risk factors for high-grade PGD or acute rejection. Despite limitations in sample size, resulting in tentative findings, the study serves as a crucial pilot study for an ongoing multicenter prospective trial in Japan. [ABSTRACT FROM AUTHOR]

Identification of cytotoxic T lymphocyte (CTL) epitopes from tumor related antigens is a promising approach for malignant tumor immunotherapy. TC2N, a recently identified tumor associated antigen from human glioblastoma, is regarded as a promising target of tumor-specific immunotherapy. As one of the most widely used histocompatibility molecules in Chinese is HLA-Ap0201, we were able to identify the TC2N peptides that are provided by this molecular type. A panel of antigenic peptides produced from TC2N were predicted by using a computer tool. The binding affinities of three peptides with the highest predicted score to the HLA-Ap0201 molecule were evaluated after synthesis. In vitro and in vivo stimulation of the main T-cell response against the predicted peptides. The results demonstrated that TC2N (152-160) was able to release IFN-? and lyse U251 cells in vitro as well as in vivo by eliciting peptide-specific CTLs. Our results indicated that peptide TC2N (152-160) (RLYGSVCDL) was a novel HLA-A2.1-restricted CTL epitope capable of inducing TC2N specific CTLs in vitro. As TC2N might qualify as a viable target for immunotherapeutic approaches for patients with GBM, we speculated that the newly identified epitope RLYGSVCDL would be of potential use in peptide-based, cancer-specific immunotherapy against GBM. [ABSTRACT FROM AUTHOR]

Background and Objectives. Numerous genome-wide association studies have highlighted that chronic lymphocytic leukemia (CLL) is a lymphoproliferative disorder with an important genetic component. An important number of genes have been implicated in CLL etiology, with some of the most important being human leukocyte antigen (HLA) genes. The aim of this study was to analyze the association of CLL with certain HLA alleles in the Romanian population and to compare our results with previous findings. Materials and Methods. This study included 66 patients with CLL, diagnosed between 2020 and 2022, and 100 healthy controls. HLA class I and class II genes (HLA-A/B/C, HLA-DQA1/DQB1/DPA1/DPB1, and HLA-DRB1/3/4/5) were investigated using next-generation sequencing technology. Results. Several HLA alleles were strongly associated with CLL. The most important finding was that HLA-DRB1 ∗ 04:02:01 (p = 0.001 , OR = 1.05) and HLA-DRB3 ∗ 02:01:01 (p = 0.009 , OR = 1.03) have a predisposing role in CLL development. Moreover, we identified that HLA-A ∗ 24:02:01 0.01 (p = 0.01 , OR = 0.38), HLA-DQA1 ∗ 05:05:01 (p = 0.01 , OR = 0.56), HLA-DQB1 ∗ 03:02:01 (p = 0.03 , OR = 0.40), and HLA-DRB4 ∗ 01:03:01 (p = 0.03 , OR = 0.54 alleles have protective roles. Correlations between HLA expression and gender showed that women had a higher expression of protective HLA alleles when compared to men. Conclusions. Our data are the first to indicate that in Romanian patients with CLL, the HLA-A ∗ 24:02:01 and HLA-DQA1 ∗ 05:05:01 alleles have a protective role against CLL development, whereas HLA-DRB1 ∗ 04:02:01 and HLA-DRB3 ∗ 02:01:01alleles are positively associated with CLL. [ABSTRACT FROM AUTHOR]

Background: Estimation of HLA (Human leukocyte Antigen) alleles' frequencies in populations is essential to explore their ethnic origin. Anthropologic studies of central Tunisian population were rarely reported. Then, in this work, we aimed to explore the origin of central Tunisian population using HLA alleles and haplotypes frequencies. Methods: HLA class I (A, B, C) and HLA class II (DRB1, DQA1, DQB1) loci genotyping of 272 healthy unrelated organ donors was performed by Polymerase Chain Reaction-Sequence Specific Oligonucleotide (PCR-SSO). We compared central Tunisians with other populations (Arabs, Berbers, Mediterraneans, Europeans, Africans, etc.) using alleles and haplotypes frequencies, genetic distances, Neighbour-Joining dendrogram and correspondence analysis. Results: Among the 19 HLA A alleles, the 26 HLA B alleles, the 13 HLA C alleles, the 15 HLA DRB1 alleles, the 6 HLA DQA1 alleles and the 5 HLA DQB1 alleles identified in the studied population, HLA A*02 (22.8%), HLA B*50 (13.1%), HLA C*06 (21.8%), HLA DRB1*07 (17.8%), HLA DQA1*01 (32.1%) and HLA DQB1*03 (31.6%) were the most frequent alleles. The extended haplotypes HLA A*02-B*50-C*06-DRB1*07-DQA1*02-DQB1*02 (1.97%) was the most frequent HLA six-loci haplotype. Conclusion: Central Tunisians were very close to other Tunisian populations, to Iberians and North Africans. They were rather distant from sub-Saharan populations and eastern Mediterraneans especially Arabs although the strong cultural and religious impact of Arabs in this population. [ABSTRACT FROM AUTHOR]

The clinical impact of tumor-specific neoantigens as both immunotherapeutic targets and biomarkers has been impeded by the lack of efficient methods for their identification and validation from routine samples. We have developed a platform that combines bioinformatic analysis of tumor exomes and transcriptional data with functional testing of autologous peripheral blood mononuclear cells (PBMCs) to simultaneously identify and validate neoantigens recognized by naturally primed CD4+ and CD8+ T cell responses across a range of tumor types and mutational burdens. The method features a human leukocyte antigen (HLA)–agnostic bioinformatic algorithm that prioritizes mutations recognized by patient PBMCs at a greater than 40% positive predictive value followed by a short-term in vitro functional assay, which allows interrogation of 50 to 75 expressed mutations from a single 50-ml blood sample. Neoantigens validated by this method include both driver and passenger mutations, and this method identified neoantigens that would not have been otherwise detected using an in silico prediction approach. These findings reveal an efficient approach to systematically validate clinically actionable neoantigens and the T cell receptors that recognize them and demonstrate that patients across a variety of human cancers have a diverse repertoire of neoantigen-specific T cells. Editor's summary: Tumors, especially those with a high mutational burden, express neoantigens that may be recognized by an individual's T cells. However, identifying and validating these neoantigens can be a tedious and sometimes unsuccessful effort. To address this, Miller et al. developed a platform that combines whole-exome sequencing and transcriptional analysis of tumors with ex vivo stimulation of peripheral blood cells to more efficiently identify neoantigens that have elicited T cell responses in patients. The approach, termed "identify-prioritize-validate" (IPV), was able to identify clinically meaningful neoantigens in patients with different types of cancer, including those with a lower mutational burden, and with different human leukocyte antigen (HLA) types. Thus, the IPV approach demonstrates an advance in identifying neoantigens that may be useful both as a biomarker and as a therapeutic target. —Courtney Malo [ABSTRACT FROM AUTHOR]

Background: With the development of Hematopoietic Stem Cell Transplantation (HSCT) technology, increasing numbers of elderly patients were undergoing allogeneic HSCT and elderly patients with hematologic malignancies could benefit most from it. Preformed donor-specific human leukocyte antigen (HLA) antibodies (DSA) were associated with graft failure in HLA-mismatched allogeneic HSCT and the absence of DSA was the main criterion of selecting the donor. Except for sensitization events such as transfusion, pregnancy or previous transplantation, ageing affects the humoral immune response both quantitatively and qualitatively. To evaluate the prevalence and distribution of anti-HLA and antibodies of MHC class I chain related antigens A (MICA) specificities in different age groups before initial HSCT would provide HLA and MICA specific antibody profiles under the impact of ageing, which could provide meaningful information in the process of selecting suitable HLA-mismatched donors by avoiding preformed DSA. Results: There were no significant differences in the distribution of anti-HLA class I, class II and anti-MICA antibodies among the three age groups in this study except that a significant lower negative ratio of anti-HLA class I, class II antibodies and higher positive rate of MICA antibodies with maximum mean fluorescent intensity (MFI) > 5000 in the elderly than in young age group. The distribution of antibody specificities against HLA -A, -B, -C, -DR, -DQ, -DP and MICA antigens in the three age groups were generally consistent. The anti-HLA class I antibody specificities with higher frequencies were A80,A68;B76,B45;Cw17, which were unlikely to become DSA in Chinese. Anti-HLA class II antibody specificities were more likely to become potential DSA than class I.DR7, DR9, DQ7, DQ8 and DQ9 were most likely to become potential DSA. Conclusions: The prevalence of anti-HLA and anti-MICA antibodies increased slightly as age increased. While ageing had a small impact on the distribution of antibody specificity frequencies against HLA-A, -B, -C, -DR,-DQ, -DP and MICA antigens in recipients awaiting initial HSCT from East China. The risk of developing preformed DSA was basically consistent in the three age groups and the elderly group might be more favorable in HLA-mismatched HSCT due to higher positive rate of anti-MICA antibody. [ABSTRACT FROM AUTHOR]

This article explores the significance of proficiency testing (PT) in the field of histocompatibility and immunogenetics, particularly in relation to laboratory procedures for organ transplantation. It discusses the historical development of PT and its role in ensuring reliable results for diagnostic work. The article also highlights the evolution of PT methods, including the use of digital data input, and emphasizes the importance of accreditation and certification. It suggests that PT organizers should focus on establishing PTs for defining unacceptable HLA antigens, which are crucial for virtual crossmatching procedures. Additionally, the article emphasizes the need for electronic data storage and analysis to prevent errors, and the importance of using PT reports for accreditation purposes. Finally, it underscores the importance of keeping PT costs low and using PT exercises for reimbursement from medical insurance bodies. [Extracted from the article]

The umbilical cord blood (UCB) donated in public UCB banks is a source of hematopoietic stem cells (HSC) alternative to bone marrow for allogeneic HSC transplantation (HSCT). However, the high rejection rate of the donated units due to the strict acceptance criteria and the wide application of the haploidentical HSCT have resulted in significant limitation of the use of UCB and difficulties in the economic sustainability of the public UCB banks. There is an ongoing effort within the UCB community to optimize the use of UCB in the field of HSCT and a parallel interest in exploring the use of UCB for applications beyond HSCT i.e., in the fields of cell therapy, regenerative medicine and specialized transfusion medicine. In this report, we describe the mode of operation of the three public UCB banks in Greece as an example of an orchestrated effort to develop a viable UCB banking system by (a) prioritizing the enrichment of the national inventory by high-quality UCB units from populations with rare human leukocyte antigens (HLA), and (b) deploying novel sustainable applications of UCB beyond HSCT, through national and international collaborations. The Greek paradigm of the public UCB network may become an example for countries, particularly with high HLA heterogeneity, with public UCB banks facing sustainability difficulties and adds value to the international efforts aiming to sustainably expand the public UCB banking system. [ABSTRACT FROM AUTHOR]

Recent developments in intensive desensitization protocols have enabled kidney transplantation in human leukocyte antigen (HLA)-sensitized recipients. However, cases of active antibody-mediated rejection (AABMR), when they occur, are difficult to manage, graft failure being the worst-case scenario. We aimed to assess the impact of our desensitization and AABMR treatment regimen and identify risk factors for disease progression. Among 849 patients who underwent living-donor kidney transplantation between 2014 and 2021 at our institution, 59 were diagnosed with AABMR within 1 year after transplantation. All patients received combination therapy consisting of steroid pulse therapy, intravenous immunoglobulin, rituximab, and plasmapheresis. Multivariable analysis revealed unrelated donors and preformed donor-specific antibodies as independent risk factors for AABMR. Five-year death-censored graft survival rate was not significantly different between patients with and without AABMR although 27 of 59 patients with AABMR developed chronic AABMR (CABMR) during the study period. Multivariate Cox proportional hazard regression analysis revealed that a donor age greater than 59 years and microvascular inflammation (MVI) score (g + ptc) ≥4 at AABMR diagnosis were independent risk factors for CABMR. Our combination therapy ameliorated AABMR; however, further treatment options should be considered to prevent CABMR, especially in patients with old donors and severe MVI. [ABSTRACT FROM AUTHOR]

Background: Autism spectrum disorders (ASDs) encompass a broad range of phenotypes characterized by diverse neurological alterations. Genomic studies have revealed considerable overlap between the molecular mechanisms implicated in the etiology of ASD and genes involved in the pharmacokinetic (PK) and pharmacodynamic (PD) pathways of antipsychotic drugs employed in ASD management. Given the conflicting data originating from candidate PK or PD gene association studies in diverse ethnogeographic ASD populations, dosage individualization based on "actionable" pharmacogenetic (PGx) markers has limited application in clinical practice. Additionally, off-label use of different antipsychotics is an ongoing practice, which is justified given the shortage of approved cures, despite the lack of satisfactory evidence for its safety according to precision medicine. This exploratory study aimed to identify PGx markers predictive of risperidone (RIS) exposure in autistic Saudi children. Methods: This prospective cohort study enrolled 89 Saudi children with ASD treated with RIS-based antipsychotic therapy. Plasma levels of RIS and 9-OH-RIS were measured using a liquid chromatography--tandem mass spectrometry system. To enable focused exploratory testing, genotyping was performed with the Axiom PharmacoFocus Array, which included a collection of probe sets targeting PK/PD genes. A total of 720 PGx markers were included in the association analysis.Results: A total of 27 PGx variants were found to have a prominent impact on various RIS PK parameters; most were not located within the genes involved in the classical RIS PK pathway. Specifically, 8 markers in 7 genes were identified as the PGx markers with the strongest impact on RIS levels (p < 0.01). Four PGx variants in 3 genes were strongly associated with 9-OH-RIS levels, while 5 markers in 5 different genes explained the interindividual variability in the total active moiety. Notably, 6 CYP2D6 variants exhibited strong linkage disequilibrium; however, they significantly influenced only the metabolic ratio and had no considerable effects on the individual estimates of RIS, 9-OH-RIS, or the total active moiety. After correction for multiple testing, rs78998153 in UGT2B17 (which is highly expressed in the brain) remained the most significant PGx marker positively adjusting the metabolic ratio. For the first time, certain human leukocyte antigen (HLA) markers were found to enhance various RIS exposure parameters, which reinforces the gut--brain axis theory of ASD etiology and its suggested inflammatory impacts on drug bioavailability through modulation of the brain, gastrointestinal tract and/or hepatic expression of metabolizing enzymes and transporters. Conclusion: Our hypothesis-generating approach identified a broad spectrum of PGx markers that interactively influence RIS exposure in ASD children, which indicated the need for further validation in population PK modeling studies to define polygenic scores for antipsychotic efficacy and safety, which could facilitate personalized therapeutic decision-making in this complex neurodevelopmental condition. [ABSTRACT FROM AUTHOR]

Precise typing of human leukocyte antigens (HLA) is crucial for clinical hematopoietic stem cell and solid organ transplantations, transfusion medicine, HLA-related disease association, and drug hypersensitivity analysis. The UCLA Cell Exchange program has played a vital role in providing educational and proficiency testing surveys to HLA laboratories worldwide for the past 5 decades. This article highlights the significant contribution of the UCLA Cell and DNA Exchange Programs in advancing HLA antibody testing, genotyping, crossmatches, and, more recently, virtual crossmatches. Additionally, we discuss future directions of the UCLA Cell Exchange program to support histocompatibility testing to adapt to the fast-evolving field of immunotherapy, tolerance and xenotransplantation. [ABSTRACT FROM AUTHOR]

The Human leukocyte antigen (HLA) molecules are central to immune response and have associations with the phenotypes of various diseases and induced drug toxicity. Further, the role of HLA molecules in presenting antigens significantly affects the transplantation outcome. The objective of this study was to examine the extent of the diversity of HLA alleles in the population of the United Arab Emirates (UAE) using Next-Generation Sequencing methodologies and encompassing a larger cohort of individuals. A cohort of 570 unrelated healthy citizens of the UAE volunteered to provide samples for Whole Genome Sequencing and Whole Exome Sequencing. The definition of the HLA alleles was achieved through the application of the bioinformatics tools, HLA-LA and xHLA. Subsequently, the findings from this study were compared with other local and international datasets. A broad range of HLA alleles in the UAE population, of which some were previously unreported, was identified. A comparison with other populations confirmed the current population's unique intertwined genetic heritage while highlighting similarities with populations from the Middle East region. Some disease-associated HLA alleles were detected at a frequency of > 5%, such as HLA-B*51:01, HLA-DRB1*03:01, HLA-DRB1*15:01, and HLA-DQB1*02:01. The increase in allele homozygosity, especially for HLA class I genes, was identified in samples with a higher level of genome-wide homozygosity. This highlights a possible effect of consanguinity on the HLA homozygosity. The HLA allele distribution in the UAE population showcases a unique profile, underscoring the need for tailored databases for traditional activities such as unrelated transplant matching and for newer initiatives in precision medicine based on specific populations. This research is part of a concerted effort to improve the knowledge base, particularly in the fields of transplant medicine and investigating disease associations as well as in understanding human migration patterns within the Arabian Peninsula and surrounding regions. [ABSTRACT FROM AUTHOR]

T-cell-engaging bispecifics have great clinical potential for the treatment of cancer and infectious diseases. The binding affinity and kinetics of a bispecific molecule for both target and T-cell CD3 have substantial effects on potency and specificity, but the rules governing these relationships are not fully understood. Using immune mobilizing monoclonal TCRs against cancer (ImmTAC) molecules as a model, we explored the impact of altering affinity for target and CD3 on the potency and specificity of the redirected T-cell response. This class of bispecifics binds specific target peptides presented by human leukocyte antigen on the cell surface via an affinity-enhanced T-cell receptor and can redirect T-cell activation with an anti-CD3 effector moiety. The data reveal that combining a strong affinity TCR with an intermediate affinity anti-CD3 results in optimal T-cell activation, while strong affinity of both targeting and effector domains significantly reduces maximum cytokine release. Moreover, by optimizing the affinity of both parts of the molecule, it is possible to improve the selectivity. These results could be effectively modelled based on kinetic proofreading with limited signalling. This model explained the experimental observation that strong binding at both ends of the molecules leads to reduced activity, through very stable target-bispecific-effector complexes leading to CD3 entering a non-signalling dark state. These findings have important implications for the design of anti-CD3-based bispecifics with optimal biophysical parameters for both activity and specificity. These studies demonstrate how to optimize the fundamental process of T-cell activation, both in terms of affinity and binding kinetics to target cell and T-cell epitopes. Current theories of T-cell biology are used to build a mathematical model that explains most features of the data. How the kinetics of target and cluster of differentiation 3 binding regulate T-cell activation in the context of the clinically validated immune mobilizing monoclonal TCRs against cancer platform, which directly targets peptide-human leukocyte antigen complexes. [ABSTRACT FROM AUTHOR]

Background Single nucleotide polymorphisms in the human leukocyte antigen (HLA) region in both maternal and fetal genomes have been robustly associated with birthweight (BW) in previous genetic association studies. However, no study to date has partitioned the association between BW and classical HLA alleles into maternal and fetal components. Methods We used structural equation modelling (SEM) to estimate the maternal and fetal effects of classical HLA alleles on BW. Our SEM leverages the data structure of the UK Biobank (UKB), which includes ∼270 000 participants' own BW and/or the BW of their firstborn child. Results We show via simulation that our model yields asymptotically unbiased estimates of the maternal and fetal allelic effects on BW and appropriate type I error rates, in contrast to simple regression models. Asymptotic power calculations show that we have sufficient power to detect moderate-sized maternal or fetal allelic effects of common HLA alleles on BW in the UKB. Applying our SEM to imputed classical HLA alleles and own and offspring BW from the UKB replicated the previously reported association at the HLA-C locus and revealed strong evidence for maternal (HLA-A*03:01, B*35:01, B*39:06, P  <0.001) and fetal allelic effects (HLA-B*39:06, P  <0.001) of non- HLA-C alleles on BW. Conclusions Our model yields asymptotically unbiased estimates, appropriate type I error rates and appreciable power to estimate maternal and fetal effects on BW. These novel allelic associations between BW and classical HLA alleles provide insight into the immunogenetics of fetal growth in utero. [ABSTRACT FROM AUTHOR]

Background: Hematopoietic stem cell transplantation (HSCT), is the only currently available curative option for SCD. Yet, the eligibility of SCD patients for HSCT is always limited by the significant associated toxicity and lack of suitable donors. At Cairo University's pediatric hematology outpatient clinic, we aimed to determine hematopoietic stem cell transplantation (HSCT) candidates among a sickle cell disease (SCD) cohort, estimate the number of possible donors, and analyze the differences between patients with and without an HSCT indication. Methods: This study was a cross-sectional analytic study including 128 SCD children. Their demographic, clinical, and laboratory profiles, total number, and number of siblings with SCD were obtained from their medical records. Results: Sixty-nine (53.9%) had at least one HSCT indication. Recurrent severe pain episodes despite hydroxyurea were the most common indication. Hemoglobin was lower, while reticulocyte count, serum ferritin, and aspartate aminotransferase were higher in HSCT candidates (p value < 0.001). Additionally, the prevalence of splenomegaly, the dose of hydroxyurea, and the number of transfusions were noticeably higher in HSCT candidates (p value = 0.013, 0.005, and < 0.0001 respectively). Among those indicated for HSCT; 75.3% had at least one healthy sibling who might be a potential donor. Conclusion: More than half were eligible for HSCT which should always be considered to provide a possible cure for the disease. Of the transplantation-eligible cases, about two-thirds had at least one healthy sibling who might potentially serve as a donor. Those meeting the requirements for HSCT eligibility should routinely undergo human leukocyte antigen (HLA) testing of their unaffected siblings. [ABSTRACT FROM AUTHOR]

In currently ongoing adoptive T-cell therapies, T cells collected from patients are given back to them after ex vivo activation and expansion. In some cases, T cells are transduced with chimeric antigen receptor (CAR) or T-cell receptor (TCR) genes during the ex vivo culture period in order to endow T cells with the desired antigen specificity. Although such strategies are effective in some types of cancer, there remain issues to be solved: (i) the limited number of cells, (ii) it is time-consuming, (iii) it is costly, and (iv) the quality can be unstable. Points (ii) and (iv) can be solved by preparing allogeneic T cells and cryopreserving them in advance and methods are being developed using healthy donor-derived T cells or pluripotent stem cells as materials. Whereas it is difficult to solve (i) and (iii) in the former case, all the issues can be cleared in the latter case. However, in either case, a new problem arises: rejection by the patient's immune system. Deletion of human leukocyte antigen (HLA) avoids rejection by recipient T cells, but causes rejection by NK cells, which can recognize loss of HLA class I. Various countermeasures have been developed, but no definitive solution is yet available. Therefore, further research and development are necessary. [ABSTRACT FROM AUTHOR]

Background: Kidney transplantation (KT) is the best therapy in children with end‐stage renal disease (ESRD), however, improving long‐term graft survival remains challenging. The aim of this study was to determine graft survival and potential risk factors in pediatric patients who undergo deceased donor KT with a steroid‐based regimen. Methods: The medical records of children who underwent their first deceased donor KT in Srinagarind Hospital (Khon Kaen, Thailand) between 2001 and 2020 were reviewed. Results: Seventy‐two patients were studied. Male adolescents were the predominant recipients and the majority of donors were young adult males. Non‐glomerular disease, particularly hypoplastic/dysplastic kidney disease, was the major cause of ESRD (48.61%). The mean cold ischemic time (CIT) was 18.29 ± 5.29 h. Most of the recipients had more than 4 human leukocyte antigen (HLA) mismatched loci with positive HLA‐DR mismatch (52.78%). Induction therapy was administered in 76.74% of recipients. Tacrolimus plus mycophenolate sodium and prednisolone was the most common immunosuppressive maintenance regimen (69.44%). Graft failure occurred in 18 patients, mostly due to graft rejection (50%). Graft survival at 1, 3, and 5 years after KT were 94.40%, 86.25%, and 74.92%, respectively. The only significant risk factor of graft failure in this study was delayed graft function (DGF) (adjusted HR = 3.55; 95%CI: 1.14, 11.12; p =.029). Patient survival at 1, 3, and 5 years was 100%, 98.48%, and 96.19%, respectively. Conclusion: The short‐term outcomes of pediatric KT from deceased donors were satisfactory; however, prevention of DGF would result in better outcomes. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is an autoimmune disease that causes inflammation, pain, and ultimately, bone erosion of the joints. The causes of this disease are multifactorial, including genetic factors, such as the presence of the human leukocyte antigen (HLA)-DRB1*04 variant, alterations in the microbiota, or immune factors including increased cytotoxic T lymphocytes (CTLs), neutrophils, or elevated M1 macrophages which, taken together, produce high levels of pro-inflammatory cytokines. In this review, we focused on the function exerted by osteoclasts on osteoblasts and other osteoclasts by means of the release of exosomal microRNAs (miRNAs). Based on a thorough revision, we classified these molecules into three categories according to their function: osteoclast inhibitors (miR-23a, miR-29b, and miR-214), osteoblast inhibitors (miR-22-3p, miR-26a, miR-27a, miR-29a, miR-125b, and miR-146a), and osteoblast enhancers (miR-20a, miR-34a, miR-96, miR-106a, miR-142, miR-199a, miR-324, and miR-486b). Finally, we analyzed potential therapeutic targets of these exosomal miRNAs, such as the use of antagomiRs, blockmiRs, agomiRs and competitive endogenous RNAs (ceRNAs), which are already being tested in murine and ex vivo models of RA. These strategies might have an important role in reestablishing the regulation of osteoclast and osteoblast differentiation making progress in the development of personalized medicine. [ABSTRACT FROM AUTHOR]

Background and Aims: The importance of human leukocyte antigen (HLA) matching between liver transplant donors and recipients on graft survival remains unclear and is not a clinical consideration in liver transplantation. This study aimed to determine the relationship between HLA matching and liver graft survival using a large-scale multi-centre database (UNOS/OPTN) and multivariate logistic analysis. The secondary aim was to determine whether this relationship was influenced by transplant indication and donor status. Methods: This retrospective observational analysis was performed using 22 702 liver transplant recipients from the UNOS/OPTN database. Patients were divided into two groups based on number of HLA mismatches (0--3 mismatches vs. 4--6 mismatches) and then subcategorized by indication and donor status. Risk-adjusted outcomes were assessed by multivariate Cox analysis adjusting for donor and recipient characteristics and visualized using Kaplan--Meier survival curves. Results: Allograft survival and risk of acute rejection were associated with degree of HLA mismatch. This association between HLA mismatch and graft survival persisted in individuals who underwent transplant for hepatitis, metabolic, drug toxicity, and congenital indications. Donor status also influenced the relationship between HLA mismatch and graft survival. Graft survival in DBD recipients was longer than in DCD in the 4--6 HLA mismatch group, whereas no significant difference was found in the 0--3 HLA mismatch group. Conclusion: HLA mismatch significantly reduced graft survival and increased risk of acute rejection. This association was noted only in specific indications. These findings are of potential clinical relevance to organ allocation, allograft matching algorithms, immunosuppression protocols, and transplant surveillance. [ABSTRACT FROM AUTHOR]

Background: Predicting whether a patient's platelet refractoriness (PR) is due to immune or nonimmune causes can be challenging. This study compared the demographics and clinical history of PR patients with human leukocyte antigen (HLA) antibodies (HLA‐PR) versus PR patients without HLA antibodies. Materials and Methods: A retrospective review of all patients with PR consults at a single institution over a 3‐year period was performed. Patient charts were reviewed for all patients with confirmed PR, and demographic information (e.g., sex, race and ethnicity, preferred language) and clinical history (e.g., pregnancy, transfusion, primary diagnosis) were collected. Patient characteristics were compared among the HLA and non‐HLA cohorts. Results: A total of 295 patients with confirmed PR were identified, of whom approximately 70% did not have HLA antibodies and 30% did. Approximately 84% of the HLA‐PR cohort was female. A history of transfusions was not associated with HLA‐PR (p =.1). A history of pregnancy was strongly associated with the occurrence of HLA‐PR (p <.001). Splenomegaly was associated with PR in the absence of HLA alloimmunization whereas infection, fever, bleeding, and disseminated intravascular coagulation were not. Conclusion: In this single‐institution retrospective review, a history of pregnancy was strongly associated with HLA‐PR, whereas a history of transfusion was not. [ABSTRACT FROM AUTHOR]

In the realm of DNA testing with legal implications, the reliability and precision of genetic markers play a pivotal role in confirming or negating paternity claims. This study aimed to assess the potential utility of human leukocyte antigen (HLA) gene polymorphism through massively parallel sequencing (MPS) technology as robust forensic markers for parentage testing involving genetic deficiencies. It sought to redefine the significance of HLA genes in this context. Data on autosomal short tandem repeat (aSTR) mutational events across 18 paternity cases involving 16 commonly employed microsatellite loci were presented. In instances where traditional aSTR analysis failed to establish statistical certainty, kinship determination was pursued via HLA genotyping, encompassing the amplification of 17 linked HLA loci. Within the framework of this investigation, phase-resolved genotypes for HLA genes were meticulously generated, resulting in the definition of 34 inherited HLA haplotypes. An impressive total of 274 unique HLA alleles, which were classified at either the field 3 or 4 level, were identified, including the discovery of four novel HLA alleles. Likelihood ratio (LR) values, which indicated the likelihood of the observed data under a true biological relationship versus no relationship, were subsequently calculated. The analysis of the LR values demonstrated that the HLA genes significantly enhanced kinship determination compared with the aSTR analysis. Combining LR values from aSTR markers and HLA loci yielded conclusive outcomes in duo paternity cases, showcasing the potential of HLA genes and MPS technology for deeper insights and diversity in genetic testing. Comprehensive reference databases and high-resolution HLA typing across diverse populations are essential. Reintegrating HLA alleles into forensic identification complements existing markers, creating a potent method for future forensic analysis. [ABSTRACT FROM AUTHOR]

Every patient with kidney failure requiring dialysis in Germany has the right to at least be evaluated for a transplantation. When an affected person can be considered for a transplantation, it must be clarified which allocation program is the right one for the person and whether a living organ donor can be considered. It should also be individually discussed with patients which type of donor organ should be accepted. Following a transplantation an individualized immunosuppression is relevant not only for the long-term survival of the transplant but also for the adherence of the patient. [ABSTRACT FROM AUTHOR]

Human leukocyte antigen‐G (HLA‐G) is classified as non‐classical HLA, located in the short arm of chromosome 6 and composed of seven introns and eight exons. The HLA‐G gene has a lower frequency polymorphism in the coding area and higher variability at the regulatory 5′‐ and 3′‐untranslated regions linked to HLA‐G microRNA regulation. HLA‐G molecule is known to have an immunomodulatory and tolerogenic features role. In 199 Saudi individuals, we examined the association between plasma soluble HLA‐G (sHLA‐G) levels and eight polymorphic different sites, including 14 bp ins/del/+3003T‐C/+3010C‐G/+3027C‐A/+3035C‐T/+3142C‐G/+3187A‐G/+3196C‐G single nucleotide polymorphisms (SNPs) in exon 8 in the HLA‐G gene. Our results revealed higher frequency for rs17179101C (97%), rs1707T (92%) and rs9380142A (73%) alleles. Greater frequencies for the tested genotypes were observed in 3027C/C (rs17179101) (93%), 14 bp (rs1704) ins/del (92%), +3003T/T (rs1707) (85%) and +3035C/T (rs17179108) (79%) SNP genotypes. Moreover, we observed a significant association of sHLA‐G with +3010G/C (rs1710) SNP. In conclusion, we showed a significant association between 3010G/C (rs1710) SNP and the sHLA‐G level among our sample for Saudi populations. Our findings demonstrated that specific SNP within the HLA‐G gene is linked to sHLA‐G molecule secretion, suggesting sHLA‐G levels may be regulated genetically. [ABSTRACT FROM AUTHOR]

To report on the value of presence of pigmentation on central anterior lens capsule (PioLe) in HLA B27- associated anterior uveitis (HLA B27-AU). 268 patients (320 eyes) with AU were reviewed. Two diagnostic models to predict probability of HLA-B27-AU were developed. The first model included 6 variables (age, gender, unilaterality, presence of non-granulomatous keratic precipitates, hypopyon, and intraocular pressure (IOP). The second model was developed to investigate the added value of PioLe into the first model. Unilaterality, presence of hypopyon, IOP <21 mmHg and PioLe were characteristic for HLA-B27 positive patients (P≤0.003 for all). All of 6 variables had area under receiver operating characteristic curves (AuROC) ≤ 60, but PioLe reached even higher value (65.5). Diagnostic model I and II had AuROC 76.3% (95%CI, 68.4%-84.2%) and 80.0% (95%CI, 72.6%-87.5%), respectively. Unilaterality, hypopyon, IOP <21 mmHg and presence of PioLe are clinical signs suggesting HLA B27- AU. [ABSTRACT FROM AUTHOR]

Anterior uveitis is the most common anatomical type of uveitis. Patients with noninfectious anterior uveitis may develop various ocular complications and eventually visual impairment. Appropriately differentiating the etiologies can help clinicians to predict the outcome, arrange clinical follow-up, and decide the treatment or prevention strategy. Adequate treatment and effective prevention strategies can reduce the frequency of recurrence and the risk of developing complications. Human leukocyte antigen (HLA)-B27 is the most common positive finding in patients with noninfectious AAU in many countries including Taiwan. To report a consensus from experienced uveitis specialists and rheumatologists was made in Taiwan. A panel of nine ophthalmologists from nine different referral centers with expertise in the management of uveitis and an experienced rheumatologist was held on January 16, 2022. A comprehensive literature review was performed. Differential diagnoses for etiologies, general treatments, and prevention strategies were discussed. Each statement in the consensus was made only if more than 70% of the experts agreed. A flow chart and seven statements regarding the differential diagnoses for etiologies, treatments and preventions, and co-management with rheumatologists were included in the consensus. This article discusses the general diagnosis, treatment, and prevention of noninfectious acute anterior uveitis, with or without HLA-B27, in adults for general ophthalmologists to improve overall outcomes of these patients [ABSTRACT FROM AUTHOR]

Introduction: We evaluated baseline Clearance of anti-tumor necrosis factors and human leukocyte antigen variant (HLA DQA1*05) in combination as poor prognostic factors (PPF) of pharmacokinetic (PK) origin impacting immune response (formation of antidrug antibodies) and disease control of inflammatory bowel disease (IBD) patients treated with infliximab or adalimumab. Methods: Baseline Clearance was estimated in IBD patients before starting treatment using weight and serum albumin concentrations. HLA DQA1*05 carrier status (rs2097432 A/G or G/G variant) was measured using real time polymerase chain reaction. The outcomes consisted of immune response, clinical and biochemical remission (C-reactive protein<3 mg/L in the absence of symptoms), and endoscopic remission (SES-CD<3). Statistical analysis consisted of logistic regression and nonlinear mixed effect models. Results and discussion: In 415 patients enrolled from 4 different cohorts (median age 27 [IQR: 15-43] years, 46% females), Clearance>0.326 L/day and HLA DQA1*05 carrier status were 2-fold more likely to have antidrug antibodies (OR=2.3, 95%CI: 1.7-3.4; p<0.001, and OR=1.9, 95%CI: 1.4-2.8; p<0.001, respectively). Overall, each incremental PPF of PK origin resulted in a 2-fold (OR=2.2, 95%CI: 1.7-2.8; p<0.11) higher likelihood of antidrug antibody formation. The presence of both PPF of PK origin resulted in higher rates of antidrug antibodies (p<0.01) and lower clinical and biochemical remission (p<0.01). Each incremental increase in PPF of PK origin associated with lower likelihood of endoscopic remission (OR=0.4, 95%CI: 0.2-0.7; p<0.001). Prior biologic experience heightened the negative impact of PPF of PK origin on clinical and biochemical remission (p<0.01). Implementation of proactive therapeutic drug monitoring reduced it, particularly during maintenance and in the presence of higher drug concentrations (p<0.001). We conclude that PPF of PK origin, including both higher Clearance and carriage of HLA DQA1*05, impact outcomes in patients with IBD. [ABSTRACT FROM AUTHOR]

Introduction: Early-onset Type 1 diabetes (EOT1D) is considered a disease subtype with distinctive immunological and clinical features. While both Human Leukocyte Antigen (HLA) and non-HLA variants contribute to age at T1D diagnosis, detailed analyses of EOT1D-specific genetic determinants are still lacking. This study scrutinized the involvement of the HLA class II locus in EOT1D genetic control. Methods: We conducted genetic association and regularized logistic regression analyses to evaluate genotypic, haplotypic and allelic variants in DRB1, DQA1 and DQB1 genes in children with EOT1D (diagnosed at ≤5 years of age; n=97), individuals with later-onset disease (LaOT1D; diagnosed 8-30 years of age; n=96) and nondiabetic control subjects (n=169), in the Portuguese population. Results: Allelic association analysis of EOT1D and LaOT1D unrelated patients in comparison with controls, revealed that the rare DRB1*04:08 allele is a distinctive EOT1D susceptibility factor (corrected p-value=7.0x10-7). Conversely, the classical T1D risk allele DRB1*04:05 was absent in EOT1D children while was associated with LaOT1D (corrected p-value=1.4x10-2). In corroboration, HLA class II haplotype analysis showed that the rare DRB1*04:08-DQ8 haplotype is specifically associated with EOT1D (corrected p-value=1.4x10-5) and represents the major HLA class II genetic driver and discriminative factor in the development of early onset disease. Discussion: This study uncovered that EOT1D holds a distinctive spectrum of HLA class II susceptibility loci, which includes risk factors overlapping with LaOT1D and discriminative genetic configurations. These findings warrant replication studies in larger multicentric settings encompassing other ethnicities and may impact target screening strategies and follow-up of young children with high T1D genetic risk as well as personalized therapeutic approaches. [ABSTRACT FROM AUTHOR]

The human leukocyte antigen (HLA) system is a major factor controlling cancer immunosurveillance and response to immunotherapy, yet its status in pediatric cancers remains fragmentary. We determined high-confidence HLA genotypes in 576 children, adolescents and young adults with recurrent/refractory solid tumors from the MOSCATO-01 and MAPPYACTS trials, using normal and tumor whole exome and RNA sequencing data and benchmarked algorithms. There was no evidence for narrowed HLA allelic diversity but discordant homozygosity and allele frequencies across tumor types and subtypes, such as in embryonal and alveolar rhabdomyosarcoma, neuroblastoma MYCN and 11q subtypes, and high-grade glioma, and several alleles may represent protective or susceptibility factors to specific pediatric solid cancers. There was a paucity of somatic mutations in HLA and antigen processing and presentation (APP) genes in most tumors, except in cases with mismatch repair deficiency or genetic instability. The prevalence of loss-of-heterozygosity (LOH) ranged from 5.9 to 7.7% in HLA class I and 8.0 to 16.7% in HLA class II genes, but was widely increased in osteosarcoma and glioblastoma (~15-25%), and for DRB1-DQA1-DQB1 in Ewing sarcoma (~23-28%) and low-grade glioma (~33-50%). HLA class I and HLA-DR antigen expression was assessed in 194 tumors and 44 patient-derived xenografts (PDXs) by immunochemistry, and class I and APP transcript levels quantified in PDXs by RT-qPCR. We confirmed that HLA class I antigen expression is heterogeneous in advanced pediatric solid tumors, with class I loss commonly associated with the transcriptional downregulation of HLA-B and transporter associated with antigen processing (TAP) genes, whereas class II antigen expression is scarce on tumor cells and occurs on immune infiltrating cells. Patients with tumors expressing sufficient HLA class I and TAP levels such as some glioma, osteosarcoma, Ewing sarcoma and non-rhabdomyosarcoma soft-tissue sarcoma cases may more likely benefit from T cell-based approaches, whereas strategies to upregulate HLA expression, to expand the immunopeptidome, and to target TAP-independent epitopes or possibly LOH might provide novel therapeutic opportunities in others. The consequences of HLA class II expression by immune cells remain to be established. Immunogenetic profiling should be implemented in routine to inform immunotherapy trials for precision medicine of pediatric cancers. [ABSTRACT FROM AUTHOR]

Background: The harmful effect of alcohol on the immune system may be due to both a direct action of the alcohol or its metabolites on immune cells as an indirect action modifying the different mechanisms of intercellular interaction. The interplay between stimulatory (aKIR) and inhibitory (iKIR) natural killer (NK) cell receptors and their corresponding human leukocyte antigen (HLA) ligands influences the outcome of virus infection. The aim was to analyze the influence of the KIR/HLA pair genetic profile in male alcoholic cirrhosis (AC) patients with and without viral infections to find susceptibility biomarkers that can help establish the risks and prevent viral infections. Methods: A total of 281 male AC patients were analyzed. The sociodemographic characteristics, viral hepatitis C (HCV), hepatitis B (HBV), and cytomegalovirus (CMV) infections were analyzed. Genomic DNA was extracted, and genetic the KIR/HLA profiles were investigated. A total of 6 KIR genes and their corresponding ligands (HLA-C) were analyzed. Patients were grouped into two groups: with and without associated viral infection. Results: A statistically significant increase in the combination of KIR2DL2+/C1C1 was observed in male AC patients with viral infection compared to those without viral infection (45.9% vs. 24.5%, p = 0.021). The analysis of KIR2DL3+/C1+ showed a high frequency comparing healthy controls and male AC patients without virus infection (85% vs. 76.4%; p = 0.026). The analysis of KIR2DL3+/C2C2 frequency showed a statistically significant increase comparing male AC patients without viral infection and healthy controls (23.6% vs. 15%; p = 0.026). Conclusions: The genetic KIR2DL2+/C2C2 profiles may play a significant role in determining the vulnerability of male AC patients to viral infections, providing valuable insights for future research and potential therapeutic interventions. [ABSTRACT FROM AUTHOR]

Adoptive cellular immunotherapy as a new paradigm to treat cancers is exemplified by the FDA approval of six chimeric antigen receptor-T cell therapies targeting hematological malignancies in recent years. Conventional αβ T cells applied in these therapies have proven efficacy but are confined almost exclusively to autologous use. When infused into patients with mismatched human leukocyte antigen, αβ T cells recognize tissues of such patients as foreign and elicit devastating graft-versus-host disease. Therefore, one way to overcome this challenge is to use naturally allogeneic immune cell types, such as γδ T cells. γδ T cells occupy the interface between innate and adaptive immunity and possess the capacity to detect a wide variety of ligands on transformed host cells. In this article, we review the fundamental biology of γδ T cells, including their subtypes, expression of ligands, contrasting roles in and association with cancer prognosis or survival, as well as discuss the gaps in knowledge pertaining to this cell type which we currently endeavor to elucidate. In addition, we propose how to harness the unique properties of γδ T cells for cellular immunotherapy based on lessons gleaned from past clinical trials and provide an update on ongoing trials involving these cells. Lastly, we elaborate strategies that have been tested or can be explored to improve the anti-tumor activity and durability of γδ T cells in vivo. [ABSTRACT FROM AUTHOR]

Heterozygosity of Human leukocyte antigen (HLA) class I genes is linked to beneficial outcomes after HIV infection, presumably through greater breadth of HIV epitope presentation and cytotoxic T cell response. Distinct allotype pairs, however, differ in the extent to which they bind shared sets of peptides. We developed a functional divergence metric that measures pairwise complementarity of allotype-associated peptide binding profiles. Greater functional divergence for pairs of HLA-A and/or HLA-B allotypes was associated with slower AIDS progression and independently with enhanced viral load control. The metric predicts immune breadth at the peptide level rather than gene level and redefines HLA heterozygosity as a continuum differentially affecting disease outcome. Functional divergence may affect response to additional infections, vaccination, immunotherapy, and other diseases where HLA heterozygote advantage occurs. [ABSTRACT FROM AUTHOR]

The heritability of susceptibility to tuberculosis (TB) disease has been well recognized. Over 100 genes have been studied as candidates for TB susceptibility, and several variants were identified by genome-wide association studies (GWAS), but few replicate. We established the International Tuberculosis Host Genetics Consortium to perform a multi-ancestry meta-analysis of GWAS, including 14,153 cases and 19,536 controls of African, Asian, and European ancestry. Our analyses demonstrate a substantial degree of heritability (pooled polygenic h2 = 26.3%, 95% CI 23.7-29.0%) for susceptibility to TB that is shared across ancestries, highlighting an important host genetic influence on disease. We identified one global host genetic correlate for TB at genome-wide significance (p<5 × 10-8) in the human leukocyte antigen (HLA)-II region (rs28383206, p-value= 5.2 × 10-9) but failed to replicate variants previously associated with TB susceptibility. These data demonstrate the complex shared genetic architecture of susceptibility to TB and the importance of large-scale GWAS analysis across multiple ancestries experiencing different levels of infection pressure. [ABSTRACT FROM AUTHOR]

Acute myeloid leukemia patients with induction failure or relapsed refractory disease have minimal chance of achieving remission with subsequent treatments. Several trials have shown the feasibility of clofarabine-based conditioning in allogeneic stem cell transplants (allo-HSCT) for non-remission AML patients. Pre-transplant conditioning with clofarabine followed by reduced-intensity allo-HSCT has also demonstrated a potential benefit in those patients with human leukocyte antigen (HLA)-identical donors, but it is not commonly used in haploidentical and mismatched transplants. In this case report, we describe our experience of seven cases of non-remission AML who received clofarabine preconditioning followed by an allo-HSCT with PTCy. The 2-year overall survival and disease-free survival was 83.3% (95% confidence interval (CI): 27.3–97.9%) and 85.7% (95% CI: 33.4–97.9%). Median days of neutrophil and platelet recovery were 16 (range of 13–23) and 28 (range of 17–75), respectively. The cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) at day 100 and chronic GVHD at 1-year showed 28.6% (95% CI: 8–74.2%) and 28.6% (95% CI: 3–63.9%), respectively. The two-year relapse rate was 14.3% (95% CI: 2.14–66.6%). One-year GVHD-free relapse-free survival (GFRS) at 1-year was 71.4% (95% CI: 25.8–92%). Our patients showed successful outcomes with clofarabine preconditioning to reduce the leukemic burden at the pre-transplant period followed by PTCy to reduce GVHD resulting in lower relapsed rate and better GFRS in these patients. [ABSTRACT FROM AUTHOR]

Studies concerning the genetic background of IgA vasculitis (IgAV), a small-vessel vasculitis occurring predominantly in childhood, have confirmed that the HLA-DRB1 gene showed a strong association with disease susceptibility. The objective was to investigate human leukocyte antigen (HLA) polymorphisms among Croatian patients with IgAV and their influence on disease susceptibility and clinical heterogeneity. Thus, 130 children with IgAV and 202 unrelated healthy individuals were enrolled in the study. Genomic DNA was extracted from whole peripheral blood, and HLA-A, -B, -DRB1 and -DQB1 gene polymorphism analysis was performed. HLA-A*03 (21.4% vs. 12.38%, p = 0.0092), HLA-B*37 (2.9% vs. 0.2%, p = 0.0054) and HLA-DRB1*12 (3.1% vs. 0.7%, p = 0.0216) alleles were significantly more frequent in IgAV patients than in controls. High-resolution typing revealed significantly higher frequency of HLA-DRB1*10:01 and -DRB1*11:03 among IgAV patients with gastrointestinal manifestations of the disease in comparison to controls (p = 0.0021 and p = 0.0301, respectively), while HLA-DRB1*14:01P occurred significantly more often in the group of patients who developed nephritis during the course of the disease (17.5% vs. 4.5%, p = 0.0006). Our results demonstrated that there is an association of HLA-A*03, HLA-B*37 and HLA-DRB1*12 alleles with susceptibility to IgAV in the examined Croatian pediatric population. Studies which aim to determine the HLA profile may contribute to the elucidation of the genetic background of autoimmune diseases, including IgAV. [ABSTRACT FROM AUTHOR]

(1) Background: Preeclampsia (PE) usually presents with hypertension and proteinuria, related to poor placentation. Reduced maternal–fetal immunological tolerance is a possible trigger of inadequate placentation. Aberrant antigen expression of HLA-DR has been observed in the syncytiotrophoblast of PE patients. In this study, we analyzed plasma levels of Human Leukocyte Antigen (HLA)-DR+ syncytiotrophoblast-derived extracellular vesicles (STEVs) during the three trimesters of pregnancy in relation to PE onset. (2) Methods: Pregnant women underwent venous blood sampling during the three trimesters. STEVs were collected from plasma via ultracentrifugation (120,000 g) and characterized by Western blot, nanotracking analysis and flow cytometry for the expression of Placental Alkaline Phosphatase (PLAP), a placental-derived marker, and HLA-DR. (3) Results: Out of 107 women recruited, 10 developed PE. STEVs were detected in all three trimesters of pregnancy with a zenith in the second trimester. A significant difference was found between the non-PE and PE groups in terms of plasma levels of HLA-DR+ STEVs during all three trimesters of pregnancy. (4) Conclusions: More research is needed to investigate HLA-DR+ as a potential early marker of PE. [ABSTRACT FROM AUTHOR]