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To optimize outcomes in solid organ transplantation, the HLA genes are regularly compared and matched between the donor and recipient. However, in many cases a transplant cannot be fully matched, due to widespread variation across populations and the hyperpolymorphism of HLA alleles. Mismatches of the HLA molecules in transplanted tissue can be recognized by immune cells of the recipient, leading to immune response and possibly organ rejection. These adverse outcomes are reduced by analysis using epitope-focused models that consider the immune relevance of the mismatched HLA.PIRCHE, an acronym for Predicted Indirectly ReCognizable HLA Epitopes, aims to categorize and quantify HLA mismatches in a patient-donor pair by predicting HLA-derived T cell epitopes. Specifically, the algorithm predicts and counts the HLA-derived peptides that can be presented by the host HLA, known as indirectly-presented T cell epitopes. Looking at the immune-relevant epitopes within HLA allows a more biologically relevant understanding of immune response, and provides an expanded donor pool for a more refined matching strategy compared with allele-level matching. This PIRCHE algorithm is available for analysis of single transplantations, as well as bulk analysis for population studies and statistical analysis for comparison of probability of organ availability and risk profiles.
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Algoritmos , Epitopos de Linfócito T , Antígenos HLA , Teste de Histocompatibilidade , Transplante de Órgãos , Humanos , Transplante de Órgãos/efeitos adversos , Teste de Histocompatibilidade/métodos , Antígenos HLA/genética , Antígenos HLA/imunologia , Epitopos de Linfócito T/imunologia , Epitopos de Linfócito T/genética , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/genética , Alelos , Doadores de TecidosRESUMO
Introduction: Human leukocyte antigen (HLA)-DPB1 mismatches during hematopoietic stem cell transplantation (HSCT) with an unrelated donor result in an increased risk for the development of graft-versus-host disease (GvHD). The number of CD8+ T-cell epitopes available for indirect allorecognition as predicted by the PIRCHE algorithm has been shown to be associated with GvHD development. As a proof of principle, PIRCHE-I predictions for HLA-DPB1 mismatches were validated in vitro and in vivo. Methods: PIRCHE-I analysis was performed to identify HLA-DPB1-derived peptides that could theoretically bind to HLA-A*02:01. PIRCHE-I predictions for HLA-DPB1 mismatches were validated in vitro by investigating binding affinities of HLA-DPB1-derived peptides to the HLA-A*02:01 in a competition-based binding assay. To investigate the capacity of HLA-DPB1-derived peptides to elicit a T-cell response in vivo, mice were immunized with these peptides. T-cell alloreactivity was subsequently evaluated using an interferon-gamma ELISpot assay. Results: The PIRCHE-I algorithm identified five HLA-DPB1-derived peptides (RMCRHNYEL, YIYNREEFV, YIYNREELV, YIYNREEYA, and YIYNRQEYA) to be presented by HLA-A*02:01. Binding of these peptides to HLA-A*02:01 was confirmed in a competition-based peptide binding assay, all showing an IC50 value of 21 µm or lower. The peptides elicited an interferon-gamma response in vivo. Conclusion: Our results indicate that the PIRCHE-I algorithm can identify potential immunogenic HLA-DPB1-derived peptides present in recipients of an HLA-DPB1-mismatched donor. These combined in vitro and in vivo observations strengthen the validity of the PIRCHE-I algorithm to identify HLA-DPB1 mismatch-related GvHD development upon HSCT.
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In kidney transplantation, donor HLA antibodies are a risk factor for graft loss. Accessibility of donor eplets for HLA antibodies is predicted by the ElliPro score. The clinical usefulness of those scores in relation to transplant outcome is unknown. In a large Dutch kidney transplant cohort, Ellipro scores of pretransplant donor antibodies that can be assigned to known eplets (donor epitope specific HLA antibodies [DESAs]) were compared between early graft failure and long surviving deceased donor transplants. We did not observe a significant Ellipro score difference between the two cohorts, nor significant differences in graft survival between transplants with DESAs having high versus low total Ellipro scores. We conclude that Ellipro scores cannot be used to identify DESAs associated with early versus late kidney graft loss in deceased donor transplants.
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Nefropatias , Transplante de Rim , Humanos , Sobrevivência de Enxerto , Alelos , Anticorpos , Rim , Epitopos , Rejeição de Enxerto , Antígenos HLA , Doadores de TecidosRESUMO
In kidney transplantation, survival rates are still partly impaired due to the deleterious effects of donor specific HLA antibodies (DSA). However, not all luminex-defined DSA appear to be clinically relevant. Further analysis of DSA recognizing polymorphic amino acid configurations, called eplets or functional epitopes, might improve the discrimination between clinically relevant vs. irrelevant HLA antibodies. To evaluate which donor epitope-specific HLA antibodies (DESAs) are clinically important in kidney graft survival, relevant and irrelevant DESAs were discerned in a Dutch cohort of 4690 patients using Kaplan-Meier analysis and tested in a cox proportional hazard (CPH) model including nonimmunological variables. Pre-transplant DESAs were detected in 439 patients (9.4%). The presence of certain clinically relevant DESAs was significantly associated with increased risk on graft loss in deceased donor transplantations (p < 0.0001). The antibodies recognized six epitopes of HLA Class I, 3 of HLA-DR, and 1 of HLA-DQ, and most antibodies were directed to HLA-B (47%). Fifty-three patients (69.7%) had DESA against one donor epitope (range 1-5). Long-term graft survival rate in patients with clinically relevant DESA was 32%, rendering DESA a superior parameter to classical DSA (60%). In the CPH model, the hazard ratio (95% CI) of clinically relevant DESAs was 2.45 (1.84-3.25) in deceased donation, and 2.22 (1.25-3.95) in living donation. In conclusion, the developed model shows the deleterious effect of clinically relevant DESAs on graft outcome which outperformed traditional DSA-based risk analysis on antigen level.
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Transplante de Rim , Humanos , Transplante de Rim/efeitos adversos , Epitopos , Antígenos HLA/genética , Relevância Clínica , Isoanticorpos , Alelos , Doadores de Tecidos , Rejeição de EnxertoRESUMO
Allorecognition of donor HLA is a major risk factor for long-term kidney graft survival. Although several molecular matching algorithms have been proposed that compare physiochemical and structural features of the donors' and recipients' HLA proteins in order to predict their compatibility, the exact underlying mechanisms are still not fully understood. We hypothesized that the ElliPro approach of single ellipsoid fitting and protrusion ranking lacks sensitivity for the characteristic shape of HLA molecules and developed a prediction pipeline named Snowball that is fitting smaller ellipsoids iteratively to substructures. Aggregated protrusion ranks of locally fitted ellipsoids were calculated for 712 publicly available HLA structures and 78 predicted structures using AlphaFold 2. Amino-acid sequence and protrusion ranks were used to train deep neural network predictors to infer protrusion ranks for all known HLA sequences. Snowball protrusion ranks appear to be more sensitive than ElliPro scores in fine parts of the HLA such as the helix structures forming the HLA binding groove in particular when the ellipsoids are fitted to substructures considering atoms within a 15 Å radius. A cloud-based web service was implemented based on amino-acid matching considering both protein- and position-specific surface area and protrusion ranks extending the previously presented Snowflake prediction pipeline.
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Transplante de Rim , Humanos , Teste de Histocompatibilidade , Alelos , Doadores de Tecidos , Sequência de Aminoácidos , Antígenos HLARESUMO
Objective: We aim to investigate the effects of genetically based HLA matching on patient and graft survival, and acute and chronic rejection after liver transplantation. Background: Liver transplantation is a common treatment for patients with end-stage liver disease. In contrast to most other solid organ transplantations, there is no conclusive evidence supporting human leukocyte antigen (HLA) matching for liver transplantations. With emerging alternatives such as transplantation of bankable (stem) cells, HLA matching becomes feasible, which may decrease the need for immunosuppressive therapy and improve transplantation outcomes. Methods: We systematically searched the PubMed, Embase, and Cochrane databases and performed a meta-analysis investigating the effect of genetic HLA matching on liver transplantation outcomes (acute/chronic rejection, graft failure, and mortality). Results: We included 14 studies with 2682 patients. HLA-C mismatching significantly increased the risk of acute rejection (full mismatching: risk ratio = 1.90, 95% confidence interval = 1.08 to 3.33, P = 0.03; partial mismatching: risk ratio = 1.33, 95% confidence interval = 1.07 to 1.66, P = 0.01). We did not discern any significant effect of HLA mismatching per locus on acute rejection for HLA-A, -B, -DR, and -DQ, nor on chronic rejection, graft failure, or mortality for HLA-DR, and -DQ. Conclusions: We found evidence that genetic HLA-C matching reduces the risk of acute rejection after liver transplantation while matching for other loci does not reduce the risk of acute rejection, chronic rejection, graft failure, or mortality.
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The guidelines for the implementation and reporting of HLA nomenclature for the World Marrow Donor Association have served as a reliable standard for communication of HLA data in the hematopoietic cell transplantation process. Wider use of next-generation sequencing made a special provision of the guidelines increasingly pertinent: how to communicate novel HLA alleles. Novel alleles need to be recognized by the WHO Nomenclature Committee for Factors of the HLA system to obtain official allele designations. Until then they have to be handled according to the specific rules. Leaving the actual rules basically unchanged we give some advice on how to communicate novel alleles to best facilitate the search process for cases where novel alleles are identified on donor or patient side.
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Medula Óssea , Transplante de Células-Tronco Hematopoéticas , Humanos , Alelos , Antígenos HLA/genética , Teste de Histocompatibilidade , Sequenciamento de Nucleotídeos em Larga EscalaRESUMO
The International HLA and Immunogenetics Workshop (IHIW) is a recurring gathering of researchers, technologists and clinicians where participants contribute to collaborative projects with a variety of goals, and come to consensus on definitions and standards for representing HLA and immunogenic determinants. The collaborative and international nature of these workshops, combined with the multifaceted goals of several specific workshop components, necessitates the collection and curation of a wide assortment of data, as well as an adaptable platform for export and analysis. With the aim of ensuring data quality and creation of reusable datasets, specific standards and nomenclature conventions are continuously being developed, and are an integral part of IHIW. Here we present the 18th IHIW Database, a purpose-built and extensible cloud-based file repository and web application for collecting and analyzing project-specific data. This platform is based on open-source software and uses established HLA data standards and web technologies to facilitate de-centralized data repository ownership, reduce duplicated efforts, and promote continuity for future IHIWs.
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Antígenos HLA , Imunogenética , Humanos , Alelos , Coleta de Dados , Bases de Dados FactuaisRESUMO
Autoimmune inflammation is characterized by tissue infiltration and expansion of antigen-specific T cells. Although this inflammation is often limited to specific target tissues, it remains yet to be explored whether distinct affected sites are infiltrated with the same, persistent T cell clones. Here, we performed CyTOF analysis and T cell receptor (TCR) sequencing to study immune cell composition and (hyper-)expansion of circulating and joint-derived Tregs and non-Tregs in juvenile idiopathic arthritis (JIA). We studied different joints affected at the same time, as well as over the course of relapsing-remitting disease. We found that the composition and functional characteristics of immune infiltrates are strikingly similar between joints within one patient, and observed a strong overlap between dominant T cell clones, especially Treg, of which some could also be detected in circulation and persisted over the course of relapsing-remitting disease. Moreover, these T cell clones were characterized by a high degree of sequence similarity, indicating the presence of TCR clusters responding to the same antigens. These data suggest that in localized autoimmune disease, there is autoantigen-driven expansion of both Teffector and Treg clones that are highly persistent and are (re)circulating. These dominant clones might represent interesting therapeutic targets.
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Artrite Juvenil , Humanos , Linfócitos T Reguladores , Inflamação , Receptores de Antígenos de Linfócitos T , Células ClonaisRESUMO
Development of donor-specific human leukocyte antigen (HLA) antibodies (DSA) remains a major risk factor for graft loss following organ transplantation, where DSA are directed towards patches on the three-dimensional structure of the respective organ donor's HLA proteins. Matching donors and recipients based on HLA epitopes appears beneficial for the avoidance of DSA. Defining surface epitopes however remains challenging and the concepts underlying their characterization are not fully understood. Based on our recently implemented computational deep learning pipeline to define HLA Class I protein-specific surface residues, we hypothesized a correlation between the number of HLA protein-specific solvent-accessible interlocus amino acid mismatches (arbitrarily called Snowflake) and the incidence of DSA. To validate our hypothesis, we considered two cohorts simultaneously. The kidney transplant cohort (KTC) considers 305 kidney-transplanted patients without DSA prior to transplantation. During the follow-up, HLA antibody screening was performed regularly to identify DSA. The pregnancy cohort (PC) considers 231 women without major sensitization events prior to pregnancy who gave live birth. Post-delivery serum was screened for HLA antibodies directed against the child's inherited paternal haplotype (CSA). Based on the involved individuals' HLA typings, the numbers of interlocus-mismatched antibody-verified eplets (AbvEPS), the T cell epitope PIRCHE-II model and Snowflake were calculated locus-specific (HLA-A, -B and -C), normalized and pooled. In both cohorts, Snowflake numbers were significantly elevated in recipients/mothers that developed DSA/CSA. Univariable regression revealed significant positive correlation between DSA/CSA and AbvEPS, PIRCHE-II and Snowflake. Snowflake numbers showed stronger correlation with numbers of AbvEPS compared to Snowflake numbers with PIRCHE-II. Our data shows correlation between Snowflake scores and the incidence of DSA after allo-immunization. Given both AbvEPS and Snowflake are B cell epitope models, their stronger correlation compared to PIRCHE-II and Snowflake appears plausible. Our data confirms that exploring solvent accessibility is a valuable approach for refining B cell epitope definitions.
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Transplante de Rim , Gravidez , Humanos , Feminino , Isoanticorpos , Epitopos de Linfócito B , Doadores de Tecidos , SolventesRESUMO
The role of the indirect T-cell recognition pathway of allorecognition in acute T cell-mediated rejection (aTCMR) is not well defined. The amount of theoretical T-cell epitopes available for indirect allorecognition can be quantified for donor-recipient combinations by the Predicted Indirectly ReCognizable HLA Epitopes algorithm (PIRCHE-II). The PIRCHE-II score was calculated for 688 donor kidney-recipient combinations and associated with the incidence of first-time diagnosed cases of TCMR. A diagnosis of TCMR was made in 182 cases; 121 cases of tubulo-interstitial rejection cases (79 cases of borderline TCMR, 42 cases of TCMR IA-B) and 61 cases of vascular TCMR (TCMR II-III). The PIRCHE-II score for donor HLA-DR/DQ (PIRCHE-II DR/DQ) was highly associated with vascular rejection. At one year after transplantation, the cumulative percentage of recipients with a vascular rejection was 12.7%, 8.6% and 2.1% within respectively the high, medium and low tertile of the PIRCHE-II DR/DQ score (p<0.001). In a multivariate regression analysis this association remained significant (p<0.001 for PIRCHE-II DR/DQ tertiles). The impact of a high PIRCHE-II DR/DQ score was mitigated by older recipient age and a living donor kidney. In conclusion, indirect antigen presentation of donor HLA-peptides may significantly contribute to the risk for acute vascular rejection.
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Transplante de Rim , Apresentação de Antígeno , Epitopos de Linfócito T , Antígenos HLA-DR , Transplante de Rim/efeitos adversos , PeptídeosRESUMO
Histocompatibility in solid-organ transplantation has a strong impact on long-term graft survival. Although recent advances in matching of both B-cell epitopes and T-cell epitopes have improved understanding of allorecognition, the immunogenic determinants are still not fully understood. We hypothesized that HLA solvent accessibility is allele-specific, thus supporting refinement of HLA B-cell epitope prediction. We developed a computational pipeline named Snowflake to calculate solvent accessibility of HLA Class I proteins for deposited HLA crystal structures, supplemented by constructed HLA structures through the AlphaFold protein folding predictor and peptide binding predictions of the APE-Gen docking framework. This dataset trained a four-layer long short-term memory bidirectional recurrent neural network, which in turn inferred solvent accessibility of all known HLA Class I proteins. We extracted 676 HLA Class-I experimental structures from the Protein Data Bank and supplemented it by 37 Class-I alleles for which structures were predicted. For each of the predicted structures, 10 known binding peptides as reported by the Immune Epitope DataBase were rendered into the binding groove. Although HLA Class I proteins predominantly are folded similarly, we found higher variation in root mean square difference of solvent accessibility between experimental structures of different HLAs compared to structures with identical amino acid sequence, suggesting HLA's solvent accessible surface is protein specific. Hence, residues may be surface-accessible on e.g. HLA-A*02:01, but not on HLA-A*01:01. Mapping these data to antibody-verified epitopes as defined by the HLA Epitope Registry reveals patterns of (1) consistently accessible residues, (2) only subsets of an epitope's residues being consistently accessible and (3) varying surface accessibility of residues of epitopes. Our data suggest B-cell epitope definitions can be refined by considering allele-specific solvent-accessibility, rather than aggregating HLA protein surface maps by HLA class or locus. To support studies on epitope analyses in organ transplantation, the calculation of donor-allele-specific solvent-accessible amino acid mismatches was implemented as a cloud-based web service.
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Aprendizado Profundo , Epitopos de Linfócito B , Algoritmos , Alelos , Antígenos HLA/genética , Antígenos HLA-A , Humanos , SolventesRESUMO
Single-cell technologies open up new opportunities to explore the behavior of cells at the individual level. For solid organ transplantation, single-cell technologies can provide in-depth insights into the underlying mechanisms of the immunological processes involved in alloimmune responses after transplantation by investigating the role of individual cells in tolerance and rejection. Here, we review the value of single-cell technologies, including cytometry by time-of-flight and single-cell RNA sequencing, in the context of solid organ transplantation research. Various applications of single-cell technologies are addressed, such as the characterization and identification of immune cell subsets involved in rejection or tolerance. In addition, we explore the opportunities for analyzing specific alloreactive T- or B-cell clones by linking phenotype data to T- or B-cell receptor data, and for distinguishing donor- from recipient-derived immune cells. Moreover, we discuss the use of single-cell technologies in biomarker identification and risk stratification, as well as the remaining challenges. Together, this review highlights that single-cell approaches contribute to a better understanding of underlying immunological mechanisms of rejection and tolerance, thereby potentially accelerating the development of new or improved therapies to avoid allograft rejection.
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Rejeição de Enxerto , Transplante de Órgãos , Transplante de Órgãos/efeitos adversos , Histocompatibilidade , Transplante Homólogo , Tolerância ImunológicaRESUMO
The identity of histocompatibility loci, besides human leukocyte antigen (HLA), remains elusive. The major histocompatibility complex (MHC) class I MICA gene is a candidate histocompatibility locus. Here, we investigate its role in a French multicenter cohort of 1,356 kidney transplants. MICA mismatches were associated with decreased graft survival (hazard ratio (HR), 2.12; 95% confidence interval (CI): 1.45-3.11; P < 0.001). Both before and after transplantation anti-MICA donor-specific antibodies (DSA) were strongly associated with increased antibody-mediated rejection (ABMR) (HR, 3.79; 95% CI: 1.94-7.39; P < 0.001; HR, 9.92; 95% CI: 7.43-13.20; P < 0.001, respectively). This effect was synergetic with that of anti-HLA DSA before and after transplantation (HR, 25.68; 95% CI: 3.31-199.41; P = 0.002; HR, 82.67; 95% CI: 33.67-202.97; P < 0.001, respectively). De novo-developed anti-MICA DSA were the most harmful because they were also associated with reduced graft survival (HR, 1.29; 95% CI: 1.05-1.58; P = 0.014). Finally, the damaging effect of anti-MICA DSA on graft survival was confirmed in an independent cohort of 168 patients with ABMR (HR, 1.71; 95% CI: 1.02-2.86; P = 0.041). In conclusion, assessment of MICA matching and immunization for the identification of patients at high risk for transplant rejection and loss is warranted.
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Transplante de Rim , Rejeição de Enxerto/genética , Sobrevivência de Enxerto/genética , Antígenos de Histocompatibilidade Classe I/genética , HumanosRESUMO
HLA-DQ heterodimers increase the susceptibility to autoimmune diseases, but their role in hematopoietic cell transplantation is unknown. We tested the hypothesis that outcome after HLA-matched and HLA-DQ-mismatched hematopoietic cell transplantation is influenced by HLA-DQ heterodimers. Heterodimers were defined in 5164 HLA-matched and 520 HLA-DQ-mismatched patients and their transplant donors according to well-established crystallographic criteria. Group 1 (G1) heterodimers are any DQA1*02/03/04/05/06α paired with any DQB1*02/03/04ß. Group 2 (G2) heterodimers are DQA1*01α paired with any DQB1*05/06ß. Multivariable models identified significantly higher relapse risk in G1G2 and G2G2 compared with G1G1 HLA-matched patients with malignant disease; risk increased with an increasing number of G2 molecules. In HLA-DQ-mismatched transplantation for malignant diseases, matching or mismatching for G2 increased relapse risk. G2 lowered disease-free survival after both HLA-matched and HLA-DQ-mismatched transplantation. A paradigm based on HLA-DQ heterodimers provides a functional definition of the hematopoietic cell transplantation barrier and a means to lower risks for future patients.
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Antígenos HLA-DQ , Transplante de Células-Tronco Hematopoéticas , Alelos , Antígenos HLA-DQ/genética , Cadeias beta de HLA-DQ , Humanos , Recidiva , Doadores de TecidosRESUMO
For liver transplantations, human leukocyte antigen (HLA) matching is not routinely performed because observed effects have been inconsistent. Nevertheless, long-term liver transplantation outcomes remain suboptimal. The availability of a more precise HLA-matching algorithm, Predicted Indirectly Recognizable HLA Epitopes II (PIRCHE-II), now enables robust assessment of the association between HLA matching and liver transplantation outcomes. We performed a single-center retrospective cohort study of 736 liver transplantation patients. Associations between PIRCHE-II and HLAMatchmaker scores and mortality, graft loss, acute and chronic rejection, ischemic cholangiopathy, and disease recurrence were evaluated with Cox proportional hazards models. Associations between PIRCHE-II with 1-year, 2-year, and 5-year outcomes and severity of acute rejection were assessed with logistic and linear regression analyses, respectively. Subgroup analyses were performed for autoimmune and nonautoimmune indications, and patients aged 30 years and younger, and older than 30 years. PIRCHE-II and HLAMatchmaker scores were not associated with any of the outcomes. However, patients who received transplants for autoimmune disease showed more acute rejection and graft loss, and these risks negatively associated with age. Rhesus mismatch more than doubled the risk of disease recurrence. Moreover, PIRCHE-II was inversely associated with graft loss in the subgroup of patients aged 30 years and younger with autoimmune indications. The absence of associations between PIRCHE-II and HLAMatchmaker scores and the studied outcomes refutes the need for HLA matching for liver (stem cell) transplantations for nonautoimmune disease. For autoimmune disease, the activated immune system seems to increase risks of acute rejection and graft loss. Our results may suggest the benefits of transplantations with rhesus matched but PIRCHE-II mismatched donor livers.
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Doenças Autoimunes , Transplante de Fígado , Algoritmos , Rejeição de Enxerto/epidemiologia , Sobrevivência de Enxerto , Antígenos HLA , Teste de Histocompatibilidade , Humanos , Transplante de Fígado/efeitos adversos , Estudos RetrospectivosRESUMO
BACKGROUND: Often only chronic kidney disease (CKD) patients with high likelihood of genetic disease are offered genetic testing. Early genetic testing could obviate the need for kidney biopsies, allowing for adequate prognostication and treatment. To test the viability of a 'genetics-first' approach for CKD, we performed genetic testing in a group of kidney transplant recipients aged <50 years, irrespective of cause of transplant. METHODS: From a cohort of 273 transplant patients, we selected 110 that were in care in the University Medical Center Utrecht, had DNA available and were without clear-cut non-genetic disease. Forty patients had been diagnosed with a genetic disease prior to enrollment; in 70 patients, we performed a whole-exome sequencing-based 379 gene panel analysis. RESULTS: Genetic analysis yielded a diagnosis in 51%. Extrapolated to the 273 patient cohort, who did not all fit the inclusion criteria, the diagnostic yield was still 21%. Retrospectively, in 43% of biopsied patients, the kidney biopsy would not have had added diagnostic value if genetic testing had been performed as a first-tier diagnostic. CONCLUSIONS: The burden of monogenic disease in transplant patients with end-stage kidney disease (ESKD) of any cause prior to the age of 50 years is between 21% and 51%. Early genetic testing can provide a non-invasive diagnostic, impacting prognostication and treatment, and obviating the need for an invasive biopsy. We conclude that in patients who expect to develop ESKD prior to the age of 50 years, genetic testing should be considered as first mode of diagnostics.
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Falência Renal Crônica , Insuficiência Renal Crônica , Estudos de Coortes , Testes Genéticos , Humanos , Falência Renal Crônica/diagnóstico , Falência Renal Crônica/genética , Pessoa de Meia-Idade , Insuficiência Renal Crônica/complicações , Estudos RetrospectivosRESUMO
CD8+ T cells play an important role in the control of untreated HIV infection. Several studies have suggested a decisive role of TCRs involved in anti-HIV immunity. HLA-B*27 and B*57 are often associated with a delayed HIV disease progression, but the exact correlates that provide superior immunity against HIV are not known. To investigate if the T cell repertoire underlies the protective effect in disease outcome in HLA-B*27 and B*57+ individuals, we analyzed Ag-specific TCR profiles from progressors (n = 13) and slow progressors (n = 11) expressing either B*27 or B*57. Our data showed no differences in TCR diversity between progressors and slow progressors. Both alleles recruit biased T cell repertoires (i.e., TCR populations skewed toward specific TRBV families or CDR3 regions). This bias was unrelated to disease progression and was remarkably profound for HLA-B*57, in which TRBV family usage and CDR3 sequences were shared to some extent even between epitopes. Conclusively, these data suggest that the T cell repertoires recruited by protective HLA alleles are highly similar between progressors and slow progressors in terms of TCR diversity, TCR usage, and cross-reactivity.
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Regiões Determinantes de Complementaridade/genética , Infecções por HIV/imunologia , HIV-1/fisiologia , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Linfócitos T/fisiologia , Alelos , Apresentação de Antígeno , Antígenos Virais/metabolismo , Células Cultivadas , Reações Cruzadas , Progressão da Doença , ELISPOT , Epitopos de Linfócito T/metabolismo , Variação Genética , Antígenos HLA-B/genética , Antígenos HLA-B/metabolismo , Antígeno HLA-B27/genética , Antígeno HLA-B27/metabolismo , Humanos , Ativação LinfocitáriaRESUMO
CD4+ T-helper cells play an important role in alloimmune reactions following transplantation by stimulating humoral as well as cellular responses, which might lead to failure of the allograft. CD4+ memory T-helper cells from a previous immunizing event can potentially be reactivated by exposure to HLA mismatches that share T-cell epitopes with the initial immunizing HLA. Consequently, reactivity of CD4+ memory T-helper cells toward T-cell epitopes that are shared between immunizing HLA and donor HLA could increase the risk of alloimmunity following transplantation, thus affecting transplant outcome. In this study, the amount of T-cell epitopes shared between immunizing and donor HLA was used as a surrogate marker to evaluate the effect of donor-reactive CD4+ memory T-helper cells on the 10-year risk of death-censored kidney graft failure in 190 donor/recipient combinations using the PIRCHE-II algorithm. The T-cell epitopes of the initial theoretical immunizing HLA and the donor HLA were estimated and the number of shared PIRCHE-II epitopes was calculated. We show that the natural logarithm-transformed PIRCHE-II overlap score, or Shared T-cell EPitopes (STEP) score, significantly associates with the 10-year risk of death-censored kidney graft failure, suggesting that the presence of pre-transplant donor-reactive CD4+ memory T-helper cells might be a strong indicator for the risk of graft failure following kidney transplantation.
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Epitopos de Linfócito T/imunologia , Rejeição de Enxerto/imunologia , Sobrevivência de Enxerto/imunologia , Antígenos HLA/imunologia , Transplante de Rim , Linfócitos T/imunologia , Adulto , Idoso , Epitopos de Linfócito T/genética , Feminino , Rejeição de Enxerto/genética , Doença Enxerto-Hospedeiro/diagnóstico , Doença Enxerto-Hospedeiro/etiologia , Doença Enxerto-Hospedeiro/mortalidade , Antígenos HLA/genética , Humanos , Transplante de Rim/efeitos adversos , Transplante de Rim/métodos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Linfócitos T/metabolismo , Doadores de Tecidos , Transplantados , Transplante Homólogo , Falha de Tratamento , Adulto JovemRESUMO
Human adenoviruses (HAdVs) are a major cause for disease in children, in particular after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Currently, effective therapies for HAdV infections in immunocompromised hosts are lacking. To decipher immune recognition of HAdV infection and determine new targets for immune-mediated control, we used an HAdV infection 3D organoid system, based on primary human intestinal epithelial cells. HLA-F, the functional ligand for the activating NK cell receptor KIR3DS1, was strongly up-regulated and enabled enhanced killing of HAdV5-infected cells in organoids by KIR3DS1+ NK cells. In contrast, HLA-A and HLA-B were significantly down-regulated in HAdV5-infected organoids in response to adenoviral E3/glycoprotein19K, consistent with evasion from CD8+ T cells. Immunogenetic analyses in a pediatric allo-HSCT cohort showed a reduced risk to develop severe HAdV disease and faster clearance of HAdV viremia in children receiving KIR3DS1+/HLA-Bw4+ donor cells compared with children receiving nonKIR3DS1+/HLA-Bw4+ cells. These findings identify the KIR3DS1/HLA-F axis as a new target for immunotherapeutic strategies against severe HAdV disease.