RESUMO
Donor-specific HLA antibody (DSA) has been recognised as an independent risk factor for graft failure in patients undergoing haploidentical haematopoietic stem cell transplantation (HID HSCT). Therapeutic plasma exchange (TPE), as a first-line strategy for DSA desensitisation, can promptly reduce serum DSA levels. This study aimed to investigate DSA characteristics and identify a biomarker predicting the efficacy of DSA desensitisation in patients proceeding to HID HSCT. We retrospectively enrolled 32 patients with DSA from April 2021 to January 2024, and analysed the mean fluorescence intensity (MFI) value of DSA at the different time points of desensitisation treatment. Compared with baseline DSA level before TPE, the median MFI of HLA class I DSA was reduced from 8178.6 to 795.3 (p < 0.001), and HLA class II DSA decreased from 6210.9 to 808.8 (p < 0.001) after TPE. The DSA level in 1:16 diluted pre-TPE serum correlated well with DSA value in post-TPE serum (class I, r = 0.85, p < 0.0001; class II, r = 0.94, p < 0.0001), predicting TPE efficacy in 84.4% of patients. Based on the degree of DSA reduction after TPE, patients were divided into complete responders (decreased by >70%), partial responders (decreased by 30 to 70%) and non-responders (decreased by <30%) and the percentages were 43.8%, 25% and 31.2%, respectively. Non-responders receiving aggressive immunotherapy had longer overall survival compared to those receiving standard strategies (p < 0.05). The 1:16 diluted pre-TPE serum may predict the efficacy of TPE and allow for more rational immunotherapy strategy for patients with DSA proceeding to HID HSCT.
Assuntos
Antígenos HLA , Transplante de Células-Tronco Hematopoéticas , Isoanticorpos , Humanos , Transplante de Células-Tronco Hematopoéticas/métodos , Masculino , Feminino , Adulto , Estudos Retrospectivos , Pessoa de Meia-Idade , Antígenos HLA/imunologia , Isoanticorpos/sangue , Isoanticorpos/imunologia , Doadores de Tecidos , Rejeição de Enxerto/imunologia , Troca Plasmática/métodos , Adolescente , Transplante Haploidêntico/métodos , Adulto Jovem , Biomarcadores/sangue , Dessensibilização Imunológica/métodosRESUMO
Complement mediated interference with the detection of antibodies targeting HLA is a known limitation of the single antigen bead (SAB) Luminex assay. Ethylenediaminetetraacetic acid (EDTA) is currently the serum treatment of choice in most histocompatibility laboratories to block complement activation by chelating calcium. The purpose of this study was to investigate a serum with an antibody reactivity to HLA-DQ6, 7, 8 and 9 molecules, in the Luminex SAB assay, that was inhibited by treatment with EDTA. Serum was from a 55-year-old highly sensitised female renal transplant candidate that contained, among others, antibodies to an epitope containing the 74EL eplet, shared by HLA-DQ6, DQ7, DQ8 and DQ9 molecules. Serum samples were treated with EDTA, dithiothreitol (DTT), or heat prior to testing by SAB assay. EDTA-treated serum was also tested after the addition of calcium chloride (CaCl2). HLA-DQ-specific antibodies were isolated by adsorption/elution method using three informative donor cells and were tested in the absence or presence of EDTA. The antibody reactivity against HLA-DQ6, DQ7, DQ8 and DQ9 in the SAB assay was significantly inhibited by treating serum and eluates with EDTA and was restored by addition of CaCl2. The study represents the first description of a calcium-dependent epitope in HLA molecules. The relevance of this finding is that the treatment of sera with EDTA could lead to false-negative reactions in the SAB assay, which may compromise virtual crossmatching.
Assuntos
Cálcio , Ácido Edético , Epitopos , Antígenos HLA-DQ , Teste de Histocompatibilidade , Humanos , Ácido Edético/farmacologia , Ácido Edético/química , Epitopos/imunologia , Feminino , Teste de Histocompatibilidade/métodos , Antígenos HLA-DQ/imunologia , Pessoa de Meia-Idade , Isoanticorpos/imunologia , Isoanticorpos/sangue , Transplante de RimRESUMO
Objective To analyze the serological characteristics and clinical significance of IgG anti-D and anti-C combined antibodies and anti-E and anti-c combined antibodies in patients negative for RhDC and RhEc antigens. Methods The clinical data and laboratory results of 12 cases with two types of irregular antibodies were recorded and analyzed, including age, sex, history of blood transfusion/pregnancy, ABO and RhD blood group identification, Rh antigen typing, irregular antibody screening, antibody-specific identification, absorption-elution tests, antibody titer determination and cross-matching tests. Results Among the 12 patients, the mean age was 51.4±16.9 years. Nine patients had a history of blood transfusion; eight patients had a history of pregnancy; five patients had both. Serological tests showed positive antibody screening and incompatible cross-matching. The results of antibody-specific identification and absorption-elution tests showed the presence of both IgG anti-D and anti-C antibodies in three patients, with anti-D titers at 16-32, and anti-C titers at 8-16. Nine patients had both IgG anti-E and anti-c antibodies, with the titers of anti-E and anti-c antibodies at 8-16. From the patients with combined anti-D and anti-C antibodies, suspended red blood cells of ABO identical type, RhD negative and other Rh antigens as ccee were selected. From patients with combined anti-E and anti-c antibodies, suspended red blood cells of ABO identical type, RhD positive and other Rh antigens as CCee were selected. Cross-matching blood test results showed no agglutination or hemolysis in saline, polycoagulant and anti-human globulin media. Conclusion Blood transfusion and/or pregnancy are the primary causes of irregular antibodies in two Rh systems, leading to positive antibody screening and cross-match incompatibility. Routine compatibility transfusion of Rh antigens, based on ABO homotypic blood transfusion, is of great value and significance for the safety of clinical blood transfusion and the prevention of hemolytic disease of the newborn.
Assuntos
Incompatibilidade de Grupos Sanguíneos , Tipagem e Reações Cruzadas Sanguíneas , Isoanticorpos , Sistema do Grupo Sanguíneo Rh-Hr , Humanos , Sistema do Grupo Sanguíneo Rh-Hr/imunologia , Feminino , Pessoa de Meia-Idade , Masculino , Adulto , Incompatibilidade de Grupos Sanguíneos/imunologia , Isoanticorpos/sangue , Isoanticorpos/imunologia , Idoso , Gravidez , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Sistema ABO de Grupos Sanguíneos/imunologia , Transfusão de SangueRESUMO
Humoral immunity is a major waypoint towards chronic allograft dysfunction in lung transplantation (LT) recipients. Though allo-immunization and antibody-mediated rejection (AMR) are well-known entities, some diagnostic gaps need to be addressed. Morphological analysis could be enhanced by digital pathology and artificial intelligence-based companion tools. Graft transcriptomics can help to identify graft failure phenotypes or endotypes. Donor-derived cell free DNA is being evaluated for graft-loss risk stratification and tailored surveillance. Preventative therapies should be tailored according to risk. The donor pool can be enlarged for candidates with HLA sensitization, with strategies combining plasma exchange, intravenous immunoglobulin and immune cell depletion, or with emerging or innovative therapies such as imlifidase or immunoadsorption. In cases of insufficient pre-transplant desensitization, the effects of antibodies on the allograft can be prevented by targeting the complement cascade, although evidence for this strategy in LT is limited. In LT recipients with a humoral response, strategies are combined, including depletion of immune cells (plasmapheresis or immunoadsorption), inhibition of immune pathways, or modulation of the inflammatory cascade, which can be achieved with photopheresis. Altogether, these innovative techniques offer promising perspectives for LT recipients and shape the 21st century's armamentarium against AMR.
Assuntos
Rejeição de Enxerto , Transplante de Pulmão , Humanos , Transplante de Pulmão/efeitos adversos , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/diagnóstico , Imunidade Humoral , Antígenos HLA/imunologia , Isoanticorpos/imunologiaRESUMO
Antibody-mediated rejection (AMR) is a major cause of graft failure limiting long-term graft survival after kidney transplantation. Current diagnostic strategy to detect AMR is suboptimal and requires further improvement. Previously suggested treatment regimens for AMR could not demonstrate efficacy, however novel therapeutic agents are currently under investigation. Donor-derived cell-free DNA (dd-cfDNA) is a novel non-invasive biomarker for allograft injury, that has been mainly studied in the context of rejection. Its short-half-life in circulation and injury-dependent release are its key advantages that contribute to its superior diagnostic accuracy, compared to traditional biomarkers. Moreover, previous studies showed that dd-cfDNA-release is well-linked to histological and molecular features of AMR, and thus able to reflect real-time injury. Further observations suggest that dd-cfDNA can be used as a suitable screening tool for early detection of AMR in patients with donor-specific-anti-HLA-antibodies (DSA), as well as for monitoring AMR activity after anti-rejection treatment. The weight of evidence suggests that the integration of dd-cfDNA in the graft surveillance of patients with AMR, or those suspicious of AMR (e.g., due to the presence of donor-specific anti-HLA-antibodies) has an added value and might have a positive impact on outcomes in this specific cohort.
Assuntos
Biomarcadores , Ácidos Nucleicos Livres , Rejeição de Enxerto , Transplante de Rim , Doadores de Tecidos , Transplante de Rim/efeitos adversos , Humanos , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/diagnóstico , Ácidos Nucleicos Livres/sangue , Biomarcadores/sangue , Antígenos HLA/imunologia , Isoanticorpos/imunologia , Isoanticorpos/sangue , Sobrevivência de Enxerto/imunologiaRESUMO
BACKGROUND: Antibody-mediated rejection (ABMR) poses a barrier to long-term graft survival and is one of the most challenging events after kidney transplantation. Removing donor specific antibodies (DSA) through therapeutic plasma exchange (PLEX) is a cornerstone of antibody depletion but has inconsistent effects. Imlifidase is a treatment currently utilized for desensitization with near-complete inactivation of DSA both in the intra- and extravascular space. METHODS: This was a 6-month, randomized, open-label, multicenter, multinational trial conducted at 14 transplant centers. Thirty patients were randomized to either imlifidase or PLEX treatment. The primary endpoint was reduction in DSA level during the 5 days following the start of treatment. RESULTS: Despite considerable heterogeneity in the trial population, DSA reduction as defined by the primary endpoint was 97% for imlifidase compared to 42% for PLEX. Additionally, imlifidase reduced DSA to noncomplement fixing levels, whereas PLEX failed to do so. After antibody rebound in the imlifidase arm (circa days 6-12), both arms had similar reductions in DSA. Five allograft losses occurred during the 6 months following the start of ABMR treatment-four within the imlifidase arm (18 patients treated) and one in the PLEX arm (10 patients treated). In terms of clinical efficacy, the Kaplan-Meier estimated graft survival was 78% for imlifidase and 89% for PLEX, with a slightly higher eGFR in the PLEX arm at the end of the trial. The observed adverse events in the trial were as expected, and there were no apparent differences between the arms. CONCLUSION: Imlifidase was safe and well-tolerated in the ABMR population. Despite meeting the primary endpoint of maximum DSA reduction compared to PLEX, the trial was unsuccessful in demonstrating a clinical benefit of imlifidase in this heterogenous ABMR population. TRIAL REGISTRATION: EudraCT number: 2018-000022-66, 2020-004777-49; ClinicalTrials.gov identifier: NCT03897205, NCT04711850.
Assuntos
Rejeição de Enxerto , Sobrevivência de Enxerto , Isoanticorpos , Falência Renal Crônica , Transplante de Rim , Plasmaferese , Humanos , Rejeição de Enxerto/etiologia , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/prevenção & controle , Feminino , Masculino , Pessoa de Meia-Idade , Seguimentos , Isoanticorpos/sangue , Isoanticorpos/imunologia , Adulto , Prognóstico , Falência Renal Crônica/cirurgia , Falência Renal Crônica/terapia , Testes de Função Renal , Complicações Pós-Operatórias , Taxa de Filtração Glomerular , Fatores de Risco , TransplantadosRESUMO
BACKGROUND: Immunohematology skill education is an important part of the transfusion medicine professional training. We tried to solve the difficulty of obtaining suitable and sufficient positive samples in the immunohematology education. METHODS: Different identification panels and panel cells were created by RhD-positive red blood cells (RBCs) and RhD-negative RBCs, according to the underlying antibodies. Diluted anti-D reagent was used as simulated plasma for identification. RESULTS: The antibody identification of single antibody with dose-effect and two antibodies present at the same time were successfully simulated. CONCLUSIONS: It is a practical and cheap method for antibody identification training to use RhD blood group, especially when positive samples are short.
Assuntos
Tipagem e Reações Cruzadas Sanguíneas , Sistema do Grupo Sanguíneo Rh-Hr , Humanos , Sistema do Grupo Sanguíneo Rh-Hr/imunologia , Sistema do Grupo Sanguíneo Rh-Hr/sangue , Tipagem e Reações Cruzadas Sanguíneas/métodos , Eritrócitos/imunologia , Isoanticorpos/sangue , Isoanticorpos/imunologia , Hematologia/métodos , Imunoglobulina rho(D)/imunologia , Imunoglobulina rho(D)/sangue , Medicina Transfusional/métodosRESUMO
Background: Pre-transplant donor-specific anti-human leukocyte antigen antibody (HLA-DSA) is a recognized risk factor for acute antibody-mediated rejection (ABMR) and allograft failure. However, the clinical relevance of pre-transplant crossmatch (XM)-negative HLA-DSA remains unclear. Methods: We investigated the effect of XM-negative HLA-DSA on post-transplant clinical outcomes using data from the Korean Organ Transplantation Registry (KOTRY). This study included 2019 living donor kidney transplant recipients from 40 transplant centers in South Korea: 237 with HLA-DSA and 1782 without HLA-DSA. Results: ABMR developed more frequently in patients with HLA-DSA than in those without (5.5% vs. 1.5%, p<0.0001). Multivariable analysis identified HLA-DSA as a significant risk factor for ABMR (odds ratio = 3.912, 95% confidence interval = 1.831-8.360; p<0.0001). Furthermore, the presence of multiple HLA-DSAs, carrying both class I and II HLA-DSAs, or having strong HLA-DSA were associated with an increased incidence of ABMR. However, HLA-DSA did not affect long-term clinical outcomes, such as allograft function and allograft survival, patient survival, and infection-free survival. Conclusion: Pre-transplant XM-negative HLA-DSA increased the risk of ABMR but did not affect long-term allograft outcomes. HLA-incompatible kidney transplantation in the context of XM-negative HLA-DSA appears to be feasible with careful monitoring and ensuring appropriate management of any occurrence of ABMR. Furthermore, considering the characteristics of pre-transplant XM-negative HLA-DSA, the development of a more detailed and standardized desensitization protocol is warranted.
Assuntos
Rejeição de Enxerto , Antígenos HLA , Teste de Histocompatibilidade , Isoanticorpos , Transplante de Rim , Sistema de Registros , Humanos , Transplante de Rim/efeitos adversos , Rejeição de Enxerto/imunologia , Masculino , Feminino , Antígenos HLA/imunologia , República da Coreia , Pessoa de Meia-Idade , Isoanticorpos/sangue , Isoanticorpos/imunologia , Adulto , Sobrevivência de Enxerto/imunologia , Fatores de Risco , Resultado do Tratamento , Doadores de TecidosRESUMO
BACKGROUND Post-transfusion purpura (PTP) is a rare delayed adverse event characterized by severe thrombocytopenia associated with mucosal bleeding and purpura. PTP is associated with the development of alloantibodies to human platelet antigens (HPAs) and should be distinguished from other thrombocytopenic syndromes. This report is of a 69-year-old man with refractory cardiogenic shock and thrombocytopenia 4 days following blood transfusion, diagnosed with post-transfusion purpura. CASE REPORT A 69-year-old man was admitted to a tertiary medical center with refractory cardiogenic shock. Four days after he received 1 unit of packed red blood cells, his platelet count plummeted from 147 K/uL to <2 K/uL within hours, associated with delayed presentation of notable hematuria and femoral catheter oozing. An extensive thrombocytopenia work-up, including an initial platelet antibody screen, was unrevealing. The patient was treated with supportive transfusions, dexamethasone, and intravenous immunoglobulin, with rapid platelet recovery. Post-transfusion purpura panel testing later identified anti-human platelet antigen-5b antibodies, confirming the diagnosis. CONCLUSIONS This report presents an unusual course and presentation of post-transfusion purpura in an elderly man. Unusual features of this case include male sex, hyper-acuity of thrombocytopenia, lack of prior transfusions, exam findings, identification of a less common alloantibody, and negative initial platelet antigen screening. This report highlights the importance of monitoring patients for post-transfusion adverse events. Although PTP is rare, rapid diagnosis and management are required to control this potentially life-threatening condition.
Assuntos
Isoanticorpos , Humanos , Masculino , Idoso , Isoanticorpos/imunologia , Reação Transfusional/diagnóstico , Reação Transfusional/imunologia , Púrpura/etiologia , Choque Cardiogênico/etiologia , Transfusão de Eritrócitos/efeitos adversosRESUMO
Maternal allo-anti-D in RhD negative pregnant women may cause mild to severe hemolytic disease of the fetus and newborn. Although several other antibodies may also destroy red blood cells of the fetus and newborn, preventive measures with anti-D immunoglobulin are only available for D antigen. Targeted antenatal care together with postpartum prophylaxis with anti-D immunoglobulin has significantly reduced the D-alloimmunization risk. Potentially sensitizing events like trauma to the pregnant abdomen, vaginal bleeding, and amniocentesis may lead to fetomaternal hemorrhage and necessitate additional doses. Despite comprehensive programs with these targeted measures, allo-anti-D is still the most common reason for severe hemolytic disease of the fetus and newborn. Where do we fail then? Here, in this review, I would therefore like to discuss the reasons for D-alloimmunizations hoping that the greater focus will pave the way for further reduction in the number of pregnancy-related allo-anti-Ds.
Assuntos
Imunoglobulina rho(D) , Humanos , Feminino , Gravidez , Sistema do Grupo Sanguíneo Rh-Hr/imunologia , Isoanticorpos/imunologiaRESUMO
Despite the growing use of desensitization strategies, hyperimmune patients remain at high risk of antibody-mediated rejection suggesting that, even when donor-specific antibodies (DSA) are effectively depleted, anti-donor specific B cells persist. We included 10 highly sensitized recipients that underwent desensitization with plasmapheresis and B cell depletion prior to kidney transplantation. We quantified changes in DSA (luminex), total B-cell subsets (flow cytometry), anti-donor HLA B cells (fluorospot), and single-cell metabolism in serially collected samples before desensitization, at the time of transplant, and at 6 and 12 months thereafter. Desensitization was associated with a decrease in DSA and total memory B cell and naive B cell percentage, while plasma cells and memory anti-donor HLA circulating B cells persisted up to 12 months after transplant. At 12-month post-transplantation, memory B cells increased their glycolytic capacity, while proliferative KI67+ plasma cells modified their metabolism by increasing fatty acid and amino acid oxidation capacity and decreasing their glucose dependence. Despite effective DSA depletion, anti-donor B cells persist in kidney transplant recipients. Due to the reliance of these cells on glycolysis, glycolysis-targeting therapies might represent a valuable treatment strategy.
Assuntos
Glicólise , Transplante de Rim , Plasmaferese , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Células B de Memória/imunologia , Células B de Memória/metabolismo , Isoanticorpos/imunologia , Dessensibilização Imunológica/métodos , Rejeição de Enxerto/imunologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Memória Imunológica , Idoso , Antígenos HLA/imunologiaRESUMO
The presence of donor-specific antibodies (DSA) such as antibodies directed against donor class I human leucocyte antigen (e.g., HLA-A) is a major barrier to kidney transplant success. As a proof of concept, functionalized magnetic nanoparticles have been designed to eliminate DSA from saline, blood and plasma of healthy donors and sensitized patients. Specific HLA-A1 protein was covalently bound to functionalized cobalt nanoparticles (fNP), human serum albumin (HSA) as control. fNP were added to anti-HLA class I-spiked saline, spiked volunteers' whole blood, and to whole blood and plasma of sensitized patients ex vivo. Anti-HLA-A1 antibody levels were determined with Luminex technology. Antibodies' median fluorescent intensity (MFI) was defined as the primary outcome. Furthermore, the impact of fNP treatment on blood coagulation and cellular uptake was determined. Treatment with fNP reduced MFI by 97 ± 2% and by 94 ± 4% (p < 0.001 and p = 0.001) in spiked saline and whole blood, respectively. In six known sensitized anti-HLA-A1 positive patients, a reduction of 65 ± 26% (p = 0.002) in plasma and 65 ± 33% (p = 0.012) in whole blood was achieved. No impact on coagulation was observed. A minimal number of nanoparticles was detected in peripheral mononuclear blood cells. The study demonstrates-in a first step-the feasibility of anti-HLA antibody removal using fNP. These pilot data might pave the way for a new personalized DSA removal technology in the future.
Assuntos
Isoanticorpos , Nanopartículas de Magnetita , Humanos , Nanopartículas de Magnetita/química , Isoanticorpos/imunologia , Isoanticorpos/sangue , Transplante de Rim , Doadores de Tecidos , Feminino , Estudo de Prova de Conceito , Masculino , Anticorpos/imunologiaRESUMO
Introduction: The aim of this study is to investigate the clinical validity of donor-derived cell-free DNA (dd-cfDNA) in comparison with that of donor specific anti-HLA antibody (DSA) for predicting biopsy-proven rejection (BPR)and severe microvascular inflammation (severe MVI) in kidney transplant recipients (KTRs). Methods: In this prospective observational investigation, 64 KTRs who underwent the indicated biopsies were included. Blood samples collected prior to biopsy were tested for dd-cfDNA and DSA. Biopsy specimens were classified by a renal pathologist according to the Banff classification. The predictive performance of dd-cfDNA and DSA for histological allograft diagnosis was assessed. Results: KTRs were categorized into the high and low dd-cfDNA groups based on a level of 0.4%. Eighteen patients (28.1%) had positive DSA at biopsy, exhibiting higher dd-cfDNA levels than the DSA-negative patients. BPR and severe MVI incidences were elevated in the high dd-cfDNA group (BPR: 42.9% vs. 3.4%, P <0.001; severe MVI: 37.1% vs. 3.4%, P = 0.001). Also, elevated glomerulitis and MVI scores were observed in the high dd-cfDNA group. DSA showed the highest predictive value for BPR (AUC = 0.880), whereas dd-cfDNA alone excelled in predicting severe MVI (AUC = 0.855). Combination of DSA and dd-cfDNA (>0.4%) yielded sensitivities of 80.0% and 50.0% with specificities of 90.7% and 88.0% for antibody-mediated rejection and severe MVI detection, respectively. Conclusion: The dd-cfDNA test is a predictive tool for BPR and severe MVI, and it can improve the performance, especially when combined with DSA for BPR.
Assuntos
Ácidos Nucleicos Livres , Rejeição de Enxerto , Transplante de Rim , Doadores de Tecidos , Humanos , Transplante de Rim/efeitos adversos , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/diagnóstico , Rejeição de Enxerto/sangue , Ácidos Nucleicos Livres/sangue , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Estudos Prospectivos , Isoanticorpos/sangue , Isoanticorpos/imunologia , Biópsia , Biomarcadores/sangue , Antígenos HLA/imunologia , Antígenos HLA/genética , Microvasos/patologia , Microvasos/imunologia , Inflamação/imunologia , Aloenxertos/imunologiaRESUMO
Xenotransplantation is a potential option for individuals for whom an acceptable human allograft is unavailable. Individuals with broadly reactive HLA antibodies due to prior exposure to foreign HLA are potential candidates for a clinical xenotransplant trial. It remains controversial if allosensitisation results in the development of cross-reactive antibodies against SLA. This may require increased histocompatibility scrutiny for highly sensitised individuals prior to enrollment in a clinical trial. Serum samples were obtained from non-human primates sensitised via serial skin transplantation from maximally MHC-mismatched donor, as reported. Sera from pre- and post-allosensitisation timepoints were assessed in a flow crossmatch (FXM) for IgM and IgG binding to pig splenocytes with or without red blood cell adsorption. Xenoreactive antibodies were eluted from pig splenocytes and screened on a single antigen HLA bead assay. A MHC Matchmaker algorithm was developed to predict potential conserved amino acid motifs among the pig, NHP, and human. Our sensitised NHP model was used to demonstrate that allosensitisation does not result in an appreciable difference in xenoreactive antibody binding in a cell-based FXM. However, antibody elution and screening on single antigen HLA beads suggest the existence of potential cross-reactive antibodies against SLA. The cross-reactive IgG after allosensitisation were predicted by comparing the recipient Mamu alleles against its previous allograft donor Mamu alleles and the donor pig SLA alleles. Our study suggests that allosensitisation could elevate cross-reactive antibodies, but a more sensitive assay than a cell-based FXM is required to detect them. The MHC Matchmaker algorithm was developed as a potential tool to help determine amino acid motif conservation and reactivity pattern.
Assuntos
Reações Cruzadas , Citometria de Fluxo , Antígenos de Histocompatibilidade Classe I , Teste de Histocompatibilidade , Animais , Humanos , Reações Cruzadas/imunologia , Teste de Histocompatibilidade/métodos , Citometria de Fluxo/métodos , Suínos , Antígenos de Histocompatibilidade Classe I/imunologia , Imunoglobulina G/imunologia , Imunoglobulina G/sangue , Isoanticorpos/imunologia , Isoanticorpos/sangue , Transplante Heterólogo , Antígenos de Histocompatibilidade Classe II/imunologia , Transplante de Pele , Imunoglobulina M/imunologia , Imunoglobulina M/sangue , Antígenos HLA/imunologia , Linfócitos/imunologia , AlgoritmosRESUMO
Transcript analyses highlight an important contribution of natural killer (NK) cells to microvascular inflammation (MVI) in antibody-mediated rejection (ABMR), but only few immunohistologic studies have quantified their spatial distribution within graft tissue. This study included 86 kidney transplant recipients who underwent allograft biopsies for a positive donor-specific antibody (DSA) result. NK cells were visualized and quantified within glomeruli and peritubular capillaries (PTC), using immunohistochemistry for CD34 alongside CD16/T-bet double-staining. Staining results were analyzed in relation to histomorphology, microarray analysis utilizing the Molecular Microscope Diagnostic System, functional NK cell genetics, and clinical outcomes. The number of NK cells in glomeruli per mm2 glomerular area (NKglom) and PTC per mm2 cortical area (NKPTC) was substantially higher in biopsies with ABMR compared to those without rejection, and correlated with MVI scores (NKglom Spearman's correlation coefficient [SCC] = 0.55, p < 0.001, NKPTC 0.69, p < 0.001). In parallel, NK cell counts correlated with molecular classifiers reflecting ABMR activity (ABMRprob: NKglom 0.59, NKPTC 0.75) and showed a trend towards higher levels in association with high functional FCGR3A and KLRC2 gene variants. Only NKPTC showed a marginally significant association with allograft function and survival. Our immunohistochemical results support the abundance of NK cells in DSA-positive ABMR.
Assuntos
Rejeição de Enxerto , Transplante de Rim , Células Matadoras Naturais , Humanos , Células Matadoras Naturais/imunologia , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/patologia , Feminino , Masculino , Pessoa de Meia-Idade , Adulto , Glomérulos Renais/patologia , Glomérulos Renais/imunologia , Biópsia , Idoso , Imuno-Histoquímica , Isoanticorpos/imunologia , Receptores de IgGRESUMO
BACKGROUND: The lack of evidence regarding optimal desensitization strategies for lung transplant candidates with preformed donor specific anti-human leukocyte antigen antibodies (DSAs) has led to varying approaches among centers towards this patient group. Our institution's desensitization protocol for recipients with preformed DSAs and negative flow cytometry crossmatch (FCXM) consists of intravenous immunoglobulin (IVIG) as the sole therapy. The study aimed to determine outcomes using this approach. METHODS: This retrospective study included adults who underwent lung-only transplantation for the first time between January 2015 and March 2022 at a single center. We excluded patients with positive or missing FCXM results. Transplant recipients with any DSA ≥ 1000 MFI on latest testing within three months of transplant were considered DSA-positive, while recipients with DSAs <1000 MFI and those without DSAs were assigned to the low-level/negative group. Graft survival (time to death/retransplantation) and chronic lung allograft dysfunction (CLAD)-free times were compared between groups using Cox proportional hazards models. RESULTS: Thirty-six out of 167 eligible patients (22%) were DSA-positive. At least 50% of preformed DSAs had documented clearance (decrease to <1000 MFI) within the first 6 months of transplant. Multivariable Cox regression analyses did not detect a significantly increased risk of graft failure (aHR 1.04 95%CI 0.55-1.97) or chronic lung allograft dysfunction (aHR 0.71 95%CI 0.34-1.52) in DSA-positive patients compared to patients with low-level/negative DSAs. Incidences of antibody-mediated rejection (p = 1.00) and serious thromboembolic events (p = 0.63) did not differ between study groups. CONCLUSION: We describe a single-center experience of administering IVIG alone to lung transplant recipients with preformed DSAs and negative FCXM. Further studies are required to confirm the efficacy of this strategy against other protocols.
Assuntos
Dessensibilização Imunológica , Citometria de Fluxo , Rejeição de Enxerto , Sobrevivência de Enxerto , Antígenos HLA , Imunoglobulinas Intravenosas , Isoanticorpos , Transplante de Pulmão , Doadores de Tecidos , Humanos , Feminino , Masculino , Estudos Retrospectivos , Pessoa de Meia-Idade , Imunoglobulinas Intravenosas/uso terapêutico , Imunoglobulinas Intravenosas/administração & dosagem , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/etiologia , Isoanticorpos/imunologia , Isoanticorpos/sangue , Sobrevivência de Enxerto/imunologia , Antígenos HLA/imunologia , Seguimentos , Prognóstico , Dessensibilização Imunológica/métodos , Teste de Histocompatibilidade , Adulto , Transplantados , Fatores de Risco , Fatores Imunológicos/uso terapêuticoRESUMO
Antibody incompatible transplantation (AIT) may be an only option for highly sensitized patients. Severe form of early antibody mediated rejection (AMR) adversely affects graft survival after AIT. The aim of this study was to identify individuals at risk of AMR. We analyzed 213 living donor AITs performed at our center. Among 120 ABOi, 58 HLAi and 35 DSA + FCXM-negative cases, the rates of early AMR were 6%, 31%, and 9%, respectively (p < 0.001). On multivariate analysis for graft loss, early AMR had a HR of 3.28 (p < 0.001). The HLAi group had worse death-censored graft survival (p = 0.003). In the HLAi group, Patients with aggressive variant AMR (AAMR) had greater percentage of C3d complement fixing DSA, higher baseline class I and total DSA MFI levels and B-cell FCXM RMF. C1q and C3d complement fixing DSA and strong positivity of baseline B- or T-cell FXCM as predictors of AAMR had 100% sensitivity. Early AMR is of significant clinical concern in AIT as it results in poor graft survival and is not well described in literature. An aggressive variant is characterized by massive rise in DSA levels at rejection. Baseline DSA, C1q, and C3d and baseline FCXM values can be used to risk-stratify candidates for AIT.
Assuntos
Rejeição de Enxerto , Sobrevivência de Enxerto , Isoanticorpos , Transplante de Rim , Doadores Vivos , Humanos , Rejeição de Enxerto/imunologia , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Sobrevivência de Enxerto/imunologia , Isoanticorpos/imunologia , Isoanticorpos/sangue , Complemento C1q/imunologia , Estudos Retrospectivos , Complemento C3d/imunologia , Idoso , Sistema ABO de Grupos Sanguíneos/imunologia , Incompatibilidade de Grupos Sanguíneos/imunologia , Antígenos HLA/imunologia , Análise MultivariadaRESUMO
BACKGROUND: We aimed to analyze the roles of M1 and M2 macrophage infiltration in post-renal transplant antibody-mediated rejection (AMR). METHODS: A total of 102 recipients who underwent renal allotransplant from January 2020 to February 2023 were divided into an immune tolerance group (n = 56) and a rejection group (n = 46). The transplant renal biopsy specimens were harvested by ultrasound-guided puncture. The M1 and M2 macrophages in renal tissues were counted, and the M1/M2 ratio was calculated. The numbers of M1 and M2 macrophages and M1/M2 ratios in patients with different severities of interstitial fibrosis/tubular atrophy (IF/TA) and different degrees of tubulointerstitial inflammatory cell infiltration were compared. The predictive values of M1 and M2 macrophages and M1/M2 ratio for post-renal transplant AMR were clarified. RESULTS: The rejection group had significantly more M1 and M2 macrophages and higher M1/M2 ratio than those of the immune tolerance group (P < 0.05). In the rejection group, infiltrating macrophages were mainly distributed in the glomerular and interstitial capillaries, with M1 macrophages being the predominant type. With increasing severity of IF/TA, the numbers of M1 and M2 macrophages and M1/M2 ratio rose in patients with post-renal transplant AMR (P < 0.05). The numbers and ratio had significant positive correlations with the levels of blood urea nitrogen and serum creatinine (P < 0.05). The areas under the curves (AUCs) of numbers and M1 and M2 macrophages and M1/M2 ratio for predicting post-renal transplant AMR were 0.856, 0.839 and 0.887, respectively. The combined detection had AUC of 0.911 (95% CI: 0.802-0.986), sensitivity of 90.43% and specificity of 83.42%. CONCLUSIONS: Significant macrophage infiltration is present in the case of post-renal transplant AMR, and closely related to the severity of IF/TA and the degree of tubulointerstitial inflammatory cell infiltration.
Assuntos
Rejeição de Enxerto , Transplante de Rim , Macrófagos , Humanos , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/patologia , Macrófagos/imunologia , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Isoanticorpos/imunologia , Rim/patologia , Rim/imunologiaAssuntos
Sobrevivência de Enxerto , Transplante de Rim , Humanos , Transplante de Rim/efeitos adversos , Biópsia , Feminino , Masculino , Pessoa de Meia-Idade , Isoanticorpos/sangue , Isoanticorpos/imunologia , Fatores de Tempo , Adulto , Rejeição de Enxerto/patologia , Rejeição de Enxerto/imunologia , Rim/patologia , Resultado do Tratamento , Estudos Retrospectivos , Fatores de RiscoRESUMO
Objective: In a cooperative study of the University Hospital Leipzig, University of Leipzig, and the Charité Berlin on kidney transplant patients, we analysed the occurrence of HLA-specific antibodies with respect to the HLA setup of the patients. We aimed at the definition of specific HLA antigens towards which the patients produced these antibodies. Methods: Patients were typed for the relevant HLA determinants using mainly the next-generation technology. Antibody screening was performed by the state-of-the-art multiplex-based technology using microspheres coupled with the respective HLA alleles of HLA class I and II determinants. Results: Patients homozygous for HLA-A*02, HLA-A*03, HLA-A*24, HLA-B*07, HLA-B*18, HLA-B*35, HLA-B*44, HLA-C*03, HLA-C*04, and HLA-C*07 in the class I group and HLA-DRB1*01, HLA-DRB1*03, HLA-DRB1*07, HLA-DRB1*15, HLA-DQA1*01, HLA-DQA1*05, HLA-DQB1*02, HLA-DQB1*03(7), HLA-DQB1*06, HLA-DPA1*01, and HLA-DPB1*04 in the class II group were found to have a significant higher antibody production compared to the heterozygous ones. In general, all HLA determinants are affected. Remarkably, HLA-A*24 homozygous patients can produce antibodies towards all HLA-A determinants, while HLA-B*18 homozygous ones make antibodies towards all HLA-B and selected HLA-A and C antigens, and are associated with an elevation of HLA-DRB1, parts of DQB1 and DPB1 alleles. Homozygosity for the HLA class II HLA-DRB1*01, and HLA-DRB1*15 seems to increase the risk for antibody responses against most of the HLA class I antigens (HLA-A, HLA-B, and HLA-C) in contrast to HLA-DQB1*03(7) where a lower risk towards few HLA-A and HLA-B alleles is found. The widely observed differential antibody response is therefore to be accounted to the patient's HLA type. Conclusion: Homozygous patients are at risk of producing HLA-specific antibodies hampering the outcome of transplantation. Including this information on the allocation procedure might reduce antibody-mediated immune reactivity and prevent graft loss in a patient at risk, increasing the life span of the transplanted organ.