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The HLA-B*51:197 allele is generated from the interlocus recombination of both HLA-B*51:01:01:01 and HLA-C*01:02:01:01 alleles.
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Alelos , Antígenos HLA-C , Recombinación Genética , Humanos , Antígenos HLA-C/genética , Prueba de Histocompatibilidad , Secuencia de Bases , Exones , Análisis de Secuencia de ADN/métodos , Antígeno HLA-B51/genética , Antígenos HLA-B/genética , Alineación de SecuenciaRESUMEN
Allogeneic stem cell transplantation (alloSCT) offers curative potential for older patients with myeloid malignancies. We evaluated the efficacy and safety of alloSCT using post-transplantation cyclophosphamide (PTCy) in combination with a very short duration of immune suppression (IS) in this population. We retrospectively analyzed 92 consecutive patients aged 65 years and older who underwent an alloSCT for myeloid malignancies between February 2018 and December 2022 at our institution. Data on patient characteristics, treatment modalities, and outcomes were collected. Ninety-two patients received an alloSCT with PTCy-based graft versus host disease (GVHD) prophylaxis. The majority had minimal comorbidities and were diagnosed with acute myeloid leukemia. Patients mostly received conditioning regimens with low to intermediate transplant conditioning intensity scores. In 43% of patients, IS could be permanently stopped at day +90, resulting in a median time of IS of 2.93 months in high-risk patients. At a median follow-up of 21.3 months, the 1- and 2-year overall survival rates were 89% and 87%, respectively. Relapse-free survival rates were 88% and 84% at 1 and 2 years, respectively. The 1- and 2-year cumulative incidences of relapse were 8% and 13%, while treatment-related mortality (TRM) estimates were 9% at both time points. Acute GVHD grade 3 to 4 occurred in 7% within the first 180 days and severe chronic GVHD in 6% of patients. This all resulted in a 1- and 2-year graft versus host and relapse-free survival of 74% and 70%, respectively. AlloSCT using PTCy in combination with a short duration of IS in older patients with myeloid malignancies demonstrates favorable survival outcomes due to low relapse rates and a low TRM. The low incidence of relapse and acceptable rates of graft-versus-host disease suggest the efficacy and safety of this approach. Further studies are warranted to validate these findings and optimize transplant strategies for older patients with myeloid malignancies.
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Ciclofosfamida , Enfermedad Injerto contra Huésped , Trasplante de Células Madre Hematopoyéticas , Trasplante Homólogo , Humanos , Ciclofosfamida/uso terapéutico , Anciano , Masculino , Femenino , Enfermedad Injerto contra Huésped/prevención & control , Estudios Retrospectivos , Trasplante de Células Madre Hematopoyéticas/métodos , Trasplante de Células Madre Hematopoyéticas/efectos adversos , Resultado del Tratamiento , Leucemia Mieloide Aguda/terapia , Leucemia Mieloide Aguda/mortalidad , Leucemia Mieloide Aguda/tratamiento farmacológico , Acondicionamiento Pretrasplante/métodos , Inmunosupresores/uso terapéuticoRESUMEN
Background: Repeated exposure to sensitizing events can activate HLA-specific memory B cells, leading to the production of donor-specific memory B cell antibodies (DSAm) that pose a risk for antibody-mediated rejection (ABMR) in kidney transplant recipients (KTRs). This single-center retrospective study aimed to identify DSAm and assess their association with outcomes in a cohort of KTRs with pretransplant serum donor-specific antibodies (DSA). Methods: We polyclonally activated pretransplant peripheral blood mononuclear cells (PBMCs) from 60 KTRs in vitro, isolated and quantified IgG from the culture supernatant using ELISA, and analyzed the HLA antibodies of eluates with single antigen bead (SAB) assays, comparing them to the donor HLA typing for potential DSAm. Biopsies from 41 KTRs were evaluated for rejection based on BANFF 2019 criteria. Results: At transplantation, a total of 37 DSAm were detected in 26 of 60 patients (43%), of which 13 (35%) were found to be undetectable in serum. No significant association was found between pretransplant DSAm and ABMR (P=0.53). Similar results were observed in a Kaplan-Meier analysis for ABMR within the first year posttransplant (P=0.29). Additionally, MFI levels of DSAm showed no significant association with ABMR (P=0.28). Conclusion: This study suggests no significant association between DSAm and biopsy-proven clinical ABMR. Further prospective research is needed to determine whether assessing DSAm could enhance existing immunological risk assessment methods for monitoring KTRs, particularly in non-sensitized KTRs.
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Rechazo de Injerto , Antígenos HLA , Isoanticuerpos , Trasplante de Riñón , Humanos , Trasplante de Riñón/efectos adversos , Estudios Retrospectivos , Masculino , Femenino , Persona de Mediana Edad , Rechazo de Injerto/inmunología , Isoanticuerpos/inmunología , Isoanticuerpos/sangre , Adulto , Antígenos HLA/inmunología , Células B de Memoria/inmunología , Donantes de Tejidos , Anciano , Receptores de Trasplantes , Supervivencia de Injerto/inmunologíaRESUMEN
In the past, identification of HLA alleles was limited to sequencing the region of the gene coding for the peptide binding groove, resulting in a lack of sequence information in the HLA database, challenging HLA allele assignment software programs. We investigated full-length sequences of 19 HLA class I and 7 HLA class II alleles, and we extended another 47 HLA class I alleles with sequences of 5' and 3' UTR regions that were all not yet available in the IPD-IMGT/HLA database. We resolved 8638 unknown nucleotides in the coding sequence of HLA class I and 2139 of HLA class II. Furthermore, with full-length sequencing of the 26 alleles, more than 90 kb of sequence information was added to the non-coding sequences, whereas extension of the 47 alleles resulted in the addition of 5.5 kb unknown nucleotides to the 5' UTR and > 31.7 kb to the 3' UTR region. With this information, some interesting features were observed, like possible recombination events and lineage evolutionary origins. The continuing increase in the availability of full-length sequences in the HLA database will enable the identification of the evolutionary origin and will help the community to improve the alignment and assignment accuracy of HLA alleles.
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Evolución Biológica , Nucleótidos , Alelos , Regiones no Traducidas 3'/genética , Membrana Celular , Nucleótidos/genéticaRESUMEN
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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Enfermedades Renales , Trasplante de Riñón , Humanos , Supervivencia de Injerto , Alelos , Anticuerpos , Riñón , Epítopos , Rechazo de Injerto , Antígenos HLA , Donantes de TejidosRESUMEN
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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Trasplante de Riñón , Humanos , Trasplante de Riñón/efectos adversos , Epítopos , Antígenos HLA/genética , Relevancia Clínica , Isoanticuerpos , Alelos , Donantes de Tejidos , Rechazo de InjertoRESUMEN
Inadequate mobilization of peripheral blood progenitor cells (PBPCs) is a limiting factor to proceeding with autologous hematopoietic cell transplantation (auto-HCT). To assess the impact of clonal hematopoiesis (CH) on mobilization failure of PBPC for auto-HCT, we investigated the characteristics of poor mobilizers (with a total PBPC collection <2 × 106 CD34+ cells per kg) in a consecutive single-center cohort of 776 patients. Targeted error-corrected next-generation sequencing of 28 genes was performed in a nested case-control cohort of 90 poor mobilizers and 89 matched controls. CH was detected in 48 out of 179 patients (27%), with most patients carrying a single mutation. The presence of CH (detected at variant allele frequency [VAF] ≥ 1%) did not associate with poor mobilization potential (31% vs 22% in controls, odds ratio, 1.55; 95% confidence interval, 0.76-3.23; P = .238). PPM1D mutations were detected more often in poor mobilizers (P = .005). In addition, TP53 mutations in this cohort were detected exclusively in patients with poor mobilization potential (P = .06). The incidence of therapy-related myeloid neoplasms (t-MN) was higher among patients with mobilization failure (P = .014). Although poor mobilizers experienced worse overall survival (P = .019), this was not affected by the presence of CH. We conclude that CH at low VAF (1%-10%) is common at the time of stem cell mobilization. TP53 mutations and PPM1D mutations are associated with poor mobilization potential and their role in subsequent development of t-MN in these individuals should be established.
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Movilización de Célula Madre Hematopoyética , Trasplante de Células Madre Hematopoyéticas , Humanos , Estudios de Casos y Controles , Hematopoyesis Clonal , Antígenos CD34 , Trasplante de Células Madre Hematopoyéticas/efectos adversosRESUMEN
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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Epítopos de Linfocito T/inmunología , Rechazo de Injerto/inmunología , Supervivencia de Injerto/inmunología , Antígenos HLA/inmunología , Trasplante de Riñón , Linfocitos T/inmunología , Adulto , Anciano , Epítopos de Linfocito T/genética , Femenino , Rechazo de Injerto/genética , Enfermedad Injerto contra Huésped/diagnóstico , Enfermedad Injerto contra Huésped/etiología , Enfermedad Injerto contra Huésped/mortalidad , Antígenos HLA/genética , Humanos , Trasplante de Riñón/efectos adversos , Trasplante de Riñón/métodos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Linfocitos T/metabolismo , Donantes de Tejidos , Receptores de Trasplantes , Trasplante Homólogo , Insuficiencia del Tratamiento , Adulto JovenRESUMEN
BACKGROUND: PNP is a malignancy-associated autoimmune mucocutaneous syndrome due to autoantibodies against plakins, desmogleins, and other components of the epidermis and basement membrane of epithelial tissues. PNP-causing malignancies comprise mainly lymphoproliferative and hematologic neoplasms. PNP is extremely rare, especially in children. METHODS: Here, we present the first case of a child who developed PNP on a PTLD after small bowel transplantation because of a severe genetic protein-losing enteropathy. RESULTS: The patient in this case report had a severe stomatitis, striate palmoplantar keratoderma, and lichenoid skin lesions. In addition, she had marked esophageal involvement. She had lung pathology due to recurrent pulmonary infections and ventilator injury. Although we found no evidence of BO, she died from severe pneumonia and respiratory failure at the age of 12 years. CONCLUSION: It is exceptional that, despite effective treatment of the PTLD, the girl survived 5 years after her diagnosis of PNP. We hypothesize that the girl survived relatively long after the PNP diagnosis due to strong T-cell suppressive treatments for her small bowel transplantation.
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Intestino Delgado/trasplante , Trastornos Linfoproliferativos/complicaciones , Síndromes Paraneoplásicos/diagnóstico , Pénfigo/diagnóstico , Enteropatías Perdedoras de Proteínas/cirugía , Niño , Resultado Fatal , Femenino , Humanos , Inmunosupresores/uso terapéutico , Gemelos MonocigóticosRESUMEN
Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disease in which gastrointestinal bleeding is a rare presenting symptom in children. Gastrointestinal bleeding in children is treated locally by endoscopy. When a focus of bleeding cannot be reached by endoscopy, management of these patients can be challenging. Previous reports showed a favorable outcome of treatment with tacrolimus in an adult HHT patient with liver vascular malformations and epistaxis and in a HHT patient with pulmonary hypertension. We report the first pediatric HHT patient who benefited from tacrolimus treatment. Our case demonstrated a remarkable decline in blood transfusions and better quality of life during the period of tacrolimus treatment.
RESUMEN
Moderate to severe chronic graft-versus-host disease (cGVHD) is associated with high morbidity, hospital dependency and poor quality of life. In this study, we analyzed a well-defined consecutive series of 98 patients with acute myelogenous leukemia/myelodysplastic syndrome (AML/MDS) who received allogeneic stem cell transplantation with non-myeloablative (NMA) conditioning to determine risk factors associated with the severity of cGVHD. cGVHD was defined according to the 2005 National Institute of Health consensus criteria. Transfusions before transplantation, presence of HLA antibodies, composition of the graft (CD3+, CD19+, CD34+ cells), sibling or matched unrelated donor, female donor to male recipient, CMV serology and the development of acute GVHD (aGVHD), were considered potential risk factors. Multivariate Cox regression analysis identified the number of CD19+ 106/kg (HR 2.79; 95% CI 1.35-5.74), CD3+ 106/kg (HR 2.18; 95% CI 1.04-4.59) infused cells and the presence of patient HLA antibodies before transplantation (HR 2.34; CI 1.11-4.95) as significant risk factors for the development of moderate to severe cGVHD. In summary, we identified in a small, but well-defined cohort, 3 risk factors associated with the severity of cGVHD that should be validated in a larger multi-center study.
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Enfermedad Injerto contra Huésped , Leucemia Mieloide Aguda/terapia , Síndromes Mielodisplásicos/terapia , Trasplante de Células Madre , Aloinjertos , Femenino , Humanos , Masculino , Riesgo , Índice de Severidad de la EnfermedadRESUMEN
Whereas regular allocation avoids unacceptable mismatches on the donor organ, allocation to highly sensitized patients within the Eurotransplant Acceptable Mismatch (AM) program is based on the patient's HLA phenotype plus acceptable antigens. These are HLA antigens to which the patient never made antibodies, as determined by extensive laboratory testing. AM patients have superior long-term graft survival compared with highly sensitized patients in regular allocation. Here, we questioned whether the AM program also results in lower rejection rates. From the PROCARE cohort, consisting of all Dutch kidney transplants in 1995-2005, we selected deceased donor single transplants with a minimum of 1 HLA mismatch and determined the cumulative 6-month rejection incidence for patients in AM or regular allocation. Additionally, we determined the effect of minimal matching criteria of 1 HLA-B plus 1 HLA-DR, or 2 HLA-DR antigens on rejection incidence. AM patients showed significantly lower rejection rates than highly immunized patients in regular allocation, comparable to nonsensitized patients, independent of other risk factors for rejection. In contrast to highly sensitized patients in regular allocation, minimal matching criteria did not affect rejection rates in AM patients. Allocation based on acceptable antigens leads to relatively low-risk transplants for highly sensitized patients with rejection rates similar to those of nonimmunized individuals.
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Rechazo de Injerto/diagnóstico , Antígenos HLA/inmunología , Histocompatibilidad/inmunología , Inmunización/métodos , Fallo Renal Crónico/inmunología , Trasplante de Riñón/efectos adversos , Selección de Paciente , Donantes de Tejidos/provisión & distribución , Femenino , Estudios de Seguimiento , Rechazo de Injerto/etiología , Rechazo de Injerto/patología , Supervivencia de Injerto/inmunología , Antígenos HLA/química , Prueba de Histocompatibilidad , Humanos , Isoanticuerpos/efectos adversos , Fallo Renal Crónico/cirugía , Trasplante de Riñón/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Pronóstico , Factores de Riesgo , Obtención de Tejidos y Órganos/métodos , Inmunología del TrasplanteRESUMEN
The clinical significance of non-HLA antibodies on renal allograft survival is a matter of debate, due to differences in reported results and lack of large-scale studies incorporating analysis of multiple non-HLA antibodies simultaneously. We developed a multiplex non-HLA antibody assay against 14 proteins highly expressed in the kidney. In this study, the presence of pretransplant non-HLA antibodies was correlated to renal allograft survival in a nationwide cohort of 4770 recipients transplanted between 1995 and 2006. Autoantibodies against Rho GDP-dissociation inhibitor 2 (ARHGDIB) were significantly associated with graft loss in recipients transplanted with a deceased-donor kidney (N = 3276) but not in recipients of a living-donor kidney (N = 1496). At 10 years after deceased-donor transplantation, recipients with anti-ARHGDIB antibodies (94/3276 = 2.9%) had a 13% lower death-censored covariate-adjusted graft survival compared to the anti-ARHGDIB-negative (3182/3276 = 97.1%) population (hazard ratio 1.82; 95% confidence interval, 1.32-2.53; P = .0003). These antibodies occur independently from donor-specific anti-HLA antibodies (DSA) or other non-HLA antibodies investigated. No significant relations with graft loss were found for the other 13 non-HLA antibodies. We suggest that pretransplant risk assessment can be improved by measuring anti-ARHGDIB antibodies in all patients awaiting deceased-donor transplantation.
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Autoanticuerpos/inmunología , Rechazo de Injerto/mortalidad , Supervivencia de Injerto/inmunología , Antígenos HLA/inmunología , Trasplante de Riñón/efectos adversos , Complicaciones Posoperatorias/mortalidad , Inhibidor beta de Disociación del Nucleótido Guanina rho/inmunología , Adulto , Femenino , Estudios de Seguimiento , Rechazo de Injerto/diagnóstico , Rechazo de Injerto/etiología , Humanos , Isoanticuerpos/inmunología , Fallo Renal Crónico/inmunología , Fallo Renal Crónico/mortalidad , Fallo Renal Crónico/cirugía , Donadores Vivos/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/etiología , Pronóstico , Estudios Retrospectivos , Factores de RiesgoRESUMEN
BACKGROUND: Few studies have evaluated the effect of different immunosuppressive strategies on long-term kidney transplant outcomes. Moreover, as they were usually based on historical data, it was not possible to account for the presence of pretransplant donor-specific human-leukocyte antigen antibodies (DSA), a currently recognized risk marker for impaired graft survival. The aim of this study was to evaluate to what extent frequently used initial immunosuppressive therapies increase graft survival in immunological low-risk patients. METHODS: We performed an analysis on the PROCARE cohort, a Dutch multicentre study including all transplantations performed in the Netherlands between 1995 and 2005 with available pretransplant serum (n = 4724). All sera were assessed for the presence of DSA by a luminex single-antigen bead assay. Patients with a previous kidney transplantation, pretransplant DSA or receiving induction therapy were excluded from the analysis. RESULTS: Three regimes were used in over 200 patients: cyclosporine (CsA)/prednisolone (Pred) (n = 542), CsA/mycophenolate mofetil (MMF)/Pred (n = 857) and tacrolimus (TAC)/MMF/Pred (n = 811). Covariate-adjusted analysis revealed no significant differences in 10-year death-censored graft survival between patients on TAC/MMF/Pred therapy (79%) compared with patients on CsA/MMF/Pred (82%, P = 0.88) or CsA/Pred (79%, P = 0.21). However, 1-year rejection-free survival censored for death and failure unrelated to rejection was significantly higher for TAC/MMF/Pred (81%) when compared with CsA/MMF/Pred (67%, P < 0.0001) and CsA/Pred (64%, P < 0.0001). CONCLUSION: These results suggest that in immunological low-risk patients excellent long-term kidney graft survival can be achieved irrespective of the type of initial immunosuppressive therapy (CsA or TAC; with or without MMF), despite differences in 1-year rejection-free survival.
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Ciclosporina/uso terapéutico , Rechazo de Injerto , Terapia de Inmunosupresión/métodos , Trasplante de Riñón , Ácido Micofenólico/uso terapéutico , Tacrolimus/uso terapéutico , Adulto , Estudios de Cohortes , Supervivencia sin Enfermedad , Femenino , Supervivencia de Injerto/inmunología , Antígenos HLA/inmunología , Humanos , Terapia de Inmunosupresión/efectos adversos , Inmunosupresores/uso terapéutico , Riñón/inmunología , Masculino , Persona de Mediana Edad , Países Bajos/epidemiología , PrednisolonaRESUMEN
BACKGROUND: Pre-transplant donor-specific anti-human leucocyte antigen (HLA) antibodies (DSAs) are associated with impaired kidney graft survival while the clinical relevance of non-donor-specific anti-HLA antibodies (nDSAs) is more controversial. The aim of the present paired kidney graft study was to compare the clinical relevance of DSAs and nDSAs. METHODS: To eliminate donor and era-dependent factors, a post hoc paired kidney graft analysis was performed as part of a Dutch multicentre study evaluating all transplantations between 1995 and 2005 with available pre-transplant serum samples. Anti-HLA antibodies were detected with a Luminex single-antigen bead assay. RESULTS: Among 3237 deceased donor transplantations, we identified 115 recipient pairs receiving a kidney from the same donor with one recipient being DSA positive and the other without anti-HLA antibodies. Patients with pre-transplant DSAs had a significantly lower 10-year death-censored graft survival (55% versus 82%, P=0.0001). We identified 192 pairs with one recipient as nDSA positive (against Class I and/or II) and the other without anti-HLA antibodies. For the patients with nDSAs against either Class I or II, graft survival did not significantly differ compared with patients without anti-HLA antibodies (74% versus 77%, P = 0.79). Only in patients with both nDSAs Class I and II was there a trend towards a lower graft survival (58%, P = 0.06). Lastly, in a small group of 42 recipient pairs, 10-year graft survival in recipients with DSAs was 49% compared with 68% in recipients with nDSAs (P=0.11). CONCLUSION: This paired kidney analysis confirms that the presence of pre-transplant DSAs in deceased donor transplantations is a risk marker for graft loss, whereas nDSAs in general are not associated with a lower graft survival. Subgroup analysis indicated that only in broadly sensitized patients with nDSAs against Class I and II, nDSAs may be a risk marker for graft loss in the long term.
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Rechazo de Injerto/inmunología , Supervivencia de Injerto/inmunología , Antígenos HLA/inmunología , Isoanticuerpos/sangre , Adulto , Femenino , Antígenos de Histocompatibilidad Clase I , Humanos , Trasplante de Riñón/mortalidad , Masculino , Persona de Mediana Edad , Países Bajos , Riesgo , Donantes de Tejidos , Adulto JovenRESUMEN
BACKGROUND: There is no consensus in the literature on the interpretation of single-antigen bead positive for a specific HLA antibody. METHODS: To inform the debate, we studied the relationship between various single-antigen bead positivity algorithms and the impact of resulting donor-specific HLA antibody (DSA) positivity on long-term kidney graft survival in 3237 deceased-donor transplants. RESULTS: First, we showed that the interassay variability can be greatly reduced when working with signal-to-background ratios instead of absolute median fluorescence intensities (MFIs). Next, we determined pretransplant DSA using various MFI cutoffs, signal-to-background ratios, and combinations thereof. The impact of the various cutoffs was studied by comparing the graft survival between the DSA-positive and DSA-negative groups. We did not observe a strong impact of various cutoff levels on 10-year graft survival. A stronger relationship between the cutoff level and 1-year graft survival for DSA-positive transplants was found when using signal-to-background ratios, most pronounced for the bead of the same HLA locus with lowest MFI taken as background. CONCLUSIONS: With respect to pretransplant risk stratification, we propose a signal-to-background ratio-6 (using the bead of the same HLA-locus with lowest MFI as background) cutoff of 15 combined with an MFI cutoff of 500, resulting in 8% and 21% lower 1- and 10-year graft survivals, respectively, for 8% DSA-positive transplants.
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Supervivencia de Injerto , Antígenos HLA/inmunología , Trasplante de Riñón , Fluorescencia , Humanos , Isoanticuerpos/sangre , Donantes de TejidosRESUMEN
Human leukocyte antigen (HLA)-DRB3 is a functional HLA class II gene, which has a limited allele diversity in the human population. Furthermore, the HLA-DRB3 gene is only present in a subset of individuals. Therefore, in organ transplantation, this HLA molecule is frequently mismatched between patient and graft donor and thus antibodies against this mismatched HLA molecule can develop. In this study, we aimed to evaluate the prevalence and reactivity of these antibodies and aimed to identify factors that underlie antibody formation against HLA-DRB3. We showed in our patient cohort that HLA-DRB3 antibodies are identified in about 7% of all patients that were screened with solid phase assays. In these assays, we observed multiple antibody reactivity patterns indicating that HLA-DRB3 harbours multiple epitopes. In those cases, where we succeeded at tracing back the induction of these antibodies to the molecular HLA typing of the immunogenic event, we noticed a different frequency of HLA-DRB1 allele groups in the donors as compared to a control group. To a certain extent this distribution (e.g. HLA-DRB1*11 individuals) could be linked to an altered expression level. However, it also appears that different HLA-DRB3 alleles (e.g. HLA-DRB3*01 group) vary in their immunogenicity without having an expression difference. In conclusion, our study provides information on the immunogenicity and reactivity patterns of antibodies against HLA-DRB3 in kidney transplantation, and it points towards the possibility of HLA expression as a factor underlying antibody formation.
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Anticuerpos/sangre , Antígenos HLA/genética , Cadenas HLA-DRB3/genética , Trasplante de Riñón , Alelos , Anticuerpos/inmunología , Epítopos/genética , Epítopos/metabolismo , Frecuencia de los Genes , Supervivencia de Injerto , Antígenos HLA/metabolismo , Cadenas HLA-DRB1/genética , Cadenas HLA-DRB1/metabolismo , Cadenas HLA-DRB3/inmunología , Cadenas HLA-DRB3/metabolismo , Prueba de Histocompatibilidad/métodos , Humanos , Donantes de TejidosRESUMEN
Background Complement-fixing antibodies against donor HLA are considered a contraindication for kidney transplant. A modification of the IgG single-antigen bead (SAB) assay allows detection of anti-HLA antibodies that bind C3d. Because early humoral graft rejection is considered to be complement mediated, this SAB-based technique may provide a valuable tool in the pretransplant risk stratification of kidney transplant recipients.Methods Previously, we established that pretransplant donor-specific anti-HLA antibodies (DSAs) are associated with increased risk for long-term graft failure in complement-dependent cytotoxicity crossmatch-negative transplants. In this study, we further characterized the DSA-positive serum samples using the C3d SAB assay.Results Among 567 pretransplant DSA-positive serum samples, 97 (17%) contained at least one C3d-fixing DSA, whereas 470 (83%) had non-C3d-fixing DSA. At 10 years after transplant, patients with C3d-fixing antibodies had a death-censored, covariate-adjusted graft survival of 60%, whereas patients with non-C3d-fixing DSA had a graft survival of 64% (hazard ratio, 1.02; 95% confidence interval, 0.70 to 1.48 for C3d-fixing DSA compared with non-C3d-fixing DSA; P=0.93). Patients without DSA had a 10-year graft survival of 78%.Conclusions The C3d-fixing ability of pretransplant DSA is not associated with increased risk for graft failure.
Asunto(s)
Anticuerpos Antiidiotipos/inmunología , Complemento C3d/inmunología , Rechazo de Injerto/inmunología , Antígenos HLA/inmunología , Trasplante de Riñón/efectos adversos , Sistema de Registros , Adulto , Distribución por Edad , Suero Antilinfocítico/inmunología , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Rechazo de Injerto/epidemiología , Humanos , Incidencia , Trasplante de Riñón/métodos , Masculino , Persona de Mediana Edad , Cuidados Preoperatorios/métodos , Estudios Retrospectivos , Medición de Riesgo , Distribución por Sexo , Donantes de Tejidos , Receptores de Trasplantes/estadística & datos numéricos , Inmunología del TrasplanteRESUMEN
Individual HLA mismatches may differentially impact graft survival after kidney transplantation. Therefore, there is a need for a reliable tool to define permissible HLA mismatches in kidney transplantation. We previously demonstrated that donor-derived Predicted Indirectly ReCognizable HLA Epitopes presented by recipient HLA class II (PIRCHE-II) play a role in de novo donor-specific HLA antibodies formation after kidney transplantation. In the present Dutch multi-center study, we evaluated the possible association between PIRCHE-II and kidney graft failure in 2,918 donor-recipient couples that were transplanted between 1995 and 2005. For these donors-recipients couples, PIRCHE-II numbers were related to graft survival in univariate and multivariable analyses. Adjusted for confounders, the natural logarithm of PIRCHE-II was associated with a higher risk for graft failure [hazard ratio (HR): 1.13, 95% CI: 1.04-1.23, p = 0.003]. When analyzing a subgroup of patients who had their first transplantation, the HR of graft failure for ln(PIRCHE-II) was higher compared with the overall cohort (HR: 1.22, 95% CI: 1.10-1.34, p < 0.001). PIRCHE-II demonstrated both early and late effects on graft failure in this subgroup. These data suggest that the PIRCHE-II may impact graft survival after kidney transplantation. Inclusion of PIRCHE-II in donor-selection criteria may eventually lead to an improved kidney graft survival.