RESUMO
Delayed graft function (DGF) after kidney transplantation heralds a worse prognosis. In patients with hyperoxaluria, the incidence of DGF is high. Oxalic acid is a waste product that accumulates when kidney function decreases. We hypothesize that residual diuresis and accumulated waste products influence the DGF incidence. Patients transplanted between 2018-2022 participated in the prospective cohort study. Pre-transplant concentrations of oxalic acid and its precursors were determined. Data on residual diuresis and other recipient, donor or transplant related variables were collected. 496 patients were included, 154 were not on dialysis. Oxalic acid, and glyoxylic acid, were above upper normal concentrations in 98.8%, and 100% of patients. Residual diuresis was ≤150 mL/min in 24% of patients. DGF occurred in 157 patients. Multivariable binary logistic regression analysis demonstrated a significant influence of dialysis type, recipient BMI, donor type, age, and serum creatinine on the DGF risk. Residual diuresis and glycolic acid concentration were inversely proportionally related to this risk, glyoxylic acid directly proportionally. Results in the dialysis population showed the same results, but glyoxylic acid lacked significance. In conclusion, low residual diuresis is associated with increased DGF incidence. Possibly accumulated waste products also play a role. Pre-emptive transplantation may decrease the incidence of DGF.
Assuntos
Função Retardada do Enxerto , Diurese , Glioxilatos , Transplante de Rim , Ácido Oxálico , Humanos , Transplante de Rim/efeitos adversos , Feminino , Masculino , Pessoa de Meia-Idade , Função Retardada do Enxerto/etiologia , Função Retardada do Enxerto/epidemiologia , Adulto , Estudos Prospectivos , Idoso , Diálise Renal , Glicolatos , Hiperoxalúria/etiologia , Fatores de Risco , IncidênciaRESUMO
BACKGROUND: Intracellular tacrolimus concentration in peripheral blood mononuclear cells (PBMCs) (TAC [PBMC] ) has been proposed to better represent its active concentration than its whole blood concentration. As tacrolimus acts on T lymphocytes and other white blood cells, including monocytes, we investigated the association of tacrolimus concentration in CD3 + T lymphocytes (TAC [CD3] ) and CD14 + monocytes (TAC [CD14] ) with acute rejection after kidney transplantation. METHODS: From a total of 61 samples in this case-control study, 28 samples were obtained during biopsy-proven acute rejection (rejection group), and 33 samples were obtained in the absence of rejection (control group). PBMCs were collected from both cryopreserved (retrospectively) and freshly obtained (prospectively) samples. CD3 + T lymphocytes and CD14 + monocytes were isolated from PBMCs, and their intracellular tacrolimus concentrations were measured. RESULTS: The correlation between tacrolimus whole-blood and intracellular concentrations was poor. TAC [CD3] was significantly lower than TAC [CD14] (median 12.8 versus 81.6 pg/million cells; P < 0.001). No difference in TAC [PBMC] (48.5 versus 44.4 pg/million cells; P = 0.82), TAC [CD3] (13.4 versus 12.5 pg/million cells; P = 0.28), and TAC [CD14] (90.0 versus 72.8 pg/million cells; P = 0.27) was found between the rejection and control groups. However, freshly isolated PBMCs showed significantly higher TAC [PBMC] than PBMCs from cryopreserved samples. Subgroup analysis of intracellular tacrolimus concentrations from freshly isolated cells did not show a difference between rejectors and nonrejectors. CONCLUSIONS: Differences in TAC [CD3] and TAC [CD14] between patients with and without rejection could not be demonstrated. However, further optimization of the cell isolation process is required because a difference in TAC [PBMC] between fresh and cryopreserved cells was observed. These results need to be confirmed in a study with a larger number of patients.
Assuntos
Nefropatias , Transplante de Rim , Estudos de Casos e Controles , Rejeição de Enxerto , Humanos , Imunossupressores , Leucócitos Mononucleares , Monócitos , Complicações Pós-Operatórias , Estudos Retrospectivos , Linfócitos T , TacrolimoRESUMO
Background: In heart transplant recipients, donor-derived cell-free DNA (ddcfDNA) is a potential biomarker for acute rejection (AR), in that increased values may indicate rejection. For the assessment of ddcfDNA as new biomarker for rejection, blood plasma sampling around the endomyocardial biopsy (EMB) seems a practical approach. To evaluate the effect of the EMB procedure on ddcfDNA values, ddcfDNA values before the EMB were pairwise compared to ddcfDNA values after the EMB. We aimed at evaluating whether it matters whether the ddcfDNA sampling is done before or after the EMB-procedure. Methods: Plasma samples from heart transplant recipients were obtained pre-EMB and post-EMB. A droplet digital PCR method was used for measuring ddcfDNA, making use of single-nucleotide polymorphisms that allowed both relative quantification, as well as absolute quantification of ddcfDNA. Results: Pairwise comparison of ddcfDNA values pre-EMB with post-EMB samples (n = 113) showed significantly increased ddcfDNA concentrations and ddcfDNA% in post-EMB samples: an average 1.28-fold increase in ddcfDNA concentrations and a 1.31-fold increase in ddcfDNA% was observed (p = 0.007 and p = 0.03, respectively). Conclusion: The EMB procedure causes iatrogenic injury to the allograft that results in an increase in ddcfDNA% and ddcfDNA concentrations. For the assessment of ddcfDNA as marker for AR, collection of plasma samples before the EMB procedure is therefore essential.
Assuntos
Ácidos Nucleicos Livres , Transplante de Coração , Aloenxertos , Biomarcadores , Biópsia , Rejeição de Enxerto/diagnóstico , Humanos , Biópsia LíquidaRESUMO
Despite modern immunosuppressive therapy, allograft rejection remains a major cause of solid organ transplant dysfunction. For clinical care, organ transplant function is routinely monitored by measuring biomarkers that, depending on the organ transplanted, include serum creatinine, N-terminal pro-hormone of brain natriuretic peptide (NT-proBNP), and aspartate aminotransferase. All can be measured easily in clinical chemistry laboratories. The main problem with these biomarkers is that they have a low sensitivity for the detection of allograft damage and are nonspecific for the detection of allograft rejection. To diagnose rejection, histologic examination of grafted tissue is necessary, which requires an invasive biopsy procedure. There is thus an unmet need in transplantation medicine for biomarkers that are specific for rejection, identify graft injury at an early stage, and may eventually overcome the need for a transplant biopsy. Recently, tremendous progress in the field of biomarkers has been made. In this narrative review, the potential of donor-derived cell-free DNA (ddcfDNA), cell-free nucleosomes, and extracellular vesicles to act as next-generation biomarkers for solid organ transplant is discussed. Based on the fact that cell content is released during rejection, these markers could serve as very specific biomarkers for allograft injury and rejection. These markers have the potential to improve rejection monitoring, evaluate the response to antirejection therapy, and may decrease the need for invasive procedures.
Assuntos
Biomarcadores/sangue , Biomarcadores/urina , Rejeição de Enxerto/diagnóstico , Biópsia Líquida/métodos , Ácidos Nucleicos Livres/sangue , Ácidos Nucleicos Livres/urina , Vesículas Extracelulares/metabolismo , Rejeição de Enxerto/sangue , Rejeição de Enxerto/urina , Humanos , Nucleossomos/metabolismoRESUMO
Memory T cells are important mediators of transplant rejection but are not routinely measured before or after kidney transplantation. The aims of this study were as follows: (1) validate whether pretransplant donor-reactive memory T cells are reliable predictors of acute rejection (AR) (2) determine whether donor-reactive memory T cells can distinguish AR from other causes of transplant dysfunction. Methods: Samples from 103 consecutive kidney transplant recipients (2018-2019) were obtained pretransplantation and at time of for-cause biopsy sampling within 6 mo of transplantation. The number of donor-reactive interferon gamma (IFN-γ) and interleukin (IL)-21-producing memory T cells was analyzed by enzyme-linked immunosorbent spot (ELISPOT) assay. Results: Of the 63 patients who underwent a biopsy, 25 had a biopsy-proven acute rejection (BPAR; 22 aTCMR and 3 aAMR), 19 had a presumed rejection, and 19 had no rejection. Receiver operating characteristic analysis showed that the pretransplant IFN-γ ELISPOT assay distinguished between patients who later developed BPAR and patients who remained rejection-free (area under the curve [AUC] 0.73; sensitivity 96% and specificity 41%). Both the IFN-γ and IL-21 assays were able to discriminate BPAR from other causes of transplant dysfunction (AUC 0.81; sensitivity 87% and specificity 76% and AUC 0.81; sensitivity 93% and specificity 68%, respectively). Conclusions: This study validates that a high number of donor-reactive memory T cells before transplantation is associated with the development of AR after transplantation. Furthermore, it demonstrates that the IFN-γ and IL-21 ELISPOT assays are able to discriminate between patients with AR and patients without AR at the time of biopsy sampling.
RESUMO
BACKGROUND: Donor-derived cell-free DNA (ddcfDNA) is a promising minimally invasive biomarker for acute rejection (AR) in kidney transplant recipients. To assess the diagnostic value of ddcfDNA as a marker for AR, ddcfDNA was quantified at multiple time points after kidney transplantation with a novel high-throughput droplet digital PCR indel method that allowed for the absolute quantification of ddcfDNA. METHODS: In this study, ddcfDNA in plasma samples from 223 consecutive kidney transplant recipients was analyzed pretransplantation; at 3, 7, and 180 d after transplantation; and at time of for-cause biopsies obtained within the first 180 d after transplantation. RESULTS: Median (interquartile range) ddcfDNA concentration was significantly higher on day 3 (58.3 [17.7-258.3] copies/mL) and day 7 (25.0 [10.4-70.8] copies/mL) than on day 180 after transplantation (4.2 [0.0-8.3] copies/mL; P < 0.001 and P < 0.001, respectively). At time of biopsy-proven AR (BPAR), between day 11 and day 180 after transplantation, ddcfDNA concentration was significantly higher (50.0 [25.0-108.3] copies/mL) than those when biopsies showed non-AR (0.0 [0.0-15.6] copies/mL; P < 0.05). ddcfDNA concentration within the first 10 d after transplantation showed no significant difference between recipients with BPAR and those with non-AR in their biopsy or between recipients with BPAR and ddcfDNA measured at day 3 and day 7. CONCLUSIONS: Unfortunately, ddcfDNA concentration is not a good biomarker to detect AR within the first 10 d after transplantation; however, BPAR occurring after 10 d after transplantation can be detected in kidney transplant recipients by ddcfDNA using a novel and unique high-throughput droplet digital PCR indel method.
Assuntos
Ácidos Nucleicos Livres , Transplante de Rim , Biomarcadores , Rejeição de Enxerto/diagnóstico , Rejeição de Enxerto/genética , Transplante de Rim/efeitos adversos , Reação em Cadeia da PolimeraseRESUMO
BACKGROUND: There is an unmet need for noninvasive markers specific for kidney transplant rejection. Such a marker may eventually overcome the need for a transplant biopsy. In this pilot study, the potential of circulating cell-free nucleosomes (CCFN) to serve as a biomarker for kidney transplant rejection was evaluated. METHODS: Forty de novo kidney transplant recipients were prospectively followed as part of a randomized, controlled clinical trial. Total CCFN (H3) and CCFN with the histone modifications H3K36me3 and H3 citrulline were measured in patients at four fixed time points: before transplantation and on days 3-6, 30 and 180 after kidney transplantation. In addition, serum collected at times of transplant rejection (n = 14) was analyzed. CCFN were measured with a Nu.Q™ Assay kit (VolitionRx), an ELISA-based assay using antibodies directed against nucleosomes. RESULTS: For total CCFN (H3), H3K36me3, and H3 citrulline, the same pattern was seen over time: Concentrations were elevated shortly after transplantation (day 3-6) followed by a decline reaching baseline (pre-transplantation) values at days 30 and 180. At times of acute rejection, the median concentration of total CCFN (H3) was significantly higher compared to the stable situation (day 30): 4309 (3435-5285) versus 2885 (1668-3923) ng/mL, p < 0.05, respectively. Total CCFN (H3) had an acceptable ability to discriminate rejection from no rejection (AUC-ROC = 0.73) with a negative predictive value of 92.9%. For both histone modifications (H3K36me3 and H3 citrulline), there was no significant difference between episodes of acute rejection and the stable situation (day 30). CONCLUSION: In this pilot study, total CCFN (H3) concentrations are increased at times of acute kidney transplant rejection. The high negative predictive value implies that whenever a patient experiences loss of renal transplant function and the total CCFN (H3) is not increased, causes other than acute rejection should be considered. Clinical implementation of total CCFN (H3) measurement may avoid unnecessary and potentially harmful kidney transplant biopsies.
Assuntos
Biomarcadores/sangue , Rejeição de Enxerto/sangue , Nefropatias/patologia , Transplante de Rim/efeitos adversos , Nucleossomos/genética , Adulto , Idoso , Anticorpos/imunologia , Biópsia/normas , Metilação de DNA , Epigênese Genética , Feminino , Rejeição de Enxerto/diagnóstico , Rejeição de Enxerto/etnologia , Código das Histonas/genética , Humanos , Nefropatias/sangue , Masculino , Pessoa de Meia-Idade , Nucleossomos/imunologia , Projetos Piloto , Valor Preditivo dos Testes , Estudos Prospectivos , Transplantados/estatística & dados numéricosRESUMO
BACKGROUND: In solid organ transplant (SOT) recipients, transplant rejection during immune checkpoint inhibitor (ICI) treatment for cancer is a clinical problem. Donor-derived cell-free DNA (dd-cfDNA) can be detected in blood and is a sensitive biomarker for diagnosis of acute rejection in SOT recipients. To our best knowledge, this is the first case report of a kidney transplant recipient with advanced cancer treated with ICI who was monitored with dd-cfDNA. CASE PRESENTATION: A 72-year old female with a long-standing renal transplant was diagnosed with advanced melanoma in 2018 and was treated with the anti-PD1 antibody nivolumab. Within 12 days after the first administration of nivolumab, dd-cfDNA ratio increased to 23%, suggesting allograft rejection. Her kidney transplant function deteriorated and acute rejection was confirmed by renal transplant biopsy. As the rejection could not be controlled despite immunosuppressive treatment, a transplant nephrectomy was necessary and haemodialysis was started. Immunological analysis of the renal explant showed infiltration of alloreactive, nivolumab-saturated, PD1+ cytotoxic T cells. After transplant nephrectomy, she experienced nivolumab-related toxicity and rapid disease progression. CONCLUSION: Clinicians prescribing ICIs should be aware that SOT recipients are at risk of transplant rejection as a result of T cell activation. Dd-cfDNA is a sensitive biomarker and should be further studied for early detection of transplant rejection. Immunological analysis of the kidney explant showed marked graft infiltration with alloreactive PD-1+ cytotoxic T cells that were saturated with nivolumab.