Kidney Transplant Outcomes Research Articles

#2149 Kidney transplantation outcomes in lupus nephritis

Abstract Background and Aims Kidney transplantation (KT) is the renal replacement therapy of choice in patients with lupus nephritis (LN) who progress to end-stage renal disease (ESRD). The latest Spanish guidelines recommend the use of hydroxychloroquine after KT in these patients. Our study aims to analyze KT outcomes in patients with LN in our center. Method Retrospective cohort study, which included all KT with a diagnosis of LN who underwent KT between April 1982 and November 2023 at Puerta del Mar University Hospital (Spain). Each KT recipient with LN was matched with two controls from the same institution by age, sex and type of donor during the same period. We collected clinical and demographical characteristics, as well as immunosuppressive (IS) therapy after KT. We analyzed the death-censored graft survival and patient survival and compiled the causes of death and graft loss, comparing them with the control group. We documented LN recurrences, KT rejections, and incidence of CMV and BK infection. Results In this period, 2055 KTs were performed in our center, of which 39 had a diagnosis of LN (1.9%). Seventy eight controls were selected. The majority of KTs were women (89.7%) with a mean age of 44 years. Induction therapy was used in 85.2% of KT with Thymoglobulin (63%) or Basiliximab (27%). Maintenance IS therapy was based on tacrolimus (93.5%), cyclosporine (6.5%), mycophenolate (100%) and prednisone (100%). Only 4 patients (10.2%), the latest ones, received hydroxychloroquine after KT. Death-censored graft survival at 1 year (87.1% SLE vs. 88.5% Non-SLE), 5 years (74.9% SLE vs. 80.8% Non-SLE), and 10 years (65.6% SLE vs. 69.5% Non-SLE) and patient survival at 1 year (97.1% SLE vs. 100% Non-SLE), 5 years (93.7% SLE vs. 95.3% Non-SLE), and 10 years (93.7% SLE vs. 91.7% Non-SLE) were similar in both groups. No graft was lost because of recurrent LN. No significant differences were found neither in the causes of death nor between the causes of graft loss. The incidence of CMV and BK infection and KT rejection rates were similar in both groups. Conclusion KT is an excellent therapeutic alternative in LN with ESRD. Despite the low use of hydroxychloroquine in our series, no recurrence of LN was detected and the KT outcomes were similar to the control group.

#1645 The role of donor Cystatin-C in posttransplant outcomes in kidney transplantation

Abstract Background and Aims Cystatin-C is an established marker of glomerular filtration rate in kidney disease. High levels of cystatin-C have been associated with unfavorable outcomes (acute kidney injury, cardiovascular morbidity) in critically ill patients. The aim of this study was to evaluate the levels of Cystatin-C in donors after brain (DBD) and circulatory death (DCD) and investigate its association with posttransplant graft function. Method Plasma samples from 303 donors (283 deceased, 20 living donors; LD) were obtained from the Quality in Organ Donation (QUOD) and the Oxford Transplant (OTB) biobanks. QUOD is a national multi-center UK wide bioresource of deceased donor clinical samples collected during donor management and organ procurement. OTB is a living donor biobank established to obtain clinical samples as control cohorts. Only deceased donors with both grafts transplanted were included in the study. Plasma Cystatin-C from LD samples as assessed as an optimal control group. The samples were linked to donor and recipient metadata obtained from the National Transplant Registry (NHSBT). Using Luminex assays, plasma Cystatin-C was quantified in samples collected during donor management (prior to cross clamp in DBDs and LDs and at withdrawal of support in DCDs). We performed descriptive statistics and multivariate linear and logistic analysis to determine the association between Cystatin-C, primary non-function (PNF), delayed graft function (DGF), acute rejection (AR) and 12-month posttransplant graft function. Results Among 303 donors (median age: 50 years), 126 were DCDs, 157 DBDs (20.1% of them were expanded criteria donors, ECD) and 20 LDs. ECDs and DCDs had significantly higher levels of Cystatin-C, compared to DBDs. In a total of 606 recipients, 11 (1.9%) developed PNF, and 128 (21%) developed DGF (24 as pairs, 80 non-pairs). Forty-six recipients (7.6%) experienced at least one AR episode and 60 (10%) donors had lost the graft during follow-up. Donor levels of Cystatin-C were associated with DGF and were further elevated in donors of kidneys which developed PNF (P-value < .0001, Fig. 1). Grafts with acute rejections were retrieved from donors with higher levels of Cystatin-C, but the difference did not meet statistical significance. Cystatin-C levels were significantly lower (P-value < .0001) in donors who offered concordant grafts with optimal 12-month post-transplant function (eGFR >60 ml/min), compared with grafts with intermediate function (GFR 30-60 ml/min) or eGFR <30ml/min (Fig. 2). LDs had significantly lower levels of Cystatin-C compared to deceased donors in all studied outcomes (Figs 1 and 2). Cystatin-C during donor management was an independent risk factor for inferior 12-month paired graft function, after the implementation of three different multivariate models, including donor (β-coef = −11.3, P-value = .001), recipient (β-coef = −16, P-value < .001) and post-transplant characteristics (β-coef = −13.1, P-value = .002). Conclusion In a large cohort of deceased and living donors, we were able to evaluate the circulating levels of Cystatin-C during donor management with the use of high-end performance technology. The concentration of Cystatin-C was notably different among donor types and was significantly higher in donors with kidneys that developed PNF or had suboptimal graft function 12-month posttransplant. Our findings suggest that Cystatin-C may have a role in identifying higher-risk donors during donor management and offers the opportunity for granular assessment of donor kidney quality prior to transplantation.

#2106 Higher daily protein intake can reduce the risk of infections in kidney transplant recipients during the early post-transplant period

Abstract Background and Aims Kidney transplantation (KT) is considered the most effective treatment for end-stage renal disease (ESRD), and it significantly contributes to enhancing the quality of life and extending the survival of patients with ESRD. After kidney transplantation, the early and heavy use of immunosuppressants and glucocorticoids can affect the recipients' immune status to varying degrees, increasing the risk of postoperative infections caused by a wide range of pathogens. Thus, the prevention and management of infectious diseases are major factors contributing to improved outcomes in kidney transplantation. Protein-energy wasting (PEW) is commonly observed in uremic patients, and it may persist even after they have undergone kidney transplantation (KT). And PEW is a significant factor in the progression of chronic kidney disease (CKD). Providing appropriate dietary guidance and intervention is essential for enhancing the immune status of recipients, promoting a positive nitrogen balance in the body, minimizing infections, and safeguarding graft function. This study aimed to investigate the relationship between daily protein intake (DPI) and postoperative infections at 3 months post-transplant, which may establish a foundation for the early postoperative protein intake regimen, reducing the incidence of postoperative infections, and improving the early prognosis of kidney transplantation. Method This is a retrospective observational study. 176 kidney transplant recipients (KTRs) who underwent kidney transplant in West China Hospital from December 2021 to June 2022 were included and followed up regularly. 24-hour urine urea data were collected at months 1 and 3 post-transplant to calculate their DPI. These KTRs were further divided into two groups according to the recommended DPI for KTRs by the 2021 Practice Guidelines for the Nutritional Management of Chronic Kidney Disease, namely high intake group (Group 1, with DPI ≥ 1.4 g/kg·d, n = 66) and low intake group (Group 2, with DPI < 1.4 g/kg·d, n = 110). Occurrence of hospitalization and postoperative infections within 3 months were recorded. Multiple logistic regression was utilized to analyze the association between DPI and early postoperative infections at 3 months post-transplant. Results Mean DPI levels at month 1 post-transplant were 1.58 ± 0.22 g/kg·d in Group 1 and 1.02 ± 0.31 g/kg·d in Group 2, respectively (P < 0.05), this huge difference in DPI between the two groups continued to month 3. There was no significant difference in age, gender, pre-transplant body mass index (BMI), dialysis type and time, donor type, or the ratio of delayed graft function (DGF) between the two groups. There was a statistically significant difference in the percentage of hospitalization between the two groups during the postoperative period of 3 months (P = 0.027). Pneumonia was the most common reason of hospitalization after transplantation, followed by urinary tract infection. The results of multiple logistic regression analysis showed that higher DPI in the early post-transplant period was a protective factor for infection after kidney transplantation. Conclusion In the early post-transplant period, consuming higher levels of dietary protein may reduce the risk of infections and complications, and help preserve the function of the transplanted kidney.

#2736 Higher daily protein intake can reduce the risk of infections in kidney transplant recipients during the early post-transplant period

Abstract Background and Aims Kidney transplantation (KT) is considered the most effective treatment for end-stage renal disease (ESRD), and it significantly contributes to enhancing the quality of life and extending the survival of patients with ESRD. After kidney transplantation, the early and heavy use of immunosuppressants and glucocorticoids can affect the recipients' immune status to varying degrees, increasing the risk of postoperative infections caused by a wide range of pathogens. Thus, the prevention and management of infectious diseases are major factors contributing to improved outcomes in kidney transplantation. Protein-energy wasting (PEW) is commonly observed in uremic patients, and it may persist even after they have undergone kidney transplantation (KT). And PEW is a significant factor in the progression of chronic kidney disease (CKD). Providing appropriate dietary guidance and intervention is essential for enhancing the immune status of recipients, promoting a positive nitrogen balance in the body, minimizing infections, and safeguarding graft function. This study aimed to investigate the relationship between daily protein intake (DPI) and postoperative infections at 3 months post-transplant, which may establish a foundation for the early postoperative protein intake regimen, reducing the incidence of postoperative infections, and improving the early prognosis of kidney transplantation. Method This is a retrospective observational study. 176 kidney transplant recipients (KTRs) who underwent kidney transplant in West China Hospital from December 2021 to June 2022 were included and followed up regularly. 24-hour urine urea data were collected at month 3 post-transplant to calculate their DPI. These KTRs were further divided into two groups according to the recommended DPI for KTRs by the 2021 Practice Guidelines for the Nutritional Management of Chronic Kidney Disease, namely high intake group (Group 1, with DPI ≥ 1.4 g/kg·d, n = 66) and low intake group (Group 2, with DPI < 1.4 g/kg·d, n = 110). Occurrence of postoperative infections events within 3 months were recorded. Multiple logistic regression was utilized to analyze the association between DPI and early postoperative infections at 3 months post-transplant. Results Mean DPI levels at month 3 post-transplant were 1.75 ± 0.56 g/kg·d in Group 1 and 0.98 ± 0.24 g/kg·d in Group 2, respectively. There was no significant difference in age, gender, pre-transplant body mass index (BMI), dialysis type and time, donor type, or the ratio of delayed graft function (DGF) between the two groups. There was a statistically significant difference in the percentage of hospitalization for infections between the two groups during the postoperative period of 3 months (P = 0.027). Pneumonia was the most common reason of rehospitalization after transplantation, followed by urinary tract infection. The results of multiple logistic regression analysis showed that higher DPI in the early post-transplant period was a protective factor for infection after kidney transplantation. Conclusion In the early post-transplant period, consuming higher levels of dietary protein can reduce the risk of infections and complications, and help preserve the function of the transplanted kidney.

#2402 Reproducibility of memory B-cell and HLA antibody detection in patients on kidney transplant waiting list

Abstract Background and Aims Detection of HLA antibodies (HLA-Abs) impacts on the access and outcomes of kidney transplantation (KT). Currently, evaluation of HLA-Abs in serum is performed using single antigen bead assays (SAB). The analysis of circulating HLA-specific memory B cells (mBc), capable of differentiating to HLA-Abs secreting cells, was conceived with the aim of complementing the study of the HLA-Abs found in serum, but there is debate regarding the representativeness and reproducibility of the test. Thus, we studied HLA-Abs generated by mBc from patients on the waiting list (WL) at two different time points without sensitizing events in between and compared them with HLA-Abs detected in serum. Method We selected 7 patients on the WL for a first KT with a cPRA of 3%-100%: 4 had pregnancies and 2 had blood transfusions as known sensitizing events. We collected blood and serum samples at 2 time points separated by an average of 3.5 months (T1, T2). We cultured polyclonally activated PBMCs and isolated and concentrated IgG from the supernatant (SN) to study HLA-Abs. We tested SN and sera with SAB assays. Beads with MFI >750 were considered positive. Results SAB serum study (Fig. 1a). Eighty-two percent of the specificities found at T1 were also detected at T2, and 97% of those identified at T2 were also observed at T1. Thus, there was good concordance between T1 and T2 samples (κ = 0.869, Cohen) and the MFI the specificities correlated (p < 0.0001, Spearman). SAB SN study (Fig. 1b). Forty-one percent of the positive specificities detected at T1 were also identified at T2, and 59% of the positive specificities found at T2 had been seen at T1. Thus, there was a moderate concordance between T1 and T2 samples (κ = 0.454, Cohen) and the MFI of the specificities still correlated (p < 0.0001, Spearman). Only 42% and 35% of the positivities found in serum were also detected in the SN at T1 and T2, respectively. However, we found 9 positivities unique to the SN T1 (100% HLA-ABC) in 2 patients with cPRA>80% and we also identified a total of 20 positivities unique to the SN at T2 (45% HLA-ABC, 55% HLA-DPDQDR) in 3 patients with cPRA>80%. Conclusion The study of the degree of sensitization with SAB serum analysis remains stable between samples along time, while the mBc analysis shows less reproducibility. We identified a higher number of HLA-Ab in the study of serum compared with the study of the SN of mBc; however, we found some HLA-Abs unique to the SN. We suggest that, probably due to the small number of circulating mBC, increasing the number of samples tested for mBc improves the representativeness of the test.

Kidney Transplant Outcomes From Deceased Donors Who Received Dialysis

Recipient outcomes after kidney transplant from deceased donors who received dialysis prior to kidney donation are not well described. To compare outcomes of transplant recipients who received kidneys from deceased donors who underwent dialysis prior to kidney donation vs recipients of kidneys from deceased donors who did not undergo dialysis. A retrospective cohort study was conducted including data from 58 US organ procurement organizations on deceased kidney donors and kidney transplant recipients. From 2010 to 2018, 805 donors who underwent dialysis prior to kidney donation were identified. The donors who underwent dialysis prior to kidney donation were matched 1:1 with donors who did not undergo dialysis using a rank-based distance matrix algorithm; 1944 kidney transplant recipients were evaluated. Kidney transplants from deceased donors who underwent dialysis prior to kidney donation compared with kidney transplants from deceased donors who did not undergo dialysis. The 4 study outcomes were delayed graft function (defined as receipt of dialysis by the kidney recipient ≤1 week after transplant), all-cause graft failure, death-censored graft failure, and death. From 2010 to 2018, 1.4% of deceased kidney donors (805 of 58 155) underwent dialysis prior to kidney donation. Of these 805 individuals, 523 (65%) donated at least 1 kidney. A total of 969 kidneys (60%) were transplanted and 641 kidneys (40%) were discarded. Among the donors with kidneys transplanted, 514 (mean age, 33 years [SD, 10.8 years]; 98 had hypertension [19.1%] and 36 had diabetes [7%]) underwent dialysis prior to donation and were matched with 514 (mean age, 33 years [SD, 10.9 years]; 98 had hypertension [19.1%] and 36 had diabetes [7%]) who did not undergo dialysis. Kidney transplants from donors who received dialysis prior to donation (n = 954 kidney recipients) were associated with a higher risk of delayed graft function compared with kidney transplants from donors who did not receive dialysis (n = 990 kidney recipients) (59.2% vs 24.6%, respectively; adjusted odds ratio, 4.17 [95% CI, 3.28-5.29]). The incidence rates did not significantly differ at a median follow-up of 34.1 months for all-cause graft failure (43.1 kidney transplants per 1000 person-years from donors who received dialysis prior to donation vs 46.9 kidney transplants per 1000 person-years from donors who did not receive dialysis; adjusted hazard ratio [HR], 0.90 [95% CI, 0.70-1.15]), for death-censored graft failure (22.5 vs 20.6 per 1000 person-years, respectively; adjusted HR, 1.18 [95% CI, 0.83-1.69]), or for death (24.6 vs 30.8 per 1000 person-years; adjusted HR, 0.76 [95% CI, 0.55-1.04]). Compared with receiving a kidney from a deceased donor who did not undergo dialysis, receiving a kidney from a deceased donor who underwent dialysis prior to kidney donation was associated with a significantly higher incidence of delayed graft function, but no significant difference in graft failure or death at follow-up.

#1987 The current status of deceased donor kidney discard in Korea with a very long waiting time

Abstract Background and Aims Increasing rates of end stage kidney disease in Asia, including Korea, are very high; however, the rates of deceased donation in this area is much lower than those in the Western countries, leading to a serious discrepancy between donor organ need and supply. Therefore, efficient utilization of deceased donor kidneys with minimizing organ discard is essential. This nationwide study analyzed the current status of donor kidney discard in Korea. Method This study included deceased donor kidneys which are candidate for kidney transplantation between 2013 and 2018 in the Korean Network for Organ Sharing. Kidneys were procured bilaterally or unilaterally, or discarded bilaterally. Unilaterally- or bilaterally-procured kidneys were used for deceased donor kidney transplantation or discarded later. Kidney discard was defined as no-procurement or discard after procurement. We analysed risk factors affecting donor kidney discard using multivariable logistic regression analysis. Moreover, we analysed graft failure rate and mortality in kidney transplant patients according to discard pattern using Log rank test and multivariable Cox regression analysis. Results Among 5,592 deceased donor kidneys, numbers of no-procurement, single-procurement, and double-procurement were 385, 63, and 5,144, respectively. Most of unilaterally-procured kidneys were transplanted, whereas one kidney was discarded later. Bilaterally-procured kidneys were accompanied by two transplantations (n = 5,058), one transplantation with discard of the other kidneys (n = 33), or discard of both kidneys (n = 20). The kidney discard rate was 7.9% (n = 439), which seemed to be lower compared to that in the Western countries. The causes of no-procurement were universally organ damage and the common causes of kidney discard after procurement were organ damage (66.6%) and absence of available candidates (12.9%). While mean kidney donor profile index (KDPI) in the discard group (1.9 ± 0.7) was higher than that of transplantation group (1.5 ± 10.5, P < 0.001), a large overlap in the quality was observed. Risk factors for kidney discard were female sex (adjusted odds ratio [OR], 1.68; 95% confidence interval [CI], 1.31-2.15), hypertension (OR, 1.65; 95% CI, 1.27-2.14), diabetes mellitus (OR, 2.82; 95% CI, 2.12-3.75), high serum creatinine levels (OR, 1.89; 95% CI, 1.78-2.01), low hemoglobin levels (OR, 0.84; 95% CI, 0.79-0.90), and non-cerebrovascular cause of death (OR, 0.70; 95% CI, 0.55-0.89). When kidney transplantation using contralateral kidneys in the discard group was compared with that in the no-discard group, there were no significant differences in either graft failure rate or mortality between the two groups (P = 0.300). Furthermore, multivariable analysis showed that discard of the contralateral kidneys did not have a negative impact on either graft survival (hazard ratio 1.67; 95% CI, 0.74-3.77; P = 0.216) or patient survival (hazard ratio 0.86; 95% CI, 0.35-2.12; P = 0.749). Conclusion The discard rate of deceased donor kidneys was low in Korea with a very long waiting time and kidney transplant outcomes using contralateral kidneys in the discard group were comparable to those in the no-discard group, supporting maximal utilization of deceased donor kidneys would contribute to expanding a donor pool without compromising post-transplant outcomes.

#2414 Hypertension resolution after kidney transplantation is associated with better kidney transplant outcomes in patients with pre-transplant hypertension

Abstract Background and Aims Hypertension is prevalent in patients with advanced chronic kidney disease (CKD), and kidney transplantation (KT) can potentially improve hypertension. Although hypertension is expected to be resolved after KT in many recipients with pre-transplant hypertension, little is known about the hypertension resolution rate and its prognostic role in KT outcomes. Method We retrospectively identified KT recipients (between 2006 and 2015) who had pre-transplant hypertension using Health Insurance Review & Assessment Service and Korea National Health Insurance System. The recipients were categorized into two groups based on their post-KT hypertension status: “persistent hypertension” and “resolved hypertension”. Cox proportional hazard analyses were performed to assess the risk of death-censored graft failure and all-cause mortality with adjusting various clinical, immunological risk factors, and socioeconomic status. Results Among 11,342 KT recipients with pre-transplant hypertension, 8,233 (73%) remained hypertensive, while 3,109 (27%) experienced hypertension resolution after KT. Recipients with resolved hypertension had lower rates of delayed graft function and major comorbidities, including diabetes mellitus, ischemic heart disease, and stroke compared to recipients who remained hypertensive. After adjusting for multiple covariates, the resolved hypertension group had 0.59-fold (95% confidence interval [CI] 0.49–0.73) lower risk for graft failure and 0.59-fold (95% CI 0.48–0.73) lower risk for all-cause mortality compared to the persistent hypertension group. Subgroup analyses revealed that the protective effect of resolved hypertension on graft survival was more pronounced in females (P for interaction = 0.045), and on overall survival was weaker in recipients with diabetes (P for interaction = 0.033). Conclusion A significant proportion of patients experienced hypertension resolution after KT, which is associated with improved graft survival and overall patient survival. The post-KT hypertension status can be used as a prognostic indicator for predicting better outcomes in KT recipients with pre-transplant hypertension.

#1847 Pregnancy impact on kidney transplant outcome

Abstract Background and Aims Renal transplantation improves the fertility of women of childbearing age. The possibility of a term pregnancy is one of the benefits of solid organ transplantation for women. Studies have also shown an increase in graft loss during and after pregnancy among sensitized patients and a higher risk of graft failure due to rejection in pregnancies occurring in the first and second-year post-transplantation. Most of these observations were found in studies using controls of non-pregnant recipients, but most did not match the study group in several critical clinical parameters, such as the gender of the controls, the creatinine level prepregnancy, or the cause of native kidney failure. The aim of our study is to investigate the long-term effects of pregnancy on graft function in female renal transplant recipients at Mansoura Urology and Nephrology center who experienced pregnancy after kidney transplantation. Method Retrospective cohort study conducted on 236 patients out of 3000 kidney transplant recipient who underwent renal transplantation (RT) at Mansoura Urology and Nephrology Centre between March 1976 and December 2019. divided into group I; 118 kidney transplant female's recipient experienced pregnancy at any time after kidney transplant and Group II; 118 kidney transplant female's recipients who didn`t experience pregnancy after renal transplantation, they were matched according to age and duration of renal transplantation and comparable in primary immunosuppressant drugs. all kidney recipients were reviewed for preoperative & operative and post-operative details also we record maternal and fetal complication. Results Our study included 118 kidney transplant recipients who got pregnant 191 times, 64 kidney transplant recipients got pregnant for the second time, while 9 of them got pregnant for the third time. We retrospectively evaluated the maternal, fetal complications and evolution of graft function after each pregnancy. Main maternal complications were gestational hypertension developed in 87 pregnancy cases out of 191 (45.5%), preeclampsia (25.1%), UTI (18.8%), gestational DM (9.9%), and graft rejection during pregnancy (4.1%). Longer hemodialysis duration (OR: 0.45, p value: 0.05), Calcineurin-based immunosuppressive protocols (Tacrolimus; OR: 2.3, p value: 0.02; Cyclosporine; OR: 0.36, p value: 0.007), Proteinuria more than or equal to 0.5 g/day (OR: 5.4, p value: 0.001) and/or serum creatinine more than or equal to 1.3 mg/dl (OR: 3.75, p value: 0.001) before pregnancy and rising of serum creatinine and/or proteinuria (Proteinuria; OR: 20.84, p value: 0.001; serum creatinine ≥1.3 mg/dl; OR: 4.3, p value: 0.001) are important risk factors associated with gestational hypertension. The mean serum creatinine level pre-pregnancy (mean ± SD) was (0.9 ± 0.2) mg/dL and 24-hour urinary protein mean ± SD before pregnancy was (0.4 ± 0.2) g/day. Serum creatinine and 24-hour urinary protein were higher during and after pregnancy with a statistically significant difference when compared to before pregnancy data (P-value: 0.001), (P- value: 0.04) retrospectively. At last follow-up, the majority of patients were alive with functioning graft with no statistically significant difference between two groups (P-value: 0.07), also no significant difference as regard graft failure incidence (p-value: 0.52). Conclusion Although the outcome of live births is favourable, the risks of maternal and fetal complications are high in kidney transplant recipients including pregnancy-induced hypertension, increased rates of preeclampsia, gestational diabetes, and caesarean section rates. The risk of miscarriage, prematurity, and low birth rate is also high. Serum creatinine and 24-hour urinary protein tend to increase during and after pregnancy which may impair the graft outcome. pregnancy counselling is necessary to avoid high-risk or unwanted pregnancies.

#2390 Does incompatible kidney transplantation provide a reliable alternative? An updated meta-analysis

Abstract Background and Aims The ABO system often poses one of the challenges to kidney transplantation, but due to the scarcity of organs, ABO incompatible kidney transplantation (ABOi-kTx) has gained the clinical attention. So, we aim in this study to evaluate the impact of ABO incompatible kidney transplantation on patients' clinical outcomes in comparison with ABO compatible kidney transplantation (ABOc-kTx). Method We searched six electronic databases: PubMed, Scopus, WOS, Cochrane, Embase, and Medline to identify relevant studies published until October 8th 2023, with no filters applied during the research process. After screening of 8562 studies, we included observational studies that compared any clinical outcomes of ABO incompatible kidney transplantation with ABO compatible kidney transplantation across various age groups. Synthesized odds ratios (ORs) with 95% confidence intervals (CIs) are used to present the differences between the two groups based on random-effects models. Results Our comprehensive search according to the eligible criteria of this study resulted in 102 studies including 254 496 patients in both groups. Due to the clinical heterogeneity, we used random effects models for quantitative synthesis of the eligible studies. Our meta-analysis showed that there was a statistically significant higher mortality ratio after one year, 3 years and 5 years (odds ratio [OR] 2.21 [95% CI 1.56–3.14], P < .00001; I² = 53%), (OR 1.86 [1.35–2.75], P = .0001; I² = 61%), (OR 1.69 [1.20–2.40], P = .003; I² = 75%), respectively. While there was no statistically significant difference at 8-years after transplantation (OR 1.05 [0.76–1.46], P = .77; I² = 58%). Pooled data of graft failure from our studies revealed higher incidence in ABOi-kTx group after one year (OR 2.44 [1.81–3.28], P < .00001; I² = 64%), 3 years (OR 1.57 [1.24–1.98], P < .00001; I² = 54%) and after 5 years (OR 1.57 [1.23–2.01], P = .0003; I² = 76%), There was not any statistically significant difference between both groups after 8 years. Acute anti-body mediated rejections were noticed to be statistically higher in ABOi-kTx group (OR 2.51 [2.12–2.97], (P < .00001); I² = 20%). Also, there was a significantly higher incidence of CMV infection in ABOi-kTx group (OR 1.27 [1.08–1.48], (P = .003); I² = 58%). Conclusion Although that ABOi-kTx is inferior to ABOc-kTx in the first 5 years after the transplantation in patient and graft mortality. Both groups are similar in both outcomes after 8 years post transplantation. Considering the higher incidence of acute rejection in the ABOi-kTx group and increased infection rate, desensitization techniques should be furtherly developed for better survival and complication outcomes.

#3036 The influence of first renal graft on second graft rejection and survival: the importance of revisiting histocompatibility and clinical outcomes

Abstract Background and Aims Kidney retransplantation confers a robust survival benefit over dialysis and recent data has shown similar outcomes to first kidney transplant. The number of HLA mismatches is an important predictor of graft loss and sensitization and the presence of donor specific antibodies (DSA) -pre and -post transplant is a major risk factor for rejection and worst outcomes. However, the importance of HLA matching of first graft and the relevance of first donor DSAs on second graft outcomes is less known. Our aim was to identify risk factors to second graft acute rejection and graft loss, related to second and first graft features. Method We performed a retrospective, longitudinal study including all patients submitted to a 2nd kidney transplant between January 2008 and December 2021, excluding patients with more than 2 grafts or multi-organ transplant. Clinical and histocompatibility data from the first and second donor and recipient were collected. HLA antibodies were detected by solid phase assays and considered if MFI >2500. For subsequent kidney transplants, repeated mismatches are not allowed and unacceptable antigens are those for which the patient has pre-formed -A, -B and -DR antibodies, with MFI>1000. Biopsy proven acute rejection was defined according to Banff 2017 criteria. Follow-up was 31st December 2023 for functioning grafts or time to graft failure, with a mean time of 92 ± 53 months. Results We included 114 patients, 73 (64%) males, mostly Caucasians (96%), with a mean age of 43.9 ± 13 years at 2nd transplant. First kidney transplant was performed before 2010 for 99 patients (87%), with a median first graft survival of 82.5 [12.5-144] months and 19 patients (16.7%) presented primary disfunction due to surgical/vascular complications. After graft loss, 43 patients (37.7%) had their graft removed. For second transplant, 11 (9.6%) patients had a living donor. Induction therapy with thymoglobulin occurred in 94 patients (83%) and maintenance therapy with mycophenolic acid, calcineurin inhibitors and steroids was prescribed in 83 patients (73%). During follow-up, 20 patients (17.5%) presented biopsy proven acute rejection, 13 (65%) T cell mediated and 7 (35%) antibody-mediated, the majority during the first-year post-transplant (N = 17, 85%). The risk factors for second graft rejection are summarized in Table 1. Patients with a first graft nephrectomy had a higher risk of acute rejection (OR 3.9, 95% CI [1.4-10.9], p < 0.006) and were more susceptible to the development of second donor post-transplant DSA (58% vs 35%, p = 0.02). Death censored second allograft loss occurred in 24 patients (21%) at follow up and acute rejection was an important risk factors (OR 4.3, 95% CI [1.5-12.1], p = 0.004). First-year graft survival was 93% and a survival at follow up was 79%. On survival analysis the presence of second graft DSA was a major risk factor for graft loss, especially class 2 -DQ and -DR. First transplant total mismatch load, especially on class 1 contributed to worst graft survival. Conclusion Worst outcomes in first kidney transplant were related with an increased risk of acute rejection in second graft and 1st graft nephrectomy increases the risk of the development of 2nd graft DSA and acute rejection. First transplant mismatch load decreased second graft survival.

#2075 Impact of chronic obstructive pulmonary disease on the outcomes of hemodialysis patients

Abstract Background and Aims Chronic obstructive pulmonary disease, COPD, is a common cause of morbidity and mortality. Comorbidities are frequent among COPD patients, some of which are explained by shared risk factors of smoking and increased age. Chronic kidney disease, leading to end-stage renal disease requiring hemodialysis (HD) is not uncommon in patients with COPD, and vice-versa. The prevalence and the impact of coexistence of COPD among HD patients was not extensively described. We aimed to measure the prevalence of COPD among a cohort of HD patients, and study how it relates to significant outcomes of mortality, morbidity, including unplanned hospital admissions, and kidney transplantation (KT). Method A retrospective study of subjects who initiated HD during 2015-2018. Participants were categorized into one of two groups, with or without COPD. Clinical, laboratory and pulmonary function tests data were extracted from medical records, as were outcomes of mortality, morbidity, and KT (until December 31st, 2021, or until death). Results Forty-three of 234 were diagnosed with COPD (18.4%). Their average FEV1%pred was 60%. Thirty-eight subjects in the COPD group (88.4%) were hospitalized for severe COPD exacerbations during a mean follow-up of 36.1 months, averaging 3.6 severe exacerbations per patient. Despite this, maintenance inhaler therapy was underutilized. All-cause mortality rates were higher for HD patients with COPD (72.1% vs. 47.1%, p=0.003), as were rates of acute coronary syndrome (39.5% vs. 23.6%, p=0.026). Conclusion COPD is common among HD patients and is associated with significant morbidity and increased mortality.

#165 Substantial variation in the evaluation of kidney transplant recipient candidates prior to waitlisting: a worldwide scoping review

Abstract Background and Aims Before patients with end stage kidney disease can undergo kidney transplantation, their suitability is assessed through a transplantation work-up. Several international guidelines have outlined the most important factors in determining patient suitability for kidney transplantation, but there is little agreement among them and it is unclear whether their recommendations have been adopted into clinical practice. Variation in the evaluation of kidney transplant recipient candidates could contribute to inefficiency and inequality in accessing the transplant waiting list and kidney transplantation. Therefore, the standardization of pre-waitlisting practice patterns is desirable and in line with recommendations from Europe [1] and the US [2]. An overview of publications on pre-waitlisting practices for kidney transplantation is needed to increase the transparency of kidney transplant recipient candidacy evaluation and is a first step towards the standardization of pre-waitlisting procedures. To date, such an overview has not been performed. Therefore, our aim was to conduct a scoping review on the evaluation of kidney transplant recipient candidates prior to waitlisting, investigating: (a) the content of the transplantation work-up; (b) contraindications to waitlisting; and (c) the organization of the transplantation work-up. Method A systematic search was conducted in Ovid Medline and Ovid EMBASE in collaboration with a medical information specialist. Studies reporting practice patterns on the evaluation of adults receiving their first kidney graft from a deceased donor were included. Studies were excluded if they only reported: on pediatric patients; from the perspective of the patients; practice patterns following waitlisting; COVID-19-related changes to practice patterns; and results from novelty screening methods used to evaluate kidney transplant recipient candidates without evidence that these methods were also used in clinical practice. Results Results from 40 studies were summarized, of which a majority were conducted in Europe (n = 11) and the US (n = 21). The content of the transplantation work-up varied widely between studied centers. Results show that the presence of a written transplantation work-up was common in the US, UK, and Norway, while in other countries, the presence of a written transplantation work-up protocol was not reported. Common domains within the transplantation work-up included screening for infections, heart disease, peripheral artery disease, and malignancy. A wide range of contraindications to waitlisting were reported. The criteria for contraindications related to obesity and age/frailty varied between studied centers and appear to have changed over time. In general, the organization of the transplantation work-up (e.g. the referral process, the transplant care team, and the use of multidisciplinary meetings) was comparable across studied centers, but differences were observed in the way the transplantation work-up was carried out. Conclusion This is the first review summarizing practice patterns related to the evaluation of kidney transplant recipient candidates prior to waitlisting. Results showed substantial variation in the evaluation of kidney transplant recipient candidates and pre-waitlisting practice patterns globally. These findings contribute to increasing the transparency of pre-waitlisting practice patterns, as was endorse by EU and US recommendations. In turn, this may aid in standardizing criteria used to evaluate kidney transplant recipient candidates prior to waitlisting, which could improve kidney transplantation access and outcomes.

#1016 Kidney transplantation in highly sensitized patients with preformed donor-specific antibodies through personalized delisting strategies

Abstract Background and Aims This study explores a personalized delisting strategy enabling kidney transplantation in highly sensitized patients with preformed donor-specific anti-HLA antibodies (DSA) trying to minimize the risk of antibody-mediated rejection (ABMR). Method Retrospective single-centre analysis of 50 kidney transplant recipients with preformed DSA (preDSA) after employing a delisting strategy to enhance their access to transplantation, and without received a pre-transplant or immediate post-transplant desensitization protocol. The delisting approach focused on allowing less deleterious antibodies according to their mean fluorescence intensity (MFI), anti-HLA class and C1q study results. The strategy consisted on eliminating as prohibited HLA antigens those recognized by antibodies with the lowest MFI in the following order: 1st- MFI < 5000; 2nd- MFI < 10000; 3rd-Any MFI. Additionally, delisting prioritized a single locus in the following order: 1st- one of the HLA class I loci (A, B, or Cw); 2nd- the rest of the class I loci; 3rd- HLA-DP, followed by DR. C1q studies were performed before delisting and transplantation was contraindicated in the presence of DSA detected in the C1q assay. Two comparative cohorts included 50 sensitized recipients without pre-transplant DSA (SwoDSA) and 50 non-sensitized recipients (NS). Results The delisting strategy allowed transplantation with preformed DSA and demonstrated comparable rejection rates to SwoDSA and NS groups (16%, 14% and 8%, respectively; log-rank = 0.28). However, the occurrence of acute ABMR was 12% in the preDSA group, significantly higher than in SwoDSA (1%) and NS (0%) (log-rank = 0.0093). The immunological risk assumed in delisting correlated with ABMR incidence (patients with ABMR had significantly higher sum MFI [mean ± SD: 9301 ± 6340 vs 4492 ± 5641; p = 0.049]), emphasizing the importance of tailored strategies. DSA persistence after transplantation correlated with higher MFI and increased ABMR risk. Of note, 16% of preDSA patients developed de novo DSA versus only the 4% of SwoDSA and 0% of NS patients (p = 0.004). After a mean follow-up of 3.1 ± 2.1 years, the 1-, 3- and 5-year death-censored allograft survival rates were 100%, 90% and 78%, respectively, in the preDSA group; 98%, 84% and 84% in the SwoDSA group and 100% in NS group (log-rank = 0.02). Conclusion The present study demonstrates the feasibility and acceptable outcomes of kidney transplantation in highly sensitized patients with preformed DSA through a personalized delisting strategy without using desensitization protocols.

#650 Predictive value of LKDPI on recipient's renal function one year after kidney transplantation: single-centre experience

Abstract Background and Aims The selection of the appropriate living kidney donor can be challenging, given the absence of a definitive method to determine the quality of the renal graft. This decision requires a delicate balance, weighing the recipient's benefits while prioritizing the safety of the donor. Recently, a tool known as the Living Kidney Donor Profile Index (LKDPI) was proposed to assess living donor kidneys, based on various donor characteristics, so as to predict the probability of recipient's graft loss; however, the validation of its effectiveness still needs to be proven. Method We evaluated retrospectively 147 stable living kidney donors, who donated between 01/2021 and 11/2023 and are currently attending the Living Donor Clinic of our Department. Our study aimed to assess the impact of the LKDPI on the recipient's estimated renal glomerular filtration rate (eGFR) (measured by the CKD-EPI) one-year posttransplant. Additionally, dialysis vintage, cause of CKD, comorbidities and medication were also determined in all recipients. Results The study comprised 147 stable kidney recipients (KTR), each with their respective living donor. Of these, 96 (65.3%) were males, with a mean age 44.02 ± 13.96 years and a mean dialysis vintage of 1.8 ± 2.3 years. In parallel, living kidney donors were predominantly females (70.7%), with a mean age of 59.08 ± 10.36 years and a mean eGFR prior to donation of 95 ± 13.11 ml/min/1.73 m². Furthermore, 20.1% of kidney transplantations were ABO incompatible and the mean LKDPI score was 34.6 ± 25.9%. Data analysis revealed a statistically significant negative correlation between LKDPI and the recipient's GFR one year after transplantation (p < 0.0001), suggesting that higher LKDPI scores were associated with lower renal function in recipients. In a post hoc analysis, KTRs who were on CKD stage 1, one-year post-transplantation, demonstrated no statistical difference in LKDPI values, compared to stage 2 (p = 0.35). Meanwhile recipients on stage 3 exhibited comparable LKDPI values to those on stage 4 (p = 0.821). The main statistical discrepancy was particularly evident between CKD stage 2 and 3, as recipients with a LKDPI surpassing 25.6, experienced a transition from stage 2 to stage 3 within the first year following transplantation (p < 0.0001). In addition, after multivariate analysis there were no correlations between KTR's eGFR and age difference between donor and recipient or recipient's smoking history or medication. Last, dialysis vintage or the number of previous transplantations did not affect recipient's kidney function. Conclusion LKDPI seems to be a promising tool for predicting the outcome of kidney transplantation, concerning the renal function of KTR particularly at the end of the first-year post-transplant However, it needs to be thoroughly evaluated before being considered as a decision-making factor in living kidney transplantations.

#2906 Kidney immune cells and endothelial cells can be modulated by low-salt and high-salt diets

Abstract Background and Aims Kidney immune cells and endothelial cells are involved in pathogenesis of kidney ischemia-reperfusion injury and potential therapeutic targets to improve kidney transplant outcomes. We hypothesized that dietary salt intake can change kidney immune cells and endothelial cells. Method C57BL/6 mice were treated with normal diet, low-salt diet, or high-salt diet. After 6 weeks of allocated diets, mice were euthanized, and their kidneys were collected. Leukocyte infiltration was assessed with CD45 immunohistochemistry. Lymphocytes were isolated from kidneys and were studied by flow cytometry. Human kidney transplant tissues obtained by a protocol biopsy at 2 weeks after kidney transplantation were stained with CD45, CD3, CD20, and CD31. Expression of each marker was quantified using an automated imaging analysis system and analyzed per donors’ pre-donation 24 h urine sodium levels. Induced pluripotent stem cell-derived endothelial cells (iPSC-ECs) from healthy individuals and end-stage kidney disease (ESKD) patients were treated with different sodium concentrations, and their proliferation was assessed. Results Kidneys from mice fed with high-salt diet had higher kidney leukocytes (CD45+) than those fed with normal diet (1.9 ± 0.3% vs 0.9 ± 0.1%, P = .043). Effector-memory CD4+ T cells (normal 44.2 ± 2.6%; low-salt 57.1 ± 3.5%, P = .020; high-salt 62.1 ± 2.5% of CD4+ T cells, P = .002) and mature B cells (70.0 ± 1.5%; 79.1 ± 1.4%, P = .001; 76.7 ± 1.6% of CD19+ cells, P = .015) increased by low-salt and high-salt diets, whereas naïve CD4+ T cells deceased (45.9 ± 2.1%; 32.7 ± 3.2%, P = .016; 27.8 ± 3.1% of CD4+ T cells, P = .001) in kidneys. Human kidney transplants from donors under low-salt diet showed lower total leukocytes (CD45+, 0.3 ± 0.1% vs 0.9 ± 0.3%, P = .019) with lower T and B cells (CD3+, 1.8 ± 0.2% vs 3.5 ± 0.4%, P<.001; CD20+, 0.8 ± 0.1% vs 2.1 ± 0.6%, P = .011) and higher capillary density (CD31+, 29.0 ± 2.2% vs 16.1 ± 1.8%, P = .009) compared to those from donors under high-salt diet. The proliferation of iPSC-ECs from healthy individuals and ESKD patients after hypoxia was reduced under higher sodium concentrations. Conclusion High-salt and low-salt diets affect kidney immune cell compositions and numbers as well as endothelial cells. Reconstitution of kidney microenvironment by modifying dietary salt intake could be a novel approach to improve kidney transplant outcomes.

#2935 Kidney transplantation outcomes following non-kidney solid organ transplantation

Abstract Background and Aims Approximately 15% of recipients of non-kidney solid organ transplantation (NKSOT) develop end-stage chronic kidney disease (CKD), requiring kidney transplantation (KT). There are controversy whether KT after NKSOT outcomes are poor or whether these patients should be prioritized. Method Retrospective analysis of KT after NKSOT in Andalusia between 1978-2023. We performed a case-control study, choosing 2 controls for each case (1 recipient of a second KT [reKT] and 1 recipient of a first KT without previous NKSOT), the closest ones with KT date and similar age and gender between donor and recipient. Patients with renopancreatic transplantation were excluded. We compared clinical characteristics and outcomes. Results During this period, we followed 12217 KT in Andalusia. Of these, 35 (0.003%) are KT after NKSOT: 26 (74.3%) liver transplant recipients, 7 (20%) heart transplant recipients and 2 (5.7%) lung transplant recipients. All of them are recipients of a first KT. When comparing KT after NKSOT vs. reKT and first KT recipients, demographic characteristics and donor type are similar in all 3 groups. The reKT recipients were on dialysis longer before receiving the second KT, with no difference between the other 2 groups. Graft survival of reKT patients was lower than the rest (vs. KT after NKSOT, p = 0.014; vs. first KT p < 0.001). Survival between KT after NKSOT and first KT was slightly worse in those who had received a previous NKSOT, but without significant differences. In multivariate analysis, adjusted for time on waiting list, reKT remained a risk factor at the limit of statistical significance (p = 0.072). There was no difference in patient survival. Conclusion KT after NKSOT has similar graft and patient survival outcomes to recipients of a first KT, and better than in recipients of a second KT.

A systematic review of kidney transplantation outcomes in patients with end-stage renal disease due to childhood lower urinary tract malformations.

Patients with lower urinary tract malformations (LUTM) were suspended from kidney transplantation (KT) programs in the past due to various concerns. Consequently, only a limited number of studies have explored this topic at hand. In this study, our objective was to perform a systematic review (SR) to evaluate the current evidence regarding KT outcomes as well as patient survival (PS), postoperative complications and urinary tract infections (UTI) in individuals with childhood LUTM. The search encompassed databases of Web of Science, Medline (via PubMed), and Embase (via Scopus) to identify all studies reporting outcomes on KT for patients with LUTM. The research included articles published in English from January 1995 till September 2023. Of the 2634 yielded articles, 15 met the inclusion criteria, enrolling a total of 284,866 KT patients. There was significantly better 5-year graft survival (GS) in recipients with LUTM compared to the control group (RR, 1.04; 95% CI 1.02-1.06); while GS at 1-year and 10-year, and PS at 1-year, 5-year and 10-year were similar between groups. On the other hand, the postoperative UTI rate was significantly higher in the LUTM group (RR: 4.46; 95% CI 1.89-10.51). However, data on serum creatinine and estimated glomerular filtration rate on follow-up were insufficient. GS and PS rates appear to be similar in patients with childhood LUTM and those with normal lower urinary tract functions. Despite a higher postoperative UTI rate within this patient group, it appears that this has no effect on GS rates.

Age Is Just a Number for Older Kidney Transplant Patients.

The rise in the mean age of the global population has led to an increase in older kidney transplant (KT) patients. This demographic shift, coupled with the ongoing organ shortage, requires a nuanced understanding of which older adults are most suitable for KT. Recognizing the increased heterogeneity among older adults and the limitations of solely relying on chronological age, there is a need to explore alternative aging metrics beyond chronological age. In this review, we discuss the impact of older age on access to KT and postoperative outcomes. Emphasizing the need for a comprehensive evaluation that extends beyond chronological age, we explore alternative aging metrics such as frailty, sarcopenia, and cognitive function, underscoring their potential role in enhancing the KT evaluation process. Most importantly, we aim to contribute to the ongoing discourse, fostering an optimized approach to KT for the rapidly growing population of older adults.

Immune monitoring in pediatric kidney transplant.

Long-term outcomes in pediatric kidney transplantation remain suboptimal, largely related to chronic rejection. Creatinine is a late marker of renal injury, and more sensitive, early markers of allograft injury are an active area of current research. This is an educational review summarizing existing strategies for monitoring for rejection in kidney transplant recipients. We summarize supporting currently available clinical tests, including surveillance biopsy, donor specific antibodies, and donor-derived cell free DNA, as well as the potential limitations of these studies. In addition, we review the current avenues of active research, including transcriptomics, proteomics, metabolomics, and torque tenovirus levels. Advancing the use of noninvasive immune monitoring will depend on well-designed multicenter trials that include patients with stable graft function, include biopsy results on all patients, and can demonstrate both association with a patient-relevant clinical endpoint such as graft survival or change in glomerular filtration rate and a potential timepoint for intervention.