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SARS-CoV-2 infection (COVID-19) has had a significant impact on transplant activity in our country. Mortality and the risk of complications associated with COVID-19 in kidney transplant recipients (KT) were expected to be higher due to their immunosuppressed condition and the frequent associated comorbidities. Since the beginning of the pandemic in March 2020 we have rapidly improved our knowledge about the epidemiology, clinical features and management of COVID-19 post-transplant, resulting in a better prognosis for our patients. KT units have been able to adapt their programs to this new reality, normalizing both donation and transplantation activity in our country.This manuscript presents a proposal to update the general recommendations for the prevention and treatment of infection in this highly vulnerable population such as KT., (© 2022 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U.)

Background: Urinary CXCL10 (uCXCL10) is associated with graft inflammation and graft survival, but the factors related to its excretion are not well known. HLA molecular matching at epitope level allow estimating the "dissimilarity" between donor and recipient HLA more precisely, being better related to further transplant outcomes. The relationship between uCXCL10 and HLA molecular mismatch has not been previously explored., Methods: HLA class I and class II typing of some 65 recipients and their donors was retrospectively performed by high resolution sequence-specific-primer (Life Technologies, Brown Deer, WI). The HLA-Matchmaker 3.1 software was used to assess eplet matching. Urine samples collected on the day of the 1-year surveillance biopsy were available of these 65 patients. uCXCL10 was measured using a commercial enzyme-linked immunoassay kit., Results: 1-year uCXCL10 was independently associated with HLA-DQB1 eplet mismatch load (β 0.300, 95%CI 0.010-0.058, p = 0.006). Kidney transplant recipients with a HLA-DQB1 eplet mismatch load >3 showed higher values of uCXCL10 at 1-year (p = 0.018) than those with ≤3. Patients with a HLA-DQB1 eplet mismatch load >3 with subclinical AbMR had significantly higher levels of the logarithm of 1-year uCXCL10 (No AbMR 0.88, IQR 0.37; AbMR 1.38, IQR 0.34, p = 0.002) than those without AbMR., Conclusions: uCXCL10 specifically relates to HLA-DQ eplet mismatch load. This relationship can partly explain the previously reported association between uCXCL10 excretion and graft inflammation. An adequate evaluation of any potential non-invasive biomarker, such as uCXCL10, must take into account the HLA molecular mismatch., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Oral fosfomycin may constitute an alternative for the treatment of lower urinary tract infections (UTIs) in kidney transplant recipients (KTRs), particularly in view of recent safety concerns with fluroquinolones. Specific data on the efficacy and safety of fosfomycin in KTR are scarce. We performed a retrospective study in 14 Spanish hospitals including KTRs treated with oral fosfomycin (calcium and trometamol salts) for posttransplant cystitis between January 2005 and December 2017. A total of 133 KTRs developed 143 episodes of cystitis. Most episodes (131 [91.6%]) were produced by gram-negative bacilli (GNB), and 78 (54.5%) were categorized as multidrug resistant (including extended-spectrum β-lactamase-producing Enterobacteriaceae [14%] or carbapenem-resistant GNB [3.5%]). A median daily dose of 1.5 g of fosfomycin (interquartile range [IQR]: 1.5-2) was administered for a median of 7 days (IQR: 3-10). Clinical cure (remission of UTI-attributable symptoms at the end of therapy) was achieved in 83.9% (120/143) episodes. Among those episodes with follow-up urine culture, microbiological cure at month 1 was achieved in 70.2% (59/84) episodes. Percutaneous nephrostomy was associated with a lower probability of clinical cure (adjusted odds ratio: 10.50; 95% confidence interval: 0.98-112.29; P = 0.052). In conclusion, fosfomycin is an effective orally available alternative for treating cystitis among KTRs., (© 2019 The American Society of Transplantation and the American Society of Transplant Surgeons.)

Background: The improvement in the definition of serum anti-HLA antibodies (HLA-Abs) profiles after Luminex-assay implementation in transplant patients follow-up is clear. This success has permitted the development of hypersensitized-recipient allocation and donor-paired exchange programs improving the access to transplantation. However, non-HLA Abs have been described in transplanted patients but their effect in hypersensitized transplanted recipients is unclear., Methods: Twenty-seven HLA hypersensitized patients awaiting for kidney transplantation (KT) were studied and 11 of them were followed after KT. The HLA Abs profile was confirmed in serum by Single Antigen Luminex assay and panel reactive of antigens >98% was achieved in all patients. Subsequently, the ability to fix complement by C1q test was also assessed. Serum non-HLA Abs before and 1 month after transplantation were measured in the 11 hypersensitized recipients., Results: 95.2% of the hypersensitized on waiting list had concomitant serum anti-HLA and non-HLA Abs. The more frequent specificity in non-HLA Abs were found against Glutathione S-transferase theta-1 (GSST-1) (in 62%) and C-terminal fragment of perlecan (LG3) (in 52%). Four out of 11 transplanted patients presented early antibody-mediated rejection (ABMR) confirmed by biopsy and had serum anti-LG3 antibodies, two of them with concomitant anti-anti-angiotensin II type I receptor. Only one patient developed de novo-donor specific HLA antibodies., Conclusions: The incidence of non-HLA antibodies in patients in the waiting list is largely underestimated. The concomitance anti-HLA and non-HLA Abs in hypersensitized patients is very common and the detection of non-HLA Abs in this population could allow to identify patients with an increased risk of humoral rejection., (Copyright © 2018. Published by Elsevier B.V.)

There are no approved treatments for chronic antibody mediated rejection (ABMR). We conducted a multicenter, prospective, randomized, placebo-controlled, double-blind clinical trial to evaluate efficacy and safety of intravenous immunoglobulins (IVIG) combined with rituximab (RTX) (EudraCT 2010-023746-67). Patients with transplant glomerulopathy and anti-HLA donor-specific antibodies (DSA) were eligible. Patients with estimated glomerular filtration rate (eGFR) <20 mL/min per 1.73m 2 and/or severe interstitial fibrosis/tubular atrophy were excluded. Patients were randomized to receive IVIG (4 doses of 0.5 g/kg) and RTX (375 mg/m 2 ) or a wrapped isovolumetric saline infusion. Primary efficacy variable was the decline of eGFR at one year. Secondary efficacy variables included evolution of proteinuria, renal lesions, and DSA at 1 year. The planned sample size was 25 patients per group. During 2012-2015, 25 patients were randomized (13 to the treatment and 12 to the placebo group). The planned patient enrollment was not achieved because of budgetary constraints and slow patient recruitment. There were no differences between the treatment and placebo groups in eGFR decline (-4.2 ± 14.4 vs. -6.6 ± 12.0 mL/min per 1.73 m 2 , P-value = .475), increase of proteinuria (+0.9 ± 2.1 vs. +0.9 ± 2.1 g/day, P-value = .378), Banff scores at one year and MFI of the immunodominant DSA. Safety was similar between groups. These data suggest that the combination of IVIG and RTX is not useful in patients displaying transplant glomerulopathy and DSA., (© 2017 The American Society of Transplantation and the American Society of Transplant Surgeons.)

Introduction: Steroid withdrawal in renal transplantation is desirable to avoid their adverse effects. However, by decreasing the immunosuppression, could lead to an increased risk for the development of HLA-Abs., Objective: Evaluate the relationship between steroid withdrawal and development of HLA-Abs in renal transplantation., Methods: We analyzed sera by Luminex from 182 kidney transplants performed from 1998 to 2011, before and two years after transplantation. All the patients had a pretransplant PRA (panel reactive of antibodies) <20% by complement-dependent cytotoxicity (CDC) and maintenance immunosuppression with tacrolimus and mycophenolate mofetil (MMF). We compared a group of steroid withdrawal at 7 months (group-I; n=130) and another control with non-withdrawal (group-II; n=52)., Results: 22 patients (16.9%) in group-I and 11 patients in group-II (21.1%) had HLA-Abs after two years (pNS). Despite excluding patients with PRA >20%, we detected HLA-Abs pretransplant by Luminex in 11.5% of patients in both groups, of which, 66.6%, versus 53% (p 0.058), developed new specificities, with a similar percentage of donor specific antibodies (DSA) in both groups (33.33% vs 36.36%), pNS. In the subgroup without pretransplant HLA-Abs (group-I; n=115, group-II; n=45), 6.08% developed de novo HLA-Abs, being DSA 3.4% (Group-I) versus 7.69% in group II with 3.84% DSA (pNS)., Conclusions: Steroid withdrawal at 7 months of renal transplantation does not entail a higher risk in terms of HLA-Abs development in patients without pretransplant HLA-Abs and treatment with tacrolimus and MMF, although larger studies are needed to confirm these findings., (Copyright © 2017 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.)

Background: Post-transplant proteinuria is associated with lower graft and patient survival. Renin-angiotensin-aldosterone system blockers are used to reduce proteinuria and improve renal outcome. Although it is known that a high salt intake blunts the antiproteinuric effect of ACEI and ARB drugs in non-transplant patients, this effect has not been studied in kidney transplant recipients., Objective: To analyse the relationship between sodium intake and the antiproteinuric effect of ACEI/ARB drugs in kidney transplant recipients., Methods: We selected 103 kidney transplant recipients receiving ACEI/ARB drugs for more than 6 months due to proteinuria>1 g/day. Proteinuria was analysed at baseline and at 6 months after starting ACEI/ARB treatment. Salt intake was estimated by urinary sodium to creatinine ratio (uNa/Cr)., Results: Proteinuria fell to less than 1g/day in 46 patients (44.7%). High uNa/Cr was associated with a smaller proteinuria decrease (r=-0.251, P=.011). The percentage proteinuria reduction was significantly lower in patients in the highest uNa/Cr tertile [63.9% (IQR 47.1%), 60.1% (IQR 55.4%), 38.9% (IQR 85.5%), P=.047]. High uNa/Cr independently relates (OR 2.406 per 100 mEq/g, 95% CI: 1.008-5.745, P=.048) to an antiproteinuric response <50% after renin-angiotensin-aldosterone system blockade., Conclusions: A high salt intake results in a smaller proteinuria decrease in kidney transplant recipients with proteinuria treated with ACEI/ARB drugs., (Copyright © 2016 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.)

Background: Since 2004, various criteria have been proposed to define and stage acute kidney injury (AKI). Nevertheless, fixed criteria for assessing severe sepsis-related AKI have not yet been established., Objectives: To assess the ability of the different AKI classification methods to predict mortality in a cohort of patients with sepsis., Methods: A prospective study of patients>18 years with septic shock admitted to the intensive care unit (ICU) of our hospital from April 2008 to September 2010 was conducted. Plasma creatinine levels were measured daily in the ICU. Patients were classified retrospectively according to RIFLE, AKIN, KDIGO and creatinine kinetics (CK) criteria., Results: The AKI rate according to the different criteria was 74.3% for RIFLE, 81.7% for AKIN, 81.7% for KDIGO and 77.5% for CK. AKI staging by RIFLE (OR 1.452, P=.003), AKIN (OR 1.349, P=.028) and KDIGO criteria (OR 1.452, P=.006), but not CK criteria (OR 1.188, P=.148) were independently related to in-hospital mortality., Conclusions: A high rate of patients with severe sepsis developed AKI, which can be classified according to different criteria. Each stage defined by RIFLE, AKIN and KDIGO related to a higher risk of in-hospital mortality. In contrast, the new CK criteria did not relate to higher mortality in patients with severe sepsis and this classification should not be used in these patients without further studies assessing its suitability., (Copyright © 2016 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.)

The aim of this study was to find noninvasive T-cell markers able to predict rejection or infection risk after kidney transplantation. We prospectively examined T-lymphocyte subsets after cell culture stimulation (according to CD38, CD69, CD95, CD40L, and CD25 expression) in 79 first graft recipients from four centers, before and after transplantation. Patients were followed up for one year. Patients who rejected within month-1 (n=10) showed high pre-transplantation and week-1 post-transplantation percentages of CD95(+), in CD4(+) and CD8(+) T-cells (P<0.001 for all comparisons). These biomarkers conferred independent risk for early rejection (HR:5.05, P=0.061 and HR:75.31, P=0.004; respectively). The cut-off values were able to accurately discriminate between rejectors and non-rejectors and Kaplan-Meier curves showed significantly different free-of-rejection time rates (P<0.005). Patients who rejected after the month-1 (n=4) had a higher percentage of post-transplantation CD69(+) in CD8(+) T-cells than non-rejectors (P=0.002). Finally, patients with infection (n=41) previously showed higher percentage of CD38(+) in CD8(+) T-cells at all post-transplantation times evaluated, being this increase more marked in viral infections. A cut-off of 59% CD38(+) in CD8(+) T-cells at week-1, week-2 and month-2 reached 100% sensitivity for the detection of subsequent viral infections. In conclusion, predictive biomarkers of rejection and infection risk after transplantation were detected that could be useful for the personalized care of kidney recipients., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The survival of patients with diabetes mellitus in the general population has improved in recent years. Here we assessed whether similar trends have occurred in 1688 kidney recipients, including 413 with diabetes prior to transplant between 1996 and 2007. Compared to patients without diabetes, the 5-year mortality was significantly increased (hazard ratio (HR) 2.68 (1.95-3.69)) due to higher cardiovascular-, infection-, and malignancy-related deaths in those with diabetes. However, 5-year mortality in patients with diabetes significantly declined over time (HR 0.883 (0.817-0.954)), narrowing the mortality difference between patients with and those without diabetes and in more recent years largely eliminating it. Post transplant, patients with diabetes experienced a significant decline in major fatal/nonfatal cardiac events (HR 0.853 (0.782-0.930)) and infectious deaths over time. In contrast, neither cardiac events nor overall mortality declined in recipients without diabetes. The decline in mortality due to diabetes did not relate to a reduced pretransplant risk profile and was independent of posttransplant variables. The use of cardioprotective medications and glycemic control improved over time post transplant. Furthermore, graft function and serum albumin significantly improved over time and these parameters related to better survival (albumin, HR 0.365 (0.223-0.599); eGFR, HR 0.803 (0.756-0.852)). Thus, survival of kidney recipients with diabetes mellitus has improved markedly since 1996 likely reflecting, at least in part, enhanced posttransplant management and outcomes.

The incidence of stroke is higher substantially among hemodialysis patients than in the overall population. In this observational cohort study, we analysed data from incident hemodialysis patients at Valdecilla University Hospital in Santander (Spain) during a 40-year period (1971-2011). A total number of 1453 patients were started on hemodialysis The total follow-up period was 4982.22 patients/year, with 84 patients having stroke. The cumulative incidence of stroke in our patients was 5.8%, with an incidence rate of 1686 strokes per 100 000 patient-years. The incidence rate in the first year was 1803 strokes per 100 000 patients-year, 6.5% higher than its average over the period studied. In the remaining period, the rates ranged between 356 and 1626 strokes per 100 000 patients-year. Significative factors related to stroke were: diabetes, myocardial infarction or angina, hypertension, arteriosclerosis/intermittent claudication, history of stroke before the HD and atrial fibrillation. Haemoglobin levels in the cohort stroke were virtually identical to those of the not stroke cohort (11.92±2.07 g/dL, compared to 11, 68±2.12 g/dL). Finally, 60.7% of the population of the stroke cohort received erythropoietin with mean dose of 9611 IU/week, compared to 51.9% and a dose of 9544 IU/week in the not stroke cohort, without significative differences among groups. In conclusion, in haemodialysis population the incidence of stroke is 7-10 times higher than in the general population. It is associated with well known factors for stroke but not with haemoglobin levels or erythropoietin dose.

ImmuKnow is an in vitro diagnosis method that uses patient samples of whole blood polyclonally stimulated with phytohaemagglutinin. It also measures adenosine triphosphate (ATP) production by CD4+ T cells. The test aims to offer an objective and overall measurement of each individual's cellular immune response. The assay was designed with the idea of individually monitoring the immunosuppression administered to transplant patients. At the same time, it aims to help achieve a balance as a way of avoiding immunosuppression excess and the associated adverse effects (infections, cancer, etc.) or an immunosuppression defect and the subsequent risk of allograft rejection. The majority of studies that have evaluated its clinical usefulness display great diversity in terms of patient recruitment, the immunosuppressant treatment received, the clinical variables analysed and, above all, the time between performing ImmuKnow and the evaluated clinical event. The most consistent data show that this assay on CD4+ T cell functioning is useful for predicting the risk of infection in renal transplant patients. However, its use as a rejection risk indicator is unclear. Lastly, given the great variability of immune response amongst individuals and that of existing publications, it can be deduced that the isolated ImmuKnow value does not have diagnostic capacity and only individual serial monitoring could provide definitive assistance in clinical decision making and immunosuppressant treatment changes. Other aspects of ImmuKnow application in the clinical routine, such as assay cycles, require randomised prospective studies for more comprehensive information.

Elevated pulse pressure in general population has been shown to be associated with cardiovascular disease, which is the main cause of death in renal transplant patients. We investigated the effect that a wider pulse pressure range may have on cardiovascular disease after renal transplantation in 532 transplant patients with functioning graft for more than 1 year. Patients were classified into two groups depending on 1-year pulse pressure (< or >/=65 mmHg) and we analyzed patient and graft survival, post-transplant cardiovascular disease and main causes of death. Higher pulse pressure was associated with older recipient age (40.8 +/- 10.8 vs. 50 +/- 11.3), higher systolic blood pressure (132.7 +/- 16.1 vs. 164.5 +/- 16), lower blood diastolic pressure (84.5 +/- 11.6 vs. 84.4 +/- 11.2), higher prevalence of diabetes (12% vs. 23%) and total cardiovascular disease (20.9% vs. 33.6%). Five- and 10-year patient survivals were lower in the group with higher pulse pressure, being vascular disease the main cause of death in both groups. In a Cox regression model increased pulse pressure was associated with higher cardiovascular disease (RR = 1.73, 95% CI: 1.13-2.32 p < 0.01). In conclusion, pulse pressure was an independent risk factor for increased cardiovascular morbidity and mortality in renal transplant patients.

Delayed graft function (DGF) is a common complication after renal transplant, affecting its outcome. A common definition of DGF is the need for dialysis within the first week of transplantation, but this criterion has its drawbacks. We tried to validate an earlier and better defined parameter of DGF based on the creatinine reduction ratio on post-transplant day 2 (CRR2). We analyzed the clinical charts of 291 cadaver kidney recipients to compare the outcome of patients with immediate graft function (IGF), dialyzed patients (D-DGF) and nondialyzed CRR2-defined DGF patients (ND-DGF) and to identify risk factors for D-DGF and ND-DGF. Creatinine reduction ratio on post-transplant day 2 correlates significantly with renal function during the first year. Patients with IGF have significantly better renal function throughout the first year and better graft survival than patients with D-DGF and ND-DGF, while we found no differences either in renal function from days 30-365 or in graft survival between D-DGF and ND-DGF patients. Defining DGF by CRR2 allows an objective and quantitative diagnosis after transplantation and can help to improve post-transplant management. Creatinine reduction ratio on post-transplant day 2 correlates with renal function throughout the first year. The worse survival in the ND-DGF group is an important finding and a major advantage of the CRR2 criterion.

Hyperlipidemia and insulin resistance frequently develop after renal transplantation, contributing to cardiovascular disease. Individual differences in response based upon genetic variations in proteins regulating lipidic and glucose tolerance metabolism could be expected. In the general population, the S2 allelic variant of the apoprotein (apo) C-III gene has been associated with hypertriglyceridemia and an insulin resistant state, whereas the E4 allele of the apo E has been associated with hypercholesterolemia and atherosclerosis. Its influence in renal transplant patients remains to be seen. In order to assess the impact of apo E and C-III major polymorphisms on atherosclerotic vascular disease, lipid profile and impaired glucose tolerance in renal transplant patients, we studied 110 consecutively examined patients undergoing kidney transplantation (age range 24-73 years). Atherosclerotic complications were detected in 25% of patients, with age, male sex and hypercholesterolemia being significant atherosclerotic risk factors. Among the male patients with E4 allele, the odds ratio for coronary disease and global atherosclerosis were 10.2 (95% CI) and 6.4 (95% CI), respectively. There were no significant differences in the frequency of any of the polymorphisms among patients with dyslipidemia and impaired glucose tolerance. As the number of patients in our sample was small, larger studies are needed to verify these issues. While in the studied population C-III polymorphism appears to have little association with the prevalence of atherosclerotic complications, E4 allele should be considered as a genetic marker of coronary artery disease and global atherosclerosis in renal transplant patients.