Background. Immunosuppression in renal transplantation, although manageable in the short-term, is a major hurdle for long-term graft survival. Recently, increased frequencies of CD4⁺CD25^high regulatory T cells (Tregs) have been described as an additional mechanism that induces alloimmune tolerance. Methods. We assessed 64 renal transplant recipients with stable renal function for at least one year. Patients were divided into two groups according to the immunosuppression they were receiving at the moment of the study: one consisted of patients receiving rapamycin (Rapa) but not calcineurin inhibitors (CNI), and the other group received CNI but not Rapa. The Rapa group was further divided into three subgroups according to their previous experience with CNI: CNI-free, CNI withdrawal, and CNI conversion. Frequencies of blood Tregs were studied by flow cytometry after staining with monoclonal antibodies specific for different markers of Tregs. Results. Frequencies of CD4⁺ T cells with regulatory phenotype and function were significantly decreased in peripheral blood of renal transplant patients receiving CNI compared with those receiving Rapa. This effect was independent of an early exposure to CNI because the CNI-free patients in the Rapa group showed similar frequencies of Tregs to the CNI withdrawal and CNI conversion groups. Conclusions. CNI, but not Rapa, induce a decrease of circulating Tregs in stable renal transplant recipients. Thus, Rapa might be further explored in strategies using preservation of Tregs for transplant tolerance. Furthermore, quantification of blood Tregs may be a suitable tool to identify renal transplant recipients who may be candidates for reduced immunosuppression.

The use of donation after circulatory death (DCD) has increased significantly during the past decade. However, warm ischemia results in a greater risk for transplantation. Indeed, controlled DCD (cDCD) was associated with inferior outcomes compared with donation after brain death. The use of abdominal normothermic regional perfusion (nRP) to restore blood flow before organ recovery in cDCD has been proposed as better than rapid recovery to reverse the effect of ischemia and improve recipients’ outcome. Here, the first Spanish series using abdominal nRP as an in situ conditioning method is reported. A specific methodology to avoid restoring circulation to the brain after death determination is described. Twenty‐seven cDCD donors underwent abdominal nRP during at least 60 min. Thirty‐seven kidneys, 11 livers, six bilateral lungs, and one pancreas were transplanted. The 1‐year death‐censored kidney survival was 91%, and delayed graft function rate was 27%. The 1‐year liver survival rate was 90.1% with no cases of ischemic cholangiopathy. Transplanted lungs and pancreas exhibited primary function. The use of nRP may represent an advance to increase the number and quality of grafts in cDCD. Poor results in cDCD livers could be reversed with nRP. Concerns about restoring brain circulation after death are easily solved.

Background Lack of adherence to immunosuppressive drugs is a risk factor for development of de novo donor-specific antibodies (dnDSA) and can contribute to antibody-mediated rejection and graft loss. Moreover, nonadherence is the main determinant of immunosuppressive drug level variability. High intrapatient variability of tacrolimus relates to a worse outcome in transplant recipients through unknown mechanisms. We hypothesized that a high within-patient variability of tacrolimus could increase the rate of dnDSA development and contribute to further death-censored graft loss (DCGL). Methods We included 310 adult renal transplants receiving twice-daily tacrolimus throughout their first posttransplant year, with (1) at least 3 blood trough levels available to calculate coefficient of variation (CV) from month 4 to 12, (2) graft survival longer than 1 year, and (3) absence of pretransplant DSA. The dnDSA were analyzed in sera at 1, 3, and 5 years and around 6 month before the last follow-up visit or graft loss by single-antigen beads. Results During the follow-up, 53 patients lost their graft excluding death. A total of 116 patients (37.4%) had a CV greater than 30% and 39 (12.6%) developed dnDSA. Coefficient of variation greater than 30% (hazards ratio, 2.613; 95% confidence interval, 1.361-5.016; P = 0.004) independently related to DCGL. Acute rejection, re-transplant and CV greater than 30% (hazards ratio, 2.925; 95% confidence interval, 1.473-5.807; P = 0.002) were the only variables related to dnDSA development by Cox regression analysis. Conclusions Tacrolimus level variability is a strong risk factor for dnDSA development and DCGL. Variability must be added to the current monitoring of kidney transplant recipients due to its relationship with adherence and to graft outcome.

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 1.73m² 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/m²) 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 m², 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.

The purpose of this study was to evaluate early cyclosporine (CsA) withdrawal from a sirolimus (SRL)-CsA-steroid (ST) regimen. Within 48 hr after transplantation, 525 primary (90%) or secondary (10%) renal allograft recipients with cadaveric (89%) or living (11%) donors received 2 mg of SRL (troughs >5 ng/mL; immunoassay), CsA, and ST. Those eligible (430) were randomly assigned (1:1) at 3 months ± 2 weeks to remain on triple-drug therapy (SRL-CsA-ST group) or to have CsA withdrawn and SRL trough concentrations targeted to 20 to 30 ng/mL (SRL-ST group) until month 12, and 15 to 25 ng/mL thereafter. At 24 months, there were no statistically significant differences in patient survival (94.0% vs. 95.3%), graft survival (91.2% vs. 93.5%), acute rejection after randomization (5.1% vs. 9.8%) or discontinuations (34% vs. 33%) for SRL-CsA-ST versus SRL-ST, respectively. Serum creatinine level was significantly better in patients who had CsA withdrawn (167 vs. 128 μmol/L, P <0.001), as was the slope of 1/creatinine. Similarly, systolic blood pressure was lower in patients who had CsA withdrawn (141 vs. 134 mm Hg, P <0.001). High-density lipoprotein cholesterol was significantly higher in the SRL-ST group, whereas total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels were not significantly different. Hypertension, creatinine increase, abnormal kidney function, toxic nephropathy, edema, hyperuricemia, cataracts, Herpes zoster, and malignancy were reported significantly more often in patients continuing CsA. Thrombocytopenia, hypokalemia, abnormal liver function tests, abnormal wound healing, ileus, and pneumonia were reported significantly more frequently with SRL-ST. Data at 2 years confirm that early CsA withdrawal followed by an SRL-ST maintenance regimen results in long-term improvement in both renal function and blood pressure, without increased risk of graft loss or late acute rejection.

New-onset diabetes after transplantation (NODAT) contributes to the risk for cardiovascular disease and infection, reducing graft and patient survival. For improvement of the outcome of kidney transplant recipients, it is of great interest to know precisely the risk factors that contribute to NODAT development. Nonmodifiable risk factors for development of NODAT are age, race, genetic background, family history of diabetes, and previous glucose intolerance. Modifiable risk factors are obesity and overweight, hepatitis C virus and cytomegalovirus infections, and immunosuppressive drugs. Both steroids and calcineurin inhibitors influence the appearance of NODAT, whereas the role of sirolimus in glucose metabolism currently is controversial.