N. Cognard

Recent changes in chronic kidney disease-mineral and bone disorders (CKD-MBD) and associated fractures after kidney transplantation.

Background The management of chronic kidney disease–mineral and bone disorders has recently changed. We investigated the modifications of chronic kidney disease–mineral and bone disorder with a special focus on the incidence of fractures in the first year after kidney transplantation (KT). Methods We retrospectively compared 2 groups of patients who consecutively underwent transplantation at our center 5 years from each other. Group 1 consisted of patients (n = 152) transplanted between 2004 and 2006, whereas patients in group 2 (n = 137) underwent KT between 2009 and 2011. Results During the end-stage renal disease phase at the time of transplant, cinacalcet, and native vitamin D were used significantly more frequently in group 2. Median intact parathyroid hormone levels were lower and severe hyperparathyroidism decreased significantly. Vitamin D deficiency dropped from 64% to 20%. After transplantation, persistent hyperparathyroidism (parathyroid hormone > 130 ng/L) and bone turnover markers were significantly reduced in group 2. Native vitamin D supplementation increased over time, whereas the use of active vitamin D was unchanged. The 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels were significantly higher. The fracture incidence at 1 year decreased significantly (3.1% vs 9.1%; P = 0.047). No steroid sparing was observed in group 2. Bisphosphonates after KT were more frequently used in group 2. Conclusions Recent changes in clinical practice are associated with reductions in pretransplant and posttransplant hyperparathyroidism, vitamin D deficiency, and fracture risk after KT.

Pre-existing donor-specific antibodies are detrimental to kidney allograft only when persistent after transplantation

Donor‐specific antibodies (DSA) increase the risk of allograft rejection and graft failure. They may be present before transplant or develop de novo after transplantation. Here, we studied the evolution of preformed DSA and their impact on graft outcome in kidney transplant recipients. Using the Luminex Single Antigen assay, we analyzed the sera on the day of transplantation of 239 patients who received a kidney transplant. Thirty‐seven patients (15.5%) had pre‐existing DSA detected the day of transplantation. After 5 years, the pre‐existing DSA disappeared in 22 patients whereas they persisted in 12. Variables associated with DSA persistence were age <50 years (P = 0.009), a history of previous transplantation (P = 0.039), the presence of class II DSA (P = 0.009), an MFI of preformed DSA >3500 (P < 0.001), and the presence of two or more DSA (P < 0.001). DSA persistence was associated with a higher risk of graft loss and antibody‐mediated rejection. Previously undetected preformed DSA are deleterious to graft survival only when they persist after transplantation.

Recurrence of renal cell cancer after renal transplantation in a multicenter French cohort

Background Renal cancer accounts for 3% of adult malignancies; renal cell carcinoma (RCC) represents 80% of all renal cancers, and is characterized by late recurrences. Recurrences after kidney transplantation are associated with a high mortality rate. We aimed to determine if recurrences are linked to tumor characteristics and to delays between diagnosis and transplantation. Methods We retrospectively analyzed data from French kidney-transplanted patients with medical histories of pretransplant renal cancer, focusing on the most common histological subtypes: clear cell and papillary cancers. Characteristics of the tumors, patients, and kidney transplantations were documented, and posttransplant patient survival was analyzed. Results Of 143 patients, 13 experienced cancer recurrence after kidney transplantation. The mean delay in recurrence was 3 ± 2.3 years posttransplantation, and the cumulative incidences of recurrence were 7.7% at 5 years and 14.9% at 10 years. The risk of recurrence was higher in patients with clear cell RCC (13% vs 0%, P = 0.015). There was no correlation between posttransplant recurrence and the interval before transplantation. Factors associated with a higher risk of cancer recurrence were histological clear cell RCC (P = 0.025), tumor stage pT2 (P = 0.002), and Fuhrman grade IV (P < 0.001). Recurrences were associated with a high mortality rate; 76.9% of patients with recurrences had died by the end of the follow-up period. Conclusions Recurrences of clear cell RCC are not uncommon after kidney transplantation and are associated with very poor prognoses. These results should be considered before listing patients with a history of renal cancer for transplantation.

Eculizumab for Thrombotic Microangiopathy Associated with Antibody-Mediated Rejection after ABO-Incompatible Kidney Transplantation

Thrombotic microangiopathy is a form of antibody-mediated rejection (ABMR): it is the main complication of ABO-incompatible (ABOi) kidney transplantation (KT). Herein, we report on two cases of ABMR with biological and histological features of thrombotic microangiopathy (TMA) that were treated by eculizumab after ABOi KT. The first patient presented with features of TMA at postoperative day (POD) 13. Because of worsening biological parameters and no recovery of kidney function, despite seven sessions of immunoadsorption, a salvage therapy of eculizumab was started on POD 23. Kidney function slightly improved during the first 4 months after transplantation. Eculizumab was stopped at month 4. However, kidney function worsened progressively, leading to dialysis at month 13 after transplantation. The second patient presented with features of TMA at POD 1. In addition to immunoadsorption therapy, eculizumab was started on POD 6. Kidney function improved. Eculizumab was stopped on POD 64 and immunoadsorption sessions were stopped on POD 102. At the last follow-up (after 9 months), eGFR was at 43 mL/min/1.73 m2. Our case reports show the beneficial effect of eculizumab to treat ABMR after ABOi KT. However, it should be given early after diagnosing TMA associated with ABMR.

Impaired P2Y12 inhibition by clopidogrel in kidney transplant recipients: results from a cohort study

BackgroundCardiovascular complications represent a major cause of morbidity and mortality for patients who received kidney transplantation (KT). However, the impact of KT and chronic immunosuppression on platelet response to clopidogrel in patients undergoing coronary or peripheral revascularization procedures remains unclear. This cohort study compares platelet responsiveness to clopidogrel as assessed byvasodilator-stimulated phosphoprotein (VASP) phosphorylation.MethodsThe study population was divided between chronic kidney disease (CKD) patients who underwent KT (n = 36) and non-transplanted CKD patients (control group, n = 126). Patients were on maintenance antiplatelet therapy with clopidogrel 75 mg daily for at least 8 days. The mean platelet reactivity index (PRI) VASP values and the prevalence of high on-treatment platelet reactivity (HPR, defined as PRI VASP ≥61 %) were compared.ResultsThe mean PRI VASP value was significantly higher in the transplant group (60.1 ± 3 vs 51.2 ± 1.6 %; p=0.014). HPR was significantly more common in the transplant group on clopidogrel maintenance therapy (58 vs. 31 %; p = 0.011). KT was the only independent predictor of HPR (odds ratio: 2.6; 95 % confidence interval: 1.03–6.27, p = 0.03). The effect of treatment with calcineurin inhibitors on clopidogrel response could not be analyzed separately from the kidney transplant status.ConclusionsKT is associated with an increased prevalence of HPR. Our results suggest that plateletfunction tests may be clinically useful for the management of this specific population.