Acute Antibody-Mediated Rejection in Kidney Transplant Based on the 2013 Banff Criteria: Single-Center Experience in Uruguay.

BACKGROUND: Acute antibody-mediated rejection (AMR) diagnosis criteria have changed in recent consensus of Banff, with current evidence of C4d-negative AMR. Our objective was to evaluate incidence of AMR in renal transplantation according to Banff 2013 criteria and to examine the histological features and outcome. METHODS: This retrospective study involved all kidney transplants with histological diagnosis of acute rejection (AR) at our center between 2000 and 2014. All the biopsies with AR were re-assessed by a nephro-pathologist and classified by use of the Banff 2013 criteria. RESULTS: Of 205 kidney transplants, biopsy-proven AR was diagnosed in 25 cases (12%). Re-assessing them according to Banff 2013 criteria, AMR was diagnosed in 17 (8.3%) and represented 68% of the confirmed rejections. AMR diagnosis was performed on day 23 ± 26, with median of 11 days. From the 17 cases, 7 had concomitant T-cell-mediated rejection. All cases presented endothelial edema and acute tubular necrosis. Glomerulitis was found in 12 cases and capillaritis in 14. In 3, associated thrombotic micro-angiopathy (TMA) was found. Intimal and transmural arteritis was evidenced in 5 and 1 patient. In 2, transplant glomerulopathy was present. Seven of the 10 biopsies with C4d staining in the peri-tubular capillaries were positive. Twelve cases received plasmapheresis, 6 received gamma-globulin, and 6 received rituximab. After administration of anti-AMR therapy, 16 cases recovered renal function, reaching a serum creatinine level of 1.5 ± 0.6 mg %. Graft survival at 1 year was lower in the AMR group versus patients without AMR (81.9% vs 98.9%, log-rank test, P < .001). Risk factors for AMR were re-transplant (30% vs 7%, P = .02), HLA-DR mismatch (1.06 ± 0.65 vs 0.7 ± 0.6, P = .03), panel-reactive antibody (28% ± 33 vs 6.2 ± 13, P = .00), and delayed graft function (82% vs 30%, P = .00). CONCLUSIONS: Adapting the new Banff 2013 criteria increased the sensitivity of the diagnosis of ARM. Regarding our data, despite an adequate response to the therapy, it resulted in a worse graft survival by the first year of renal transplant.

First 1500 Kidney Transplants at the Institute of Nephrology and Urology in Uruguay: Analysis of the Results.

BACKGROUND: The Institute of Nephrology and Urology (INU) has performed 75% of kidney transplantations (KT) in Uruguay during its 35 years of activity, with 90.6% from cadaveric donors. We investigated the risk factors (RF) for delayed graft function (DGF) and patient and graft survival (SV). METHODS: We analyzed retrospectively the characteristics and evolution of 1500 KT performed by INU until December 2014. The incidence of DGF and RF for patient and graft SV were analyzed in 4 eras, according to the year that KT was performed. RESULTS: The number of KT per year has progressively increased until reaching 40 KT per million population in 2006, with a decrease of the living donor KT (LDKT) rate. The age of the donors (D) and recipients (R) as well as the time on dialysis (TOD) have progressively increased over the different eras. Five hundred twenty-five R (35%) presented with DGF. The RF for DGF were the age of the R and the D, the TOD, the DDKT, and the warm ischemia time (WIT). In the DDKT group, the cold ischemia time and "died of stroke" were added factors. The death-censored graft SV at 1, 5, 10, and 15 years were 90%, 76%, 62%, and 49%, respectively. They improved as from era I, the patient SV being 92%, 83%, and 75% at 1, 5, and 10 years, in era I; 98%, 93%, and 86% in era II; 98%, 92%, and 83% in era III; and 95% and 90% at 1 and 5 years in era IV (P < .001). The graft SV over the same periods was 76%, 58%, and 40% in era I; 88%, 68%, and 52% in era II; 93%, 81%, and 70% in era III; and 93% and 85% at 1 and 5 years in era IV (P < .0001). The RF for patient SV were diabetes mellitus, era I, lower albuminemia, older age or TOD, and DGF. For kidney SV, the era, the age of the R, TOD, DGF, and D older than 60 years were RF associated with a worse evolution. In DDKT, the RF for the graft SV were the era, younger age of the R, and DGF. The group with the worst graft SV was the one made up of children and adolescents. CONCLUSIONS: Our results relating to patient and graft SV are acceptable and comparable to those mentioned on large records such as the OPNT/SRTR and the Collaborative Transplant Study. This has been the case, even though we have transplanted increasingly aged patients, with increasingly aged donors, or donors with associated pathology. The risk factors that we found both for DGF and SV have also been pointed out by other authors. The validity of some findings has the limitation of being from a retrospective analysis; hence, they should be corroborated by a prospective study.

Preemptive kidney transplantation--a team experience in Uruguay.

Kidney transplantation is the best treatment for end-stage chronic renal disease. In Uruguay, the prevalence of patients on dialysis is 757 patients per millon inhabitants, plus 316 alive with a functioning renal graft. We install a preemptive renal transplantation program. Twenty-five patients received grafts without dialysis from 2004 to 2013, 5 receiving their 2nd transplantation and 17 from cadaveric donors, with 7.4 ± 7.7 months in the waiting list. At 24 months, patients' survival rate was 100% and the grafts' 97%, with a serum creatinine of 1.4 ± 0.6 mg%. The developed programs of dialysis and renal health care contributed install our preemptive kidney transplantation. Kidney transplantation should be proposed to selected patients with chronic renal failure as primary therapy of substitution of renal function.

Can we use 99mTc-MIBI in functional studies of the parathyroid gland?

The usefulness of technetium-99m-sestamibi (99mTc-MIBI) in patients with secondary hyperparathyroidism on haemodialysis was assessed. We studied 33 patients with parathyroid scintigraphy with i.v. (99mTc-MIBI). Static images in a scintillation camera were taken at 15 and 120 min after the injection. With P x Ca<80, we performed an inhibition test with calcitriol i.v. 2 microg, three times a week, for 2 weeks. The MIBI study and assessment of intact parathyroid hormone (iPTH) were performed before (baseline study) and after inhibition. A 'focal positive study' corresponded to one or more areas of abnormal hypercaptation in relation to surrounding thyroid tissue seen in early images and persisting in later images, and a 'negative study' did not correspond to the previous image. In the baseline study, iPTH in the positive MIBI group was significantly greater than in the negative group. Eight positive MIBI patients had a bone biopsy; six corresponded to severe osteitis fibrosa and two to mild osteitis fibrosa. In the negative MIBI group, four of the six patients who had bone biopsy had mild forms of osteitis fibrosa (Fisher=0.03); the other two had low turnover forms. A positive inhibition test was defined when the basal uptake disappeared after calcitriol administration. In these patients, we observed a significant decrease of iPTH, not observed in the negative inhibition test. In 10 patients who had been parathyroidectomized, those with alpha positive basal MIBI result had a nodular parathyroid hyperplasia. We conclude that a scintigraphic parathyroid study with 99mTc-MIBI showed a good correlation with functional parathyroid status. With the same inhibition test, only some glands were inhibited, suggesting that this could be the expression of different vitamin D receptor densities in inhibited glands and/or a different kind of proliferation in those glands. This test would be of value in functional studies when a therapeutic decision must be made.