Long-term effects of hypercalcemia in kidney transplant recipients with persistent hyperparathyroidism.

BACKGROUND: Hypercalcemia is highly prevalent in kidney transplant recipients with hyperparathyroidism. However, its long-term impact on graft function is uncertain. METHODS: We conducted a prospective cohort study investigating adverse graft outcomes associated with persistent hypercalcemia (free calcium > 5.2 mg/dL in ≥ 80% of measures) and inappropriately elevated intact parathyroid hormone (> 30 pg/mL) in kidney transplant recipients. Asymptomatic mild hypercalcemia was monitored unless complications developed. RESULTS: We included 385 kidney transplant recipients. During a 4-year (range 1-9) median follow-up time, 62% of kidney transplant recipients presented persistent hypercalcemia. Compared to kidney transplant recipients without hypercalcemia, there were no significant differences in graft dysfunction (10% vs. 12%, p = 0.61), symptomatic urolithiasis (5% vs. 3%, p = 0.43), biopsy-proven calcium deposits (6% vs. 5%, p = 1.0), fractures (6% vs. 4%, p = 0.64), and a composite outcome of urolithiasis, calcium deposits, fractures, and parathyroidectomy indication (16% vs. 13%, p = 0.55). In a subset of 76 kidney transplant recipients, subjects with persistent hypercalcemia had higher urinary calcium (median 84 [43-170] vs. 38 [24-64] mg/day, p = 0.03) and intact fibroblast growth factor 23 (median 36 [24-54] vs. 27 [19-40] pg/mL, p = 0.04), and lower 25-hydroxyvitamin D levels (11.3 ± 1.2 vs. 16.3 ± 1.4 ng/mL, p < 0.001). In multivariate analysis, pretransplant intact parathyroid hormone < 300 pg/mL was associated with a reduced risk of post-transplant hypercalcemia (OR 0.51, 95% CI 0.32-0.80). CONCLUSIONS: Long-term persistent mild hypercalcemia (tertiary hyperparathyroidism) was frequent in kidney transplant recipients in our series. This condition presented with lower phosphate and 25-hydroxyvitamin D, and higher urinary calcium and intact fibroblast growth factor 23 levels compared to kidney transplant recipients without hypercalcemia, resembling a mild form of primary hyperparathyroidism. Despite these metabolic derangements, the risk of adverse graft outcomes was low.

Sub-classification of borderline changes into diffuse or focal and its impact on long-term renal transplant outcomes.

BACKGROUND: Borderline changes (BL) with stable renal function is a controversial category in renal transplantation, given its contradictory outcomes. The aim of this study was to compare the clinical outcomes of BL in patients with stable renal function classified as focal and diffuse according to the extent of tubulitis. METHODS: Patients with no history of rejection with a surveillance graft biopsy at 3 or 12 months showing BL (n = 40), acute cellular rejection (n = 20) or normal biopsies (n = 20), were included in this study. Biopsies with BL were divided into diffuse BL (BLD) and focal BL (BLF) according to the extent of tubulitis. Because of the low frequency of subclinical ACR (ACRND) (n = 12), biopsies with ACR and graft dysfunction (ACRD) (n = 8) were also included. A composite outcome that included the presence of rejection in subsequent biopsies, graft loss, patient death, decrease in GFR ≥30% or presence of de novo DSA (dnDSA) during the first year of follow-up was evaluated. RESULTS: The primary composite outcome occurred in five patients of each of the Normal, BLF and ACRND, eight patients with BLD and six patients with ACRD (p = 0.105). A trend towards more rejection episodes was observed in the ACRND and ACRD. Also, a shorter time to rejection in the BLD, ACRND and ACRD groups compared to BLF and Normal groups (p = 0.039) was observed. During the first year of follow-up, no patient in the ACRND group developed dnDSA, compared to 15-25% in the other groups. The median time of dnDSA development in the BLF group was 45 months, and in the BLD group was 10 months (p = 0.020). CONCLUSION: Classifying BL biopsies with stable renal function into focal and diffuse categories, is a simple and feasible strategy that helps to differentiate between BLD with a phenotype that shows a trend towards worse outcomes, and BLF that behaves more similar to normal biopsies.

Spironolactone reduces oxidative stress in living donor kidney transplantation: a randomized controlled trial.

Mineralocorticoid receptor antagonism prevents acute kidney injury induced by ischemia-reperfusion in rodent and pig preclinical models. In a pilot study, we showed that spironolactone (25 mg) reduced oxidative stress after 5 days of kidney transplant (KT). In the present study, we investigated the effects of higher doses (50 and 100 mg) of spironolactone on kidney function, tubular injury markers, and oxidative stress in living donor KT recipients. We included KT recipients aged 18 yr or older who received immunosuppression therapy with IL-2 receptor antagonist, mycophenolate mofetil, corticosteroids, and tacrolimus with negative cross-match, and compatible blood group. Patients were randomized to receive placebo (n = 27), spironolactone (50 mg, n = 25), or spironolactone (100 mg, n = 25). Treatment was given from 3 days before and up to 5 days after KT. Serum creatinine, K+, urine neutrophil gelatinase-associated lipocalin-2, heat shock protein 72, and 8-hydroxy-2-deoxyguanosine levels were assessed. As expected, kidney function was improved after KT. Serum K+ remained in the normal range along the study. There was no significant effect of spironolactone on urinary neutrophil gelatinase-associated lipocalin-2 levels, whereas the increase in urinary heat shock protein 72 levels tended to be less intense in the 100 mg spironolactone-treated group (P = 0.054). In the placebo-treated group, urinary 8-hydroxylated-guanosine levels increased on days 3 and 5 after transplantation. This effect was prevented in patients that received spironolactone. In conclusion, spironolactone reduces the acute increase in urinary oxidative stress in living donor KT recipients.

Antibody-mediated rejection in the Banff classifications of 2007 and 2017: A comparison of renal graft loss prediction capability.

BACKGROUND: Antibody-mediated rejection (ABMR) is the leading cause of kidney graft loss worldwide. Criteria for acute humoral rejection (currently labeled active humoral rejection) established by the 2007 Banff classification are highly specific but lack sensitivity. Modifications to the Banff classification were introduced for its 2013 and 2017 versions in order to identify more cases of this entity. PURPOSE: We intend to demonstrate that, compared to its 2007 version, the 2017 Banff classification bears an improved capacity for graft loss prediction when histologic criteria for active ABMR are met. PATIENTS AND METHODS: Single-center retrospective cohort study. A random sample of 201 kidney recipients who underwent a graft biopsy since January 2004 was analyzed. Patients were classified as ever developing histologic characteristics of acute ABMR (2007 Banff) or not and renal survival between groups was compared. The same patients were then classified as ever developing histologic characteristics of active ABMR (2017 Banff) or not and renal survival was again compared. Presence of circulating donor-specific antibodies (DSA) was not taken into consideration. RESULTS: Patients were followed for a median 13.9 ±â€¯7.9 years, during which grafts were biopsied on 537 occasions (2.7 ±â€¯1.6 biopsies per graft). Baseline eGFR was 73.26 ±â€¯17.6 ml/min and baseline creatinine 1.14 ±â€¯0.25 mg/dl. Graft loss occurred in 38 recipients (18.9%) mainly due to ABMR (60.5%). Acute ABMR (2007 Banff) was identified in 11 recipients (5.5%) and graft survival did not differ between groups with and without active ABMR occurrence (log-rank p = 0.939). Active ABMR (2017 Banff) was found in 59 recipients (29%) and graft survival was better from the second post-transplant year onward in the group of patients without active ABMR occurrence (log-rank p = 0.001). Moderate microvascular inflammation was present in 89.6% of the 48 additional patients with active ABMR. CONCLUSION: The 2017 Banff classification identifies more patients who develop active ABMR and stratifies graft loss risk better than the 2007 version.

Graft immunologic events in deceased donor kidney transplant recipients with preformed HLA-donor specific antibodies.

INTRODUCTION: Pretransplant donor-specific HLA alloantibodies detected with the Single Antigen Bead (SAB) assay reflect an increased risk for acute antibody-mediated rejection (AMR). We herein report the incidence of both acute AMR and acute cellular rejection (ACR) during the first year posttransplantation, in a cohort of kidney transplant recipients (KTR) of deceased donor (DD) grafts, according to their DSA status. Pretransplant DSA do not preclude DD-KT in negative CDC-XM recipients at our center. PATIENTS AND METHODS: 246 KT were performed at our center between 01/2012 and 12/2015 and 100 KTR obtained from a DD were analyzed; 24% harbored DSA by SAB assay, MFI values >500 were considered positive. All recipients received thymoglobulin induction and generic tacrolimus-based maintenance therapy. Graft biopsies were performed by protocol on months 3 and 12 as well as per indication. The incidence of AMR and ACR was correlated with the existence of pretransplant DSA. RESULTS: Overall, 34% of patients developed an acute rejection episode, 54.2% in the DSA group versus 27.6% in the non-DSA group (p=0.032), and most of these events were detected as subclinical conditions in protocol biopsies. AMR events developed in 33.3% and 19.7% (p=0.176) in the DSA and the non-DSA groups, respectively. ACR events were found in 16.6% and 6.6% (p=0.127) in the DSA and non-DSA groups, respectively. Graft function was similar between groups at the end of the 1st year posttransplant and no immunological graft loss occurred. CONCLUSION: Despite the use of depleting induction therapy and adequate tacrolimus trough levels along with MMF and steroids, a high rate of rejection events was observed during the first year post-transplantation.

Influenza Immunization and the Generation of Anti-HLA and Anti-MICA Antibodies in Patients with Renal Failure and in Kidney Transplant Recipients.

The aim of this study was to determine whether the influenza vaccine induces the development of anti-human leukocyte antigen (HLA) and anti-major histocompatibility complex class I - chain A (MICA) antibodies. We determined the presence or de novo development of anti-HLA and anti-MICA antibodies in 3 groups of patients vaccinated against influenza: A) 42 healthy adults; B) 40 end-stage kidney disease patients; C) 25 kidney transplant recipients; and, D) 22 healthy adults who refused vaccination. Serum samples per subject were obtained: prior to vaccination, one week after vaccination, and on a monthly basis for 6 months. They were analyzed by LABScreen® Single Antigen, Luminex. The proportions of de novo antibodies (anti-HLA and anti-MICA) in the 4 groups were 2.4%, 17.5%, 20%, and 0%, respectively. Some patients developed the antibodies later, unrelated to the vaccine. We found preformed antibodies (anti-HLA and anti-MICA) in 67%, 78%, 88%, and 27% of cases in groups A, B, C, and D, respectively. The presence of preformed antibodies was the only predictive factor for the development of de novo antibodies. In conclusion, the development of de novo anti-HLA and anti-MICA antibodies after an external stimulus other than HLA antigens is possible. However, not all cases can be attributed to the vaccine.

Bortezomib for acute humoral rejection treatment at the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán in Mexico City: an update.

The use of bortezomib as a treatment modality of AHR improved and stabilized graft function (clinical response) in the majority of patients. Its use in single dose, even combined with rituximab, does not seem to be useful to obtain a sustained clinical response, or to reduce HLAabs level. The use of 4 doses of bortezomib in days 1, 4, 7, and 10 (1.3 mg/m2 BSA each) plus plasmapheresis produced both a good clinical response and a reduction in DSA. Moving forward, it will be necessary to define the long-term effectiveness of bortezomib and whether rituximab administration is indispensable to achieve this goal. Until now, it is evident that many patients needed retreatment and they were well tolerated.