Pediatric kidney dimensions and risk of persistent albuminuria in Mexican adolescents

In Mexico, chronic kidney disease of unknown origin is highly prevalent. Screening studies in adolescents have shown persistent microalbuminuria (pACR), adaptive podocytopathy and decreased kidney volume (KV). Here, we sought to develop normality tables of kidney dimensions by ultrasound in the Mexican state of Aguascalientes pediatric population (0 to 18y) and evaluate the relationship between the KV and pACR among the region's adolescents in a cross-sectional study. Kidney length (KL) and KV were determined by ultrasound. Our findings were compared with those in international literature of different populations where tables and graphs of normal kidney dimensions by ultrasound were reported. We compared organ dimensions in individuals above the age of 11 without albuminuria with those in patients with pACR recruited through screening studies in adolescents in Aguascalientes. This included 1068 individuals to construct percentile tables and graphs of the KL. Kidney dimensions were significantly lower when compared with all international comparisons. From a total 14,805 screen individuals, we compared 218 adolescents with pACR and 377 individuals without significant albuminuria. The Total KV adjusted to body surface (TKVBS) was significantly associated with pACR (odds ratio 1.03, 95% confidence interval 1.02-1.03). The upper quartile of TKVBS was highly associated with pACR (7.57, 4.13-13.87), hypertension (2.53, 1.66-3.86), and hyperfiltration (26 vs 11.5%). Thus, TKVBS is directly associated with pACR while greater KV, arterial hypertension, and hyperfiltration in patients with pACR suggest that the increase in volume is secondary to kidney hypertrophy. Additionally, the adaptative podocytopathy with low fibrosis seen on kidney biopsy which was performed in a subset of patients, and the smaller kidney dimensions in our population point to prenatal oligonephronia as the primary cause of the detected kidney disease.

Changes in the commercial brand of tacrolimus lead to subtherapeutic trough levels and acute rejection in renal transplant recipients

BACKGROUND

The vigilance of tacrolimus (TAC) trough levels is an essential part of renal transplant follow up. Reduced TAC trough levels and high variability are related to adverse outcomes. The aim of this study was to evaluate the impact of brand changes on tacrolimus (TAC) subtherapeutic (SubT) trough levels, acute rejection (AR), and kidney function.

METHODS

This is a prospective, observational cohort study of renal transplant recipients, between January 2016 and October 2018. Tacrolimus trough levels and brand used by the patient were both registered at every consult. Tacrolimus values ≤3.5 ng/mL were considered SubT.

RESULTS

445 patients were included. The median number of TAC brand changes was 2 (IQR, 1-4). Patients were grouped according to the number of brand changes: Group 1 = 0 (n = 107), Group 2 = 1-4 (n = 236), and Group 3 = ≥5 (n = 102). Patients with the greatest number of brand changes had a greater proportion and number of SubT TAC trough levels (Group 1 = 36.4%, average 0.53; Group 2 = 39.8%, average 0.65, Group 3 = 59.8%, average 1.17, P < .001) and AR (Group 1 = 0.9%, Group 2 = 11%, Group 3 = 14.7%, P < .001). On multivariate analysis, SubT levels and the number of brand changes were related to AR.

CONCLUSIONS

In Mexico, changes in TAC brand are associated with an elevated frequency of SubT levels. Brand changes and SubT levels are independently associated with acute rejection. The supply policies on TAC brands in Mexico require revision to avoid changing brands as much as possible.

Tissue talks: immunophenotype of cells infiltrating the graft explains histological findings and the benefits of belatacept at 10 years

Previously, we found a substantial number of regulatory T cells (T_regs ) and fewer senescent and T helper type 17 (Th17) and a decrease in interstitial fibrosis (IF) in 12-month graft biopsies in belatacept versus cyclosporin (CNI)-treated patients [Belatacept Evaluation of Nephroprotection and Efficacy as First-line Immunosuppression Trial (BENEFIT) study]. Seven years after kidney transplantation (KT), mean estimated glomerular filtration rate (eGFR), patient and graft survival were significantly higher with belatacept versus CNI treatment. The aim of this study was to determine whether the immunophenotypes of inflammatory and regulatory cell subsets infiltrating the grafts contribute to the BENEFIT's clinical findings a decade after KT. Twenty-three adult patients with functionally stable KT treated with belatacept and 10 treated with CNI were enrolled. Biopsies were analyzed by histomorphometry and immunohistochemistry for proliferation, senescence, apoptosis, inflammatory and regulatory cell markers in a blinded manner. Significantly lower percentages of inflammatory/fibrogenic cells [interleukin (IL)-22⁺ /Th17/Th2/M1 macrophages] were observed in patients treated with belatacept than in patients treated with CNI. By contrast, remarkably higher percentages of regulatory cells [T_regs /B_regs / plasmacytoid dendritic regulatory cells (pDC_regs )/M2] were found in belatacept-treated patients than in CNI-treated patients. Conspicuously lower percentages of apoptosis and senescence and higher proliferation markers were found in belatacept-treated patients than in CNI-treated patients. Consequently, there was significantly more inflammation in the microvascular compartments as well as increased tubular atrophy and IF in CNI-treated patients. These findings strongly suggest that regulatory mechanisms, along with the absence of deleterious effects of CNI, contribute to the long-term graft histology and function stability in patients treated with belatacept.

Tacrolimus Trough Levels as a Risk Factor for Acute Rejection in Renal Transplant Patients

BACKGROUND

Use of tacrolimus (TAC) is pivotal to renal transplant (RT) immunosuppressive maintenance regimens. The aim of this study was to evaluate the relationship between TAC trough levels and the development of acute rejection (AR).

MATERIAL AND METHODS

This was a retrospective cohort study. We included recipients transplanted between 01/2008 and 05/2012. Regression analyses (Cox's proportional hazards model) and sub-analysis of AR and TAC levels over different time periods were performed.

RESULTS

We included 198 patients with an average age of 32 years (±12.1) and predominantly male (54.5%). Mean follow-up was 2 years (min-max 15d - 5.2yrs). Sixty-two AR events were documented (BL: 31, Cellular AR: 19, Humoral AR: 12). We found that TAC levels (HR 0.76, 0.65-0.88, p<0.001), a high risk for CMV infection (D+/R-) (HR 2.92, 1.47-1.014, p=0.002), pre-transplant donor-specific HLA antibodies (DSA) (HR 3.04 1.29-7.16, p=0.011), and post-RT DSA (HR 2.4, 1.16-4.9, p=0.018) were significantly associated with AR. The relationship between TAC levels and rejection was independent of follow-up duration.

CONCLUSIONS

In this analysis, TAC though levels were directly related to AR events; trough levels >8 ng/ml were the most effective in decreasing immunological adverse events. A decrease in TAC levels throughout the post-transplant follow-up period should be considered due to its possible association with AR events.

Renal flare prediction and prognosis in lupus nephritis Hispanic patients

We performed a retrospective cohort analysis focusing on lupus nephritis renal flare incidence and outcome predictors. One hundred and eighteen patients with biopsy-proven lupus nephritis were segregated by induction/maintenance regimes. The primary outcome was the proportion of patients experiencing renal flare. Secondary assessment included doubling of serum creatinine and development of end-stage renal disease. After a median follow-up of 31 months (interquartile range 21–46) from the date of response to induction therapy, 47 patients (39.8%) developed a renal flare. Azathioprine-maintained patients had a higher risk of renal flare compared with mycophenolate mofetil-maintained patients (hazard ratio 2.53, 95% confidence interval 1.39–4.59, p < 0.01). Age (hazard ratio 0.96, 0.92–0.99, p = 0.03), serum creatinine at presentation (hazard ratio 1.76, 1.13–2.76, p = 0.01), complete remission after induction therapy (hazard ratio 0.28, 0.14–0.56, p < 0.001) and azathioprine maintenance therapy (hazard ratio 4.78, 2.16–10.6, p < 0.001) were associated with renal flare on multivariate analysis. Ten patients progressed to end-stage renal disease (8.5%) by a median 32.5 months. Age (hazard ratio 0.88, 0.77–0.99, p = 0.05), complete remission after induction therapy (hazard ratio 0.08, 0.01–0.94, p = 0.04) and severe nephritic flare (hazard ratio 13.6, 1.72–107.7, p = 0.01) were associated with end-stage renal disease development. Azathioprine maintenance therapy is associated with a higher incidence of relapse in the Mexican-mestizo population. Younger age and nephritic flares predict development of end-stage renal disease.

Comparison of Lupus Nephritis Induction Treatments in a Hispanic Population: A Single-center Cohort Analysis

OBJECTIVE

To evaluate response rates in an adult lupus nephritis (LN) cohort in Mexico City, Mexico.

METHODS

We analyzed 165 patients with biopsy-proven LN histological International Society of Nephrology/Renal Pathology Society classes III, IV, or V, distributed by treatment drug in 3 groups: mycophenolate mofetil (MMF; dosage > 2 g/day per 6 mos, n = 63), intravenous cyclophosphamide (IVC; 0.7 g/m(2) body surface area monthly per 6 pulses, n = 66), or azathioprine (AZA; dosage > 1.5 mg/kg/day per 6 mos, n = 36). Median followup was 31 ± 18 months. The primary endpoint was the proportion of patients achieving complete renal response (CR). Secondary endpoints included the proportion of patients achieving renal response (complete or partial), renal flare-free survival, doubling of serum creatinine, and progression to endstage renal disease (ESRD).

RESULTS

MMF induction was superior to IVC (HR 2.00, 95% CI 1.23-3.25, p = 0.005) and AZA (HR 2.12, 95% CI 1.23-3.66, p = 0.007) in the primary endpoint. Censored CR rates at 6, 12, 24, and 36 months were 32.6%, 56.1%, 76.6%, and 94.1% for MMF; 24.2%, 34.4%, 57.9%, and 62.1% for IVC; and 8.4%, 39.8%, 49.7%, and 49.7% for AZA. MMF was also superior in renal response to treatment and renal flare-free survival outcomes. There were no differences between groups in doubling of serum creatinine or progression to ESRD. The induction treatment with MMF (HR 2.04, 95% CI 1.25-3.33, p = 0.005) and absence of vascular lesions on renal biopsy (HR 2.05, 95% CI 1.25-3.37, p = 0.004) were associated with CR, whereas proteinuria at the time of presentation was negatively associated with CR (HR 0.91, 95% CI 0.84-0.98, p = 0.013).

CONCLUSION

MMF induction therapy is superior to IVC and AZA in patients with LN of Mexican-mestizo race.

Pre-transplant angiotensin II type 1receptor antibodies: a risk factor for decreased kidney graft function in the early post-transplant period?

Angiotensin II type 1 receptor antibodies (AT1Rab) are associated to a significantly lower graft survival and a higher risk of acute rejection after kidney transplantation. This study aimed to evaluate graft function and BPAR during the 1st year post-transplant (PT) in adult kidney transplant recipients (KTR), between 03/2009 and 08/2012. Pre-KT sera were screened for AT1Rab (ELISA) and HLA-DSA (Luminex). Three groups were analyzed: AT1Rab only (n = 13); HLA-DSA only (n = 8); and no AT1Rab or HLA-DSA (n = 90). No differences were observed in clinical characteristics across groups. A higher percentage of BPAR was observed in the AT1Rab positive group, but this difference was not significant. KTR with AT1Rab had a lower mean eGFR (20 mL/min/1.73m2) when compared to KTR with no Abs at 12 months. The significant difference in eGFR was observed since the 1st month PT. Multivariate analysis showed 4 factors independently and significantly associated with eGFR at 12mos PT: BPAR (-18.7 95%, CI -28.2 to -9.26, p<0.001), AT1Rab (-10.51, CI -20.9 to -0.095, p = 0.048), donor age (-0.42, CI -0.75 to -0.103 p = 0.010), and recipient age (-0.36, CI -0.67 to -0.048, p = 0.024). In this study AT1Rab in pre-transplant sera from KTR, was an independent and significant risk factor contributing to a lower eGFR 12 months. PT. This finding deserves to be confirmed in a larger KTR population.

Pre-nephrectomy angiotensin II type 1 receptor antibodies in living kidney donors: A concern?

Angiotensin II type 1 receptor (AT1R) autoantibodies (AT1Rab) have been associated with pre-eclampsia and malignant hypertension. Overactivity of the angiotensin-II/AT1R complex has also been implicated in cardiac, renal, and vascular remodeling, leading to mortality and morbidity from cardiovascular disease. Pre-donation prevalence and possible post-donation effects of AT1Rab in living kidney donors (LKD) are unknown. In this study, sera obtained the day before nephrectomy and kept frozen at -70 degrees C from 113 strictly normotensive and non-obese LKD were tested for AT1Rab by OneLambda detection assay. AT1Rab titers >or=17 international units were considered positive. Pre-donation renal function [estimated glomerular filtration rate (eGFR)] and blood pressure at 1 and 12 months post-donation were recorded in every patient. Ten of 113 (8.8%) LKD yielded a positive AT1Rab result. History of sensitization events was similar in both groups. There was no difference in renal function between LKD with positive and negative AT1Rab results, 1 (mean eGFR 73.8 versus 72.4 mL/min/1.73m2) and 12 months post-donation (mean eGFR 74.1 versus 74.5 mL/min/1.73m2). During follow-up, none of the LKD developed hypertension (defined as blood pressure >130/85), nor did they require antihypertensive drugs. AT1Rab are apparently indolent in healthy adults after short-term follow-up. Longer observation of all LKD will be necessary to draw final conclusions.

Pre-transplant angiotensin II type 1 receptor antibodies: A risk factor for decreased kidney graft function in the early post-transplant period?

Angiotensin II type 1 receptor antibodies (AT,Rab) are associated with a significantly lower graft survival and a higher risk of acute rejection after kidney transplantation. This study aimed to evaluate graft function and biopsy proven acute rejection (BPAR) during the first year post-transplant in adult renal transplant recipients (RTR), between 03/2009 and 08/2012. Pre-transplant sera were screened for AT1Rab (via enzyme linked immunosorbent assay) and donor specific anti-human leukocyte antigen antibodies (HLA-DSA, via Luminex). Three groups were analyzed: AT1Rab only (n=13); HLA-DSA only (n=8); and no AT1Rab or HLA-DSA (n=90). No differences were observed in clinical characteristics across groups. A higher percentage of BPAR was observed in the AT1Rab positive group, but this difference was not significant. RTR with AT1Rab had a lower median estimated glomerular filtration rate (eGFR=20 ml/min/1.73m2) when compared to RTR with no antibodies at 12 months. A significant difference in eGFR was observed since the first month post-transplant. Multivariate analysis showed four factors independently and significantly associated with eGFR at 12 months post-transplant: BPAR (beta -18.7, 95% CI -28.2 to -9.26, p<0.001), AT,Rab (beta -10.51, 95% CI -20.9 to -0.095 p=0.048), donor age (beta -0.42, 95% CI -0.75 to -0.103, p=0.010), and recipient age (3 -0.36, 95% CI -0.67 to -0.048, p= 0.024). In this study, AT1Rab in pre-transplant sera from RTR was an independent and significant risk factor contributing to a lower eGFR at 12 months posttransplant. This finding deserves to be confirmed in a larger RTR population.