Pre-transplant angiotensin II receptor type I antibodies in pediatric renal transplant recipients: An observational cohort study

BACKGROUND

The role of angiotensin II type 1 receptor antibodies (AT1R-Ab) in pediatric renal transplantation is unclear. Here, we evaluated pre-transplant AT1R-Ab on transplant outcomes in the first 5 years. Secondary analysis compared pre-transplant AT1R-Ab levels by age.

METHODS

Thirty-six patients, 2-20 years old, were divided into two groups: pre-transplant AT1R-Ab- (<17 U/ml; n = 18) and pre-transplant AT1R-Ab+ (≥17 U/ml; n = 18). eGFR was determined at 6-month, 1-, 2-, and 4-year post-transplant. Allograft biopsies were performed in the setting of strong HLA-DSA (MFI > 10 000), AT1R-Ab ≥17 U/ml, and/or elevated creatinine.

RESULTS

Mean age in pre-transplant AT1R-Ab- was 13.3 years vs. 11.0 in pre-transplant AT1R-Ab+ (p = 0.16). At 6 months, mean eGFR was 111.3 ml/min/1.73 m² in pre-transplant AT1R-Ab- vs. 100.2 in pre-transplant AT1R-Ab + at 1 year, 103.6 ml/min/1.73 m² vs. 100.5; at 2 years, 98.9 ml/min/1.73 m² vs. and 93.7; at 4 years, 72.6 ml/min/1.73 m² vs. 80.9. 11/36 patients had acute rejection (6 in pre-transplant AT1R-Ab-, 5 in pre-transplant AT1R-Ab + ). There was no difference in rejection rates. All 6 subjects with de novo HLA-DSA and AT1R-Ab ≥17 U/ml at the time of biopsy experienced rejection. Mean age in those with the AT1R-Ab ≥40 U/ml was 10.0 years vs. 13.2 in those <40 U/ml (p = 0.07).

CONCLUSION

In our small cohort, pre-transplant AT1R-Ab ≥17 U/ml was not associated with reduced graft function or rejection. The pathogenicity of pre-transplant AT1R-Ab in pediatric kidney transplantation requires further investigation.

Use of Rituximab for persistent EBV DNAemia, and Its effect on donor-specific antibody development in pediatric renal transplant recipients: A case series

INTRODUCTION

Persistent EBV DNAemia (PEBV) is associated with late-onset PTLD. The efficacy of rituximab in PEBV is not conclusive. We monitored PEBV and DSA in pediatric kidney transplant patients with or without rituximab.

METHODS

13 PEBV patients received standard treatment with immunosuppression reduction and valganciclovir, with or without IVIG; 5/13 were further treated with rituximab.

RESULTS

All Rituximab-treated and 6/7 No-Rituximab patients were EBV seronegative at transplant and seroconverted post-transplant. Peak EBV PCR levels were lower in No-Rituximab than Rituximab patients and all No-Rituximab patients cleared PEBV after standard treatment. Additional 1-2 doses of rituximab reduced EBV PCR levels in all 5 Rituximab patients, 3 cleared PEBV. One No-Rituximab patient developed localized PLTD. None of Rituximab patients developed de novo DSA, while 4/8 No-Rituximab patients did: 2/4 had ABMR. 1/5 Rituximab and 5/8 No-Rituximab patients had acute rejection. There was no change in eGFR between pre-EBV DNAemia and follow-up in Rituximab patients, while reduction in No-Rituximab patients was found. There was no difference in graft and patient survival.

CONCLUSIONS

While early intervention with rituximab in pediatric patients with PEBV may reduce viral load and PTLD, we observed a slower development of de novo DSA, and rejection and maintenance of eGFR.

Association between Psychiatric Disorders and Glomerular Disease

Introduction

Patients with chronic health conditions, particularly chronic kidney disease, are at heightened risk for psychiatric disorders; yet, there are limited data on those with primary glomerular disease.

Methods

This study included patients with glomerular disease enrolled in the kidney research network multisite patient registry. Registry data include encounter, diagnoses, medication, laboratory, and vital signs data extracted from participants' electronic health records. ICD-9/10 diagnosis codes were used to identify a subset of psychiatric disorders focused on anxiety, mood, and behavioral disorders. Time-varying Cox proportional hazard models were used to analyze time from the onset of kidney disease to diagnosis of psychiatric disorder. Adjusted models retained significant covariates from the full list of potential confounders, including age, sex, race, ethnicity, time-varying treatment, the estimated glomerular filtration rate, and proteinuria (urine protein-to-creatinine ratio [UPCR]). Analogous models examined diagnosis of psychiatric disorder as a predictor of time to end-stage kidney disease (ESKD).

Results

Data were available for 950 participants, with a median of 58 months of follow-up. 110 (12%) participants were diagnosed with psychiatric disorder during the follow-up. The estimated rate of psychiatric diagnosis after kidney disease was 14.7 cases per 1,000 person-years and was highest among those of adolescent age at the time of kidney disease diagnosis. Adjusted analyses found adolescent age (vs. adult, hazard ratio [HR] = 3.11, 95% confidence interval [CI] 1.87-5.17) and Asian race (vs. white, HR = 0.34, 95% CI 0.16-0.71) were associated with psychiatric diagnosis. A higher UPCR per 1 log unit (HR 1.13, 95% CI 1.01-1.27) and a higher total number of oral medications were associated with psychiatric disorder (p < 0.001). Psychiatric diagnosis was also associated with progression to ESKD (HR = 2.45, 95% CI 1.53-3.92) in adjusted models.

Discussion/Conclusion

Psychiatric disorders were documented in approximately one-eighth of patients with glomerular disease and correlated with clinical disease characteristics such as age, race, proteinuria, and oral medication burden. These findings suggest mental health screening is warranted in patients of all ages with glomerular disease.

The Development and Use of an EHR-Linked Database for Glomerular Disease Research and Quality Initiatives

Background and Objective

The use of electronic health record (EHR) data can facilitate efficient research and quality initiatives. The imprecision of ICD-10 codes for kidney diagnoses has been an obstacle to discrete data-defined diagnoses in the EHR. This manuscript describes the Kidney Research Network (KRN) registry and database that provide an example of a prospective, real-world data glomerular disease registry for research and quality initiatives.

Methods

KRN is a multicenter collaboration of patients, physicians, and scientists across diverse health-care settings with a focus on improving treatment options and outcomes for patients with glomerular disease. The registry and data warehouse amasses retrospective and prospective data including EHR, active research study, completed clinical trials, patient reported outcomes, and other relevant data. Following consent, participating sites enter the patient into KRN and provide a physician-confirmed primary kidney diagnosis. Kidney biopsy reports are redacted and uploaded. Site programmers extract local EHR data including demographics, insurance type, zip code, diagnoses, encounters, laboratories, procedures, medications, dialysis/transplant status, vitals, and vital status monthly. Participating sites transform data to conform to a common data model prior to submitting to the Data Analysis and Coordinating Center (DACC). The DACC stores and reviews each site's EHR data for quality before loading into the KRN database.

Results

As of January 2021, 1,192 patients have enrolled in the registry. The database has been utilized for research, clinical trial design, clinical trial end point validation, and supported quality initiatives. The data also support a dashboard allowing enrolling sites to assist with clinical trial enrollment and population health initiatives.

Conclusion

A multicenter registry using EHR data, following physician- and biopsy-confirmed glomerular disease diagnosis, can be established and used effectively for research and quality initiatives. This design provides an example which may be readily replicated for other rare or common disease endeavors.

Time to Initiation of Antihypertensive Therapy After Onset of Elevated Blood Pressure in Patients With Primary Proteinuric Kidney Disease

Rationale & Objective

The objective of the study was to estimate the prevalence of hypertension in patients with proteinuric kidney disease and evaluate blood pressure (BP) control.

Study Design

Retrospective cohort study.

Setting & Participants

Data from adults and children with proteinuric kidney disease enrolled in the multicenter Kidney Research Network Registry were used for this study.

Exposure

Proteinuric kidney disease.

Outcomes

Hypertension and BP control.

Analytical Approach

Patients with white-coat hypertension were excluded. Patients were censored at end-stage kidney disease onset. Patients were defined as hypertensive either by hypertension diagnosis code, having 2 or more encounters with elevated BPs, or treatment with antihypertensive therapy excluding renin-angiotensin-aldosterone system blockade. Elevated BP was defined as greater than 95th percentile for children and >140/90 mm Hg in adults. Sustained BP control was defined as 2 or more consecutive encounters with BPs lower than 95th percentile for children and <140/90 mm Hg for adults. Kaplan-Meier and Cox proportional hazards analyses were used to evaluate the time to initiation of antihypertensive therapy.

Results

842 patients, 69% adults and 31% children, with a total observation period of 6,722 patient-years were included in the analysis. 644 (76%) had hypertension during observation. There was no difference in the prevalence of hypertension between children and adults (74% vs 78%; P = 0.3). Hypertension was most common among those of African American race compared with other races (90% vs 72%-75%; P = 0.003). 504 (78%) patients with hypertension achieved BP control but only 51% achieved control within 1 year. 140 (22%) patients with hypertension never achieved BP control during a median of 41 (IQR, 24-73) months of observation.

Limitations

Differing BP control goals that may lead to overestimation of the controlled patient population.

Conclusions

Hypertension affects most patients with proteinuric kidney disease regardless of age. Time to BP control exceeded 1 year in 50% of patients with hypertension and 22% did not demonstrate control. This study highlights the need to address hypertension early and completely in disease management of patients with proteinuric kidney disease.

Steroid-Associated Side Effects in Patients With Primary Proteinuric Kidney Disease

Introduction

The goal of this study was to assess the occurrence of steroid-associated adverse events (SAAE) in patients with primary proteinuric kidney disease.

Methods

The Kidney Research Network Registry consists of children and adults with primary proteinuric kidney disease. SAAEs of interest were hypertension, hyperglycemia and diabetes, overweight and obesity, short stature, ophthalmologic complications, bone disorders, infections, and psychosis. Events were identified using International Classification of Diseases, Ninth Revision/Tenth Revision codes, blood pressures, growth parameters, laboratory values, and medications. Poisson generalized estimating equations tested the association between steroid onset and dose on SAAE risk.

Results

A total of 884 participants were included in the analysis; 534 (60%) were treated with steroids. Of these, 62% had at least one SAAE. The frequency of any SAAE after initiation of steroids was 293 per 1000 person-years. The most common SAAEs were hypertension (173.7 per 1000 person-years), diabetes (78.7 per 1000 person-years), obesity (66.8 per 1000 person-years), and infections (46.1 per 1000 person-years). After adjustment for demographics, duration of kidney disease, estimated glomerular filtration rate (eGFR), proteinuria, and other therapies, steroid exposure was associated with a 40% increase in risk of any SAAE (Relative risk [RR]: 1.4; 95% confidence interval [CI]: 1.3–1.6). A 1-mg/kg per day increase in steroid dose was associated with a 2.5-fold increase in risk of any SAAE.

Conclusion

Most patients with primary proteinuric kidney disease treated with steroids experienced at least one SAAE. Steroid therapy increased risk of hypertension, diabetes, weight gain, short stature, fractures, and infections after adjusting for disease-related factors. This study highlights the importance of surveillance and management of SAAE and provides rationale for the development of steroid minimization protocols.

An Outcomes-Based Definition of Proteinuria Remission in Focal Segmental Glomerulosclerosis

BACKGROUND AND OBJECTIVES

Proteinuria is used as an indicator of FSGS disease activity, but its use as a clinical trial end point is not universally accepted. The goal of this study was to refine proteinuria definitions associated with long-term kidney survival.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data on 466 patients with primary FSGS with proteinuria (urine protein-to-creatinine ratio >1 g/g) were analyzed from five independent cohorts. Proteinuria by months 1, 4, and 8 after study baseline was categorized by conventional definitions of complete (<0.3 g/g) and partial remission (<3.5 g/g and 50% reduction in proteinuria). Novel remission definitions were explored using receiver operating curves. Kaplan-Meier methods were used to estimate the associations of proteinuria with progression to ESRD or a 50% loss in kidney function. Propensity score-adjusted Cox proportional hazards models were used to adjust for baseline proteinuria, eGFR, and therapy.

RESULTS

In the initial derivation cohort, conventional partial remission was not associated with kidney survival. A novel definition of partial remission (40% proteinuria reduction and proteinuria<1.5 g/g) on the basis of receiver operating curve analyses of 89 patients was identified (Sensitivity=0.70; Specificity=0.77). In the validation cohort analyses, complete remission was associated with better prognosis (6 out of 41 patients progressed to kidney failure; 6.6 per 100 patient-years) as was the novel partial remission (13 out of 71 progressed; 8.5 per 100 patient-years), compared with those with no response (51 out of 116 progressed; 20.1 per 100 patient-years). Conventional partial remission at month 8, but not month 4, was also associated with better response (19 out of 85 patients progressed; risk=10.4 per 100 patient-years). Propensity score-adjusted analyses showed the novel partial remission was associated with less progression at months 4 and 8 (month 4: hazard ratio, 0.50; P=0.01; month 8: hazard ratio, 0.30; P=0.002).

CONCLUSIONS

Reaching either a complete or partial remission using a novel or conventional definition was associated with better long-term outcomes in patients with FSGS.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2018_02_20_CJASNPodcast_18_3_T.mp3.

Risk factors for the development of antibody-mediated rejection in highly sensitized pediatric kidney transplant recipients

ABMR remains a significant concern for early graft loss, especially for those who are HS against HLA antigens. We sought to determine the risk factors leading to ABMR in HS pediatric kidney transplant recipients. From January 2009 to December 2015, 16 HS pediatric kidney transplant patients at our center (age range 2-21) were retrospectively reviewed for outcomes and risk factors for ABMR. All HS patients received desensitization with high-dose IVIG/rituximab prior to transplant. Two groups were examined: ABMR⁺ (n = 7) and ABMR^- (n = 9). Patient survival was 100%; however, one patient in the ABMR⁺ group suffered graft loss from ABMR 16 months post-transplant. ABMR⁺ patients had higher Class I PRA at the time of transplant (Class I: 73.1 ± 19.1 vs 49.1 ± 28.3, P = .075), although not statistically significant. ABMR⁺ patients were more likely to have a history of transplant nephrectomy (P = .013). The characteristic that most strongly correlated with ABMR was the DSA-RIS (P = .045), a scoring system used to quantify cumulative intensity of all DSA. In conclusion, DSA, as quantified by the RIS at the time of transplant, should be considered as part of the initial allocation strategy and patients with high RIS monitored closely for ABMR post-transplant.

A novel SLC12A1 gene mutation associated with hyperparathyroidism, hypercalcemia, nephrogenic diabetes insipidus, and nephrocalcinosis in four patients

Solute Carrier Family 12 member 1 (SLC12A1) gene encodes the sodium-potassium-chloride co-transporter (NKCC2) at the apical membrane of the thick ascending loop of Henle (TAL). Bartter's syndrome (BS) type I is a rare, autosomal recessive, renal tubular disorder associated with mutation of the SLC12A1 gene. Presenting features include: hypokalemic metabolic alkalosis, hypercalciuria and nephrocalcinosis. The many allelic variants reported present with a spectrum of phenotypes, biochemical abnormalities and clinical severities. However, to date, only two reports have described hyperparathyroidism and hypercalcemia in patients with SLC12A1 gene mutations. We describe 4 patients with 4 novel mutation variants in the SLC12A1 gene (c.735C>G, c.1137del, c.2498-2499del, and c.1833delT) presenting with variable degrees of hyperparathyroidism, hypercalcemia, hypokalemic metabolic alkalosis, nephrocalcinosis, and nephrogenic diabetes insipidus. The link between calcium and parathyroid hormone abnormalities in patients with SLC12A1 mutations is unclear; the cases described suggest an association between primary hyperparathyroidism and loss of function mutation of SLC12A1, which may result in an aberrant threshold of the calcium sensing receptor at the level of the kidney.

Hemodialysis vascular access options in pediatrics: considerations for patients and practitioners

Recent data indicate that the incidence of end-stage renal disease (ESRD) in pediatric patients (age 0-19 years) has increased over the past two decades. Similarly, the prevalence of ESRD has increased threefold over the same period. Hemodialysis (HD) continues to be the most frequently utilized modality for renal replacement therapy in incident pediatric ESRD patients. The number of children on HD exceeded the sum total of those on peritoneal dialysis and those undergoing pre-emptive renal transplantation. Choosing the best vascular access option for pediatric HD patients remains challenging. Despite a national initiative for fistula first in the adult hemodialysis population, the pediatric nephrology community in the United States of America utilizes central venous catheters as the primary dialysis access for most patients. Vascular access management requires proper advance planning to assure that the best permanent access is placed, seamless communication involving a multidisciplinary team of nephrologists, nurses, surgeons, and interventional radiologists, and ongoing monitoring to ensure a long life of use. It is imperative that practitioners have a long-term vision to decrease morbidity in this unique patient population. This article reviews the various types of pediatric vascular accesses used worldwide and the benefits and disadvantages of these various forms of access.

Preventing recurrence of focal segmental glomerulosclerosis following renal transplantation: a case report

While the recurrence of FSGS in a primary renal transplant has been well studied, strategies to prevent subsequent recurrence in later transplants, has not been well formulated. This is important considering that one center's experience with adults reported an initial recurrence rate of 57% with reoccurrence of 37% in subsequent transplants. However, renal function was maintained in 62% (1). In pediatrics, data from a single-center reported 100% recurrence of FSGS in the second allograft after an initial recurrence of 52% (2). Two commentaries reviewing such data, one each in adults and pediatrics, suggested that the benefits of living-related donation might not be realized in patients with FSGS because of this frequent recurrence (3, 4). Here, we report a patient who was considered to be at very high risk for post-transplant recurrence of FSGS, because of the established risk factors, who was successfully retransplanted after a course of pretransplant plasmapheresis, followed by post-transplant plasmapheresis and the use of cyclosporine. Eighteen months post-transplant, he has no proteinuria and his serum creatinine is 1.2 mg/dL.

Experience with autogenous arteriovenous access for hemodialysis in children and adolescents

The National Kidney Foundation's DOQI-NKF recommendation to construct an autogenous arteriovenous access (AAVA) for chronic hemodialysis whenever possible can be a challenge in the pediatric population. This report reviews recent surgical experience in this patient subgroup. From March 1999 to April 2004, 47 consecutive children requiring permanent vascular access had construction of AAVA. There were 16 girls and 31 boys, with a mean age of 14.6 years (range 5-20). The surgeon preoperatively mapped veins with ultrasound in all patients. Access sites were radial-cephalic (n = 16), upper arm brachial-cephalic (n = 15), transposed upper arm brachial-basilic (n = 7), and transposed femoral vein (n = 9). An operating microscope was used to construct three radial-cephalic accesses in individuals with small arteries. Three forearm cephalic veins were transposed (one at the original surgical procedure and two postoperatively). Five upper arm cephalic veins were transposed (three at the original surgical procedure and two postoperatively). Femoral vein accesses were constructed for either exhausted access in the upper extremities (n = 7) or patient preference (n = 2). Primary patency at 1 and 2 years was 100% and 96%, respectively. Secondary patency at 1 and 2 years was 100%. One individual with a radial-cephalic AAVA and severe radial artery calcification required an inflow procedure. Thirty-five accesses are currently in use (functionally patent), eight are in individuals with successful renal transplants, and two are maturing; one individual declines using the access. Two accesses are secondarily patent (thrombosed and repaired 12 and 29 months after construction, respectively), and one access thrombosed after 27 months (abandoned). Construction of an AAVA is possible in virtually all pediatric age individuals if attention is given to preoperative vein mapping, selective use of an operating microscope, and creation of a transposed femoral vein when upper extremity access is neither possible nor desired.

Recurrent and de novo diabetic nephropathy in renal allografts

BACKGROUND

Histologic findings of diabetic nephropathy (DN) are observed in allografts of patients with pretransplant (PreTx) diabetes mellitus (DM) and in patients who develop DM posttransplant (PostTx). Patients with allograft biopsies (Bx) were retrospectively studied to determine the incidence of recurrent and de novo DN and to ascertain what, if any, risk factors predispose to histologic DN in either patient population.

METHODS

From the renal transplant services at four hospitals from 1992 to 2000, the authors identified all patients with PreTxDM and PostTxDM (n=81). Those with renal biopsies performed >/=18 months PostTx were classified according to the presence or absence of histologic DN (Bx-positive, n=23; Bx-negative, n=35). Patients were then subdivided into four categories-recurrent DN (n=16), de novo DN (n=7), no recurrent DN (n=27), and no de novo DN (n=8)-for analyses.

RESULTS

Among these 58 patients, 74.1% had PreTx and 25.9% had PostTx diabetes. Of those with histologic DN, 69.6% were recurrent DN and 30.4% were de novo DN, making de novo DN at least as likely to develop as recurrent DN. After the onset of diabetes in the de novo population, the time to development of histologic DN was similar in the recurrent and the de novo patients (6.68+/-3.86 years vs. 5.90+/-3.13 years, P=0.66) and more rapid than previously reported. Apart from a more frequent family history of hypertension in patients with allograft DN compared with those without allograft DN, known risk factors for the development of native DN did not significantly differ among patients in the four cohorts. Proposed risk factors related to transplantation did not correlate with the development of recurrent or de novo DN.

CONCLUSION

Among patients with histologic DN, de novo DN occurred at least as frequently as recurrent DN, and the time to onset of histologically apparent DN was more rapid than previously reported. Neither the usual clinical predictors of DN nor clinical variables related to transplantation clearly distinguished the group with DN from the group without it, potentially implicating novel mechanisms in its pathogenesis.

Nephrocalcinosis and renal cysts associated with apparent mineralocorticoid excess syndrome

Apparent mineralocorticoid excess (AME) syndrome is a rare inherited disorder caused by 11beta-hydroxysteroid dehydrogenase (11-HSD 2) isozyme deficiency in the kidney. This enzyme is responsible for oxidizing cortisol to its inactive metabolite cortisone. An elevated tetrahydrocortisol (THF) and allotetrahydrocortisol (aTHF) to tetrahydrocortisone (THE) ratio in the urine is pathognomonic of AME syndrome. Clinical features include hypertension, hypokalemia, alkalosis, reduced plasma renin activity (PRA), low aldosterone levels, and occasionally nephrocalcinosis. Here we describe a 13-year-old boy who presented with severe hypertension, hypokalemia, low PRA and aldosterone levels, and elevated THF plus aTHF/THE ratio in the urine consistent with a diagnosis of AME syndrome. On ultrasound examination, he had severe nephrocalcinosis, and bilateral renal cysts. Renal cysts have not been previously reported in AME syndrome. The development of nephrocalcinosis and renal cysts may be associated with chronic long-standing hypokalemia. An early diagnosis and treatment of AME syndrome could help to prevent these sequelae, and to preserve renal function.

Recent advances in the understanding and management of primary vesicoureteral reflux and reflux nephropathy

Vesicoureteral reflux and reflux nephropathy continue to be active areas of clinical investigation. There is conclusive evidence that vesicoureteral reflux is inherited. Prenatal diagnosis offers the opportunity for early recognition and intervention that may reduce the incidence of complications of vesicoureteral reflux such as pyelonephritis episodes and the development of reflux nephropathy.

Nephronophthisis associated with Ellis-van Creveld syndrome

Ellis-van Creveld (EvC) and Jeune's asphyxiating thoracic dystrophy (ATD) are related disorders characterized by narrow thoracic cage and short-limbed dwarfism. Some patients have overlapping features of both ATD and EvC, indicating that these syndromes may be a part of a disease spectrum. Nephronophthisis has been occasionally reported in patients with ATD, but not with EvC syndrome. We report a patient who was diagnosed with EvC syndrome at birth. He developed hypertension at 5 months of age and gradually progressive renal failure, requiring renal transplantation at 8 years. Histopathological findings in the nephrectomy specimen were indicative of nephronophthisis. The association of nephronophthisis in a patient with EvC syndrome has not been reported previously. This association further supports the hypothesis that ATD and EvC syndromes are related and represent a spectrum of disorders.

Protracted, gross hematuria in sickle cell trait: response to multiple doses of 1-desamino-8-D-arginine vasopressin

Gross and microscopic hematuria are well-known complications in patients with sickle cell hemoglobinopathy. Most of these episodes of gross hematuria are self limiting, but rarely may be severe and persistent requiring definitive intervention. Before subjecting these patients to surgical management such as partial or total nephrectomy, several medical therapies of variable benefit have been suggested. We report a patient with sickle cell trait who experienced severe, intractable gross hematuria for 5 months and showed a dramatic response to multiple doses of 1-desamino-8-D-arginine vasopressin (DDAVP) infusion. The remarkable response observed in this patient suggests that treatment with DDAVP infusion may be considered in patients with unremitting gross hematuria associated with sickle cell trait.

Long-term cyclosporine A treatment of steroid-resistant and steroid-dependent nephrotic syndrome

Eighteen patients with steroid-resistant nephrotic syndrome (SRNS) and steroid-dependent nephrotic syndrome (SDNS) were treated with cyclosporine A (CyA) (6 mg/kg/d) for 2 to 29 months. CyA levels were monitored monthly and plasma levels by Abbott TDX (Therapeutic Drug Analyzer System) fluorescence polarization immunoassay were maintained at 100 to 150 ng/mL. The corticosteroid dosage administered at the time CyA therapy was initiated was variable and was continued following CyA therapy. Six of these patients (all with SDNS and minimal change nephrotic syndrome [MCNS]) had been treated with one or more courses of cytotoxic drug therapy, and all had clinical evidence of corticosteroid toxicity after receiving corticosteroid therapy for 26 to 120 months. The corticosteroid dosage was reduced by slow tapering and was ultimately discontinued in six patients. These patients were maintained on CyA monotherapy for 7 to 21 months at a dose of 3.2 to 6.7 mg/kg/d. Following 11 to 29 months of CyA therapy, seven patients underwent an elective renal biopsy, which showed nephrotoxicity in all seven. This led to discontinuation of CyA in four patients. Following discontinuation of CyA monotherapy, all four patients relapsed within 2 to 4 months. CyA therapy did not achieve a remission in 10 patients with SRNS regardless of the presence of focal segmental glomerulosclerosis (FSGS) or MCNS on renal biopsy. In conclusion, CyA has limited effectiveness in patients with SDNS who manifest corticosteroid toxicity; however, CyA should be used cautiously because of the potential for CyA nephrotoxicity and the failure to obtain a sustained remission following discontinuation of CyA monotherapy. CyA dependence is substituted for corticosteroid dependence.

Improved cadaveric renal transplant outcome in children

We analyzed the results of 165 pediatric cadaver renal transplants performed at the University of California at Los Angeles to identify the factors which are linked to improved allograft survival. Both univariate life-table analysis and the Cox proportional hazard model were used. The use of a sequential immunosuppressive regimen (P less than 0.001) and kidneys from donors of more than 6 years of age (P less than 0.001) were found to be the factors having the most influence on primary graft survival. The sequential regimen was the only factor favorably influencing retransplants. With sequential therapy 1- and 2-year actuarial graft survival rates were 94% and 91% in primary transplants, and 82% and 70% in retransplants. Medication noncompliance exerted a large negative effect on transplant outcome. Of 70 recipients who had been on cyclosporine for at least 6 months, 50% evidenced noncompliance. Sixty-four percent of adolescents were noncompliant. Thirteen percent of the recipients lost their graft because of noncompliance. We conclude that good results can be obtained with cadaver renal transplants in children with a sequential immunosuppressive regimen and the use of kidneys from adolescent and adult donors. Noncompliance is a great barrier to long-term success in pediatric transplantation.

Induction of membranous nephropathy in rabbits by administration of an exogenous cationic antigen

We examined the role of antigenic electrical charge as a determinant of glomerular immune complex localization in the rabbit. Serum sickness nephritis was induced in groups of New Zealand white rabbits by daily 25-mg intravenous injections of bovine serum albumin (BSA) chemically modified to be cationic (pI > 9.5) or more anionic (pI, 3.5-4.6); an additional group received unmodified native BSA (pI, 4.5-5.1). Factors known to influence immune complex localization, e.g., molecular size of the administered antigen and resulting circulating immune complexes, immunogenicity, and disappearance time from the circulation were examined and found to be similar for both anionic and cationic BSA. Charge modification did increase the nonimmune clearance of cationic and anionic BSA compared with native BSA. Injected cationic BSA was shown in paired label experiments to bind directly to glomeruli compared with native BSA. The renal lesion produced by cationic BSA was markedly different from that found in rabbits given anionic or native BSA. Animals receiving cationic BSA uniformly developed generalized diffuse granular capillary wall deposits of IgG, C3, and BSA detected after 2 wk of injections and increasing until death at 6 wk. Qualitatively similar deposits were produced by the administration of low doses of cationic BSA of only 1 or 10 mg/d. In contrast, the injection of both anionic and native BSA resulted in mesangial deposits at 2 and 4 wk with capillary wall deposits appearing by 6 wk. Ultrastructural examination of animals receiving cationic BSA revealed pure, extensive formation of dense deposits along the lamina rara externa of the glomerular basement membrane whereas such deposits were absent or rare in animals injected with the anionic or native BSA. Albuminuria was significantly greater at 6 wk in the groups receiving cationic BSA with a mean of 280 mg/24 h compared with 53 mg/24 h in the combined groups injected with anionic or native BSA. Blood urea nitrogen values were similar in all groups at 2 and 4 wk but higher in the animals receiving cationic BSA at 6 wk. These experiments describe the reproducible induction of epimembranous immune deposits by administration of an exogenous cationic antigen. They suggest that antigenic charge can play an important role in the pathogenesis of membranous nephropathy by permitting direct glomerular binding of an antigen and predisposing to in situ immune complex formation.