Post-transplant nephrotic syndrome: A comprehensive clinicopathologic study

Consequences of Nephrotic Proteinuria and Nephrotic Syndrome after Kidney Transplant

Proteinuria is the main predictor of kidney graft loss. However, there is little information regarding the consequences of nephrotic proteinuria (NP) and nephrotic syndrome (NS) after a kidney transplant. We aimed to describe the clinical and histopathological characteristics of kidney recipients with nephrotic-range proteinuria and compare the graft surveillance between those who developed NS and those who did not. A total of 204 patients (18.6% of kidney transplants in the study period) developed NP, and 68.1% of them had NS. Of the 110 patients who underwent a graft biopsy, 47.3% exhibited ABMR, 21.8% the recurrence of glomerulonephritis, 9.1% IFTA, and 7.3% de novo glomerulonephritis. After a median follow-up of 97.5 months, 64.1% experienced graft loss. The graft survival after the onset of NP declined from 75.8% at 12 months to 38% at 5 years, without significant differences between those with and those without NS. Patients who developed NS fewer than 3 months after the onset of NP exhibited a significantly higher risk of death-censored graft loss (HR: 1.711, 95% CI: 1.147-2.553) than those without NS or those with late NS. In conclusion, NP and NS are frequent conditions after a kidney transplant, and they imply extremely poor graft outcomes. The time from the onset of NP to the development of NS is related to graft survival.

Transplant kidney biopsy for proteinuria with stable creatinine: Findings and outcomes

INTRODUCTION

Little is known aboutbiopsy findings and outcomes when kidney transplant recipients (KTRs) undergo biopsy for isolated proteinuria with stable serum creatinine (SCr).

METHODS

We analyzed all KTRs who underwent biopsy for isolated proteinuria with stable SCr between January 2016 and June 2020. Patients were divided into three groups based on the biopsy findings: Active Rejection (AR), Glomerulonephritis (GN), and Other.

RESULTS

A total of 130 KTRs fulfilled our selection criteria; 38 (29%) in the AR group, 26 (20%) in the GN group, and 66 (51%) in the Other group. Most baseline characteristics were similar between the groups. In multivariate analysis, higher HLA mismatch (HR per mismatch: 1.30; 95% CI:1.06-1.59; P = .01) and male gender (HR: .45; 95% CI .23-.89; P = .02) were associated with AR. There was no significant correlation between the degree of proteinuria and rejection (r = .05, P = .58) or GN (r = .07, P = .53). Graft survival was also similar between the groups. Likely due to the early diagnosis without a significant rise in SCr, outcomes were similar among all three groups.

CONCLUSION

Routine monitoring for proteinuria followed by a biopsy and appropriate management may help to identify early acute graft injury and prevent graft failure.

First and second morning spot urine protein measurements for the assessment of proteinuria: a diagnostic accuracy study in kidney transplant recipients

BACKGROUND

Quantification of proteinuria in kidney transplant recipients is important for diagnostic and prognostic purposes. Apart from correlation tests, there have been few evaluations of spot urine protein measurements in kidney transplantation.

METHODS

In this cross-sectional study involving 151 transplanted patients, we investigated measures of agreement (bias and accuracy) between the estimated protein excretion rate (ePER), determined from the protein-to-creatinine ratio in the first and second morning urine, and 24-h proteinuria and studied their performance at different levels of proteinuria. Measures of agreement were reanalyzed in relation to allograft histology in 76 patients with kidney biopsies performed for cause before enrolment in the study.

RESULTS

For ePER in the first morning urine, percent bias ranged from 1 to 28% and accuracy (within 30% of 24-h collection) ranged from 56 to 73%. For the second morning urine, percent bias ranged from 2 to 11%, and accuracy ranged from 71 to 78%. The accuracy of ePER (within 30%) in first and second morning urine progressively increased from 56 and 71% for low-grade proteinuria (150-299 mg/day) to 60 and 74% for moderate proteinuria (300-999 mg/day), and to 73 and 78% for high-grade proteinuria (≥1000 mg/day). Measures of agreement were similar across histologic phenotypes of allograft injury.

CONCLUSIONS

The ability of ePER to accurately predict 24-h proteinuria in kidney transplant recipients is modest. However, accuracy improves with an increase in proteinuria. Given the similar accuracy of ePER measurements in first and second morning urine, second morning urine can be used to monitor protein excretion.

Recurrence of immunoglobulin A nephropathy after kidney transplantation: a narrative review of the incidence, risk factors, pathophysiology and management of immunosuppressive therapy

Glomerulonephritis (GN) is the underlying cause of end-stage renal failure in 30–50% of kidney transplant recipients. It represents the primary cause of end-stage renal disease for 25% of the dialysis population and 45% of the transplant population. For patients with GN requiring renal replacement therapy, kidney transplantation is associated with superior outcomes compared with dialysis. Recurrent GN was previously considered to be a minor contributor to graft loss, but with the prolongation of graft survival, the effect of recurrent disease on graft outcome assumes increasing importance. Thus the extent of recurrence of original kidney disease after kidney transplantation has been underestimated for several reasons. This review aims to provide updated knowledge on one particular recurrent renal disease after kidney transplantation, immunoglobulin A nephropathy (IgAN). IgAN is one of the most common GNs worldwide. The pathogenesis of IgAN is complex and remains incompletely understood. Evidence to date is most supportive of a several hit hypothesis. Biopsy is mandatory not only to diagnose the disease in the native kidney, but also to identify and characterize graft recurrence of IgAN in the kidney graft. The optimal therapy for IgAN recurrence in the renal graft is unknown. Supportive therapy aiming to reduce proteinuria and control hypertension is the mainstream, with corticosteroids and immunosuppressive treatment tailored for certain subgroups of patients experiencing a rapidly progressive course of the disease with active lesions on renal biopsy and considering safety issues related to infectious complications.

Membranous Nephropathy Posttransplantation: An Update of the Pathophysiology and Management

Membranous nephropathy (MN) is a common cause of nephrotic syndrome after transplantation and is associated with an increased risk of allograft loss. MN may occur either as a recurrent or as a de novo disease. As in native kidneys, the pathophysiology of the MN recurrence is in most cases associated with antiphospholipid A2 receptor antibodies. However, the posttransplant course has some distinct features when compared with primary MN, including a lower chance of spontaneous remission and a greater requirement for adjuvant immunosuppressive therapy to induce complete remission. Although the efficacy of rituximab in primary MN is now well established, no randomized studies have assessed its effectiveness in MN after transplant, and there are no specific recommendations for the management of these patients. This review aims to synthesize and update the pathophysiology of posttransplant MN, as well as to address unsolved issues specific to transplantation, including the prognostic value of antiphospholipid A2 receptor, the risk of living-related donation, the link between de novo MN and rejection, and different therapeutic strategies so far deployed in posttransplant MN. Lastly, we propose a management algorithm for patients with MN who are planning to receive a kidney transplant, including pretransplant considerations, posttransplant monitoring, and the clinical approach after the diagnosis of recurrence.

Late-Onset De Novo Minimal Change Disease Presenting With Nephrotic Range Proteinuria More Than 1 Year After Combined Heart-Kidney Transplant: A Case Report

We present a case of de novo minimal change disease occurring more than 1 year after transplant in a combined heart-kidney transplant recipient. A 68-year-old white man with past medical history of nonischemic cardiomyopathy with left-ventricular assist device and end-stage renal disease due to type 2 diabetes mellitus and cardiorenal syndrome underwent a combined heart-kidney transplant in a sequential manner in August 2016. He was induced with rabbit antithymocyte globulin and methylprednisolone; he was maintained on mycophenolate mofetil, tacrolimus, and a protocolized tapering dose of prednisone. More than 1 year after transplant, in December 2017, he had about 2.3 g of proteinuria. Kidney function remained stable with a creatinine of 1.2 mg/dL. Serologic and infectious workup was nonrevealing. Proteinuria peaked at 4.5 g in January 2018, and kidney biopsy results were consistent with minimal change disease. After the biopsy, his prednisone dosage was escalated to 80.0 mg daily and slowly tapered to 2.5 mg (including most recent follow-up data from May 2019) daily, in alignment with improvement in his proteinuria and creatinine. Proteinuria decreased to 130.0 mg/g. To our knowledge, this is the first reported case of its kind in a combined heart-kidney transplant patient.

Recurrent glomerulonephritis following renal transplantation and impact on graft survival

Background

Recurrence of primary glomerulonephritis in the post-transplant period has been described in the literature but the risk remains poorly quantified and its impact on allograft outcomes and implications for subsequent transplants remain under-examined. Here we describe the rates and timing of post-transplant glomerulonephritis recurrence for IgA nephropathy, focal segmental glomerulosclerosis, mesangiocapillary GN and membranous GN based on 28 years of ANZDATA registry transplant data.

Methods

We investigated the rates of GN recurrence and subsequent graft outcomes in 7236 patient from 28 years of ANZDATA transplant registry data. Data were analysed in R, using Kaplan Meier Survival analysis and adjusted analyses performed using Cox Proportional Hazards methods. A competing risk model was also analysed.

Results

GN recurrence occurred in 10.5% of transplants and was most common in mesangiocapillary GN. Median time to recurrence was shorter for FSGS compared to IGAN. GN recurrence was less common in patients over 50 years of age and after unrelated kidney donation. We identified a significantly higher risk of recurrence in secondary grafts following recurrence in a primary allograft for FSGS (RR 5.70, 95 CI: 2.41–13.5, p < 0.001) but not IGAN, MCGN or MN. At 10 years, recurrence occurs in 8.7, 10.8, 13.1, and 13.4% of allografts for FSGS, IGAN, MCGN and MN respectively. In all GN, recurrence significantly reduced death censored graft survival at 5 and 10 years.

Conclusions

GN recurrence occurs in a minority of patients at a significantly different rate for each GN. After a recurrence, there is no evidence for an increased risk of further recurrence in a subsequent graft except in FSGS.

Prevalence and Causes of Proteinuria in Kidney Transplant Recipients: Data from a Single Center

Introduction. Proteinuria after renal transplantation increases the risk of graft failure and mortality. The aim of the study was to determine the prevalence and causes of proteinuria in kidney transplant recipients. Methods. All kidney transplant recipients followed up in our clinic were included in the study. As a center protocol 24-hour urine collections were used to quantify protein excretion with 3-month intervals posttransplantation during the first year, and yearly thereafter. The etiology of chronic kidney disease and demographic characteristics of the study group were obtained from outpatient records. Data regarding the immunosuppressive regimens used, 24-hour proteinuria levels and creatinine clearences, new-onset hypertension, new-onset diabetes mellitus, rejection episodes, infections like cytomegalovirus (CMV) and polyoma (BK), and biopsy findings were noted. Results. A total of 260 kidney transplant recipients (97 females, mean age 42.3±12.3 years) were evaluated. Median follow-up period was 36 months; 137 of all transplantations were from living donors. Mean age of donors was 42.7±15 years and 133 were female. Proteinuria with protein excretion ≥300 mg/d was present in 35.4% of patients. The most common cause of biopsy-proven proteinuria was transplant-specific conditions (acute rejection, and borderline changes). Conclusion. The prevalence of proteinuria was 35.4%. The transplant-specific diagnoses were the most likely causes. Even in nonnephrotic ranges it was associated with decreased graft survival.

Reduced human transitional B cell T1/T2 ratio is associated with subsequent deterioration in renal allograft function

Human transitional B cells express relatively high IL-10 and low TNF-α levels, which correlate with B regulatory activity in vitro. Herein, we aim to further define B regulatory phenotype and determine whether B regulatory activity can serve as a prognostic marker for renal allograft dysfunction (graft loss or 2-fold fall in estimated glomerular filtration rate). Transitional B cells can be divided into T1 and T2 subsets based on surface phenotype. T1 cells express a significantly higher ratio of IL-10 to TNF-α than T2 cells or other B subsets. When analyzed in 45 kidney transplant recipients at the time of late for-cause biopsy, the T1/T2 ratio was independently associated with allograft dysfunction over the next 5 years. Next, the T1/T2 ratio was examined in an independent set of 97 clinically stable kidney transplant recipients 2 years after transplant. Again, the T1/T2 ratio was strongly and independently associated with allograft dysfunction over the ensuing 5 years. In these clinically quiescent patients, a low T1/T2 ratio identified a 41-patient subgroup in which 35% developed allograft dysfunction, with 25% losing their allografts. However, none of the 56 patients with a high ratio developed graft dysfunction. In both the initial study and validation groups, the T1/T2 ratio was a much stronger predictor of graft dysfunction than donor-specific antibodies or the estimated glomerular filtration rate. Thus, the T1/T2 ratio, a relative measure of expressing an anti-inflammatory cytokine profile, is a novel prognostic marker that might inform individualized immunosuppression.

Concomitance of IgA nephropathy and diabetic nephropathy in a kidney allograft: case report and review of the literature

Whereas diabetic nephropathy is the most common cause of end-stage renal disease (ESRD), IgA nephropathy is the most common glomerulonephritis in the world. We report a case of a kidney transplant recipient whose native renal disease was presumptive diabetic nephropathy. Five years after transplantation, the patient developed proteinuria, hematuria, and allograft dysfunction. Transplant biopsy revealed IgA nephropathy superimposed on diabetic nephropathy.

Management of proteinuria in the transplanted patient

Proteinuria is a relatively frequent complication in children after renal transplantation (40-80 %). It is usually mild and non-nephrotic in nature and predominantly tubular in origin. The major causes of post-transplant proteinuria are recurrence of primary glomerulonephritis [mostly focal segmental glomerulosclerosis (FSGS)], rejection (acute and chronic), mTOR inhibitors or hypertension. Proteinuria is a risk factor for graft loss and patient death in adults, and even a mild proteinuria (0.1-0.2 g/day) is associated with impaired graft and patient survival. In children, proteinuria seems to be associated with graft but not patient survival. Proteinuria (protein/creatinine ratio) should be assessed regularly in all children. In children with prior chronic kidney disease due to idiopathic FSGS, proteinuria should be assessed daily during the first month after transplantation to enable early diagnosis of recurrence. The cause of proteinuria should be identified, and graft biopsy should be considered in children with unexplained proteinuria, especially with new onset proteinuria or deterioration of previously mild proteinuria. Treatment must be primarily targeted at the cause of proteinuria, and in normotensive children symptomatic antiproteinuric therapy with angiotensin-converting enzyme inhibitors/angiotensin II receptor antagonists should also be initiated. Other antihypertensive drugs should be used to achieve target blood pressure of <75th percentile. Target proteinuria should be <20 mg/mmol creatinine.

Renal dysfunction and intragraft proMMP9 activity in renal transplant recipients with interstitial fibrosis and tubular atrophy

Chronic renal allograft injury is reflected by interstitial fibrosis and tubular atrophy (IF/TA) and by the accumulation of extracellular matrix (ECM). Metalloproteinases (MMPs) are renal physiologic regulators of ECM degradation. Changes in MMPs expression or activity may disturb ECM turnover leading to glomerular scarring and worsening renal function. Our goal was to investigate intragraft MMP2 and MMP9 activities and their correlation with renal dysfunction. Plasma MMP2 and MMP9 activities were analyzed as noninvasive markers of renal allograft deterioration. Transplanted patients were biopsied and histopathologically characterized as IF/TA+ or IF/TA-. Renal function was evaluated by serum creatinine, glomerular filtration rate (GFR) estimated by Modification of Diet in Renal Disease equation and urinary protein/creatinine ratio. Kidney and plasma MMP2 and MMP9 activities were analyzed by zymography. A significant renal dysfunction was observed in IF/TA+ patients. Intragraft proMMP9 showed a significant higher activity in IF/TA+ than in IF/TA- samples and was inversely correlated with the GFR. Intragraft proMMP2 activity tended to increase in IF/TA+ samples, although no statistic significance was reached. Circulating proMMP2 and proMMP9 activities did not show significant differences between groups. Our data provide evidence that correlates intragraft proMMP9 activity with the fibrotic changes and renal dysfunction observed in IF/TA.

A de novo monoclonal immunoglobulin deposition disease in a kidney transplant recipient: a case report

Introduction

Myeloma following kidney transplantation is a rare entity. It can be divided into two groups: relapse of a previous myeloma and de novo myeloma. Some of these myelomas can be complicated by a monoclonal immunoglobulin deposition disease, which is even less common. Less than ten cases of monoclonal immunoglobulin deposition disease after renal graft have been reported in the literature. The treatment of these patients is not well codified.

Case presentation

We report the case of a 43-year-old white European man who received a renal transplant for a nephropathy of unknown etiology and developed a nephrotic syndrome with kidney failure at 2-years follow-up. We diagnosed a de novo monoclonal immunoglobulin deposition disease associated with a kappa light chain multiple myeloma, which is a very uncommon presentation for this disease. Three risk factors were identified in this patient: Epstein–Barr virus reactivation with cytomegalovirus co-infection; intensified immunosuppressive therapy during two previous rejection episodes; and human leukocyte antigen-B mismatches. Chemotherapy treatment and decrease in the immunosuppressive therapy were followed by remission and slight improvement of renal function. A relapse occurred 8 months later and his renal function worsened rapidly requiring hemodialysis. He died from septic shock 4 years after the diagnosis of monoclonal immunoglobulin deposition disease.

Conclusions

This rare case of post-transplant lymphoproliferative disorder with an uncommon presentation illustrates the fact that treatment in such a situation is very difficult to manage because of a small number of patients reported and a lack of information on this disease. There are no guidelines, especially concerning the immunosuppressive therapy management.

De novo lupus nephritis in a renal transplanted child: a case report

De novo lupus nephritis (LN) is a rare complication in renal transplantation recipients. We present the clinical manifestations of de novo LN in a 12-year-old boy who received a cadaveric renal transplant. The cause of end-stage renal disease was prune belly syndrome with renal dysplasia. His immunosuppressive drugs included tacrolimus, mycophenolate sodium, and prednisolone. After 3 years of treatment, he developed nephrotic syndrome (NS) without other symptoms of systemic lupus erythematosus (SLE). The renal pathology of the transplanted kidney showed suspicious acute cellular rejection and LN World Health Organization class IV-G (A/C). Antinuclear antibody was positive, but anti-dsDNA and anti-Smith were negative. The serum complements were initially normal. Pulse methylprednisolone was given and the dosages of all immunosuppressive drugs increased; notwithstanding, his edema and hypoalbuminemia worsened. Repeated biopsy of the transplanted kidney was done. A full-house pattern was documented under immunofluorescent examination which confirmed LN WHO class IV-G (A/C) without evidence of rejection. He then developed macrophage-associated hemophagocytic syndrome and cytomegalovirus pneumonia. He ultimately developed pulmonary hemorrhage and died owing to severe pneumonia. De novo LN should be considered in renal transplant recipients with new onset of NS despite there not being any other clinical manifestations of SLE.

De novo minimal change disease after ABO-incompatible kidney transplantation

We report the clinical and pathological findings of a case of de novo minimal change disease (MCD) after ABO-incompatible living kidney transplantation. A 62-yr-old man with end-stage renal disease associated with type I diabetes received ABO-incompatible kidney transplantation from his 58-yr-old wife. Although allograft function was excellent immediately after surgery, massive proteinuria (35 g/d) appeared on post-transplantation day 5. After the allograft biopsy taken on post-transplantation day 6, he was treated with 12 cycles of plasma exchange, but the nephrotic-range proteinuria showed no remission. The biopsy specimen showed no significant pathological findings on light microscopy, but electron microscopy showed diffuse effacement of podocyte foot processes. Based on the diagnosis of de novo MCD, the patient received intravenous methylprednisolone pulse therapy, followed by high-dose steroid maintenance therapy. The steroid therapy induced complete remission of nephrotic syndrome and stable allograft function immediately, which was also maintained at one yr after the transplantation.

Electron microscopy in determining the etiology of kidney allograft dysfunction

BACKGROUND

Biopsy of the transplanted kidney serves a definitive role in elucidating the possible causes of allograft dysfunction. At our transplant clinic we have observed that electron microscopy (EM) does not usually refine the findings initially disclosed by light microscopy with direct immunofluorescence (LM).

METHODS

We studied whether EM results differ from or add to LM results. We compared the reports of 65 allograft biopsies performed on 60 patients over 82 consecutive weeks. We classified biopsy interpretations by 15 possible diagnoses and categorically by glomerular versus nonglomerular disease. We determined agreement between LM and EM reports by Cohen's kappa statistic, and applied the McNemar test to determine whether EM interpretation yielded significantly more glomerular diagnoses on the same biopsy samples.

RESULTS

There was strong agreement (kappa, 0.94: 95% confidence interval [CI], 0.88-1.00), between the EM- and LM-based interpretations. EM did not detect more glomerular disease than LM (discordance rate, 4.6%: 95% CI, -1.92% to 4.62%: P = .25). EM did not add to the diagnosis of rejection. EM described 3 additional cases of transplant glomerulopathy, but did not lead in a change in management of kidney allograft dysfunction.

CONCLUSION

Electron microscopy, used routinely, does not add to light microscopy in the evaluation of kidney transplant dysfunction.

The prevalence of immunologic injury in renal allograft recipients with de novo proteinuria

Post-transplant proteinuria is a common complication after renal transplantation; it is associated with reduced graft and recipient survival. However, the prevalence of histological causes has been reported with considerable variation. A clinico-pathological re-evaluation of post-transplant proteinuria is necessary, especially after dismissal of the term “chronic allograft nephropathy,” which had been considered to be an important cause of proteinuria. Moreover, urinary protein can promote interstitial inflammation in native kidney, whether this occurs in renal allograft remains unknown. Factors that affect the graft outcome in patients with proteinuria also remain unclear. Here we collected 98 cases of renal allograft recipients who developed proteinuria after transplant, histological features were characterized using Banff scoring system. Cox proportional hazard regression models were used for graft survival predictors. We found that transplant glomerulopathy was the leading (40.8%) cause of post-transplant proteinuria. Immunological causes, including transplant glomerulopathy, acute rejection, and chronic rejection accounted for the majority of all pathological causes of proteinuria. Nevertheless, almost all patients that developed proteinuria had immunological lesions in the graft, especially for interstitial inflammation. Intraglomerular C3 deposition was unexpectedly correlated with the severity of proteinuria. Moreover, the severity of interstitial inflammation was an independent risk factor for graft loss, while high level of hemoglobin was a protective factor for graft survival. This study revealed a predominance of immunological parameters in renal allografts with post-transplant proteinuria. These parameters not only correlate with the severity of proteinuria, but also with the outcome of the graft.

Posttransplantation proteinuria: an approach to diagnosis and management

Proteinuria is a common problem encountered in the treatment of renal transplant recipients, occurring in up to 45% of patients. Proteinuria from native kidneys falls rapidly after renal transplantation, and persistent or worsening proteinuria is usually indicative of allograft pathology. Biopsy studies of transplant patients with proteinuria have confirmed that transplant-specific diagnoses (transplant glomerulopathy, interstitial fibrosis and tubular atrophy, and acute rejection) are more commonly found than other proteinuric conditions, such as glomerulonephritis. As in the nontransplant setting, proteinuria is associated with worse clinical outcomes, including an increased risk for death, cardiovascular events, and graft loss. Blockade of the renin-angiotensin-aldosterone system with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers will reduce proteinuria, but the long-term effect of these medications on patient and graft survival remains unknown.

Hypertension after kidney transplant

Hypertension in kidney transplant recipients is a major "traditional" risk factor for atherosclerotic cardiovascular disease. Importantly, atherosclerotic cardiovascular disease is the leading cause of premature death and a major factor in death-censored graft failure in transplant recipients. The blood pressure achieved after transplant is related inversely to postoperative glomerular filtration rate (GFR), with many patients experiencing a significant improvement in blood pressure control with fewer medications within months of surgery. However, the benefits of improved GFR and fluid status may be affected by the immunosuppression regimen. Immunosuppressive agents affect hypertension through a variety of mechanisms, including catechol- and endothelin-induced vasoconstriction, abrogation of nitric oxide-induced vasodilatation, and sodium retention. Most notable is the role of calcineurin inhibitors in promoting hypertension, cyclosporine more so than tacrolimus. Additionally, the combination of calcineurin- and mammalian target of rapamycin (mTOR)-inhibitor therapy is synergistically nephrotoxic and promotes hypertension, whereas steroid withdrawal and minimization strategies seem to have little or no impact on hypertension. Other important causes of hypertension after transplant, beyond a progressive decrease in GFR, include transplant renal artery stenosis and sequelae of antibody-mediated rejection. Calcium channel blockers may be the most useful medication for mitigating calcineurin inhibitor-induced vasoconstriction, and use of such agents may be associated with improvements in GFR. Use of inhibitors of the renin-angiotensin system, such as angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, remains an attractive strategy for many transplant recipients, although some recipients may have significant adverse effects associated with these medications, including decreased GFR, hyperkalemia, and anemia. In conclusion, hypertension control affects both patient and long-term transplant survival, and its best management requires careful analysis of causes and close monitoring of therapies.

Impact of patterns of proteinuria on renal allograft function and survival: a prospective cohort study

BACKGROUND

Proteinuria is an important complication in renal transplant recipients. The aim of this prospective study was to evaluate the long-term impact of transplant proteinuria patterns on allograft function and survival.

METHODS

We analyzed urinary protein of a cohort of 83 renal transplants with proteinuria ≥0.5 g/d by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and radial immunogel diffusion assay. After initial stratification and analysis, the cohort was followed up for 16 yr. The graft outcome and survival were analyzed using Cox regression model to determine their association with different patterns of initial transplant proteinuria.

RESULTS

Group with predominantly glomerular (middle- and high-molecular-weight with or without low-molecular-weight) proteinuria (61%) had higher serum creatinine (p < 0.001) than the group with predominantly tubular (low-molecular-weight) proteinuria (39%). The incidences of chronic graft dysfunction and graft loss had increased in the glomerular proteinuria group (p < 0.001, hazard ratio 3.6, 95% confidence interval 1.7-7.5 and p < 0.001, hazard ratio 4.9, 95% confidence interval 1.9-12.1, respectively). Patient death did not differ (p = 0.434, hazard ratio 1.5, 95% confidence interval 0.5-4.5).

CONCLUSION

  Proteinuria in renal transplants can be differentiated into glomerular and tubular types based on molecular weight. Glomerular proteinuria is associated with significant increase in graft dysfunction and graft loss.

A primer on recurrent and de novo glomerulonephritis in renal allografts

Accumulating evidence indicates that recurrent glomerulonephritis is the third most important cause of renal allograft loss at 10 years after transplantation. The proteinuria and elevated serum creatinine levels that result from recurrent glomerulonephritis are associated with cardiovascular morbidity and mortality. The exact prevalence of either recurrent or de novo post-transplantation glomerulonephritis is unknown because a considerable number of patients never undergo allograft biopsy, meaning that glomerulonephritis remains undiagnosed and a diagnosis of 'chronic rejection/chronic allograft nephropathy' is sometimes presumed. The lack of consensus regarding evaluation of kidney transplant recipients who exhibit slow deterioration of graft function is a major reason for underdiagnosis. All forms of glomerular disease can recur after transplantation, but the likelihood of recurrence differs according to type. Focal segmental glomerulosclerosis, membranoproliferative glomerulonephritis, IgA nephropathy and idiopathic diarrhea-negative hemolytic uremic syndrome often recur. Membranous nephropathy, focal segmental glomerulosclerosis, anti-glomerular basement membrane nephritis associated with Alport syndrome, and drug-induced thrombotic microangiopathy are the most common forms of de novo glomerulonephritis. This Review discusses the prevalence, risk factors, pathogenesis, clinicopathological features, and effects on graft outcome of recurrent and de novo glomerulonephritis in renal allografts. Treatment options are briefly outlined.

De novo membranous nephropathy associated with donor-specific alloantibody

Recent evidence suggests that alloantibody may play an aetiological role in the pathogenesis of membranous glomerulopathy in native kidneys. There is an increased awareness of the significance of alloantibody on renal transplant outcome, particularly with the development of more sensitive assays. We describe a kidney transplant patient who developed de novo membranous glomerulopathy (DNMG) with heavy proteinuria in the context of a donor-specific alloantibody (DSA) directed against HLA DQ7. Proteinuria resolved and kidney function stabilized following treatment with mycophenolate mofetil and an angiotensin receptor blocker. The titre of the DSA fell in parallel with resolution of the proteinuria. This is the first reported case of DNMG after kidney transplantation clearly associated with a DSA. We hypothesize that de novo membranous glomerulopathy may be an atypical manifestation of acute antibody-mediated damage. Cases of DNMG should be screened for alloantibody and the presence of alloantibody may influence the choice of therapy.

Posttransplantation glomerulonephritis: risk factors associated with kidney allograft loss

AIM OF THE STUDY

Chronic glomerulonephritis (GN) is reported as a common cause of late kidney allograft loss. The aim of this study was to identify risk factors associated with kidney allograft loss in the course of posttransplantation GN.

PATIENTS AND METHODS

The study analyzed 75 kidney allograft recipients with biopsy-confirmed posttransplantation GN, including 27 cases of immunoglobulin (Ig)A nephropathy (IgAN), 30 of membranous GN (MGN), 6 of mesangiocapillary GN (MCGN); and 12 of focal segmental GN (FSGS). The risk factors for kidney allograft loss, defined as dialysis reintroduction after GN onset, were identified through are historical cohort study.

CLINICAL FINDINGS

After the onset of posttransplantation GN, the median time to dialysis introduction was 46 months. The risk factors for kidney allograft loss were as follows: male gender (hazard ratio [HR] = 1.92; 95% confidence intervall [CI] 1.0-3.70; P = .052), initial unsatisfactory kidney function (HR = 1.86 per 1 mg/dL serum creatinine increment; 95% CI 1.0-3.46; P < .05), graft dysfunction at diagnosis (HR = 1.65 per 1 mg/dL serum creatinine increment; 95% CI 1.32-2.07; P < .001), nephrotic syndrome (HR = 2.3; 95% CI 1.13-4.99; P < .05) late-onset GN (HR = 1.1 per each additional year of observation, 95% CI 1.0-1.21; P < .05), and MPGN as a type of GN. Enhanced immunosuppression increased and ACEI and/or statin treatment decreased the risk of return to dialysis, respectively: HR = 1.56, 95% CI 0.76-3.18, P = .22; HR = 0.39, 95% CI 0.16-0.98, P = .0037; and HR = 0.367, 95% CI 0.15-0.88, P = .025.

CONCLUSIONS

Identification of risk factors can help discover patients who will have a faster progression to kidney allograft loss due to GN. In posttransplantation GN, statins and/or ACEI should be prescribed, if there are no contraindications.

Prognostic factors associated with poor graft outcomes in renal recipients with post-transplant glomerulonephritis

BACKGROUND

Little data are available concerning post-transplantation glomerulonephritis (PTx-GN) and its prognostic factors associated with graft outcomes.

METHODS

We retrospectively evaluated patients with de novo and recurrent PTx-GN to identify the factors associated with their negative impact on graft and patient outcomes. PTx-GN was diagnosed in 55 patients, wherein 17 (31%) had recurrent glomerulonephritis (GN) and 16 (29%) had de novo.

RESULTS

Our enrolled population consisted of 34 +/- 13.7-yr-old male patients (72%), on hemodialysis for a median of 18 months (0-204) and mainly grafted from living donors (76%). The median onset time of proteinuria and hematuria was 50 d (10-2160) and 30 d (4-1170), respectively. One-yr graft survival rates after PTx-GN diagnosis was 64%. The most frequent de novo GN was membranous GN (26%), while focal segmental glomerulosclerosis was the most frequent recurrent GN (41%), with a very early onset (median of three months). One-yr graft survival was better in the recurrent disease than in the de novo patients, 76% vs. 55% (p = 0.24). The best predictor factors that correlated with graft survival were: proteinuria <3.5 g [relative risk (RR) = 0.24, p = 0.017], serum creatinine below 2.0 mg/dL (RR = 0.06, p = 0.016) at the time of biopsy and the use of angiotensin-converting enzyme inhibitors (ACEI) (RR = 0.12, p = 0.005). The use of ACEI markedly improved one-yr graft survival rates (92% vs. 47%, p < 0.001).

CONCLUSION

PTx-GN has a strong negative impact on kidney graft survival. De novo GN appears to have a poorer prognosis than the recurrent type. Patients who used ACEI showed a better survival rate in the follow-up.

Impact of Therapeutic Changes on Renal Graft Survival With Posttransplant Glomerulonephritis

INTRODUCTION

Posttransplant glomerulonephritis (GN) is the third cause of graft loss after 1 year of transplant follow-up; few approaches have been efficient in reversing this outcome. The aim of this study was to evaluate whether the modification of the immunosuppressive therapy for treating posttransplant GN had an impact on allograft survival.

PATIENTS AND METHODS

Forty-nine patients who underwent renal transplantation and developed posttransplant GN were divided into two groups: group 1, 22 patients with modified immunosuppressive treatment (72.3%, pulse of methylprednisolone; 13.6%, high-dose oral corticosteroid), and group 2, where it was maintained. Additionally, the impact of the concomitant use of drugs that promote the renin-angiotensin-aldosterone system blockade (RAASB) was analyzed in terms of graft survival.

RESULTS

We established the diagnosis of GN at 17.9 months (range, 0.57 to 153.4) after transplantation, when serum creatinine (Cr) was 2.2 mg/dL (range, 0.8 to 12.5) and proteinuria 3.2 g/L (range, 0.2 to 24.2). Graft survivals at 1 and 3 years after diagnosis were 69.2% and 52.9%, respectively. The patients of group 1 showed a lower prevalence of graft loss (27.2% versus 48.1%, P = .40) and better survival at the end of 1 year (73.2% versus 60.4%) and 3 years (62.5% versus 38.0%, P = .26), but the differences were not significant. RAASB showed a positive impact on survival at the end of 3 years in both groups: for group 1, 83.8% with RAASB, 41.4% without RAASB; and for group 2, 75% with RAASB and 14.8% without RAASB (P < .001).

CONCLUSION

Although treatment of posttransplant GN with modification of immunosuppression seemed to improve graft survival in the first 3 years after diagnosis, RAASB improved this effect.

Long-term patient survival: strategies to improve overall health

The use of potent immunosuppressant therapy has led to an increase in number of patients with successful long-term kidney transplants. These individuals come to kidney transplantation with varying levels of comorbidity associated with end-stage renal disease and are susceptible to immunologic and nonimmunologic comorbidities that arise late after transplantation, including cardiovascular disease, infection, malignancy, and bone disease, which negatively impact on patient and graft survival. In addition, nonadherence to immunosuppressant regimens increases with time after transplantation, which further augments the risk for late-term graft failure and mortality. Consistent and frequent follow-up of kidney transplant recipients beyond the first year permits early diagnosis and successful treatment of many posttransplantation comorbidities. Implementation of preventive practices and aggressive management of risk factors throughout the life of the transplant improves overall health and long-term outcomes. Establishment and maintenance of close relationships among transplant centers, physicians, patients, and their families improves patient adherence to medications and reduces the risk for morbidity and mortality.

Chronic allograft nephropathy

With the advent of calcineurin inhibitors, the success of kidney and other solid-organ transplants has improved significantly from the standpoint of reducing the incidence of acute rejection. Over the past 2 decades, both short-term allograft survival and acute rejection rates have dramatically improved with improved diagnostic and therapeutic techniques such as standardized pathology scoring; potent antirejection drugs such as anti-thymocyte globulin, interleukin-2 receptor antibodies, cyclosporine, tacrolimus, sirolimus, and mycophenolate mofetil; and improved infection control such as valganciclovir and antifungal therapy. However, long-term graft loss has remained at nearly constant levels over the same period of time, with the average half-life of a deceased-donor kidney transplant in the United States remaining approximately 1 decade. In addition to death with a functioning allograft and calcineurin toxicity, a chronic fibrotic process-known at various times as chronic rejection, chronic allograft dysfunction, and chronic allograft nephropathy (CAN)-account for the leading causes of transplant failure.

Proteinuria Following a Switch from Calcineurin Inhibitors to Sirolimus

BACKGROUND

Sirolimus is an alternative option for kidney transplant patients treated with calcineurin inhibitors (CNI) when renal function is deteriorating. However, the incidence of proteinuria following a switch from CNI to sirolimus has caused concern, and was therefore investigated here.

METHODS

In a retrospective study, 68 renal transplant recipients were switched from CNI to sirolimus. Proteinuria was measured using 24-hour urine collection before the switch and collections 3, 6, 12, and 24 months thereafter. In addition, proteinuria was measured in patients who had to be switched back to CNI due to side effects. Survival analyses were performed.

RESULTS

Baseline proteinuria was 0.39+/-0.69 g/day in all 68 patients. It increased to a mean 1.44+/-1.90 g/day at 3 months (P<0.001) and remained elevated at 6, 12 and 24 months. When sirolimus was withdrawn after the CNI-sirolimus switch for 19 patients, proteinuria decreased from 1.95+/-2.06 g/day to 0.9+/-1.4 g/day (P<0.05). Proteinuria above 0.3 g/day before the CNI-sirolimus switch correlated significantly with the decrease of renal function thereafter.

CONCLUSION

CNI-treated kidney transplant recipients may develop reversible proteinuria when switched to sirolimus.

Posttransplant de novo membranous nephropathy in childhood

Posttransplant proteinuria is a recognized, but relatively uncommon, presentation of renal transplant dysfunction. Significant proteinuria occurs in around 10-15% of renal transplant recipients. We present a case of de novo posttransplant membranous nephropathy in childhood complicating renal transplantation for severe congenital obstructive uropathy and review the pathology, pathogenesis, and clinical implications of this condition. In the majority of cases, the cause of posttransplant proteinuria is either related to chronic allograft nephropathy or recurrence of the glomerulonephritis for which transplantation was indicated. In a minority, however, de novo posttransplant membranous nephropathy (DNPMN) is identified on biopsy. The histopathological findings in some cases may either be similar to those of classical membranous nephropathy, or may be more subtle, showing focal segmental variation in severity, often in conjuction with the features of chronic allograft nephropathy. The use of ancillary techniques including immunohistochemistry and electron microscopy may be required to confirm the diagnosis. The presence of posttransplant de novo membranous nephropathy may be associated with an increased risk of graft loss.