Kidney transplant nephrotic syndrome: relationship between allograft histopathology and natural course

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.

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.

Use of genomic and functional analysis to characterize patients with steroid-resistant nephrotic syndrome

BACKGROUND

Children with genetic causes of steroid-resistant nephrotic syndrome (SRNS) usually do well after renal transplantation, while some with idiopathic SRNS show recurrence due to a putative podocyte-toxic factor. Distinguishing different forms of SRNS based on clinical criteria has been difficult. The aim of our study was to test a novel approach that allows categorization of patients into clinically useful subgroups.

METHODS

Seventeen patients with clinically confirmed SRNS were analyzed by next-generation sequencing (NGS) of 37 known SRNS genes and a functional assay of cultured human podocytes, which indirectly tests for toxicity of patients' sera by evidenced loss of podocyte focal adhesion complex (FAC) number.

RESULTS

We identified a pathogenic mutation in seven patients (41%). Sera from patients with monogenic SRNS caused mild loss of FAC number down to 73% compared to untreated controls, while sera from seven of the remaining ten patients with idiopathic SRNS caused significant FAC number loss to 43% (non-overlapping difference 30%, 95% CI 26-36%, P < 0.001). All patients with recurrent SRNS (n = 4) in the graft showed absence of podocyte gene mutations but significant FAC loss. Three patients had no mutation nor serum podocyte toxicity.

CONCLUSIONS

Our approach allowed categorization of patients into three subgroups: (1) patients with monogenic SRNS; (2) patients with idiopathic SRNS and marked serum podocyte toxicity; and (3) patients without identifiable genetic cause nor evidence of serum podocyte toxicity. Post-transplant SRNS recurrence risk appears to be low in groups 1 and 3, but high in group 2.

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.

Early posttransplant nephrotic range proteinuria as a presenting feature of minimal change disease and acute T cell-mediated rejection

Early-onset nephrotic range proteinuria is an extremely rare presentation of an acute rejection episode. Herein, we have reported a patient who developed nephrotic range proteinuria 7 days after receiving a renal allograft from his sister despite minor changes in serum creatinine levels. A kidney biopsy spcimen revealed a T cell-mediated acute rejection process concomitant with minimal change disease (MCD). Proteinuria and renal dysfunction improved dramatically in response to corticosteroids. The possibility of acute cellular rejection and coexisting MCD should be considered in patients with early posttransplantation nephrosis and normal serum creatinine levels. The coexistence of these entities provides support for the role of T cells in the pathogenesis of MCD.

Podocyte foot process effacement in postreperfusion allograft biopsies correlates with early recurrence of proteinuria in focal segmental glomerulosclerosis

BACKGROUND

Focal segmental glomerulosclerosis (FSGS) is a relatively prevalent glomerular disorder that often progresses to end-stage renal disease. Thirty to 80% of kidney transplant (KT) recipients with FSGS will experience recurrence characterized by proteinuria and podocyte damage. We hypothesized that the degree of podocyte foot process (FP) effacement in postreperfusion transplant biopsies can be used to predict the development of clinical recurrence of FSGS.

METHOD

Nineteen pairs of pre- and postreperfusion biopsy specimens were studied. We evaluated the degree of FP effacement in postreperfusion KT biopsies by counting the number of widened FP per capillary loop. Early recurrence of FSGS was defined as development of nephrotic range proteinuria between days 3 and 30 posttransplant.

RESULTS

Early recurrence occurred in 7 of 19 grafts (36.8%) at a mean of 4.29±1.89 days. The mean score of FP effacement in postreperfusion allograft biopsies was 0.72±0.31 and 1.35±0.63 in the nonrecurrent and recurrent group, respectively (P=0.039). There was an association between FP effacement and proteinuria (P = 0.04). The FP effacement score predicts early recurrence with a sensitivity of 71.4% and specificity of 91.7%.

CONCLUSION

FP effacement can be observed within minutes after reperfusion in renal transplantation of recipients with FSGS that will ultimately develop recurrent FSGS. This suggests a key role for the podocyte injury in the pathogenesis of recurrent FSGS and further supports the presence of circulating factors causing FP effacement. The FP effacement score in the postreperfusion KT biopsy may become a useful predictive test if validated in larger studies.

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.

Early onset proteinuria after renal transplantation: a marker for allograft dysfunction

The objective of this study was to determine whether early proteinuria after renal transplantation affected long-term allograft survival. The 130 patients included 105 men and 25 women of overall mean age, 29.6 +/- 9.6 years. There were 105 living related and, 25 cadaveric donor transplants. Proteinuria was defined as a level in of more than 300 mg/d. Donor and recipient age at transplantation, duration of pretransplant dialysis, donor type (living related or cadaveric), the presence of delayed graft function or acute rejection, panel-reactive antibodies, the number of human leukocyte antigen mismatches, and the systolic blood pressure level were retrospectively recorded for the study subjects. Cox regression analysis was used to determine the effects of proteinuria on allograft survival. Patients with proteinuria demonstrated significantly lower graft survival rates than did those without proteinuria (54.17% vs 82.62%, respectively; P<.002). Proteinuria at the third month after transplantation (P<.004, odds ratio [OR]=3.26, confidence interval [CI]=1.46 to 7.29), donor age (P<.001, OR=1.06, CI=1.02 to 109), and panel-reactive antibodies (P<.041, OR=1.06, CI=1.00 to 1.12) were significantly associated with decreased allograft survival. Early proteinuria after renal transplantation was indicative of a high risk for allograft dysfunction. A reduction of proteinuria may be associated with improved graft survival.

The clinical impact of chronic transplant glomerulopathy in cyclosporine era

BACKGROUND

The clinical impact of chronic transplant glomerulopathy (CTG) on the outcome of kidney allograft receiving calcineurin inhibitors (CNIs) remains uncertain. A retrospective study of renal transplant recipients at Ospedale Maggiore of Milan was undertaken to evaluate the clinical outcome of patients with CTG.

METHODS

Among 666 biopsies taken at least 6 months after transplantation (Tx) in 498 transplant patients treated with CNIs, 28 cases (5.6%) of chronic transplant glomerulopathy (CTG) were identified and their clinical features at Tx, at follow-up and graft survival were compared with those of 56 controls transplanted in the same period and with kidney functioning 12 months after Tx. Clinical characteristics at biopsy and at 1 year after Tx were similar in the two groups.

RESULTS

After diagnosis graft function deteriorated in 22 patients (78.5%), while it remained stable in 6. Graft loss developed in 92 % of patients with proteinuria >2.5 g/day and in 33 % of those with lower proteinuria (P<0.005). In cases with more severe CTG the rate of graft loss was higher, though not significantly. Graft survival at 10 years was 48% in patients with CTG and 88% in controls (P<0.0001).

CONCLUSIONS

The incidence and clinical course of CTG do not seem to be modified by CNI-based immunosuppression. The evolution is unpredictable but the severity of glomerulopathy and proteinuria at follow-up are associated with progression to graft failure. Patients with CTG have a graft survival significantly worse than that of the general population of transplanted patients.

Preemptive plasmapheresis and recurrence of FSGS in high-risk renal transplant recipients

Recurrent focal segmental glomerulosclerosis (FSGS) following transplantation is ascribed to the presence of a circulating FSGS permeability factor (FSPF). Plasmapheresis (PP) can induce remission of proteinuria in recurrent FSGS. This study addressed the efficacy of pre-transplant PP in decreasing the incidence of recurrence in high-risk patients. Ten patients at high-risk for FSGS recurrence because of rapid progression to renal failure (n = 4) or prior transplant recurrence of FSGS (n = 6) underwent a course of 8 PP treatments in the peri-operative period. Recurrences were identified by proteinuria >3 g/day and confirmed by biopsy. Seven patients, including all 4 with first grafts and 3 of 6 with prior recurrence, were free of recurrence at follow-up (238-1258 days). Final serum creatinine in 8 patients with functioning kidneys averaged 1.53 mg/dL. FSGS recurred within 3 months in 3 patients, each of whom had lost prior transplants to recurrent FSGS. Two of these progressed to end-stage renal disease (ESRD) and the third has significant renal dysfunction. Based on inclusion criteria, recurrence rates of 60% were expected if no treatment was given. Therefore, PP may decrease the incidence of recurrent FSGS in high-risk patients. Definitive conclusions regarding optimal management can only be drawn from larger, randomized, controlled studies.

Post-transplant nephrotic syndrome: A comprehensive clinicopathologic study

BACKGROUND

Post-transplant (Tx) nephrotic syndrome (NS) is not well defined.

METHODS

Seventy-four renal transplant recipients with NS were studied.

RESULTS

Biopsies showed chronic allograft nephropathy (CAN) in 31 patients; recurrent glomerular disease (GN) in 15, de novo GN in 18, and undetermined GN in 9. NS developed 0.25 to 384 months post-Tx and was treated with angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) in 18 patients; calcium channel blockers in 25; or both drugs in 31. NS remitted in 24% of cases 2 to 28 months after onset, and this persisted in all except 3 patients. The remission rate was lowest (9%) for CAN and highest (47%) for de novo GN. Compared with persistent NS, those with remission showed higher prevalence of de novo GN (53% vs. 17%), lower prevalence of CAN (18% vs. 50%), earlier onset of NS (39 vs. 59 months), lower serum SCr at onset (2.3 vs. 2.9 mg/dL), and higher incidence of treatment with ACE or ARB. The 5-year graft loss rates for CAN, recurrent and de novo GN were 57%, 36%, and 23%, respectively. Compared with the functioning grafts, the failed grafts showed higher prevalence of CAN (60% vs. 16%), lower prevalence of de novo GN (12% vs. 46%), earlier onset of NS (47 vs 65 months post-Tx), higher serum SCr at onset (3.3 vs. 2.0 mg/dL), lower prevalence of remission of NS (5% vs. 48%), and higher proteinuria at follow-up (5.1 vs. 2.5 g/day). Graft survival improved with NS remission (88% vs. 18%).

CONCLUSION

Post-Tx NS displays distinctive clinicopathologic features with pathogenetic and therapeutic implications.

Recurrence of primary disease in children after renal transplantation: an evidence-based update

The availability of new and more effective anti-rejection therapy has succeeded in reducing the incidence of acute cellular rejection in first months post-renal transplant. This in turn has escalated the order of significance of recurrence of primary disease in the renal allograft as a cause for patient morbidity and graft loss during this period. The aim of this review is to survey current literature, identify issues and potential areas for future research related to recurrence of primary disease after renal transplant. Our review of published reports suggests that our current knowledge and practice, related to the management of recurrence of primary disease, are mainly based on non-randomized and uncontrolled case series. The future need for well designed mechanistic as well as therapeutic, controlled and randomized multicenter clinical trials cannot be overemphasized.

Peritubular capillary changes and C4d deposits are associated with transplant glomerulopathy but not IgA nephropathy

We examined our renal transplant population for glomerular diseases demonstrated on biopsy between January 1993 and April 2002, focusing on transplant glomerulopathy (TGP). Of 1156 patients followed in our clinics during this period, glomerular disease was diagnosed in 132 cases (11.4%). Glomerulonephritis was diagnosed in 86 transplants (7.4%), with IgA nephropathy (IgAN) being the commonest diagnosis [32 cases (2.8%)]. Thirty-one cases (2.7%) of biopsy-proven TGP were analyzed for associated factors compared with 27 cases (2.3%) of recurrent IgAN. Transplant glomerulopathy was less frequent with mycophenolate mofetil (MMF) and/or tacrolimus, whereas recurrent IgAN showed no such tendency (P= 0.02). Peritubular capillary (PTC) C4d deposition was observed in six of 24 cases (25%) with TGP but none with recurrent IgAN (P= 0.02). Peritubular capillary basement membrane (BM) multilayering was significantly greater in TGP (4.92 +/- 2.94) than in recurrent IgAN (1.86 +/- 1.04) (P < 0.001). The graft survival of TGP was worse than recurrent IgAN (P= 0.05). The association of TGP with BM multilayering and C4d deposits in PTC suggests a generalized disorder of the graft microcirculation and its BM, owing to antibody-mediated rejection in at least some cases. Transplant glomerulopathy has a serious prognosis but is less frequent in patients on newer immunosuppression, unlike recurrent IgAN.

New aspects of posttransplant nephrotic syndrome: clinicopathologic correlations with outcomes

Although posttransplant nephrotic syndrome is frequent, its structural basis and prognosis have not been clearly defined. The biopsy findings of 54 patients with this disorder posttransplant, among 375 total renal transplant recipients engrafted during a 10-year period, were correlated with clinical follow-up data. The mean patient age was 41.7 +/- 12.3 years, female/male ratio 22/32, and cadaveric/living-related donor ratio 37/17. The nephrotic syndrome developed 3 to 91 months posttransplant. At the onset the mean values of serum creatinine was 2.9 +/- 1.8 mg/dL and proteinuria 4.5 +/- 0.8 g/d. The index biopsy findings showed chronic allograft nephropathy (CAN) in 33; de novo glomerulonephritis (GN) in 6, recurrent GN in 9, and undetermined GN in 6 who had an unknown primary renal disease. Among 21 follow-up biopsies during a mean of 44.3 +/- 28 months the CAN progressed but the GN remained the same. The treatment included augmented steroids alone (n = 1) or in combination with cyclophosphamide (n = 2) and with plasmapheresis (n = 1); angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) along (n = 5); calcium channel blockers (CCB) alone (n = 24); or the two types of drugs together (n = 22). Complete or partial remission was achieved in 8 and 5, respectively, but nephrotic syndrome recurred in 3 of these patients at 45.1 +/- 18 months later. Sustained remission was more likely in cases of GN (minimal change disease and IgA nephropathy) and ACEI-ARB treatment (P <.01). Graft failure, which occurred in 35 patients, correlated strongly with serum creatinine at onset, being significantly greater in patients with CAN (P <.005). Both remission of the nephrotic syndrome and graft survival were greater among patients with GN as compared to those with CAN.

The remission of post-transplant nephrotic syndrome clinicopathologic characterization

Among 67 renal transplant recipients with nephrotic syndrome (NS), nine episodes were reversible in eight patients. Biopsies showed minimal-change disease, focal segmental membranous glomerulonephritis and acute glomerulitis, IgA nephropathy and acute glomerulitis or thrombotic microangiopathy, and chronic transplant nephropathy with or without acute glomerulitis. NS developed 1-4 months post transplant in the four patients with minimal-change disease, but later (33-151 months) in the others. At onset, serum creatinine was normal or elevated. Treatment included calcium-channel blockers, angiotensin-converting enzyme inhibitors, or both, together with routine antirejection therapy. Remission was achieved 4-12 months after onset, when renal function remained normal in four, improved in four, and worsened in one. At last follow-up, six patients still had remission and functional grafts. One lost graft to chronic transplant nephropathy while NS remained in remission. In the remaining patient, proteinuria, which was due to chronic transplant glomerulopathy unrelated to the initial minimal-change disease-associated NS, recurred 50 months post transplant. Remission of post-transplant NS is possible. It is often associated with minimal-change diseases and less frequently with other glomerular lesions, including acute glomerulitis. Reversible post-transplant NS does not have an adverse effect on the renal allografts.

De novo minimal change disease associated with reversible post-transplant nephrotic syndrome. A report of five cases and review of literature

Nephrotic syndrome (NS) is frequent in renal transplant recipients and may be related to a large variety of glomerular lesions. In some of these cases, the transplant biopsy showed no significant glomerular changes and the NS was reversible, but the primary renal disease was not minimal change disease (MCD), suggesting that MCD may develop de novo in renal transplant setting. Knowledge of this entity, however, is limited. Among 67 cases of post-transplant NS encountered in a 12-yr period, five were found to be associated with de novo MCD. A critical review of the literature revealed nine additional cases of de novo MCD. The data from these 14 cases show that patients with de novo MCD had a large variety of primary renal diseases but MCD or focal segmental glomerulosclerosis was not among them. Eight of the 14 transplanted kidneys (60%) were from living related donors, suggesting this as a risk factor. Nephrotic range proteinuria (3-76 g/d) developed immediately or shortly after transplantation (within 4 months for all reported cases, except for one at 24 months). The serum creatinine when NS was first diagnosed was normal or mildly elevated, but acute renal failure occurred in three patients. On biopsy, the glomeruli were normal or, more frequently, displayed mild, focal segmental mesangial sclerosis, hypercellularity, deposition of IgM/C3, or accumulation of mononuclear inflammatory cells in some glomerular capillaries. The tubulointerstitial compartment was normal in cases with normal renal function; displayed mild acute and/or chronic rejection that correlated with a mildly elevated serum creatinine; or showed acute changes including acute rejection, acute tubular necrosis, or acute cyclosporin A toxicity, which accounted for both acute renal failure at presentation and its subsequent reversibility. Under various treatments, including increased steroids, angiotensin converting enzyme inhibitors, calcium channel blockers and angiotensin receptor blockers, sustained remission of NS was achieved in 13 cases, within a year (0.5-12 months) in 10 and later (24, 34 and 98 months, respectively) in three. In the remaining case, the patient died of septic shock 2 months after transplantation. After remission of the NS, the grafts functioned well without or with minimal proteinuria for several years. De novo MCD has characteristic clinical and pathologic features. It represents an important but hitherto underemphasized cause of post-transplant NS, which is potentially reversible and does not adversely affect the renal transplants.

Recommendations for the outpatient surveillance of renal transplant recipients. American Society of Transplantation

Many complications after renal transplantation can be prevented if they are detected early. Guidelines have been developed for the prevention of diseases in the general population, but there are no comprehensive guidelines for the prevention of diseases and complications after renal transplantation. Therefore, the Clinical Practice Guidelines Committee of the American Society of Transplantation developed these guidelines to help physicians and other health care workers provide optimal care for renal transplant recipients. The guidelines are also intended to indirectly help patients receive the access to care that they need to ensure long-term allograft survival, by attempting to systematically define what that care encompasses. The guidelines are applicable to all adult and pediatric renal transplant recipients, and they cover the outpatient screening for and prevention of diseases and complications that commonly occur after renal transplantation. They do not cover the diagnosis and treatment of diseases and complications after they become manifest, and they do not cover the pretransplant evaluation of renal transplant candidates. The guidelines are comprehensive, but they do not pretend to cover every aspect of care. As much as possible, the guidelines are evidence-based, and each recommendation has been given a subjective grade to indicate the strength of evidence that supports the recommendation. It is hoped that these guidelines will provide a framework for additional discussion and research that will improve the care of renal transplant recipients.

Acute rejection presenting as nephrotic syndrome

BACKGROUND

Early diagnosis and treatment of acute rejection is important to prevent continued renal injury. Acute rejection most commonly presents with asymptomatic rise in serum creatinine. Proteinuria associated with acute rejection is well established; however, there is limited documentation of the presentation of acute rejection as nephrotic syndrome in the literature.

METHODS AND RESULTS

We report a renal transplant patient who presented with early onset nephrotic syndrome without change in serum creatinine, whose allograft biopsy confirmed acute glomerulitis and vascular rejection. Treatment of the acute rejection was accompanied by resolution of the nephrotic syndrome. A second episode of acute rejection was also manifested as nephrotic range proteinuria.

CONCLUSION

The nephrotic syndrome in early post-transplantation period should prompt a work-up for acute rejection even in the absence of the common findings of this complication.

The prognostic importance of severity and type of post-transplant proteinuria

Proteinuria, developing after renal transplantation may influence allograft and patient outcomes. This study aimed to investigate the effect of proteinuria on patient and allograft survival. Among 514 patients, 56 (11%) patients with good allograft function and proteinuria were evaluated retrospectively. Patients with proteinuria were classified as group P (20 patients with permanent proteinuria, Male/Female: 16/4) and group T (36 patients with temporary proteinuria, M/F: 29/7) according to the type of proteinuria. Also, considering the amount of proteinuria, patients were classified as group M (32 patients with massive proteinuria, M/F: 29/3) and group NM (24 patients with non-massive proteinuria, M/F: 16/8). The mean time interval between transplantation and appearance of proteinuria was 23.7 months (range 0-121 months) and no difference was found between groups. Two- and 5-yr allograft survival rates were found to be 85 and 80% in group M, and 95 and 82% in group NM. respectively (p = 0.24). In terms of type of proteinuria, 2- and 5-yr allograft survival rates were found to be 70 and 58% in group P and 92 and 87% in group T, respectively. The difference between groups P and T was found to be statistically significant (p = 0.02). Most (85%) of the patients with permanent proteinuria also had massive proteinuria. In conclusion, we found a significant relation between type and severity of proteinuria. The type of post-transplant proteinuria had a stronger effect on allograft outcome than the severity of proteinuria.

Collapsing glomerulopathy in renal allografts: a morphological pattern with diverse clinicopathologic associations

We reviewed the clinical and pathological characteristics of seven patients with collapsing glomerulopathy (CG) in renal allograft biopsy specimens. All patients underwent biopsies for graft dysfunction. Two patients had nephrotic proteinuria (protein, >3.5 g/24 h), whereas all others had only modest or insignificant proteinuria. In five of seven patients, additional pathological processes, including microvascular injury, acute rejection, recurrent diabetic nephropathy, and immune complex glomerulonephritis, were present, each of which likely contributed to graft dysfunction and proteinuria. None of the patients in this series had nephrotic syndrome solely attributable to CG. Three biopsy specimens had features consistent with chronic rejection. The development of CG in renal allograft biopsy specimens was associated with graft dysfunction and a high rate of graft loss. These findings emphasize the prognostic significance of CG in renal allografts and suggest that CG may result from diverse pathogenic mechanisms.

Percutaneous renal graft biopsy: a clinical, laboratory and pathological analysis

CONTEXT

Renal allograft biopsies have been used as a good method for monitoring the evolution of kidney transplants for at least 20 years. Histological analysis permits differential diagnosis of the causes of allograft dysfunction to be made.

OBJECTIVES

To correlate the data of urinalysis and serum creatinine with histological diagnosis of renal graft in a group of renal transplant patients.

DESIGN

Accuracy study, retrospective analysis.

SETTING

A university terciary referral center.

SAMPLE

339 percutaneous allograft biopsies obtained from 153 patients. Blood and urine samples were obtained before the graft biopsy.

MAIN MEASUREMENTS

Laboratory evaluation and hystological analysis (light microscopy, immunofluorescent electronic microscopy).

RESULTS

Most of the biopsies (58.9%) were performed during the first month post-transplant. An increase in serum creatinine was associated with acute tubular and/or cortical necrosis. Proteinuria and normal serum creatinine were associated with glomerular lesions. Non-nephrotic range proteinuria and an increase in serum creatinine were associated with chronic rejection.

CONCLUSION

Evaluation of serum creatinine and urinalysis can be useful in suggesting the histological graft diagnosis.

Chronic renal allograft rejection: immunologic and nonimmunologic risk factors

The pathogenesis of chronic renal allograft rejection is unknown. It is also unclear why cyclosporine has failed to prevent chronic rejection. We examined possible risk factors for graft loss to chronic rejection among 706 renal transplants using the Cox proportional hazards model with fixed and time-dependent covariates. Both the number and the severity of acute rejection episodes were independent risk factors for chronic rejection [relative risk (95% confidence interval) 2.31 (2.04 to 2.60) and 1.53 (1.27 to 1.84), respectively]. Cyclosporine and cyclosporine withdrawal had no effect on chronic rejection. Acute rejections occurring within the first three months after transplantation, when cyclosporine most effectively prevented acute rejection, also had no effect on chronic rejection. Risk factors that were independent of acute rejection and not clearly attributable to immune mechanisms included serum albumin [0.20 (0.10 to 0.38) for each g/dl], proteinuria [1.42 (1.29 to 1.57) for each g/24 hr], and serum triglycerides -1.09 (1.03 to 1.16) for each 100 mg/dl-. These results suggest that the reduction in acute rejection episodes from cyclosporine has failed to reduce graft failure from chronic rejection, possibly because the early (within the first 3 months) and mild acute rejection episodes that are most effectively prevented by cyclosporine do not cause chronic rejection. In addition, the results suggest that there may be a number of nonimmunologic risk factors for chronic rejection.

Living-related donor transplants should be performed with caution in patients with focal segmental glomerulosclerosis

The success rates of living-related donor (LRD) transplants are clearly superior to those obtained with cadaver donors. However, caution should be exercised when considering LRD transplantation for a condition which has an increased chance of recurring after transplantation and causing ultimate graft failure. The recurrence rate of focal segmental glomerulosclerosis (FSGS) in the allograft is 20%-40%, with graft failure resulting in 40%-50% of these cases. However, these figures may be an underestimation of the true rate of recurrence of FSGS. Once a first transplant fails due to recurrent disease, the risk of recurrence in the second transplant approaches 80%. Subgroups of patients at high risk for recurrence have been identified. In patients not at high risk for recurrent FSGS, the use of a LRD should be considered, provided that the donor and recipient and their families have been informed that the disease may recur and lead to graft failure. In patients at high risk for recurrence, a LRD transplant should be avoided. Hopefully, future development of a simple and reliable test to predict the likelihood of recurrence will enable us to counsel and advise our patients with FSGS about the wisdom or dangers of proceeding with a LRD transplant.

Recurrent diseases in the kidney transplant

Virtually all diseases affecting the native kidney recur in the kidney transplant with the exception of Alport syndrome, polycystic kidney disease, hypertension, chronic pyelonephritis, and chronic interstitial nephritis. Fortunately, in the majority of patients, recurrence of the original disease has minimal clinical impact, with only approximately 5% of all graft loss occurring as a result of recurrent disease. The primary renal diseases that commonly recur include membranoproliferative glomerulonephritis type II, IgA nephropathy, and focal and segmental glomerular sclerosis. The most common systemic disease that recurs is diabetic nephropathy. Living-related transplantation should be used with caution in patients with the hemolytic uremic syndrome, recurrent focal and segmental glomerular sclerosis, and membraneous glomerulonephritis. Fabry disease and primary hyperoxaluria type I are no longer absolute contraindications to kidney transplantation.

Post-transplantation nephrosis in congenital nephrotic syndrome of the Finnish type

Congenital nephrotic syndrome of the Finnish type (CNF) is an autosomal recessively inherited disease manifesting as massive proteinuria, edema and ascites in the neonatal period. The disease is believed to be limited to the kidneys and recurrences after renal transplantation have not been reported. At our center 29 transplantations have been performed on 28 CNF patients. One to 33 months after transplantation, seven grafts (24%) of six patients have developed a steroid-resistant nephrotic syndrome. The clinical data and renal histology of these patients were analyzed in order to elucidate the cause of the proteinuria. At the onset of six of the seven episodes of nephrosis, the patient had evidence of a preceding CMV- or EBV-infection and the remaining patient had sinusitis. Upon light and electron microscopy examination, endothelial swelling of the glomerular capillaries resembling transplant glomerulopathy (TG) was seen, but unlike TG, the glomerular basement membranes were normal. The response of proteinuria to steroid or cyclophosphamide therapy was poor, with total remission in only two patients and partial remission in one patient, all treated with methylprednisolone and cyclophosphamide immediately after the diagnosis. Four grafts have been lost. Our data show that CNF patients have an increased tendency for post-transplantation nephrosis.

Effect of enalapril on proteinuria after kidney transplantation

We studied the effect of enalapril, an inhibitor of angiotensin-converting enzyme (iACE), on proteinuria and renal function in recipients of renal allografts. Twenty-two patients with post-transplant nephrotic syndrome were treated with incremental doses of enalapril for 1 year. Urinary protein excretion decreased after 2 months of treatment from a mean of 8.9 g/day (range 4.0-18.9 g/day) to 4.5 g/day (range 0.4-10.0 g/day; P < 0.01) and remained significantly low for the rest of the study. However, in the same period, creatinine clearance did not change significantly; it went from 47.8 ml/min (range 17.1-110.3 ml/min) before treatment to 44.2 ml/min (range 16.5-88.5 ml/min) after 2 months of iACE therapy. Analysis of individual data showed that there was a significant reduction in proteinuria in 14 of the 22 patients and that the rate of deterioration of renal function did not increase in 17 of the 22 patients. We did not observe any serious side effects of enalapril administration. The results of our study prove that iACE can be used safely and effectively to reduce post-transplant proteinuria.

Recurrent and de novo renal disease after kidney transplantation with or without cyclosporine A

We evaluated the clinical course of 700 renal transplantations, including 1,305 transplant histologies performed in 611 patients between 1970 and 1988, to estimate the influence of cyclosporine A (CsA) after kidney transplantation on the incidence of recurrent or de novo renal disease. Primary renal disease recurred in 11 of 583 functioning transplants (1.9%) with transplant loss in seven patients (1.2%): focal segmental glomerulosclerosis (FSGS, three patients); membranous glomerulonephritis (GN, one patient); mesangiocapillary GN (one patient); rapidly progressive IgA nephropathy (one patient); hemolytic-uremic syndrome (HUS, three patients); and oxalosis in two transplants (one patient). De novo renal disease occurred in six patients (1.0%), including mesangiocapillary GN type I (three patients); nonpurulent focal GN in septicemia (one patient); HUS (one patient); and nodular glomerulosclerosis in steroid diabetes (one patient). De novo membranous GN was seen in 14 additional cases (2.4%). No statistically significant difference could be established between the treatment groups without (n = 225) and with (n = 358) CsA in recurrent and de novo renal disease (n = 7/225 v 10/358, NS); in recurrent and de novo GN (n = 4/225 v 6/358, NS); in recurrent FSGS (n = 1/7 v 2/8, NS); in recurrent and de novo HUS (n - 1/1 v 2/7, NS); and in de novo membranous GN (n = 7/225 v 7/358, NS). Transplant loss by recurrent and de novo GN was higher without than with CsA (n = 4/4 v 1/6, P = 0.004). On the basis of our investigation, we conclude that recurrent and de novo renal disease in the transplant occur rarely and are not prevented by CsA. However, even if the incidence of transplant GN is unchanged by CsA treatment, its clinical course seems to be mitigated. CsA treatment also does not increase the incidence of HUS.

De novo membranous glomerulonephropathy in renal allografts: a report of ten cases and review of the literature

De novo posttransplantation membranous glomerulonephropathy (MGN) is the most common form of de novo glomerulopathy in renal allografts. The clinical and pathological features of ten patients with de novo MGN were studied and the related literature was reviewed to assess the clinical features, morphologic characteristics, and natural course of this disease. De novo MGN may occur in both living related and cadaveric allografts at any time after transplantation. It presents clinically either as asymptomatic proteinuria or the nephrotic syndrome, a feature of poor prognostic implication. Morphologically, de novo MGN in most instances has distinct differences from idiopathic MGN in native kidneys and is accompanied by varying features of rejection. About 50% of grafts which develop de novo MGN eventually fail. This rather poor outcome may not represent the natural history of de novo MGN per se but rather the consequences of associated chronic rejection. Evidence is presented that many of the cases of so-called de novo MGN may be a complication of transplant glomerulopathy rather than being caused by mechanisms totally independent from rejection.

Recurrence of disease following renal transplantation

The diagnosis of recurrent renal disease after transplantation is dependent on an accurate and complete diagnosis of the initial cause of renal failure and a similar determination of the cause of graft failure. To be classified as recurrent, the disease in the renal graft must be identical to that seen in the native kidneys. Recurrence of disease accounts for less than 2% of all graft failures, but the overall incidence of recurrent disease is probably 5 to 10 times more common. The most frequent cause of recurrent disease is glomerulonephritis, which was first recognized to recur soon after renal transplantation was introduced. It was then recognized that a variety of metabolic disorders would recur, but it has taken 25 years of experience for a clear picture to emerge of recurrence in most conditions. No initial cause of renal failure poses a contraindication to at least one attempt at transplantation, although with Fabry's disease and oxalosis, a special assessment of the risks for the individual recipient is warranted. In some patients, experience has shown the need for a delay in the commitment to transplantation (eg, in those with anti-glomerular basement membrane [GBM] antibody glomerulonephritis or Henoch Schonlein purpura), the need for the choice of a particular immunosuppressive regimen (eg, in hemolytic uremic syndrome [HUS]), the need for avoidance of primary nonfunction (eg, in oxalosis), and the desirability of avoiding live kidney donation (eg, in heterozygote donors in Fabry's disease, high-risk recipients with focal glomerulosclerosis, and in recipients with HUS). Probably all types of glomerulonephritis recur, but with great variation in frequency and severity. In some forms of glomerulonephritis, recurrence may be frequent and definite on histopathological criteria but may only have a minor clinical expression (eg, dense deposit disease, anti-GBM antibody glomerulonephritis, IgA nephropathy), but in others, recurrence is less predictable yet it is clearly associated with premature graft failure (eg, focal glomerulosclerosis, membranous nephropathy). A common theme emerging is that where the initial glomerulonephritis is aggressive and causes kidney failure over a short time, recurrence is more likely, and when present, it will lead to graft failure with an increased frequency. Clinical manifestations, the frequency of recurrence, and the prognosis of the graft are now identified for most conditions. Unexpected observations have included the rarity of recurrent systemic lupus erythematosus (SLE), the immediate return of heavy proteinuria in focal glomerulosclerosis, and the predictable return of dense deposit disease.(ABSTRACT TRUNCATED AT 400 WORDS)

Nephrotic range proteinuria with "minimal change glomerulopathy" in human renal allografts: report of four cases

Four patients who received renal allografts developed nephrotic range proteinuria 2 to 16 months after renal transplantation. Twenty-four-hour urine protein excretion at the time of renal allograft biopsy ranged from 5.9 to 17.0 g/24 hours. The serum creatinine at the time of renal allograft biopsy ranged from 2.0 to 3.9 mg/dl (180 to 350 mumol/L). Biopsies of the allografts demonstrated minimal glomerular abnormalities by light microscopy, immunomicroscopy, and electron microscopy. Two biopsies exhibited severe interstitial fibrosis. These four cases illustrate the unusual finding of "minimal change glomerulopathy" in renal allograft recipients exhibiting nephrotic range proteinuria. All four patients progressed to dialysis 4, 36, 46, and 53 months after transplantation. Transplant nephrectomy was performed in three patients. One showed acute cortical necrosis. Two showed glomerular, vascular, and tubular-interstitial features of chronic rejection.

Glomerular lesions in the transplanted kidney in children

The glomerular pathology of 634 transplant specimens (526 biopsies and 108 transplantectomies) from 410 children was studied. Three types of glomerulopathies were observed: (1) recurrent glomerulonephritis (GN) (40 of 142 patients with glomerular nephropathy), (2) de novo GN (52 grafts), and (3) transplant glomerulopathy (29 grafts). The study of recurrent GN is considered of great interest because of the possible insight into the nature of the original disease and the opportunity to observe the evolution of the disease in sequential biopsies of the transplant. The two major forms of de novo GN were membranous GN and IgG linear deposits along glomerular and tubular basement membranes. Transplant glomerulopathy, although distinctive morphologically, may resemble membranoproliferative GN (MPGN) or thrombotic microangiopathy.

Urinary protein/creatinine ratio as an indicator of allograft function following live related donor renal transplantation

In a study of 656 urine specimens from 53 consecutive recipients of live related donor renal allografts we found an excellent correlation between the protein content of 24-h urines and protein/creatinine ratio (Up/Ucr) in overnight urine samples. Using this ratio, we evaluated proteinuria up to 180 days after renal transplantation (overnight urine samples analysed, n = 2745). Heavy proteinuria in the immediate post-operative period had no prognostic significance. Eighty-nine percent of all clinically observed acute rejection episodes were accompanied by an increase over baseline of Up/Ucr; in 56.5% of these episodes elevation of Up/Ucr preceded that of serum creatinine. However, as a marker of rejection the usefulness of this parameter was limited owing to large number of false positive elevations. In 50 recipients whose grafts survived for more than 3 mth, proteinuria was graded into minimal, moderate and heavy. Renal function at the end of six months was good in all patients who exhibited proteinuria with Up/Ucr less than 100 mg/mmol creatinine. Persistent proteinuria with Up/Ucr above 100 mg/mmol preceded significant deterioration of graft function. Therefore, a protein-creatinine ratio of 100 mg/mmol can be considered as an apparent cut-off to differentiate stable from deteriorating graft function in long term evaluation of transplant recipients.

Glomerular epithelial cell lesions in rat renal isografts

Visceral glomerular epithelial cell lesions--microvillus formation, loss of foot processes, osmiophilic inclusion droplets, balloon-like malformation of cell processes, degeneration, necrosis, and loss of cell processes from capillary basement membranes--are found in rat renal isografts 1 mth after transplantation. The lesions, which are most readily recognized in perfusion-fixed material, are essentially focal, affecting neither all glomeruli, nor all cells in any glomerulus, bear no relation to the degree of interstitial nephritis in the graft, and are associated with albuminuria and with focal capillary sclerosis in some glomeruli. They are not restricted to renal isografts but are found in aging rats, in different experimental models of glomerular disease and in clinical glomerular disorders, again in association with proteinuria and glomerulosclerosis. It is therefore proposed that glomerular epithelial cell damage increases capillary permeability and impairs maintenance of the integrity of the capillary wall, leading to proteinuria and focal glomerulosclerosis.

Transplant glomerulopathy: evolution of morphologically distinct changes

The study was undertaken to redefine morphological appearance and clinical implications of the diagnosis of transplant glomerulopathy (TGP). Fifty-seven renal transplant biopsy specimens from thirty patients with the diagnosis of TGP were evaluated. Multiple repeat biopsies in several cases enabled us to follow the pattern of the evolution of the changes. Transplant dysfunction manifested itself 8 days to 13 years post-transplantation by proteinuria and/or elevated creatinine level. The earliest recognizable morphological change was the swelling of endothelial and mesangial cells. This stage was called evolving TGP. The intermediate stage was characterized by enlarged glomeruli with lobular simplification, spongy matrix, and glomerular basement membrane (GBM) deformities. The advanced stage of TGP showed pronounced GBM changes (reduplication, interposition). These light microscopic changes were associated with vascular rejection. Immunofluorescence showed significant glomerular deposition of IgM (83% of biopsies) and fibrinogen (66%). Electron microscopy at an early stage showed subendothelial widening with cellular debris and focal endothelial damage with fibrin deposition. In the advanced stage, complex GBM changes developed as a reparative response to the capillary wall injury. Effacement of foot processes was a constant finding at all stages. In follow-up, twenty-three allografts failed (77%), five patients are stable, and two died due to other causes. TGP has specific morphology with an attendant poor long-term prognosis for the allograft.

Renal allografts with glomerulonephritic change and proteinuria

Eight cases of renal allografts with glomerulonephritic change and proteinuria were classified into three groups according to the morphological features of the glomerular lesions. Group I (3 cases): By light microscope, remarkable reduplication of glomerular basement membrane (GBM), widening of mesangial region, and slight increase in mesangial cells, were observed. Electron microscopy revealed thickening of subendothelial space by deposition of electron-lucent material, mesangial interposition, and dense deposits in various regions (mainly in the subendothelial space). Group II (3 cases): By light microscope, crescent formation and reduplication of GBM were observed, while by electron microscope, changes of GBM similar to group I, but less remarkable, were seen. Group III (2 cases): Light microscope revealed spike formation in one case, but not in the other. With an electron microscope, subepithelial dense deposits were observed in both cases. Thickening of subendothelial space by deposition of electron-lucent material was noted in one case, while thickening of lamina densa was observed in the other case. Morphological change caused by rejection was observed in all eight cases, with six cases showing massive proteinuria and the other two showing slight proteinuria.