Prednisolone and chlorambucil treatment in idiopathic membranous nephropathy with deteriorating renal function

Therapies for Membranous Nephropathy: A Tale From the Old and New Millennia

Primary Membranous Nephropathy (PMN) is the most frequent cause of nephrotic syndrome in adults. If untreated, PMN can lead to end-stage renal disease; moreover, affected patients are at increased risk of complications typical of nephrotic syndrome such as fluid overload, deep vein thrombosis and infection. The association of PMN with HLA-DQA1 and the identification in around 70% of cases of circulating autoantibodies, mainly directed towards the phospholipase A2 receptor, supports the autoimmune nature of the disease. In patients not achieving spontaneous remission or in the ones with deteriorating kidney function and severe nephrotic syndrome, immunosuppression is required to increase the chances of achieving remission. The aim of this review is to discuss the evidence base for the different immunosuppressive regimens used for PMN in studies published so far; the manuscript also includes a section where the authors propose, based upon current evidence, their recommendations regarding immunosuppression in the disease, while highlighting the still significant knowledge gaps and uncertainties.

Immunosuppressive Therapy in Primary Membranous Nephropathy with Compromised Renal Function

INTRODUCTION

Renal dysfunction at presentation is uncommon in primary membranous nephropathy (PMN). The data on the outcome of PMN patients with renal dysfunction at outset are scarce. The objective of the current study was to report the clinical outcomes of PMN patients with renal dysfunction.

MATERIAL AND METHODS

This prospective longitudinal observational study included PMN patients (both incident and treatment resistant) with an estimated glomerular filtration rate of <60 mL/min/1.73 m2. Immunosuppressive treatment was as per the unit's protocol. Patients were evaluated for proteinuria, creatinine, and serum albumin at monthly intervals for 6 months, then quarterly for a year, and then biannually. Both serum and tissue anti-PLA2R were performed at baseline.

OUTCOME

Percentage of patients achieving clinical remission.

RESULTS

Sixty-four adults met study criteria and were analysed. The median (IQR) age of the patients was 48 (40, 56) years. PMN was PLA2R related in 52 (81.3%) patients. Twenty-eight (43.8%) and 30 (46.9%) patients were in remission at 12 months and at the end of the study [median (IQR) follow up: 24 months (12, 35)], respectively. Eight (12.5%) had progressed to end-stage renal disease at the last follow-up. Median (IQR) baseline anti-PLA2R titre was 150.1 RU/mL (38.5, 308). Nineteen (61.3%) and 18 (58.1%) patients with >90% reduction in anti-PLA2R titres at 12 months were in clinical remission at 12 months and at the end of the follow-up, respectively. Both cyclical cyclophosphamide/steroids (cCYC/GC) and rituximab were equally effective in inducing remission, but rituximab had a favourable adverse event profile compared to cCYC/GC.

CONCLUSION

To conclude, both cCYC/GC and rituximab are equally effective in inducing remission of nephrotic state with compromised renal function due to PMN. Immunosuppression induces remission in up to 50% PMN patients with CKD-stage 3-4.

Glomerular diseases: membranous nephropathy--a modern view

Membranous nephropathy (MN) is an autoimmune disease usually associated with a nephrotic syndrome and it may progress to ESRD in the long term. Its etiology is often unknown (idiopathic MN), whereas other cases have a recognizable etiology (secondary MN). In idiopathic MN, the glomerular lesions are mainly caused by autoantibodies against a podocyte membrane protein, the M-type of phospholipase A2 receptor 1. The natural course of idiopathic MN is quite varied with spontaneous complete or partial remissions a relatively common occurrence. Patients with asymptomatic non-nephrotic proteinuria seldom progress and need only conservative management. Those with persistent full-blown nephrotic syndrome and those with declining renal function are candidates for specific treatment with any of several regimens. Cyclical therapy with alternating monthly intravenous and oral glucocorticoids combined with a cytotoxic agent can induce remission and preserve renal function in the long term. Cyclosporine or tacrolimus can induce remission, but relapses are frequent after the drug withdrawal. Mycophenolate mofetil monotherapy seems to be ineffective, but may be beneficial when administered together with steroids. The experience with adrenocorticotropic hormone, natural or synthetic, is limited to a few studies with short-term follow-up, but high rates of remission can be seen after prolonged treatment. A high rate of remission and good tolerance have also been reported with rituximab. Patients with moderate renal insufficiency may also benefit from treatment, but at a price of frequent and serious side effects. With these limitations in mind, idiopathic MN may be considered a treatable disease in many patients.

Immunosuppression for progressive membranous nephropathy: a UK randomised controlled trial

BACKGROUND

Membranous nephropathy leads to end-stage renal disease in more than 20% of patients. Although immunosuppressive therapy benefits some patients, trial evidence for the subset of patients with declining renal function is not available. We aimed to assess whether immunosuppression preserves renal function in patients with idiopathic membranous nephropathy with declining renal function.

METHODS

This randomised controlled trial was undertaken in 37 renal units across the UK. We recruited patients (18-75 years) with biopsy-proven idiopathic membranous nephropathy, a plasma creatinine concentration of less than 300 μmol/L, and at least a 20% decline in excretory renal function measured in the 2 years before study entry, based on at least three measurements over a period of 3 months or longer. Patients were randomly assigned (1:1:1) by a random number table to receive supportive treatment only, supportive treatment plus 6 months of alternating cycles of prednisolone and chlorambucil, or supportive treatment plus 12 months of ciclosporin. The primary outcome was a further 20% decline in renal function from baseline, analysed by intention to treat. The trial is registered as an International Standard Randomised Controlled Trial, number 99959692.

FINDINGS

We randomly assigned 108 patients, 33 of whom received prednisolone and chlorambucil, 37 ciclosporin, and 38 supportive therapy alone. Two patients (one who received ciclosporin and one who received supportive therapy) were ineligible, so were not included in the intention-to-treat analysis, and 45 patients deviated from protocol before study end, mostly as a result of minor dose adjustments. Follow up was until primary endpoint or for minimum of 3 years if primary endpoint was not reached. Risk of further 20% decline in renal function was significantly lower in the prednisolone and chlorambucil group than in the supportive care group (19 [58%] of 33 patients reached endpoint vs 31 [84%] of 37, hazard ratio [HR] 0·44 [95% CI 0·24-0·78]; p=0·0042); risk did not differ between the ciclosporin (29 [81%] of 36) and supportive treatment only groups (HR 1·17 [0·70-1·95]; p=0·54), but did differ significantly across all three groups (p=0·003). Serious adverse events were frequent in all three groups but were higher in the prednisolone and chlorambucil group than in the supportive care only group (56 events vs 24 events; p=0·048).

INTERPRETATION

For the subset of patients with idiopathic membranous nephropathy and deteriorating excretory renal function, 6 months' therapy with prednisolone and chlorambucil is the treatment approach best supported by our evidence. Ciclosporin should be avoided in this subset.

FUNDING

Medical Research Council, Novartis, Renal Association, Kidney Research UK.

Management of idiopathic membranous nephropathy

IMPORTANCE OF THE FIELD

Idiopathic membranous nephropathy (IMN) can have a variable natural course. Treatments able to induce remission can improve the long-term prognosis. However, the optimal therapy for IMN remains controversial.

AREA COVERED IN THIS REVIEW

We reviewed the historical and current literature from 1979 to 2010 regarding the natural course of IMN and the possible treatments giving special emphasis to randomized controlled trials and to more recent approaches.

WHAT THE READER WILL GAIN

The reader will gain a comprehensive review of the available treatments of IMN. A personal therapeutic algorithm for nephrotic patients with IMN is also provided.

TAKE HOME MESSAGE

At least five different treatments showed efficacy in many (but not all) patients with IMN.

Idiopathic membranous nephropathy: management strategies

Treatment of idiopathic membranous nephropathy is based on a 'symptomatic' therapy that includes ACE inhibitors or angiotensin II receptor antagonists, and on an 'aetiological' therapy aimed at modulating underlying immunological mechanisms. The role of the latter is still debated given the usually indolent course of disease; furthermore, traditional immunosuppressants would not have an impact on patient and renal survival according to a systematic review of literature. However, up to 40% of untreated patients eventually develop end-stage renal disease and remission of nephrotic syndrome protects patients from related life-threatening complications and is the strongest positive prognostic factor for long-term kidney function. Therefore, immunosuppressive therapy seems to be rational in high-risk patients with nephrotic syndrome or deteriorating renal function. This article outlines a possible role for each 'aetiological' therapy on the basis of available evidence in order to provide some practical recommendations. The first-line therapy is based on a 6-month regimen of alternating corticosteroids and an alkylating agent ('Ponticelli' regimen), whereas oral ciclosporin and intramuscular corticotrophin (adrenocorticotrophic hormone) are alternatives that provide comparable results in terms of remission of proteinuria, with a different adverse effect profile. New drugs are emerging as potential treatments, such as mycophenolate mofetil, tacrolimus, intravenous immunoglobulins and rituximab. Specific settings, such as chronic renal failure or elderly age, require a careful balance between benefits and toxicity of immunosuppression. The tailor-made use of this repertoire of drugs can provide a tool to achieve remission of proteinuria and modify the natural course of idiopathic membranous nephropathy.

Idiopathic Membranous Nephropathy: Outline and Rationale of a Treatment Strategy

Idiopathic membranous nephropathy is a common cause of nephrotic syndrome. The treatment of patients with idiopathic membranous nephropathy is heavily debated. Based on literature data and our own experience, we propose a rational treatment strategy. Patients with renal insufficiency (serum creatinine level > 1.5 mg/dL [> 135 micromol/L]) are at greatest risk for the development of end-stage renal disease and should receive immunosuppressive therapy. In patients with normal renal function (serum creatinine level < 1.5 mg/dL [< 135 micromol/L]), risk for developing end-stage renal disease can be estimated by measuring urinary excretion of beta2-microglobulin or alpha1-microglobulin and immunoglobulin G. For low-risk patients, a wait-and-see policy is advised. High-risk patients likely benefit from immunosuppressive therapy. Currently, combinations of steroids with chlorambucil or cyclophosphamide are the best studied. We prefer cyclophosphamide in view of its fewer side effects. Cyclosporine may be an alternative option in patients with well-preserved renal function, although long-term data are lacking. Other immunosuppressive agents, such as mycophenolate mofetil or rituximab, currently are under study; however, data are insufficient to support their routine use.

Recent developments in the management of membranous nephropathy

Idiopathic membranous nephropathy is one of the most commonly encountered forms of nephrotic syndrome in adults. The natural history of the disease, observed in a small sample of untreated patients, reveals that a large proportion of patients experience spontaneous remission, whereas approximately one third of them progress towards renal insufficiency, and thus require dialysis. Hence, several attempts to treat this condition have been investigated and several protocols, based on different combinations of corticosteroids and/or immunosuppressive agents, have been proposed. However, none of these protocols has been uniformly adopted by renal physicians, either because of no or limited efficacy of most of them, or due to the potential of short- and long-term untoward effects. In this review, we examine the available data on the natural course of the disease and the possibility of identifying clinical and laboratory characteristics that could help to predict the course of membranous nephropathy. We also summarise the results of the most relevant clinical trials, and offer an updated meta-analysis of treatment studies, including the latest data on cyclosporin.

Developments in Glucocorticoid Therapy

Recent evidence for a disease-modifying potential of low-dose glucocorticoids (GCs) in the treatment of rheumatoid arthritis has renewed the debate on the risk benefit ratio with this therapy. Two recent developments are described that might have a positive influence on these risk benefit ratios. One is the improvement in new GC compounds--designer GCs, alterations in bioactivity, and alterations in formulations. The other is a better understanding and management of the toxicity of GCs.

Urinary Excretion of β2-Microglobulin and IgG Predict Prognosis in Idiopathic Membranous Nephropathy: A Validation Study

An accurate prediction of the prognosis of patients with idiopathic membranous nephropathy (iMN) should allow restriction of immunosuppressive treatment to patients who are at highest risk for ESRD. On the basis of retrospective studies, it has previously been suggested that the urinary excretions of beta2-microglobulin (Ubeta2m) and IgG (UIgG) are useful predictors of renal insufficiency in patients with iMN. The threshold values of 0.5 micro/min (Ubeta2m) and 250 mg/24 h (UIgG) have been validated in a new and larger patient cohort. From 1995 onward, 57 patients with iMN (38 men, 19 women; age 48 +/- 16 yr), a nephrotic syndrome, and a serum creatinine level </=1.5 mg/dl were studied prospectively. At baseline, a standardized measurement was carried out to determine renal function and protein excretion. The end point renal death was defined as a serum creatinine exceeding 1.5 mg/dl or a rise of serum creatinine of >50%. Mean (+/-SD) follow-up was 53 +/- 23 mo. Thus far, 25 (44%) of the patients have reached the end point renal death. Multivariate analysis confirmed Ubeta2m as the strongest independent predictor for the development of renal insufficiency. Sensitivity and specificity were 88 and 91%, respectively, for Ubeta2m, and both were 88% for UIgG. When the excretions of both proteins were combined, specificity improved to 97%. It is concluded that the present data validate the accuracy of Ubeta2m and of UIgG in predicting renal outcome in patients with iMN. These markers can be used to guide decisions on the start of immunosuppressive treatment.

Restrictive use of immunosuppressive treatment in patients with idiopathic membranous nephropathy: high renal survival in a large patient cohort

BACKGROUND

Immunosuppressive treatment initiated at an early stage in patients with idiopathic membranous nephropathy (iMN) improves renal survival. Treatment should ideally be restricted to high-risk patients.

AIM

To evaluate the efficacy of a restrictive immunosuppressive treatment strategy for patients with iMN.

DESIGN

Prospective cohort study evaluating a predefined treatment protocol.

METHODS

From 1988, we adopted a restrictive treatment strategy: immunosuppressive treatment, mainly consisting of cyclophosphamide and steroids, was advised only in patients with renal insufficiency or severe intolerable nephrotic syndrome. We evaluated this strategy in a large patient cohort. To exclude any bias, we included all adult patients with iMN biopsied in the study period with a serum creatinine (Scr) < 135 micromol/l, a proteinuria > or = 3.0 g/day and/or a serum albumin (Salb) < or = 30 g/l at the time of biopsy. Analysis was according to the intention-to-treat principle.

RESULTS

We studied 69 patients. At the time of biopsy, mean age was 51 years, Scr 90 micromol/l, Salb 23 g/l and proteinuria 6.7 g/day. Average follow-up was 5.5 years. Thus far 33 (48%) patients have received immunosuppressive therapy, mainly because of renal insufficiency (n = 24). Status at the end of follow-up was: complete remission n = 22 (32%), partial remission n = 24 (35%), nephrotic syndrome n = 15 (22%), persistent proteinuria n = 1 (1.4%), ESRD n = 6 (8.7%), death n = 1 (1.4%; due to bladder carcinoma after cyclophosphamide therapy). Patient survival was 100% at 5 and 7 years. Renal survival was 94% at 5 years and 88% at 7 years.

DISCUSSION

In patients with iMN, a restrictive treatment policy assures a favourable prognosis, while preventing exposure to immunosuppressive therapy in >50% of the patients.

Conservative versus immunosuppressive treatment of patients with idiopathic membranous nephropathy

BACKGROUND

Treatment of idiopathic membranous glomerulonephritis (MGN) is a controversial issue. Whereas some authors recommend early immunosuppressive treatment of all patients with nephrotic syndrome, others do not support aggressive therapies, based on the spontaneous long-term favorable outcome of most patients. However, 20 to 50% of untreated patients develop progressive renal insufficiency.

METHODS

All of the patients with biopsy-proven MGN who developed renal insufficiency at our Hospital during the period of 1975 to 2000 were studied. Selected patients (N=39) were separated into two groups according to the two different therapeutic policies followed at our department: a conservative approach during the first period, 1975 to 1989 (group I, N=20), and a course of immunosuppressive therapy (oral prednisone for six months and concurrent oral chlorambucil, 0.15 mg/kg/day, during the first 14 weeks) during the second period, 1990 to 2000 (group II, N=19).

RESULTS

There were no significant differences between both groups at the time of renal biopsy, nor at the onset of renal function decline. All group I patients showed a progressive renal insufficiency; at the end of the follow-up 13 patients (65%) were on chronic dialysis, 2 (10%) showed advanced renal failure, and 5 (25%) had died. In contrast, most of group II patients showed an improvement or stabilization of serum creatinine (SCr; 2.3 +/- 0.9 mg/dL at onset of treatment, 2 +/- 1.5 mg/dL at the end of follow-up) together with decreased proteinuria (11.2 +/- 3.3 vs. 5.2 +/- 6.7 g/24 h). At the end of the follow-up 58% of group II patients had a SCr value < or =1.5 mg/dL and 36% showed a complete or partial remission, whereas no patient in group I showed remission. After four years of follow-up the probability of renal survival without dialysis was 55% in group I and 90% in group II (P < 0.001), and after seven years the renal survival was 20% and 90%, respectively (P < 0.001). Side effects of immunosuppressive treatment were uncommon but severe, as two patients suffered Pneumocystis carinii pneumonia.

CONCLUSION

A course of immunosuppressive treatment administered early at the onset of renal function decline induces a favorable effect in most of patients with MGN and deteriorating renal function. Untreated patients progressed without exception toward advanced renal failure.

Cyclosporine in patients with steroid-resistant membranous nephropathy: a randomized trial

BACKGROUND

A clinical trial of cyclosporine in patients with steroid-resistant membranous nephropathy (MGN) was conducted. Although MGN remains the most common cause of adult-onset nephrotic syndrome, its management is still controversial. Cyclosporine has been shown to be effective in cases of progressive MGN, but it has not been used in controlled studies at an early stage of the disease.

METHODS

We conducted a randomized trial in 51 biopsy-proven idiopathic MGN patients with nephrotic-range proteinuria comparing 26 weeks of cyclosporine treatment plus low-dose prednisone to placebo plus prednisone. All patients were followed for an average of 78 weeks, and the short- and long-term effects on renal function were assessed.

RESULTS

Seventy-five percent of the treatment group versus 22% of the control group (P < 0.001) had a partial or complete remission of their proteinuria by 26 weeks. Relapse occurred in 43% (N = 9) of the cyclosporine remission group and 40% (N = 2) of the placebo group by week 52. The fraction of the total population in remission then remained almost unchanged and significant different between the groups until the end of the study (cyclosporine 39%, placebo 13%, P = 0.007). Renal function was unchanged and equal in the two groups over the test medication period. In the subsequent follow-up, renal insufficiency, defined as doubling of baseline creatinine, was seen in two patients in each group, but remained equal and stable in all of the other patients.

CONCLUSION

This study suggests that cyclosporine is an effective therapeutic agent in the treatment of steroid-resistant cases of MGN. Although a high relapse does occur, 39% of the treated patients remained in remission and were subnephrotic for at least one-year post-treatment, with no adverse effect on filtration function.

Treatment of idiopathic membranous nephropathy (IMN)

The best treatment of idiopathic membranous nephropathy remains an area of clinical controversy. At the moment only patients with nephrotic syndrome and/or declining renal function should be treated. Despite the negative trials, prolonged oral administration of corticosteroids alone may be a safe and an effective first-line treatment in nephrotic patients. If corticosteroids are ineffective, prolonged use of cyclosporine in low-doses can be recommended as an alternative treatment, that diminishes rapidly proteinuria in the majority of patients. Both treatments (intravenous high doses of corticosteroids and cyclosporine) may also be effective in patients with declining renal function. Because of their toxicity, the routine use of alkylating agents for patients with nephrotic syndrome is not justified. They may be retained for patients, in whom other treatment modalities have failed. Chlorambucil may be preferred over cyclophosphamide since it carries less toxicity. A lower dose of chlorambucil, than that usually suggested, for a short period of time seems to be prudent in an effort to avoid serious side-effects.

Does immunosuppression with prednisolone and azathioprine alter the progression of idiopathic membranous nephropathy?

The role of immunosuppressive drugs in the treatment of idiopathic membranous nephropathy (IMN) remains controversial. The effect of treatment with prednisolone and azathioprine in patients with nephrotic-range proteinuria and biopsy-proven IMN from a single center (Sheffield Kidney Institute, Sheffield, UK) is described. In this retrospective study, 58 patients with IMN and nephrotic-range proteinuria were followed up for 4 years. Thirty-eight patients were treated with prednisolone (1 mg/kg body weight/d) and azathioprine (2 mg/kg body weight/d) orally for a median period of 26 months (range, 6 to 48 months). Twenty patients received no specific treatment for IMN and served as a control group. Clinical, biochemical, and histopathologic features at presentation were similar between the groups. Renal function (RF), measured by serum creatinine (Scr) level, deteriorated in both treated and control groups during the follow-up period. The median initial and final Scr levels (at the end of follow-up) in the treated group were 1.6 and 2. 1 mg/dL, respectively, and in the control group were 1.3 and 1.7 m/dL, respectively (P = not significant). Neither the rate of RF decline (measured by the slope of reciprocal of Scr against time) nor the proportion of patients with deteriorating RF differed significantly between the groups (37%, treated group; 30%, control group). A significant reduction in proteinuria was observed in both groups (P < 0.01, either group). Also, the rate of remission of nephrotic-range proteinuria was not significantly different between groups (55%, treated group; 65%, control group). The only prognostic factor that correlated with RF outcome (expressed by final Scr level) in a given patient was the mean proteinuria during follow-up in either group (r = 0.493; P < 0.01, treated group; r = 0.651; P < 0.01, control group). Adverse effects of immunosuppressive treatment were observed in nine patients (24%). These were serious in four patients (10%) and included squamous cell carcinoma (two patients), bacterial meningitis (one patient), and septicemia (one patient). In conclusion, treatment with prednisolone and azathioprine for patients with IMN did not show significant beneficial effects on the progression of disease. Furthermore, this treatment was associated with frequent and serious adverse effects.

Management of idiopathic membranous nephropathy: evidence-based recommendations

Membranous nephropathy is a frequent cause of nephrotic syndrome in adults, and in one third of these patients, it leads to end-stage renal disease. Based on an extensive critical review of the literature, the following recommendations are offered. Oral high-dose corticosteroids are ineffective in producing either a sustained remission of nephrotic syndrome or in preserving renal function in patients with membranous nephropathy, and should not be used as the sole therapy (grade A recommendation). The use of azathioprine is not associated with any significant benefits, so its use is not justified (grade C). The alkylating agents cyclophosphamide and chlorambucil are both effective in the management of membranous nephropathy. Because of growing concern about long-term toxicity, especially with cyclophosphamide, these drugs should be reserved for patients who exhibit clinical features, such as severe or prolonged nephrosis, renal insufficiency, or hypertension, that predict a high likelihood of progression to end-stage renal disease. Chlorambucil in conjunction with oral steroids is the drug of first choice (grade A). Cyclophosphamide and oral steroids are alternatives (grade B). Cyclosporine may, in the future, become the agent of choice for membranous nephropathy. Currently, it is recommended (grade B) that cyclosporine use be considered in patients at high risk for progression in membranous nephropathy or if alkylating agents are contraindicated or ineffective.

Diagnosis and management of glomerular diseases

Glomerular diseases are a diagnostic challenge. Early recognition and timely institution of appropriate treatment are critical to optimum outcome in many patients, especially those with rapidly progressive glomerulonephritis. The clinical presentations and laboratory data provide adequate presumptive diagnoses in some patients; however, renal biopsy evaluation is often required for a definitive diagnosis.

Beneficial effects of systemic immunoglobulin in experimental membranous nephropathy

To test the hypothesis that systemic administration of immunoglobulin might reduce glomerular injury in membranous nephropathy through mechanisms involving inhibition of complement activation, we studied the passive Heymann nephritis (PHN) model of membranous nephropathy in rats. The daily administration of immunoglobulin goat IgG (600 mg/kg i.p.) reduced proteinuria by 52%. Quantitative immunohistochemical analysis showed that the glomerular deposition of C3c, an indicator of ongoing complement attack, and of C5b-9 was significantly decreased in the immunoglobulin treated group, while deposition of anti-Fx1A was not affected. Electron microscopic analysis demonstrated that the extent of subepithelial immune complexes did not appreciably differ between treated and control animals. Systemic complement levels were not altered by immunoglobulin treatment. These data suggest that the reduction in proteinuria that resulted from systemic immunoglobulin administration was mediated by modifying the effect of complement induced glomerular injury. This interpretation was further supported by in vitro data that documented a significant reduction in C5b-9 induced glomerular epithelial cell lysis in the presence of both goat and rat IgG. These results indicate that systemic administration of immunoglobulin can substantially reduce ongoing complement activation in the glomerulus in PHN rats and that this effect is associated with a significant reduction in glomerular injury.

The primary glomerulopathies

Disorders of glomerular structure and function are encountered frequently in clinical medicine. Many arise as part of a well-defined multisystem or multi-organ disease process, while in others the clinical and laboratory manifestations are consequent to the sole or predominant involvement of glomeruli. The latter are known as the primary glomerulopathies. These disorders can evoke a variety of clinical syndromes, including acute glomerulonephritis, rapidly progressive glomerulo-nephritis, nephrotic syndrome, "symptomless" hematuria and/or proteinuria, and chronic glomerulonephritis. The identification of underlying morphology, through the application of renal biopsy techniques, can provide useful information for both prognosis and treatment. Pathogenic mechanisms involved in the primary glomerulopathies are varied, but immunologic perturbations underlie many disease entities. This article describes the clinical features, pathology, natural history, and treatment of the main categories of primary glomerulonephritis, with emphasis on recent developments and practical aspects of diagnosis and management.

Urinary C5b-9 excretion and clinical course in idiopathic human membranous nephropathy

Recent reports suggested that the presence of terminal complement complex (C5b-9) in urine from patients with idiopathic membranous nephropathy (IMN) may indicate on-going immunological damage. This report documents the relationship between C5b-9 excretion and clinical outcome in 35 adult patients with biopsy-proven IMN and progressively declining renal function. There were two groups of patients. Group I received one of three treatment regimens: prednisolone alone, prednisolone and chlorambucil, or prednisolone and cyclophosphamide (N = 22). Group II received no immunosuppressive therapy (N = 17). Three of the 18 patients receiving immunosuppressive drugs had more than one treatment regimen as they experienced a clinical relapse during the study period; hence 22 treatments were available for analysis. Urine samples were collected regularly and urinary C5b-9 (uC5b-9) was determined by ELISA. Both groups were similar with respect to age, sex distribution, and the duration of follow-up. An improvement in proteinuria and creatinine clearance was noted in the immunosuppressed group. Thirty-five patients were excreting C5b-9 initially (18 from group I and 17 from group II); 17 patients continued to excrete C5b-9 at the end of the observation period. These 17 patients had a significantly worse clinical outcome when compared to the 18 patients whose C5b-9 excretion became negative, either spontaneously or with treatment (P < 0.005). These results indicate that continuing C5b-9 excretion is correlated with a poor clinical outcome. They also suggest that uC5b-9 is a dynamic marker of ongoing immunological injury, and therefore may be useful in the initial assessment and monitoring of patients with IMN and in identifying patients who may derive benefit from immunosuppressive therapy.

A review of therapeutic studies of idiopathic membranous glomerulopathy

The treatment of idiopathic membranous glomerulopathy remains an enigma. We have reviewed many of the important clinical trials concerning membranous glomerulopathy using a meta-analysis and a secondary pooled analysis to test the effects of corticosteroid or alkylating, therapy compared with no treatment on renal survival and complete remission of the nephrotic syndrome. A search was performed using MEDLINE (1968 through 1993) for articles on idiopathic membranous glomerulopathy and glomerulonephritis. Bibliographies of articles were reviewed for completeness. Sixty-nine articles were reviewed. Meta-analysis was performed for four trials that evaluated corticosteroids compared with no treatment and for three trials that evaluated alkylating therapy compared with no treatment. Pooled analysis was performed on randomized and prospective studies (10 studies) and then with 22 case series added. All studies evaluated renal biopsy-proven disease. Meta-analysis was performed on the relative chance of being in complete remission for each study. Renal survival could be evaluated by pooled analysis only. For pooled analyses, Cox's proportional hazard and logistic regression models were used to test the effect of therapy on renal survival and the nephrotic syndrome, respectively. Data concerning gender, nephrotic syndrome, and geographic region were used in all statistical models. Evaluation of renal survival revealed no differences by treatment group (P > 0.1). By meta-analysis, the relative chance of complete remission was not improved for corticosteroid-treated patients (1.55; 95% confidence interval, 0.99 to 2.44; P > 0.1), but was improved for patients treated with alkylating agents (4.8; 95% confidence interval, 1.44 to 15.96; P < 0.05) when compared with no treatment. Pooled analysis of randomized and prospective studies, as well pooled analysis with all studies, supported the findings of the meta-analysis. Corticosteroids or alkylating therapy did not improve renal survival in idiopathic membranous glomerulopathy. Complete remission of the nephrotic syndrome was observed more frequently with the use of alkylating agents.

A controlled trial of cyclosporine in patients with progressive membranous nephropathy. Canadian Glomerulonephritis Study Group

A controlled trial of cyclosporine in patients diagnosed with progressive membranous nephropathy (MGN) was carried out to determine whether cyclosporine (D) would be more effective than placebo (P) in reducing the rate of deterioration in renal function. Patients (N = 64) with MGN were placed on a restricted protein diet (< or = 0.9 g/kg) and followed closely for 12 months (Part 1). Patients at high risk of progression based on an absolute loss in creatinine clearance (CCr) of > or = 8 ml/min and persistent nephrotic range proteinuria (Pr) were selected and randomly assigned to either (D) (N = 9) or (P) (N = 8) for 12 months (Part 2). No differences in the two groups were noted at entry. After 12 months, the improvement in CCr slope in ml/min/month was significantly greater in the D patients (D + 2.1 vs. P + 0.5, mean difference 1.6; 95% CI 0.3 to 3.0, P < 0.02). This improvement was maintained in six of eight D (75%) over a mean follow-up period of 21 months. Daily Pr also improved with D (by month 3, D - 4.5 g/day vs. P + 0.7 g/day, P = 0.02) and was sustained in six of eight (75%) D patients. When Pr was expressed as a function of their concurrent CCr, the D versus P patients' time to halving was faster (P = 0.02) and absolute number higher (4/9 D vs 0/8 P). In the D group a trend towards worse hypertension and an increase in the number of transient rises in serum creatinine were noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Fundamental concepts and immunosuppressive treatment in the various forms of glomerulonephritis

Immunosuppressive treatment in glomerulonephritis (GN) is still controversial. Most of the secondary forms of glomerulonephritis have the histologic features of one of the primary types of glomerulonephritis. Eight histologic expressions of primary glomerulonephritis can be distinguished and ordered in terms of severity of symptoms and prognosis: endocapillary GN, minimal change GN, mesangioproliferative GN, membranous GN, focal-sclerosing GN, membranoproliferative GN, focal-necrotizing GN, and rapidly progressive GN. Agreement exists only to the extent that immunosuppression is not required in endocapillary glomerulonephritis, although it is recommended in the other extreme of rapidly progressive GN. Primarily, an indication for immunosuppression is given by the severity of symptoms with a urinary protein excretion > 3.5 g per day and/or serum creatinine > 150 mumol per liter. As for anti-GBM, the type of glomerulonephritis is more important than the severity of symptoms in guiding therapy, whereas for IgA nephropathy it is controversial whether the prospective prognosis of even inexorably deteriorating renal function justifies immunosuppression. Renal biopsy is required to identify the type of glomerulonephritis so as to establish the specific immunosuppressive concept with different intensity and duration of treatment. Immunosuppression can reduce urinary protein excretion and improve deterioration of renal function; however, the proportion of patients responding varies with and depends on the different forms of GN.

Therapy for idiopathic membranous nephropathy: tailoring the choice by decision analysis

Two Italian controlled trials demonstrated that the difference in remission rates obtained with six months of methylprednisolone and chlorambucil (MP+Ch) compared to MP was smaller than MP+Ch versus symptomatic therapy in the treatment of idiopathic membranous nephropathy nephrotic syndrome (NS). A decision analysis was used to compare the three treatment strategies, assuming triple probabilities and costs for MP+Ch complications compared to MP, with no risk for supportive therapy, referring to an average 40-year-old patient and using the quality-adjusted life expectancy year (QALY) as the utility scale. With MP+Ch the difference in expected QALY was 7.2 years compared to supportive therapy, and 2.6 years compared to MP. To offset the longer survival obtained with MP+Ch versus MP, it was assumed that all patients treated with MP+Ch would undergo either fatal (5% vs. 0.3% with MP) or non-fatal complications (95% vs. 15% with MP). This threshold denotes a great stability of the inequality in the expected QALY. Consequently, treatment with MP or with MP+Ch is justified if their side effects are considered to be a suitable trade-off for a five or seven QALY, respectively, longer survival. Only an absurd increase in the death rate with MP+Ch could offset the difference.

Prognosis of untreated patients with idiopathic membranous nephropathy

BACKGROUND

Defining the most appropriate treatment for patients with idiopathic membranous nephropathy is a matter of controversy. The course of the disorder is often benign, and the immunosuppressive regimens used in some patients have uncertain benefits and substantial risks. We studied the natural history of idiopathic membranous nephropathy in patients who received only symptomatic therapy.

METHODS

We prospectively studied 100 consecutive patients (68 men and 32 women; mean [+/- SD] age, 51 +/- 17 years) with biopsy-proved idiopathic membranous nephropathy. The patients received diuretic or antihypertensive drugs as needed, but no glucocorticoid or immunosuppressive drugs. We examined the patients and measured their urinary protein excretion and serum creatinine concentrations every 6 months for a mean of 52 months.

RESULTS

Twenty-four (65 percent) of the 37 patients followed for at least five years had complete or partial remission of proteinuria; in 6 others (16 percent), end-stage renal disease developed, and they required dialysis. As calculated by the Kaplan-Meier method, the estimated probability (+/- the standard error of the estimate) of retaining adequate kidney function was 88 +/- 5 percent after five years and 73 +/- 7 percent after eight years. The prognosis was poorer in men and in patients over 50 years of age, but not in patients with the nephrotic syndrome, hypertension, or hypercholesterolemia.

CONCLUSIONS

Most untreated patients with idiopathic membranous nephropathy maintain renal function for prolonged periods and are likely to have spontaneous remission. These results do not support the use of glucocorticoids and immunosuppressive drugs in patients with idiopathic membranous nephropathy.

Methylprednisolone plus chlorambucil as compared with methylprednisolone alone for the treatment of idiopathic membranous nephropathy. The Italian Idiopathic Membranous Nephropathy Treatment Study Group

BACKGROUND AND METHODS

Treatment with methylprednisolone and chlorambucil may protect renal function and increase the chance of remission of the nephrotic syndrome in patients with idiopathic membranous nephropathy. To determine whether similar results might be obtained with methylprednisolone alone, we compared the effects of methylprednisolone and chlorambucil with those of methylprednisolone alone in 92 patients with the nephrotic syndrome caused by idiopathic membranous nephropathy. The patients were randomly assigned to receive either alternating one-month courses of methylprednisolone and then chlorambucil for a total of six months (group 1) or methylprednisolone alone for six months at the same cumulative dosage (group 2).

RESULTS

Four of the 45 patients in group 1 (9 percent) and 1 of the 47 in group 2 (2 percent) stopped treatment because of side effects. At one, two, and three years, the percentage of patients who did not have the nephrotic syndrome was significantly higher in group 1 than in group 2. It was 58, 54, and 66 percent, respectively, in group 1, as compared with 26, 32, and 40 percent in group 2 (P = 0.002, 0.029, and 0.011). By year 4, the difference was no longer statistically significant: 62 percent of the patients in group 1 and 42 percent of those in group 2 did not have the nephrotic syndrome (P = 0.102). The patients in group 1 were in remission longer than those in group 2 (P = 0.008).

CONCLUSIONS

In patients with the nephrotic syndrome caused by idiopathic membranous nephropathy, treatment with methylprednisolone and chlorambucil for six months induces an earlier remission of the nephrotic syndrome than methylprednisolone alone, but the difference may diminish with time.

Long-term follow-up in children with steroid-resistant nephrotic syndrome

A prospective study was performed in order to evaluate the efficacy of oral cyclophosphamide and chlorambucil in inducing a remission in children with steroid-resistant primary nephrotic syndrome (NS). Out of 215 children with steroid-resistant primary NS, 164 had been followed from one to 10 years. The children had a mean age of 8.2 years, with a range from one to 16 years. Steroid resistance was more common in children over six years of age compared with the other age groups. Hematuria was seen in 68 of the 164 children (41%); hypertension in 41 (25%); and hyperlipidemia in 112 (68%). Hypocomplementemia was noted in 24 of the 65 (37%) children in whom complement concentrations were determined. Renal biopsy was performed in 117 of the children. Pathologic changes consisted of minimal change nephrotic syndrome (MCNS) in 14 children (12%), membranoproliferative glomerulonephritis (MPGN) in 45 (38%), focal segmental glomerulosclerosis (FSGS) in 20 (25%), mesangial proliferation (MP) in 23 (20%), and membranous glomerulonephritis in six children (5%). Cyclophosphamide (2 mg/kg/day) was given to 164 patients, with complete remission and partial remission rates of 20.7% (34 of 164 children) and 24.4% (40 of 164 children), respectively. In this group, sustained remission and sustained partial remission rates were found in 20% (32 children) and 13% (21 children), respectively. Chlorambucil was given to 40 children with steroid- and cyclophosphamide-resistant nephrotic syndrome, with total remission and partial remission rates of 20% (eight children), and 12.5% (five children), respectively. These rates did not change during the follow-up. Thus, cyclophosphamide is valuable in the treatment of children with steroid-resistant NS with a variety of histologic changes.

Long-term benefits of therapy with cyclophosphamide and prednisone in patients with membranous glomerulonephritis and impaired renal function

Long-term follow-up data are provided for a previously reported study of patients with membranous glomerulonephritis (MGN), nephrotic syndrome, and renal function impairment. Nine patients were treated with cyclophosphamide (1 to 2 mg/kg) and six of these received concurrent prednisone; they are compared with 17 concurrent controls (14 of whom had received prednisone at some time). The mean follow-up is 83 +/- 13 months in the treated patients and 64 +/- 7 months in the controls. Of the nine treated patients, four achieved a complete remission from the nephrotic syndrome (proteinuria less than 0.5 g/d), and five a partial remission (proteinuria decreased by at least 50% and to less than 3.5 g/d). One of the nine treated patients and 10 of the 17 controls have reached end-stage renal disease (ESRD) (P less than 0.05). Nine of the controls reaching ESRD had persistent nephrotic syndrome, whereas of the seven controls who have not yet reached ESRD, only two have persistent nephrotic syndrome (chi 2, P less than 0.02). There have been four relapses in three treated patients, and three of the four have responded to repeat therapy. One patient refused full therapy and remains nephrotic. Life-table analysis demonstrates significantly increased survival from ESRD in treated patients as compared with controls (P = 0.04).

Therapeutic effects of leflunomide, a new antirheumatic drug, on glomerulonephritis induced by the antibasement membrane antibody in rats

Leflunomide is a new antirheumatic drug. It was evaluated, in comparison with azathioprine (AZA) and methylprednisolone acetate (MPA), for its therapeutic effects on the glomerulonephritis induced in rats by rabbit antiserum against the rat glomerular basement membrane. Its effect on body weight was also determined. Leflunomide (2 and 10 mg/kg/day, po), AZA (20 mg/kg/day, po), and MPA (2 mg/kg/day, sc) were administered for 28 days from 5 days after the intravenous injection of the rabbit antiserum. Leflunomide at both doses significantly decreased the urinary total protein, plasma total cholesterol, and plasma fibrinogen. On the other hand, neither AZA nor MPA affected the parameters except that they tended to reduce the urinary total protein. All three compounds decreased the plasma rat anti-rabbit IgG titer. Histologically, leflunomide at the high dose showed apparent therapeutic effects on the glomerulonephritis, as judged by light and electron microscopy and by immunofluorescence; the lesions were improved and deposits of rat IgG and C3 along the glomerular capillary wall decreased to a great extent. AZA and MPA exerted no therapeutic effects on the histological parameters except that MPA tended to reduce rat IgG and C3 deposits. Body weights increased favorably and slightly during leflunomide and AZA administration, respectively, but decreased during MPA treatment. Thus, leflunomide had more potent therapeutic effects on glomerulonephritis and less side effects than the already marketed drugs, suggesting that the compound is highly effective in improving immunologically mediated forms of glomerulonephritis, including membranous glomerulonephritis, at their early stages.

Crescentic transformation in primary membranous glomerulonephritis

A 31 year old man first developed steroid-resistant idiopathic membranous glomerulonephritis in 1981. Stable normal renal function was maintained until August 1988 when he suffered a clinical relapse with heavy proteinuria and declining renal function. Immunosuppressive therapy with prednisolone and cyclophosphamide was instituted in an attempt to arrest this relapse. Despite this, he later developed acute renal failure with histological evidence of crescentic transformation of his nephritis. This unusual transformation was not associated with features of systemic vasculitis or positive anti-glomerular basement membrane and anti-neutrophil cytoplasmic antibodies.

Membranous nephropathy in childhood and its treatment

Membranous nephropathy is predominantly a disease of middle-aged and elderly individuals, and is thus rather an uncommon finding in proteinuric and nephrotic children. In children, it differs in several important respects from the disease as seen in adults: an apparent associated cause is more common, macroscopic haematuria is seen quite frequently, a relapsing course is more often noted, renal venous thrombosis is not found and evolution into renal failure is the exception. Nevertheless, a proportion of children with membranous nephropathy do evolve into renal failure, and their management is discussed with particular reference to recent papers on the treatment of membranous nephropathy in adults. An aggressive search for associated disease is worthwhile in children, and one should wait to see what the evolution or proteinuria and renal function may be. If a progressive course becomes evident, then a trial of treatment with corticosteroids is worthwhile, but if this is ineffective then a more aggressive approach involving the use of alkylating agents may be justified. It remains undetermined what the best regime in children and adolescents may be.

Autoimmunity and the pathogenesis of glomerulonephritis

Self-tolerance is maintained by: thymic influences on developing T cells; peripheral mechanisms that can tolerise post-thymic T cells; and to a variable extent the tolerisation of potentially autoreactive B cells. The presence of autoreactive T cells in normal individuals suggests that mechanisms to control the activity of such cells may be important. Failure of any of these processes may lead to autoimmunity. The relationship between glomerulonephritis and the mechanisms leading to breakdown of self-tolerance remains elusive. An important observation is that autoimmune diseases are strongly associated with particular products of the major histocompatibility complex (MHC). This association may reflect the intimate involvement of the MHC in thymic T cell education. Another explanation is that T cells only recognise antigens presented in the context of MHC molecules. Although there has been progress in identifying the targets recognised by autoantibodies in vasculitis and anti-GBM disease, nothing is known about the T cells involved. Despite our ignorance, therapy aimed specifically at the T cell can be effective. This approach is being supplemented by attempts to engage immunoregulatory mechanisms, such as idiotype-antiidiotype interactions. The hope is that such treatments, or combinations thereof, will allow a more focused suppression of the autoimmune response, in contrast to the non-specific (and therefore potentially dangerous) methods of immunosuppression available at present.