Gerald B. Appel

The Classification of Glomerulonephritis in Systemic Lupus Erythematosus Revisited

The currently used classification reflects our understanding of the pathogenesis of the various forms of lupus nephritis, but clinicopathologic studies have revealed the need for improved categorization and terminology. Based on the 1982 classification published under the auspices of the World Health Organization (WHO) and subsequent clinicopathologic data, we propose that class I and II be used for purely mesangial involvement (I, mesangial immune deposits without mesangial hypercellularity; II, mesangial immune deposits with mesangial hypercellularity); class III for focal glomerulonephritis (involving <50% of total number of glomeruli) with subdivisions for active and sclerotic lesions; class IV for diffuse glomerulonephritis (involving > or =50% of total number of glomeruli) either with segmental (class IV-S) or global (class IV-G) involvement, and also with subdivisions for active and sclerotic lesions; class V for membranous lupus nephritis; and class VI for advanced sclerosing lesions. Combinations of membranous and proliferative glomerulonephritis (i.e., class III and V or class IV and V) should be reported individually in the diagnostic line. The diagnosis should also include entries for any concomitant vascular or tubulointerstitial lesions. One of the main advantages of the current revised classification is that it provides a clear and unequivocal description of the various lesions and classes of lupus nephritis, allowing a better standardization and lending a basis for further clinicopathologic studies. We hope that this revision, which evolved under the auspices of the International Society of Nephrology and the Renal Pathology Society, will contribute to further advancement of the WHO classification.

Mycophenolate Mofetil versus Cyclophosphamide for Induction Treatment of Lupus Nephritis

Recent studies have suggested that mycophenolate mofetil (MMF) may offer advantages over intravenous cyclophosphamide (IVC) for the treatment of lupus nephritis, but these therapies have not been compared in an international randomized, controlled trial. Here, we report the comparison of MMF and IVC as induction treatment for active lupus nephritis in a multinational, two-phase (induction and maintenance) study. We randomly assigned 370 patients with classes III through V lupus nephritis to open-label MMF (target dosage 3 g/d) or IVC (0.5 to 1.0 g/m(2) in monthly pulses) in a 24-wk induction study. Both groups received prednisone, tapered from a maximum starting dosage of 60 mg/d. The primary end point was a prespecified decrease in urine protein/creatinine ratio and stabilization or improvement in serum creatinine. Secondary end points included complete renal remission, systemic disease activity and damage, and safety. Overall, we did not detect a significantly different response rate between the two groups: 104 (56.2%) of 185 patients responded to MMF compared with 98 (53.0%) of 185 to IVC. Secondary end points were also similar between treatment groups. There were nine deaths in the MMF group and five in the IVC group. We did not detect significant differences between the MMF and IVC groups with regard to rates of adverse events, serious adverse events, or infections. Although most patients in both treatment groups experienced clinical improvement, the study did not meet its primary objective of showing that MMF was superior to IVC as induction treatment for lupus nephritis.

Efficacy and safety of rituximab in patients with active proliferative lupus nephritis: The lupus nephritis assessment with rituximab study

OBJECTIVE To evaluate the efficacy and safety of rituximab in a randomized, double-blind, placebo-controlled phase III trial in patients with lupus nephritis treated concomitantly with mycophenolate mofetil (MMF) and corticosteroids. METHODS Patients (n = 144) with class III or class IV lupus nephritis were randomized 1:1 to receive rituximab (1,000 mg) or placebo on days 1, 15, 168, and 182. The primary end point was renal response status at week 52. RESULTS Rituximab depleted peripheral CD19+ B cells in 71 of 72 patients. The overall (complete and partial) renal response rates were 45.8% among the 72 patients receiving placebo and 56.9% among the 72 patients receiving rituximab (P = 0.18); partial responses accounted for most of the difference. The primary end point (superior response rate with rituximab) was not achieved. Eight placebo-treated patients and no rituximab-treated patients required cyclophosphamide rescue therapy through week 52. Statistically significant improvements in serum complement C3, C4, and anti-double-stranded DNA (anti-dsDNA) levels were observed among patients treated with rituximab. In both treatment groups, a reduction in anti-dsDNA levels greater than the median reduction was associated with reduced proteinuria. The rates of serious adverse events, including infections, were similar in both groups. Neutropenia, leukopenia, and hypotension occurred more frequently in the rituximab group. CONCLUSION Although rituximab therapy led to more responders and greater reductions in anti-dsDNA and C3/C4 levels, it did not improve clinical outcomes after 1 year of treatment. The combination of rituximab with MMF and corticosteroids did not result in any new or unexpected safety signals.

Randomized trial of an inhibitor of formation of advanced glycation end products in Diabetic nephropathy

Background/Aims: Pimagedine inhibits the formation of advanced glycation end products and slows the progression of diabetic complications in experimental models. This study was undertaken to determine if pimagedine ameliorates nephropathy in type 1 (insulin-dependent) diabetes mellitus. Methods: This was a randomized, double-masked, placebo-controlled study performed in 690 patients with type 1 diabetes mellitus, nephropathy, and retinopathy. The patients received twice daily dosing with placebo, pimagedine 150 mg, or pimagedine 300 mg for 2–4 years. The primary end point was the time to doubling of serum creatinine; the secondary end points included evaluations of proteinuria, kidney function, and retinopathy. Results: Serum creatinine doubled in 26% (61/236) of the placebo-treated patients and in 20% (91/454) of those who received pimagedine (p = 0.099). The estimated glomerular filtration rate decreased more slowly in the pimagedine-treated patients with a 36-month decrease from baseline of 6.26 ml/min/1.73 m2 as compared with 9.80 ml/min/1.73 m2 in the placebo-treated patients (p = 0.05), and pimagedine reduced the 24-hour total urinary proteinuria. (The mean reduction from baseline at month 36 was 732 mg/24 h at the low dose and 329 mg/24 h at the high dose as compared with 35 mg/24 h in the placebo group; p ≤ 0.001.) Fewer pimagedine-treated patients with baseline and end point evaluations (31/324; 10%) as compared with those receiving placebo (16%; 28/179) experienced a three-step or greater progression of the retinopathy (Early Treatment of Diabetic Retinopathy Study) score (p = 0.030). Three patients receiving high-dose pimagedine but none receiving low-dose treatment developed glomerulonephritis. Conclusions: While this study did not demonstrate a statistically significant beneficial effect of pimagedine on the progression of overt nephropathy resulting from type 1 diabetes, it is noteworthy in providing the first clinical proof of the concept that inhibiting advanced glycation end product formation can result in a clinically important attenuation of the serious complications of type 1 diabetes mellitus.

Mycophenolate versus Azathioprine as Maintenance Therapy for Lupus Nephritis

BACKGROUND Maintenance therapy, often with azathioprine or mycophenolate mofetil, is required to consolidate remission and prevent relapse after the initial control of lupus nephritis. METHODS We carried out a 36-month, randomized, double-blind, double-dummy, phase 3 study comparing oral mycophenolate mofetil (2 g per day) and oral azathioprine (2 mg per kilogram of body weight per day), plus placebo in each group, in patients who met response criteria during a 6-month induction trial. The study group underwent repeat randomization in a 1:1 ratio. Up to 10 mg of prednisone per day or its equivalent was permitted. The primary efficacy end point was the time to treatment failure, which was defined as death, end-stage renal disease, doubling of the serum creatinine level, renal flare, or rescue therapy for lupus nephritis. Secondary assessments included the time to the individual components of treatment failure and adverse events. RESULTS A total of 227 patients were randomly assigned to maintenance treatment (116 to mycophenolate mofetil and 111 to azathioprine). Mycophenolate mofetil was superior to azathioprine with respect to the primary end point, time to treatment failure (hazard ratio, 0.44; 95% confidence interval, 0.25 to 0.77; P = 0.003), and with respect to time to renal flare and time to rescue therapy (hazard ratio, <1.00; P < 0.05). Observed rates of treatment failure were 16.4% (19 of 116 patients) in the mycophenolate mofetil group and 32.4% (36 of 111) in the azathioprine group. Adverse events, most commonly minor infections and gastrointestinal disorders, occurred in more than 95% of the patients in both groups (P = 0.68). Serious adverse events occurred in 33.3% of patients in the azathioprine group and in 23.5% of those in the mycophenolate mofetil group (P = 0.11), and the rate of withdrawal due to adverse events was higher with azathioprine than with mycophenolate mofetil (39.6% vs. 25.2%, P = 0.02). CONCLUSIONS Mycophenolate mofetil was superior to azathioprine in maintaining a renal response to treatment and in preventing relapse in patients with lupus nephritis who had a response to induction therapy. (Funded by Vifor Pharma [formerly Aspreva]; ALMS ClinicalTrials.gov number, NCT00377637.).

Membranoproliferative Glomerulonephritis Type II (Dense Deposit Disease): An Update

Membranoproliferative glomerulonephritis type II (MPGN II) is a rare disease characterized by the deposition of abnormal electron-dense material within the glomerular basement membrane of the kidney and often within Bruchs membrane in the eye. The diagnosis is made in most patients between the ages of 5 and 15 yr, and within 10 yr, approximately half progress to end-stage renal disease, occasionally with the late comorbidity of visual impairment. The pathophysiologic basis of MPGN II is associated with the uncontrolled systemic activation of the alternative pathway (AP) of the complement cascade. In most patients, loss of complement regulation is caused by C3 nephritic factor, an autoantibody directed against the C3 convertase of the AP, but in some patients, mutations in the factor H gene have been identified. For the latter patients, plasma replacement therapy prevents renal failure, but for the majority of patients, there is no proven effective treatment. The disease recurs in virtually all renal allografts, and a high percentage of these ultimately fail. The development of molecular diagnostic tools and new therapies directed at controlling the AP of the complement cascade either locally in the kidney or at the systemic level may lead to effective treatments for MPGN II.

C3 glomerulopathy: consensus report

C3 glomerulopathy is a recently introduced pathological entity whose original definition was glomerular pathology characterized by C3 accumulation with absent or scanty immunoglobulin deposition. In August 2012, an invited group of experts (comprising the authors of this document) in renal pathology, nephrology, complement biology, and complement therapeutics met to discuss C3 glomerulopathy in the first C3 Glomerulopathy Meeting. The objectives were to reach a consensus on: the definition of C3 glomerulopathy, appropriate complement investigations that should be performed in these patients, and how complement therapeutics should be explored in the condition. This meeting report represents the current consensus view of the group.

Long-term follow-up of patients with lupus nephritis: A study based on the classification of the World Health Organization

The long-term course of 56 patients with systemic lupus erythematosus who had precisely defined renal histology and carefully assessed clinical status at the time of their initial renal biopsy prior to 1976 was evaluated and analyzed by life-table analysis. The average length of follow-up has now been greater than 10 years since initial biopsy. Patients with mesangial lesions (World Health Organization [WHO] classes IIA and IIB) had a more favorable renal and patient survival at five and 10 years than did patients in the other WHO classes (III, IV, and V). Individual renal histologic features of activity and chronicity when combined into an activity index and a chronicity index did not significantly predict renal survival in this population, nor did the presence of hypertension or renal dysfunction at the time of the initial renal biopsy significantly influence renal or patient survival. Patients with the nephrotic syndrome at initial biopsy had a poorer renal survival than did patients without the nephrotic syndrome. However, patients who experienced a remission of the nephrotic syndrome fared better in terms of both renal and patient survival than did those patients without a remission. By life-table analysis, patient survival was significantly better for patients in whom biopsy was performed after 1973 than for those in whom biopsy was performed prior to that time despite similar clinical features and WHO histology in each group interval. Our data suggest that improved survival for patients in recent studies may relate to better supportive care and more selective use of immunosuppressive therapy in patients with milder forms of lupus nephritis.

NPHS2 mutations in late-onset focal segmental glomerulosclerosis: R229Q is a common disease-associated allele

Mutations in NPHS2, encoding podocin, have been identified in childhood onset focal and segmental glomerulosclerosis (FSGS). The role of NPHS2 in adult disease is less well defined. We studied 30 families with FSGS and apparent autosomal recessive inheritance and 91 individuals with primary FSGS. We screened family members for NPHS2 mutations. NPHS2 mutations appeared to be responsible for disease in nine of these families. In six families, the affected individuals were compound heterozygotes for a nonconservative R229Q amino acid substitution. This R229Q variant has an allele frequency of 3.6% in a control population. In these families, R229Q was the only mutation identified on one of the two disease-associated NPHS2 alleles. We used in vitro-translated podocin and purified nephrin to investigate the effect of R229Q on their interaction and found decreased nephrin binding to the R229Q podocin. These data suggest that this common polymorphism contributes to the development of FSGS. Chromosomes bearing the R229Q mutation share a common haplotype defining an approximately 0.2-Mb region. R229Q appears to enhance susceptibility to FSGS in association with a second mutant NPHS2 allele. Identification of R229Q mutations may be of clinical importance, as NPHS2-associated disease appears to define a subgroup of FSGS patients unresponsive to corticosteroids.

The Hyperlipidemia of the Nephrotic Syndrome

Lipid abnormalities in patients with the nephrotic syndrome have long been recognized. However, the significance of these lipid abnormalities, the mechanisms producing them, and their potential treatment have all been a cause of debate. Recent data have helped clarify each of these areas of controversy. Studies of the lipoprotein abnormalities of patients with the uncomplicated nephrotic syndrome have shown that many will have elevated levels of total and low-density lipoprotein cholesterol, whereas only a few will have elevated levels of high-density lipoprotein cholesterol. If these lipid abnormalities have the same significance in this population as in other populations studied, then some patients with unremitting nephrotic syndrome will be at high risk for cardiovascular disease. The elevated cholesterol levels noted in the nephrotic syndrome are caused primarily by enhanced hepatic synthesis, with lesser contributions by decreased clearance and altered enzyme activities. The signal for enhanced hepatic lipogenesis may relate to changes in plasma albumin concentration, plasma oncotic pressure, a local effect of viscosity at the hepatic sinusoidal level, or a loss of urinary proteins or other liporegulatory substances. Recently, a number of short-term studies in nephrotic patients have documented the safety and efficacy of lipid-lowering drugs such as the bile acid-binding resins, probucol, and the HMGCoA (hydroxymethylglutaryl coenzyme A) reductase inhibitors.