Comparison of Idiopathic and Systemic Lupus ErythematosusAssociated Membranous Glomerulonephropathy in Children

Clinical presentation and outcomes of childhood-onset membranous lupus nephritis

BACKGROUND

Best practices for managing childhood-onset membranous lupus nephritis (MLN) are not yet established. Most studies involve primarily or exclusively adult cohorts or pediatric cohorts with combinations of pure or mixed membranous and proliferative nephritis.

METHODS

We performed a single-center cohort study of consecutively diagnosed children with pure MLN from 1990 and 2016. Patients received care in Houston, Texas, one of the most diverse metropolitan areas in North America. Renal outcomes were obtained using consensus definitions from the Childhood Arthritis and Rheumatology Research Alliance (CARRA). Logistic regression was used to detect predictors of complete renal response.

RESULTS

A total of 56 children with MLN were identified (82% females, 44% black, 35% Hispanic) with a median follow-up time of 4.1 years. The mean age of MLN onset was 13.7 ± 3.4 years. On initial presentation 69% had nephrotic syndrome and 11% had acute kidney injury. Glucocorticoids were prescribed in 96% of patients and anti-malarials in 88%. Mycophenolate mofetil was the most common non-steroid immunosuppressive agent (69%), followed by rituximab (25%), cyclophosphamide (18%), and azathioprine (9%). Renin-angiotensin aldosterone system blocking agents were prescribed in 78% of patients. Of 37 patients with ≥2 years of follow-up, 74% achieved complete renal response at 24 months. No predictor variable of complete renal response was identified in this small cohort. Renal flares occurred in 48% of patients (86% proteinuric, 14% nephritic). On subsequent renal biopsy, 13% patients had developed proliferative nephritis.

CONCLUSIONS

This single-center cohort of childhood-onset MLN showed favorable outcomes. Utilizing pediatric renal outcomes definitions, we found that response rates were high, as were rates of renal flare.

Lupus-like membranous nephropathy: Is it lupus or not?

BACKGROUND

Membranous glomerulonephritis is typically classified as idiopathic or secondary to systemic lupus erythematosus (SLE), hepatitis B, drugs, toxins, other infections, or malignancy. Not infrequently in some patients without a definite diagnosis of SLE, pathologic features of secondary membranous nephropathy are seen e.g., mesangial and/or subendothelial deposits, tubuloreticular inclusions, and full house immunofluorescence. In these patients, there is uncertainty about the etiology, response to therapy, and prognosis of membranous GN.

METHODS

We retrospectively reviewed the charts of 98 patients with membranous GN at San Francisco General Hospital and John Stroger Hospital of Cook County over a 10-year period. Data were collected and analyzed using SPSS.18.

RESULTS

Thirty-nine (40 %) had idiopathic membranous GN (Group 1), thirty-six (37 %) had lupus membranous GN (Group 2) and twenty-three (23 %) had some pathological features of secondary membranous GN, but no definite etiology of membranous GN (Group 3). At baseline (at time of renal biopsy) and after mean follow-up of 3.5 years, the average serum creatinine (in mg/dL) in Group 1 was (1.6 ± 1.0 versus 1.6 ± 1.7), Group 2 was (1.8 ± 2.5 versus 1.2 ± 0.9) and Group 3 was (1.1 ± 0.4 versus 1.27 ± 0.83), respectively. For the same time points, the average urine protein to creatinine ratio (g/g) in Group 1 was (9.8 ± 7.1 versus 5.7 ± 6.7), Group 2 was (4.2 ± 3.9 versus 1.7 ± 2.2), and Group 3 was (7.4 ± 5.7 versus 3.1 ± 3.8). In addition, during the follow-up period, eleven of 39 (28 %) in Group 1, two of 36 (6 %) in Group 2, and three of 23 (13 %) in Group 3 progressed to end-stage renal disease and were started on dialysis.

CONCLUSIONS

It appears that patients with lupus membranous GN have better renal prognosis than patients with idiopathic membranous GN. The renal prognosis for patients with pathological features of lupus membranous but no diagnosis of systemic lupus (lupus-like membranous GN) falls in between. Further studies are needed to determine if Group 3 patients can (a) definitively be classified as true idiopathic membranous GN or lupus membranous GN or (b) they have a separate disease from either M-type phospholipase A2 receptor membranous nephropathy or systemic lupus-induced membranous nephropathy.

Membranous glomerulonephritis: treatment response and outcome in children

The aim of this study was to characterize clinical features, treatment response, and outcome of idiopathic membranous glomerulonephritis (MGN) in a single-center cohort of children. A retrospective review of biopsy-proven idiopathic MGN in 12 children (mean age 11.9 years) was undertaken. Presentation was nephrotic syndrome (NS) (75%), hematuria/proteinuria (17%), and asymptomatic proteinuria (8%). Ten patients (83%) with NS and nephrotic range proteinuria (NRP) were treated with prednisone, and two patients with non-NRP were not treated with immunosuppressive medications. Steroid response in the treated patients was complete (10%), partial (40%), and absent (50%), respectively. Oral cyclophosphamide was used in seven patients of whom five were steroid resistant, one was steroid dependent, and one was partially responsive. At the mean follow up of 27 months, outcome parameters included an estimated glomerular filtration rate of 128 cc/min per 1.73 m(2), albumin of 4.2 gm/dL, and a urine protein/creatinine ratio of 0.87 [median 0.16 (range 0.02-6.52)]. Remission was complete in 75% of the patients and partial in 17%. One patient (8%) with chronic kidney disease (stage 2) was unresponsive to therapy. Complete remission was significantly associated with the absence of chronic histological changes (p = 0.03). In conclusion, children with NS and/or NRP associated with MGN appear to have a good prognosis when treated with a combination of corticosteroids and cyclophosphamide.

Idiopathic membranous nephropathy in children

Idiopathic membranous nephropathy (MN) is a rare cause of asymptomatic proteinuria (AP) or nephrotic syndrome (NS) in childhood. To improve our understanding of its clinical course, we retrospectively reviewed 19 cases of idiopathic MN seen in our hospital over a period of 28.5 years, i.e., from January 1977 to July 2005. Eight patients (39%) had AP and 11 (61%) presented with NS. All eight AP patients achieved remission, regardless of treatment modality. Oral corticosteroid was given to all 11 NS patients, but only three of them responded to corticosteroid. Of the eight steroid non-responders, three achieved remissions with the addition of cyclosporine, and the five who were not administered additional immunosuppressive drugs had persistent NS. At the latest evaluation, all six NS patients that achieved remission remained free of proteinuria and had a normal renal function. Moreover, two of the 5 steroid non-responders showed persistent nephrotic-range proteinuria but a stable renal function. The remaining three steroid non-responders progressed into chronic renal insufficiency, and this progression was preceded by renal vein thrombosis (RVT) in two of the three patients. Presentation with NS (P=0.045) and the development of RVT (P=0.010) were identified as poor prognostic factors.

Prognosis of lupus membranous nephropathy in children

The occurrence of membranous nephropathy in pediatric series of systemic lupus erythematosus has been reported only rarely, probably due to a very low frequency. One hundred fifty-four children who were seen in 100 French pediatric centers between January 2002 and April 2005 were included. Fifteen (12 girls and three boys) out of the 81 (18.5 %) children with renal involvement presented histological features of membranous nephropathy. Their ages ranged from six to 15 years old (mean=11.3) at the age of SLE diagnosis and 8/15 children were of African origin. Isolated membranous nephropathy was observed in nine patients, of whom five patients displayed a complete recovery following immunosuppressive treatment. Associated proliferative lesions were observed on the first kidney specimen in two patients and in a further renal biopsy in four other patients, leading to a less favorable course of lupus nephropathy.

Mycophenolate therapy of SLE membranous nephropathy

BACKGROUND

The immunosuppressant mycophenolic acid (MMF) has been used successfully to manage proliferative forms of systemic lupus erythematosus (SLE) glomerulonephritis (GN) World Health Organization (WHO) Classes III and IV. Less is known about MMF treatment of membranous SLE GN (WHO Class V, SLE MN).

METHODS

We report our experience with MMF therapy in 13 consecutive SLE MN patients participating in a prospective study of risk factors for SLE flare.

RESULTS

Baseline characteristics were: mean age 33 +/- 14 SD years, female/male ratio 11/2, Caucasians 7, African Americans 5, Oriental 1, serum creatinine 1.02 +/- 0.41, and mean 24-hour urine protein (P)/creatinine (C), ratio 5.1 +/- 4.1. Initial therapy was prednisone mean dose 31 +/- 17 mg/day, and MMF mean dose 1173 +/- 746 mg/day. Therapy also featured interventions to achieve renoprotection and proteinuria reduction. At 6 months of therapy, complete or partial remission was achieved in 10 of 13 patients. At most recent follow-up visit (mean follow-up 16 +/- 8 months), 9 of 13 patients were in complete remission, and in 11 of 13 patients, urine P/C ratio was < 0.8. During follow-up, serum creatinine either stabilized or was improved. The only serious complication during 208 patient months of follow-up was histoplasma pneumonia in 1 patient.

CONCLUSION

These promising results suggest that moderate dose MMF in combination with renoprotective/antiproteinuria therapy warrants further study in the management of SLE MN.

IgG subclass deposits in glomeruli of lupus and nonlupus membranous nephropathies

Membranous nephropathy (MN) accounts for approximately 10% of all renal lesions of systemic lupus erythematosus (SLE). These membranous lesions often have a clinical presentation similar to that of idiopathic MN and may present before SLE is apparent clinically. However, unlike proliferative lesions of lupus nephritis (LN), membranous LN often does not show a "full-house" pattern of glomerular immunoglobulin and complement (C) deposits by immunofluorescence (IF); only nine of 14 such lesions that we examined stained for all of the following: IgG, IgA, IgM, C3, and C1q. Iskandar et al reported in 1992 that most cases of diffuse proliferative LN showed IgG3 as the major IgG subclass present in glomerular deposits; by contrast, IgG4 predominated in six of seven cases of MN of unspecified etiology. If IgG subclass deposition is similar in membranous and proliferative lesions of LN, then IF staining for IgG3 and IgG4 may be helpful in distinguishing lupus from nonlupus lesions in patients with MN who are lacking a firm diagnosis of SLE. We therefore stained cryostat sections of renal biopsies from 14 patients with SLE and MN (without a proliferative component; World Health Organization [WHO] classes Va and Vb) and 28 non-SLE patients with MN for IgG subclasses by direct IF; the observer was blind to the diagnosis for each case until all were read. The intensity of glomerular staining was graded on a 0 to 4+ scale with increments of 0.5+.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical course and outcome of idiopathic membranous nephropathy in Japanese children

We retrospectively studied 12 Japanese children (8 boys, 4 girls) with idiopathic membranous nephropathy (IMN), aged 2.9-15.8 (mean 7.7) years at onset. All patients were identified through either screening or a routine urinalysis; proteinuria was present in all, haematuria, which was macroscopic in 4, in 11. Three had nephrotic syndrome (NS) at or soon after onset. Stages on electron microscopy, performed in 10 patients, were I in 3, II in 5 and III in 2. Steroids alone or with cyclophosphamide were administered to 5 patients, including the 3 patients showing NS. Complete remission of proteinuria occurred in 8 patients 0.3-1.6 (mean 0.6) years after onset, and proteinuria did not recur. After a follow-up of 1.6-11.6 (mean 5.9) years, these 8 patients were in complete remission and the remaining 4 had only mild proteinuria; none had hypertension or impaired renal function. Thus, we infer that IMN in Japanese children may have a better course and outcome than IMN in non-Japanese children. Based on a comparative study of Japanese (previously reported cases added to ours) and non-Japanese (mostly Caucasian) children with IMN, this was confirmed; it is possible that steroid therapy in Japanese patients is more effective in inducing remission of NS and preserving renal function.

Glomerular lesions in adolescents with gross hematuria or the nephrotic syndrome. Report of the Southwest Pediatric Nephrology Study Group

We report clinical and pathological data in 56 adolescents presenting with gross hematuria (GH) and 65 presenting with idiopathic nephrotic syndrome (INS). IgA nephropathy (present in 52%) and other mesangial lesions were found in the majority of the 56 patients with GH. Many of these patients had complex urological procedures prior to consideration of a nephrological problem. This often led to significant delays in making the appropriate diagnosis. Pathological lesions in the 65 patients with INS included minimal change NS (MCNS) in 31%, membranous glomerulonephritis (MGN) and focal segmental glomerulosclerosis (FSGS) in 18.5% each, and membranoproliferative GN (MPGN) in 12%. In 47 of the patients with INS, in whom no specific treatment had been given prior to renal biopsy, MCNS and MGN were observed with a similar frequency (26% and 23%, respectively), with FSGS and MPGN being found in 21% and 11%. These results indicate that the pathological lesions in adolescents with INS who undergo a renal biopsy more closely resemble those in adults, and are usually more severe than those in young children. However, it should be noted that our study was retrospective. Hence, there were probably some adolescents with INS who had a successful response to therapy and therefore did not have a renal biopsy performed.

Trials and tribulations of multicenter studies. Lessons learned from the experiences of the Southwest Pediatric Nephrology Study Group (SPNSG)

Multicenter studies in Pediatric Nephrology have been acknowledged in recent years as an important mechanism for studying renal disease in children. The purpose of this review is to describe some of the experiences of the Southwest Pediatric Nephrology Study Group (SPNSG) in order to assist others in developing their own multicenter studies. The importance of protocol development, including adequate attention to study design, data management, and data analysis, is emphasized. Mechanisms for facilitating the frequency and productivity of study group meetings that are so essential for the success of multicenter studies, are described in some detail. The need and some of the methods for achieving ongoing collaboration within a climate of critical peer review are also discussed. Controversial issues such as authorship and the question of institutional credit for involvement in multicenter studies are discussed in brief. Finally, some of the features of the SPNSG that have permitted us to maintain a relatively high rate of productivity are described. The two most important of these, ongoing commitment to the group and willingness to collaborate across differences of opinion, are stressed throughout the review.

Micro-angiopathic haemolysis, thrombocytopenia and nephrotic syndrome associated with membranous nephropathy in a Vietnamese boy

The unique association of idiopathic diffuse membranous nephropathy and micro-angiopathic haemolytic anaemia and thrombocytopenia is described. A 7 year old Vietnamese boy with a 1-month history of anaemia resistant to oral iron supplements presented with acute onset of nephrotic syndrome. Investigations revealed a micro-angiopathic haemolytic anaemia and thrombocytopenia. There was no associated oliguria or uraemia. Diffuse membranous nephropathy was diagnosed by renal biopsy. Apart from a fourfold rise in enterovirus titres, no underlying cause for the haematological or glomerular abnormalities was found. There was an apparent, partial haematological response to fresh frozen plasma infusions, but not to Vitamin E.

Overview of pediatric nephropathology

I have given a brief overview of the morphologic basis of renal disease in children. Obviously I have been unable to include all the important and well-done studies of various conditions, which together cover the entire spectrum of pediatric renal disease. It is evident from the many studies that the renal biopsy has been, is, and will be quite helpful in elucidating the histologic pattern and severity of injury in the child with clinical evidence of renal disease. As therapy becomes more effective for renal diseases known to cause progressive renal insufficiency, the impact of the renal biopsy will become even greater. Because of the frequent discordance between clinical laboratory findings and renal histologic severity, an initial or baseline biopsy is often the only way to stage the alterations in renal structure. Present tests of renal function are imperfect and are insensitive parameters of insidious and progressive renal disease. The capacity of the kidney to compensate for nephron loss by hypertrophy and modification of the remaining nephrons can mask progressive renal disease and thus impair our ability to detect meaningful differences in therapeutic results. A repeated biopsy or "second look" allows detailed comparison and study of the effects of various therapeutic regimens on the renal disease process. Continued, detailed clinical-morphologic correlations and studies using improved techniques hopefully will provide us with better profiles or predictors of the type, severity, and pathogenesis of the renal disease in the individual patient. Determination of the histologic pattern by renal biopsy at present remains one of the, if not the, most important and reliable prognostic indicators in the individual patient and allows us a unique look at the host response to the varying types of injuries leading to pediatric renal disease.