Mesangial IgA deposits with steroid responsive nephrotic syndrome: probable minimal lesion nephrosis

Mild mesangial proliferative IgA nephropathy with and without minimal change disease

Mild mesangial proliferative IgA nephropathy with minimal change disease (MCD-IgAN) and mild mesangial proliferative IgA nephropathy without minimal change disease (Non-MCD-IgAN) have similar characteristics on light microscopy. Nevertheless, their discrepancies in clinicopathological features and prognosis remain unknown. A total of 589 patients with biopsy-proven mild mesangial proliferative IgA nephropathy (M-IgAN) combined with light microscopy and immunofluorescence were enrolled. Firstly, the diagnoses of the patients by electron microscopy were recorded and used as the gold standard. We calculated the sensitivity and specificity using nephrotic syndrome (NS) as the diagnostic criteria to identify MCD-IgAN. Then, excluding patients with a 24-h urinary total protein less than 0.5 g/day, incomplete clinical data, or less than the six-month follow-up, we included 184 cases of non-MCD-IgAN and 98 cases of MCD-IgAN. The patients' clinicopathological and outcome data were collected and compared. Among the 589 patients, according to electron microscopy, 381 were diagnosed with non-MCD-IgAN, 167 with MCD-IgAN, and 41 with M-IgAN complicated by other glomerular diseases. Using NS as the diagnostic criteria to distinguish non-MCD-IgAN and MCD-IgAN, the sensitivity and specificity were 83.8% and 99.5%, respectively. The patients in the MCD-IgAN group tended to be younger, hypotensive, with lower urinary erythrocytes, and more likely to achieve complete remission, and fewer patients progressed to the endpoint than those in the non-MCD-IgAN group (all P < 0 .05). NS appears to be an objective indicator for differentiating MCD-IgAN from non-MCD-IgAN. Non-MCD-IgAN varies greatly from MCD-IgAN in clinicopathology and treatment response, with a poorer prognosis.

Characterization of patients with IgA nephropathy with and without associated minimal change disease

Introduction

Immunoglobulin A nephropathy (IgAN) presents various clinical manifestations and pathological phenotypes. Approximately 5% of patients with IgAN present with early onset nephrotic syndrome, mild mesangial lesions, and diffuse foot process effacement of podocytes, which resemble minimal change disease (MCD). These patients are defined as MCD-IgAN. Whether MCD-IgAN is a special type of IgAN or simply MCD accompanied by IgA deposition remains controversial.

Methods

A total of 51 patients diagnosed with MCD-IgAN at Beijing Anzhen Hospital from January 2010 to September 2022 were recruited. The clinical and pathological characteristics of IgA-MCD were analyzed. Patients with IgAN but without MCD (non-MCD-IgAN) and healthy participants were enrolled as controls. Galactose-deficient immunoglobulin A1 (Gd-IgA1) and complement C3 were detected both in the circulation and in renal tissues.

Results

We found that the levels of serum Gd-IgA1 were lower in participants with MCD-IgAN than in those with non-MCD-IgAN, but higher than in healthy participants. Gd-IgA1 was rarely deposited in the glomeruli of participants with MCD-IgAN, with a positive rate of only 13.7% (7/51); in contrast, the positive rate in participants with non-MCD-IgAN was 82.4% (42/51). Among renal Gd-IgA1-positive patients, Gd-IgA1 and immunoglobulin A (IgA) colocalized along the glomerular mesangial and capillary areas. Interestingly, we found that the circulating levels of complement C3 were significantly higher in participants with MCD-IgAN than in participants with non-MCD-IgAN. In addition, the intensity of C3c in glomeruli in participants with MCD-IgAN was significantly weaker than in participants with non-MCD-IgAN.

Conclusions

Our study suggests that, in MCD-IgAN, most of the IgA that is deposited on glomeruli is not the same pathogenic Gd-IgA1 as found in general IgAN. Complement activation both in the circulation and in the renal locality was much weaker in MCD-IgAN than in non-MCD-IgAN. Our study suggests that IgAN with MCD might be MCD with coincidental IgA deposition.

A Case of a Pregnant Woman with IgA Nephropathy Showing Histological Preeclampsia Findings without Hypertension Treated with Steroids: A Case Report and Literature Review

A 35-year-old woman pregnant with twins developed nephrotic syndrome (NS) at 33 weeks' gestation, but her blood pressure remained within the normal range throughout gestation and puerperium. At 34 weeks' gestation, she delivered healthy twins via Caesarean section. After delivery, she developed massive proteinuria (21.1 g/day) and severe hypoalbuminemia (1.0 g/dL). A renal biopsy performed 19 days after delivery revealed IgA nephropathy (IgAN) and preeclampsia. She was treated with steroids, and the NS gradually resolved. This is a rare case of massive gestational proteinuria with IgAN and preeclampsia pathologically that did not meet the clinical criteria for preeclampsia.

Demyelinating disease (multiple sclerosis) in a patient with psoriatic arthritis treated with adalimumab: a case-based review

Over the past two decades, tumor necrosis factor-α (TNF-α) inhibitors became one of the most important drugs in the treatment of patients with psoriatic arthritis. Unfortunately, some of the patients exhibit unwanted side effects of the treatment. We describe a patient with psoriasis, psoriatic arthritis and uveitis who was treated with adalimumab and after 4 months of the treatment developed clinical and neuroradiological signs of demyelinating disease of the central nervous system. She experienced no signs and symptoms of neurological disease prior to adalimumab administration. After a detailed neurological work-up she was diagnosed with relapsing-remitting type of multiple sclerosis and treated with oral and pulse glucocorticoids and later with dimethyl fumarate. Adalimumab was discontinued. The question remains was the demyelination induced by the TNF-α blockade or was it unmasked by the introduction of the cytokine blocking agent. In patients suffering from inflammatory arthritis, treating disease to target as well as a close follow-up and knowledge of potential side effects of treatment remains crucial in good clinical practice.

Primary IgA nephropathy with nephrotic-range proteinuria in Chinese children

To investigate the clinicopathological features and outcomes of primary IgA nephropathy with nephrotic-range proteinuria in Chinese children. Patients with biopsy-proven IgA nephropathy and nephrotic-range proteinuria between January 2011 and December 2017 were included, and their proteinuria and renal function were followed up. A total of 90 patients were enrolled, and 21.1% (19/90) of them had decreased renal function at diagnosis. Complete remission, partial remission, and no response of proteinuria occurred in 88.6% (70/79), 10.1% (8/79), and 1.3% (1/79), respectively, of the 79 patients who were followed up for 6 to 104 months. 73.7% (14/19) of the patients with decreased renal function at diagnosis recovered to normal level while 26.3% (5/19) of them did not recover or progressed to end-stage renal disease. Two patients with normal renal function at diagnosis progressed to renal insufficiency during follow-up period. By multivariate analysis, the risk for renal function deterioration was significantly higher in the partial remission and no response groups than in the complete remission group. Remission of proteinuria was important for improving renal prognosis in children with IgA nephropathy and nephrotic-range proteinuria. The outcomes for pediatric patients appeared to be better than that reported in adults.

Characterization of IgA Deposition in the Kidney of Patients with IgA Nephropathy and Minimal Change

Approximately 5% of patients with IgA nephropathy (IgAN) exhibit mild mesangial lesions with acute onset nephrotic syndrome and diffuse foot process effacement representative of minimal change disease (MCD). It is not clear whether these unusual cases of IgAN with MCD (IgAN-MCD) are variant types of IgAN or coincidental deposition of IgA in patients with MCD. In a retrospective multicenter cohort study of 18 hospitals in Korea, we analyzed 46 patients with IgAN-MCD. Patients with endocapillary proliferation, segmental sclerosis, and crescent were excluded, and the clinical features and prognosis of IgAN-MCD were compared with those of pure MCD. In addition, we performed galactose-deficient IgA1 (KM55) staining to characterize IgAN-MCD. Among the 21,697 patients with glomerulonephritis enrolled in the database, 46 patients (0.21%) were diagnosed with IgAN-MCD, and 1610 patients (7.4%) with pure MCD. The 46 patients with IgAN-MCD accounted for 0.6% of primary IgAN patients (n = 7584). There was no difference in prognosis between patients with IgAN-MCD and those with only MCD. IgA and KM55 showed double positivity in all patients with IgAN-MCD (n = 4) or primary IgAN (n = 5) under double immunofluorescent staining. However, in four patients with lupus nephritis, mesangial IgA was deposited, but galactose-deficient-IgA1 (Gd-IgA1) was not. These findings suggest that IgAN-MCD is a dual glomerulopathy in which MCD was superimposed on possibly indolent IgAN. We confirmed by KM55 staining that IgAN-MCD is true IgAN, enabling better characterizations of the disease. Furthermore, IgAN-MCD shows a good prognosis when treated according to the usual MCD treatment modality.

Steroid therapy in children with IgA nephropathy

IgA nephropathy (IgAN) is one the most common primary glomerulonephritis in children and adolescents worldwide, with 20% of children developing end-stage kidney disease (ESKD) within 20 years of diagnosis. There is a need for treatment guidelines, especially for steroids in children with primary IgAN, since the STOP-IgA trial casts doubts on the use of steroids in adults with intermediate risk. Pediatricians are prone to prescribe steroids in addition to renin-angiotensin system blockade (RASB) when proteinuria is > 0.5 g/l, eGFR deteriorates < 70 ml/min/1.73 m², or when a biopsy sample shows glomerular inflammation. Lack of randomized controlled trials (RCTs) in children with IgAN has led to an absence of consensus on the use of immunosuppressive agents in the treatment of progressive IgAN. This literature review evaluates the available evidence on steroid treatment in children with IgAN.

IgA nephropathy with presentation of nephrotic syndrome at onset in children

BACKGROUND

Despite a low incidence, nephrotic syndrome (NS) can present with IgA nephropathy (IgAN). The clinical characteristics and long-term outcomes of pediatric patients with IgAN presenting with NS (NS-IgAN) at onset have not been fully elucidated.

METHODS

We retrospectively analyzed 426 patients, and compared clinical and pathological (Oxford) findings between those with NS-IgAN and those with non-NS-IgAN.

RESULTS

Among 426 patients, 30 (7.0 %) had NS-IgAN. Logistic analyses showed that male sex (OR: 7.6, p = 0.0002), M1 (OR: 10.3, p = 0.002), and E1 (OR: 15.2, p = 0.0001) were significantly related to NS. The mean observation period was 6.2 ± 3.2 years. Although NS-IgAN was associated with significantly lower renal survival than non-NS-IgAN according to Kaplan-Meier analysis (p = 0.02), renal survival of NS-IgAN was good (92.4 % at 10 years). The most significant prognostic factor for renal survival was remission of proteinuria after treatment, and NS at onset is also a significant prognostic factor for renal survival after adjusting for remission of proteinuria. Twenty children with NS-IgAN were treated with prednisolone alone, or prednisolone and immunosuppressant. Remission of proteinuria occurred in 21 patients. Three cases of NS-IgAN progressed to stage III-V chronic kidney disease at the most recent observation. They all demonstrated heavy proteinuria after the 2-year initial treatment. The significant factor for persistent proteinuria at 5 years was S1 in NS-IgAN.

CONCLUSIONS

The most significant factor for renal survival was responsiveness to treatment, not NS itself. As modifiable acute lesions are the dominant pathological findings in NS-IgAN, histological improvements achieved by appropriate treatments can result in a favorable prognosis.

IgA nephropathy with minimal change disease

BACKGROUND AND OBJECTIVES

Patients with IgA nephropathy typically present with hematuria and subnephrotic proteinuria. Nephrotic syndrome is uncommon in IgA nephropathy, and when present, it is usually associated with severe histologic features, such as endocapillary proliferation, segmental sclerosis, and crescent formation. Rarely, patients with IgA nephropathy present with nephrotic syndrome and only mild mesangial disease. This study sought to better characterize these patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A retrospective review of cases of IgA nephropathy diagnosed from 2004 to 2011 identified patients with nephrotic range proteinuria and histologically mild IgA nephropathy. Specifically, using the Oxford Classification of IgA Nephropathy, we identified cases that lacked endocapillary proliferation or segmental sclerosis.

RESULTS

The cohort consisted of 17 patients, including 10 men and 15 adults. The median serum creatinine was 0.9 mg/dl (range=0.7-3.1), median 24-hour urine protein was 8.0 g/d (3.0-18.0 g), and 14 patients were fully nephrotic, whereas the remaining 3 patients fulfilled two of three criteria for nephrotic syndrome. Biopsies revealed IgA-dominant or codominant deposits accompanied by mesangial proliferation in 14 patients (82.4%). Electron microscopy showed mesangial deposits and extensive foot process effacement (median=90%). Initial treatment consisted of corticosteroids, although many patients required additional agents to maintain remission status. Over a median follow-up of 20 months (2.2-82 months), 14 patients experienced a complete response, and 3 patients showed a partial response, with a median response time of 2 months (0.5-27 months). At least one relapse of nephrotic syndrome occurred in nine patients (53%). All patients exhibited stable or improved renal function over the follow-up period.

CONCLUSIONS

The findings in this cohort and previous studies suggest that rare cases of mild IgA nephropathy with nephrotic range proteinuria exhibit a clinical presentation, biopsy findings, treatment response, and outcome more typical of IgA nephropathy with superimposed minimal change disease. This study favors the view that such cases represent a dual glomerulopathy.

Corticosteroid therapy in IgA nephropathy with minimal change-like lesions: a single-centre cohort study

BACKGROUND

There is a lack of high-quality evidence that advocates the use of corticosteroids for IgA nephropathy (IgAN) with minimal change-like lesions (also called IgAN with minimal change disease, MCD-IgAN).

METHODS

Twenty-seven biopsy-proven adult MCD-IgAN patients were enrolled. Daily single dose of 1 mg/kg (maximum 60 mg/day) prednisone was given until complete remission (CR), followed by gradually decreasing dosage. The clinical data were collected from baseline up to 12 weeks of treatment (Certification No. 2011NLY-006, Clinical trials gov ID. NCT01451710).

RESULTS

The patient cohort consisted of 15 males and 12 females. The mean age of the patients was 29.2 ± 10.8 years (range 18-60 years) at the time when they were subject to renal biopsy. All patients had hypoalbuminaemia (23.7 ± 4.13 g/L) and heavy proteinuria (>3.5 g/24 h). Cumulative CR (proteinuria < 0.4 g/24 h) rates were 3.70, 48.1, 92.6 and 100% after 1, 2, 4 and 8 weeks of treatment, respectively. Two cases relapsed after CR, one at 6 weeks of treatment, likely due to failure to follow the corticosteroid withdrawal schedule, and the other one at 8 weeks of treatment accompanied with an upper respiratory infection. Infection, alanine aminotransferase elevation (>2-folds), fasting blood glucose (FBG) elevation (>6.2 mmol/L) and hypopotassaemia (<3.5 mmol/L) occurred in 2, 5, 2 and 5 cases, respectively, but were eliminated after treatment.

CONCLUSION

Corticosteroid therapy is likely effective and safe for MCD-IgAN patients.

A case of minimal change nephrotic syndrome with immunoglobulin A nephropathy transitioned to focal segmental glomerulosclerosis

A 50-year-old woman with a 1-month history of lower extremity edema and a 5 kg weight increase was admitted to our hospital with suspected nephrotic syndrome in October 1999. Urine protein level was 3.5 g per day, 10-15 erythrocytes in urine per high-power field, and serum albumin level 2.5 g/dl. Furthermore, an accumulation of pleural effusion was confirmed by chest X-ray. The results of a renal biopsy indicated slight mesangial proliferation in the glomeruli by light microscopy, and an immunofluorescence study confirmed the deposition of immunoglobulin (Ig) A and C3 in the mesangial area. Diffuse attenuation of foot processes and dense deposits in the mesangial area were observed by electron microscopy. Treatment with 40 mg/day of prednisolone was effective, and proteinuria was negative 1 month later. Because of this course, we diagnosed minimal change nephrotic syndrome complicated by mild-proliferative IgA nephropathy. In November 2000, there was a relapse of nephrotic syndrome, which was believed to be induced by an influenza vaccination, but response to increased steroid treatment was favorable, and proteinuria disappeared on day 13 of steroid increase. A second relapse in May 2001, showed steroid resistance with renal insufficiency, and an increase in the selectivity index to 0.195. Light microscopy revealed focal sclerotic lesions of the glomeruli, and an immunofluorescence study revealed attenuation of mesangial IgA and C3 deposition. These findings led to the diagnosis that minimal change nephrotic syndrome had transitioned to focal segmental glomerulosclerosis, whereby mesangial IgA deposition was reduced by immunosuppressive treatment. Subsequently, her renal function gradually worsened to the point of end-stage renal failure by 27 months after the second relapse of nephrotic syndrome.

Clinical features and outcomes of IgA nephropathy with nephrotic syndrome

BACKGROUND AND OBJECTIVES

Nephrotic syndrome (NS) is a rare manifestation of IgA nephropathy (IgAN). Clinical characteristics and long-term outcomes of this condition have not yet been explored.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A multicenter observational study was conducted between January 2000 and September 2010 in 1076 patients with biopsy-proven IgAN from four medical centers in Korea. The primary outcome was a doubling of the baseline serum creatinine concentration.

RESULTS

Of the 1076 patients, 100 (10.2%) presented with NS; complete remission (CR), partial remission (PR), and no response (NR) occurred in 48 (48%), 32 (32%), and 20 (20%) patients, respectively. During the median follow-up of 45.2 months, 24 patients (24%) in the NS group reached the primary endpoint compared with 63 (7.1%) in the non-NS group (P<0.001). The risk of reaching the primary endpoint was significantly higher in the PR (P=0.04) and NR groups (P<0.001) than in the CR group. Among patients with NS, 24 (24%) underwent spontaneous remission (SR). SR occurred more frequently in female patients and in patients with serum creatinine levels ≤1.2 mg/dl and a >50% decrease in proteinuria within 3 months after NS onset. None of the patients with SR reached the primary endpoint and they had fewer relapses during follow-up.

CONCLUSIONS

This study demonstrated that the prognosis of NS in IgAN was not favorable unless PR or CR was achieved. In addition, SR was more common than expected, particularly in patients with preserved kidney function and spontaneous decrease in proteinuria shortly after NS onset.

Spontaneous remission of nephrotic syndrome in patients with IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN) can be complicated by nephrotic syndrome. Because the spontaneous resolution of heavy proteinuria is rare, corticosteroid therapy should be considered in such cases, particularly when IgAN is combined with minimal-change disease. Here, we report our experience of spontaneous remission of nephrotic syndrome in patients with IgAN and the long-term outcomes of these patients.

METHODS

Two hundred and thirty-three patients with biopsy-proven IgAN were enrolled between January 2001 and March 2009. Demographic, clinical and laboratory data were collected retrospectively based on medical records. In addition, pathologic findings were reviewed for glomerular and tubulointerstitial lesions. Outcome data for complete or partial remission, spontaneous remission, relapse, deterioration of renal function, and end-stage renal disease were recorded.

RESULTS

Twenty-four patients (10.3%) presented nephrotic syndrome. Among them, five patients underwent spontaneous remission within 6 months after the presentation of nephrotic syndrome. Interestingly, spontaneous remission occurred even in two patients who had elevated serum creatinine levels and advanced renal damage. During follow-up, neither recurrence nor relapse occurred, and no patients showed progressive deterioration of kidney function. Conclusions. This study suggests that spontaneous remission of nephrotic syndrome may occur in any stage of IgAN and carries a favourable long-term outcome without relapse. Given the possibility of under-reported cases, large-scale studies are required, and careful attention should be paid to such complicated cases.

Idiopathic immunoglobulin A nephropathy in children and adolescents

Immunoglobulin A nephropathy is now recognized as the glomerular disease most often associated with progressive renal failure in patients around the world. In many cases it is not known when the disease starts to inflict glomerular injury, but recent studies that have shown genetically determined abnormalities in glycosylation of the IgA molecule suggest that this may begin in early life. This review focuses on recent advances in our understanding of IgA nephropathy, with special emphasis on clinical aspects of the disease when it presents in children and adolescents. In addition, the sections dealing with therapeutic options for patients with IgA nephropathy concentrate on studies that have been carried out on children. Whenever possible, data from randomized controlled clinical trials have formed the basis for recommendations. Unfortunately, this is not always possible, because of the lack of such trials in patients with IgA nephropathy.

Clinicopathologic characteristics of IgA nephropathy with steroid-responsive nephrotic syndrome

Nephrotic syndrome is an unusual manifestation of IgA Nephropathy (IgAN). Some cases respond to steroid treatment. Here we describe a case-series of IgAN patients with steroid-responsive nephrotic syndrome. Twelve patients with IgAN with steroid-responsive nephrotic syndrome were evaluated and followed up. All patients presented with generalized edema. Renal insufficiency was found in two patients. The renal biopsy of eight patients revealed wide foot process effacement in addition to the typical features of IgAN. They showed complete remission after steroid therapy. Seven relapses were reported in five patients; six of the relapsed cases responded to steroid therapy. Compared with steroid-non-responsive patients, the patients with steroid-responsive nephrotic syndrome had shorter symptom duration, more weight gain, more proteinuria, and lower histologic grade than did those that had steroid-non-responsive nephrotic syndrome at presentation. None of the responders progressed to end stage renal disease, whereas five (38%) non-responders required dialysis or renal transplantation. Patients with IgAN who have steroid-responsive nephrotic syndrome likely have both minimal change disease and IgAN. The clinical features of sudden onset of generalized edema, initial heavy proteinuria and initial severe hypoalbuminemia might help identify the subset of patients, especially in low grade IgAN.

Have we ignored the role of oncotic pressure in the pathogenesis of glomerulosclerosis?

Focal and segmental glomerulosclerosis (FSGS) develops in a number of renal conditions, especially those associated with severe nephrotic syndrome or a reduction in renal mass. Strong evidence suggests that in diseases associated with reduced renal mass that FSGS develops as a consequence of elevated glomerular hydrostatic pressure (P(GC)) resulting from single nephron hyperfiltration. In nephrotic syndrome, the contribution of an elevated P(GC) is less certain. We hypothesize that in both conditions there is an elevation in net ultrafiltration pressure (P(UF)), which in nephrotic syndrome is secondary to a reduction in glomerular plasma oncotic pressure (piGC) and in conditions with reduced renal mass is secondary to an elevated P(GC). The elevated P(UF) would result in increased convective forces with trafficking and deposition of macromolecules in the mesangium, a process that could trigger local cytokine release with the stimulation of cell proliferation and matrix synthesis. In addition to explaining why FSGS develops in both nephrotic syndrome and with reduced renal mass, the hypothesis explains why the lesion in FSGS is segmental and preferentially involves the hilar area. This is because P(UF) varies along the glomerular capillary, being highest at the proximal (afferent arteriolar) end. In contrast, an elevated P(GC) alone does not readily explain the segmental nature of FSGS, because P(GC) remains relatively constant within the glomerulus. Thus, the hypothesis suggests an important role for the plasma oncotic pressure in the pathogenesis of FSGS. Future studies examining the role of P(UF) and piGC in FSGS would be of interest.

Chronic glomerulonephritis in childhood. Membranoproliferative glomerulonephritis, Henoch-Schönlein purpura nephritis, and IgA nephropathy

The chronic glomerulonephritides that lead to permanent loss of renal function may present with an acute nephritic syndrome, nephrotic syndrome, or asymptomatic hematuria and proteinuria. Membranoproliferative glomerulonephritis, Henoch-Schönlein purpura nephritis, and IgA nephropathy are common childhood glomerulonephritides that may lead to chronic renal failure. Their clinical manifestations, natural history, and long-term prognosis are distinct. This article reviews various presentations of these common childhood glomerulonephritides and an approach to management and potential therapy.

Double-blind, controlled trial of short-term prednisone therapy in immunoglobulin A glomerulonephritis

Twenty children and adolescents with IgA glomerulonephritis were enrolled in a crossover trial. Each received 12 weeks of prednisone therapy and 12 weeks of placebo dosing. Urinary protein and erythrocyte excretion were monitored during both courses. There was no evidence that, under the conditions of the study, corticosteroid therapy was effective in IgA nephropathy.

Spontaneous remission of nephrotic syndrome in a patient with IgA nephropathy

A patient with spontaneous remission of nephrotic syndrome (NS) associated with IgA nephropathy is described. The patient presented at the age of 8 years with asymptomatic proteinuria, and at the age of 11 years developed classical features of NS. A percutaneous renal biopsy showed mild mesangial prominence without significant hypercellularity, electron-dense deposits within the mesangium, and 3+ mesangial staining with IgA and IgG. NS resolved 6 weeks after onset without any form of therapy; absence of proteinuria persisted 6 months later. This report demonstrates clearly that patients with NS associated with IgA nephropathy may undergo spontaneous resolution of their proteinuria.

Mesangial IgA nephropathy with steroid-responsive nephrotic syndrome: disappearance of mesangial IgA deposits following steroid-induced remission

This report describes the clinical features and renal biopsy pathology in two patients with immunoglobulin A (IgA) nephropathy and nephrotic syndrome before and after steroid-induced remission. Apart from confirming the frequently relapsing course and mild glomerular changes observed in patients with IgA nephropathy and steroid-responsive nephrotic syndrome (SRNS), we were able to show that mesangial expansion and mesangial IgA deposits disappeared or were greatly reduced in repeat renal biopsies following steroid-induced remission. Because mesangial IgA deposits usually persist in repeat biopsies obtained from patients with typical IgA nephropathy, their resolution in our patients following steroid remission would support the proposal that the association of IgA nephropathy and SRNS may represent a distinct clinical syndrome. It is postulated that the presence of mesangial IgA deposits during nephrotic presentation and their disappearance following steroid-induced remission may result from increased mesangial sequestration of IgA circulating immune complexes (CIC) during the period of enhanced glomerular permeability and that the increased load of IgA CICs may reflect a common defect in mucosal immunity or immunoregulation in these patients.

Immunopathological findings in idiopathic nephrosis: clinical significance of glomerular "immune deposits"

Idiopathic nephrosis (IN), which includes minimal change (MCD), diffuse mesangial proliferation (DMP) and focal segmental glomerular sclerosis (FSGS), is classically characterized by the absence of significant deposits by immunofluorescence microscopy (IF), except for the focal lesions of segmental sclerosis and/or hyalinosis of FSGS, which fix IgM and C3 antiserums. Since IF is available in most centres, an increasing number of unexpected findings has been reported. In order to evaluate the clinical significance of the glomerular deposits revealed by IF in some instances, we reviewed the renal biopsy findings of 222 consecutive children presenting with IN and in whom IF microscopy was available. By light microscopy, 122 patients showed MCD, 10 DMP, and 90 FSGS with DMP (11 cases) or without (79 cases). By IF, 125 specimens were negative and served as controls; 54 showed mesangial IgM deposits, 24 mesangial IgG deposits (associated with Clq deposits in 16), 15 scattered granules of C3 and 4 predominant deposits of mesangial IgA. We correlated these findings with initial response to steroid therapy and outcome and could find no significant difference between the various categories defined by IF and the control group. Repeat biopsies, performed in 21 cases, showed the persistence of deposits in 11 and their transformation in 10. The particular problem raised by the patients who present with IN and mesangial IgA deposits is discussed. Our results demonstrate that patients presenting with IN and "positive IF", whether showing IgM, IgG and Clq, C3 or IgA, do not represent distinct clinicopathological entities.