Clinical course of immunoglobulin A nephropathy in children

Lisinopril versus lisinopril and losartan for mild childhood IgA nephropathy: a randomized controlled trial (JSKDC01 study)

BACKGROUND

Persistent proteinuria seems to be a risk factor for progression of renal disease. Its reduction by angiotensin-converting inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) is renoprotective. Our previous pilot study showed that 2-year lisinopril therapy is effective and safe for children with mild IgA nephropathy. When combined with ACEI and ARB, reported results are of greater decrease in proteinuria than monotherapy in chronic glomerulonephritis, including IgA nephropathy. To date, however, there have been no randomized controlled trials in children.

METHODS

This is an open-label, multicenter, prospective, and randomized phase II controlled trial of 63 children with biopsy-proven proteinuric mild IgA nephropathy. We compared efficacy and safety between patients undergoing lisinopril monotherapy and patients undergoing combination therapy of lisinopril and losartan to determine better treatment for childhood proteinuric mild IgA nephropathy.

RESULTS

There was no difference in proteinuria disappearance rate (primary endpoint) between the two groups (cumulative disappearance rate of proteinuria at 24 months: 89.3% vs 89% [combination vs monotherapy]). Moreover, there were no significant differences in side effects between the two groups.

CONCLUSIONS

We propose lisinopril monotherapy as treatment for childhood proteinuric mild IgA nephropathy as there are no advantages of combination therapy.

CLINICAL TRIAL REGISTRATION

Clinical trial registry, UMIN ID C000000006, https://www.umin.ac.jp .

Biopsy timing and Oxford classification variables in childhood/adolescent IgA nephropathy

BACKGROUND

Although the Oxford classification of IgA nephropathy appears valid, we found crescents were significantly related to renal outcome in our cohort, whereas segmental glomerulosclerosis (S) was not. The timing of renal biopsy may significantly affect the variables in the Oxford classification.

METHOD

The relationship between biopsy timing and pathological variables (mesangial hypercellularity score [M], endocapillary hypercellularity [E], S, tubular atrophy/interstitial fibrosis [T], crescents, and global glomerulosclerosis [G]) was analyzed retrospectively in 250 children with IgA nephropathy.

RESULTS

The median time from disease onset to renal biopsy was 5.1 months (interquartile range, 2.7-15.4). M (ρ = -0.26, P < 0.0001), E (ρ = -0.34, P < 0.0001), and crescents (ρ = -0.14, P = 0.023) showed significant negative correlations, and S (ρ = 0.15, P = 0.018) and G (ρ = 0.25, P < 0.0001) showed significant positive correlations with time to biopsy (Spearman test). M, E, and crescents differed significantly in renal biopsies obtained before and after 3 years from onset (Wilcoxon test). Most crescents (92.9 %) were cellular/fibrocellular and were acute lesions. As crescents formed early after disease onset and decreased over time, they may be prognostic for acute phase, but not for chronic phase disease.

CONCLUSIONS

Renal biopsy timing may alter the significance of variables used in the Oxford classification.

Spontaneous remission in children with IgA nephropathy

BACKGROUND

Some patients with IgA nephropathy (IgAN) achieve spontaneous remission even when not receiving medication. However, details on such remissions remain unknown. The aim of our study was to clarify this information in the clinical setting of childhood IgAN with minor glomerular abnormalities or focal mesangial proliferation (MGA/FMP).

METHODS

This study was a retrospective analysis of 96 children with MGA/FMP who did not receive medication from among the 555 patients with newly diagnosed childhood IgAN treated between January 1972 and December 2000. The Kaplan-Meier method and Cox proportional hazard model were used for the analysis.

RESULTS

Of the 96 pediatric patients who did not receive medication, 57 (59.4 %) achieved spontaneous remission. The cumulative spontaneous remission rates among these patients were 57.5 and 77.4 % at 5 and 10 years, respectively, from onset. The mean time from onset to remission was 5.9 ± 0.4 years. Clinical and histological findings were similar between the remission and non-remission groups. Of the 57 patients with spontaneous remissions, ten (17.5 %) also developed a recurrence of urinary abnormalities. The cumulative recurrence-free rates were 79.9 and 67.9 % at 5 and 10 years, respectively, after remission.

CONCLUSIONS

The spontaneous remission rate in childhood IgAN with MGA/FMP was higher than expected. Our results suggest that physicians should consider the potential for spontaneous remission and refrain from very aggressive treatment in IgAN patients with MGA/FMP.

Identification of alternatively activated macrophages in new-onset paediatric and adult immunoglobulin A nephropathy: potential role in mesangial matrix expansion

AIMS

New onset of the clinical symptoms of immunoglobulin A (IgA) nephropathy (IgAN) manifests with proliferative glomerular lesions in children, whereas adults exhibit mesangial matrix expansion and interstitial fibrosis. Alternatively, activated (M2) macrophages have been implicated in promoting tissue fibrosis in some settings. Therefore, the aim of this study was to investigate whether M2 macrophages are present in new-onset IgAN and if they are related to pathological differences between paediatric and adult disease.

METHODS AND RESULTS

Biopsy specimens from paediatric (<10 years, n=14; >12 years, n=15) and adult (n=27) IgAN showed a significant infiltrate of CD68(+) macrophages. M2 macrophages, identified by CD163 or CD204 expression, were detected in glomeruli and the interstitium, being more prominent in adults versus young children. CD163(+) and CD204(+) macrophages were present in areas of fibrosis containing myofibroblasts, and double staining showed that CD163(+) cells produced the profibrotic molecule, connective tissue growth factor. In young children, total CD68(+) macrophages, but not M2 macrophages, correlated with glomerular hypercellularity. In contrast, in adults and older children, mesangial matrix expansion correlated with M2 macrophages but not with the total CD68(+) macrophage infiltrate.

CONCLUSIONS

Alternatively activated M2 macrophages are present in new-onset paediatric and adult IgAN, and this population may promote the development of fibrotic lesions.

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.

Efficacy and safety of lisinopril for mild childhood IgA nephropathy: a pilot study

Even in children with mild immunoglobulin (Ig)A nephropathy (IgA-N) showing minimal/focal mesangial proliferation, persistent proteinuria seems to be a risk factor for progression of the disease, indicating the need for an effective and safe treatment even in such cases. Studies carried out to date have indicated that angiotensin-converting enzyme inhibitors (ACEIs) reduce urinary protein excretion and preserve renal function in adult IgA-N. However, no prospective study of ACEI only for childhood IgA-N has yet been carried out. In this prospective single-arm pilot trial, we administered lisinopril (0.4 mg/kg per day) as therapeutic treatment to 40 children with mild IgA-N with proteinuria [morning urinary protein/creatinine ratio (uP/Cr) >or= 0.2 g/g]. Thirty-three patients reached the primary endpoint (uP/Cr < 0.2) during the 2-year treatment period. The cumulative disappearance rate of proteinuria determined by the Kaplan-Meier method was 80.9%. Mean uP excretion was reduced from 0.40 to 0.18 g/m(2)/day (p < 0.0001). Of the 40 patients treated, five (12.5%) showed dizziness, and four of these five needed the lisinopril dose reduced. However, lisinopril therapy was continued in all patients during the 2-year treatment period. No other side effect, such as cough, was observed. We conclude that the efficacy and safety of lisinopril is seemingly acceptable for the treatment of children with mild IgA-N.

Combination therapy with mizoribine for severe childhood IgA nephropathy: a pilot study

In two previous randomized controlled trials we showed that treatment of severe childhood immunoglobulin A nephropathy (IgA-N) using prednisolone, azathioprine, heparin-warfarin, and dipyridamole prevented any increase of sclerosed glomeruli and that prednisolone alone did not prevent a further increase of sclerosed glomeruli. Accordingly, the immunosuppressant is considered to be important. Often, however, we were unable to complete azathioprine regimen due to toxicity. Therefore, a different but effective immunosuppressant may be worth trying. Mizoribine, like azathioprine, is an antimetabolite that exerts its immunosuppressant effect by inhibiting lymphocyte proliferation. In this pilot study, we administered mizoribine instead of azathioprine as part of the combination therapy for treating 23 children with severe IgA-N and evaluated the efficacy and safety. Eighteen patients reached the primary endpoint (urine protein/creatinine ratio <0.2) during the 2-year treatment period. The cumulative disappearance rate of proteinuria determined by Kaplan-Meier was 80.4%. Median protein excretion was reduced from 1.19 g/m(2)/day to 0.05 g/m(2)/day (p < 0.0001). After treatment, the median percentage of glomeruli showing sclerosis was unchanged in comparison with that before treatment. No patients required a change of treatment. In conclusion, the efficacy and safety of the mizoribine combination seems to be acceptable for treating children with severe IgA-N.

Improved renal survival in Japanese children with IgA nephropathy

Since the beginning of the 1990s, Japanese medical practitioners have extensively prescribed angiotensin-converting enzyme (ACE) inhibitors for children with mild IgA nephropathy (IgA-N) and steriods for those with severe IgA-N. We have performed a retrospective cohort study to clarify whether the long-term outcome has improved in Japanese children with IgA-N. Renal survival was defined as the time from onset to end-stage renal disease (ESRD). We divided the study period into two time periods based on the occurrence of the initial renal biopsy:1976-1989 and 1990-2004. Actuarial survivals were calculated by Kaplan-Meier method, and comparisons were made with the logrank test. The Cox proportional hazard model was used for multivariate analysis. Between 1976 and 2004, 500 children were diagnosed as having IgA-N in our hospitals. The actuarial renal survival from the time of apparent disease onset was 96.4% at 10 years, 84.5% at 15 years and 73.9% at 20 years. Renal survival in the 1990-2004 period was significantly better than that in 1976-1989 (p=0.008), and a marked improvement in renal survival in patients with severe IgA-N was also observed (p=0.0003). Multivariate analysis indicated that diagnosis year was a significant factor for ESRD-free survival independently of baseline characteristics. The results of this study show that there has been an improvement in terms of renal survival in Japanese children with IgA-N.

Steroid Treatment for Severe Childhood IgA Nephropathy: A Randomized, Controlled Trial

A previous trial showed that treatment of children with severe IgA nephropathy (IgAN) using prednisolone, azathioprine, heparin-warfarin, and dipyridamole for 2 yr early in the course of disease reduced the severity of immunologic renal injury and prevented any increase in the percentage of sclerosed glomeruli. This study compared the effects of prednisolone, azathioprine, warfarin, and dipyridamole (combination) with those of prednisolone alone in 80 children with newly diagnosed IgAN that showed diffuse mesangial proliferation. Patients were randomly assigned to receive either the combination or prednisolone alone for 2 yr. The primary end point was the disappearance of proteinuria, defined as urinary protein excretion <0.1 g/m2 per d, and the secondary end points were urinary protein excretion at the end of treatment, the change in the percentage of sclerosed glomeruli during the trial, and adverse effects. The two study groups were similar in terms of baseline characteristics. Thirty-nine of the 40 patients who received the combination and 39 of the 40 who received prednisolone completed the trial. Thirty-six (92.3%) of the 39 patients who received the combination and 29 (74.4%) of the 39 who received prednisolone reached the primary end point by the 2-yr follow-up point (P = 0.007 log-rank). The percentage of sclerosed glomeruli was unchanged in the patients who received the combination but increased from 3.1 +/- 4.8 to 14.6 +/- 15.2% in the prednisolone group (P = 0.0003). The frequency of adverse effects was similar in the two groups. It is concluded that combination treatment may be better for severe IgAN than treatment with prednisolone alone.

Rapidly progressive IgA nephropathy

A 14-year-old boy presented with macroscopic hematuria and a rapid deterioration in renal function. Percutaneous renal biopsy demonstrated severe crescentic IgA nephropathy (IgAN) with extensive (88%) glomerular crescent formation. After started intravenous administration of high-dose pulse methylprednisolone, severe nausea and general malaise accompanied by a rapid increase in Blood Urea Nitrogen (BUN) and serum creatinine levels appeared, however, the renal function ameliorated rapidly and fully revovered by following oral administration of corticosteroid. The clinical presentation of our case seems to be very remarkable compared to previously reported cases of rapidly progressive IgAN.

Clinicopathological correlation of childhood IgA glomerulonephritis presenting diffuse endocapillary proliferation

The aim of the present study is to clarify the clinicopathological correlation of childhood IgA glomerulonephritis (GN) presenting diffuse endocapillary proliferation. Twenty-seven patients were used in the present study. The 27 patients were divided into three groups (mild, moderate and severe) according to the percentage of glomeruli displaying global endocapillary proliferation per total glomeruli at the first biopsy. The degree of both cellular crescent and lysis of the glomerular basement membrane (GBM) at the first biopsy was semiquantitatively evaluated. The degree of cellular crescent and lysis in the GBM was greater in the severe group than in the mild group. The degree of lysis of the GBM positively correlated with the degree of distribution of endocapillary proliferation. The degree of glomerular sclerosis at the second biopsy was greater in the severe group compared with the other two groups. The severity of cellular crescent at the first biopsy positively correlated with that of glomerular sclerosis at the second biopsy. Multiple logistic regression analysis indicated that the risk of glomerular sclerosis at the second biopsy was 19-fold higher in the odds ratio in the severe group compared with the mild group. In conclusion, the progression of glomerular sclerosis in serial biopsy is dependent on the degree of distribution of endocapillary proliferation and the severity of cellular crescents at the first biopsy in childhood IgA GN presenting diffuse endocapillary proliferation.

Pediatric IgA nephropathies: clinical aspects and therapeutic approaches

The pediatric IgA nephropathies are IgA nephrothapy (Berger's Disease) and Henoch-Schönlein purpura nephritis. Both conditions are reviewed in detail with respect to epidemiology, clinical features, outcome, prognostic markers, and therapeutic approaches. For both conditions variable disease severity and outcome along with the lack of conclusive evidence for efficacy of treatment based on randomized clinical trials makes it difficult to make strong recommendations regarding therapy.

A-20C angiotensinogen gene polymorphism and proteinuria in childhood IgA nephropathy

We have previously reported that the TT genotype of the angiotensinogen gene and the ID/DD genotype of the angiotensin-converting enzyme gene are associated with increased severity of proteinuria in IgA nephropathy in Japanese children. Recently it was reported that polymorphism at -20 from adenine to cytosine in the angiotensinogen gene, increasing the level of this transcript, was associated with the progression of renal dysfunction in adult IgA nephropathy. We therefore investigated whether this polymorphism is involved in IgA nephropathy in Japanese children. We identified this polymorphism in 105 children with IgA nephropathy and 119 healthy adults using polymerase chain reaction/restriction fragment length polymorphism analysis. At the time of biopsy, all patients had normal blood pressure and renal function. There were no differences in the genotypes and allele frequencies of this polymorphism between patients with IgA nephropathy and controls. The number of patients with the AC/CC genotype showing heavy proteinuria (>or=1.0 g/day per m(2) body surface area) at biopsy was significantly higher than that with the AA genotype ( P=0.039, chi-squared test). The AC/CC genotype of this polymorphism may be associated with an increased severity of proteinuria, suggesting that this polymorphism may play a significant role in the progression of IgA nephropathy in Japanese children.

Efficacy of immunosuppressive therapy in IgA nephropathy presenting with isolated hematuria

The role of immunosuppressive therapy in the management of IgA nephropathy (IgAN) remains controversial. No consensus has yet emerged on the specific treatment of IgAN and this is mostly related to the lack of complete understanding of the multifactorial pathogenesis of the disease. Choice of appropriate therapeutic agents is further limited by the difficulty in identifying patients who would most likely benefit from therapy. Immunosuppressive therapy has not been recommended in patients with isolated hematuria and well preserved renal function because of their generally favourable prognosis and there are no clinical trials in this area. Considering that mild IgAN may be an early stage of the disease and can be reversed by immunosuppressive agents we have used prednisolone and azathioprine in patients with isolated hematuria in a prospective, randomized, controlled study since 1988. In this prospective study we have evaluated the effect of prednisolone with azathioprine on the clinical course of IgAN and its impact on histologic parameters and prevention of progression in patients with isolated hematuria. We studied 43 biopsy-proven IgAN patients (29 males and 14 females, aged between 13-63 years, mean age 28+/-6) with isolated hematuria and well-preserved renal function (Ccr 89.2+/-10.2 ml/min). The patients were assigned to two groups: 21 patients received prednisolone (40 mg/day) and azathioprine (100 mg/day) orally for four months (group A) and 22 patients received no specific treatment for IgAN and served as a control group (group B). In Group A prednisolone was reduced to 20 mg/day at the end of the second month, then slowly tapered over a two-month period and stopped. The median duration of follow-up was 60 months (range 12-120 months). At the end of the therapy hematuria disappeared in 17 patients. In three patients who did not respond to therapy, microscopic hematuria persisted. Of the 22 patients of group B, three had episodes of gross hematuria and proteinuria >500 mg/day. No significant changes in biochemical profile were observed in either group. Thirteen patients (eight from the treated, five from the untreated group) underwent a repeat biopsy after 12+/-6 months (range 10-25). An improvement of histopathological features was noted in Group A, while deterioration was noted in Group B. We conclude that early treatment with prednisolone and azathioprine appears to be beneficial in preventing the progression of immunologic renal injury and in improving histopathological features in IgAN patients with isolated hematuria.

Association of the uteroglobin gene polymorphism with IgA nephropathy

Immunoglobulin A (IgA) nephropathy results from the abnormal deposition of IgA in the renal mesangium. Genetic factors may be involved in the development and progression of IgA nephropathy. Uteroglobin (UG) is a steroid-inducible, cytokine-like, multifunctional protein with anti-inflammatory and immunomodulatory properties. The knockout or antisense mouse of the UG gene develops renal disease similar to IgA nephropathy. We analyzed the UG gene as a candidate for a predisposing factor in 61 Japanese patients with IgA nephropathy (23 children, 38 adults) and detected only the G38A mutation. The gene frequency of the G38A mutation in patients was 0.43, not significantly different from the frequency of 0.36 in healthy controls. However, the frequency of patients homozygous for G38A was twice that of controls, and a significant increase was seen in child patients. We measured serum UG levels in patients and healthy adults. A significant decrease in serum UG levels in homozygotes of G38A compared with homozygotes of G38 was detected only in adult women patients and controls. There is no information on where serum UG is produced or how UG may work in association with IgA nephropathy. However, it is possible that the effect of G38A may be apparent under such stimulation as sex steroids or infections, and homozygotes of the G38A mutation cannot produce sufficient UG in response to stimulation and may be predisposed to IgA nephropathy, especially in childhood.

Primary IgA nephropathy in children: association of clinical and pathological findings with prognosis

Primary IgA nephropathy is a disease characterized by recurrent macroscopic or microscopic hematuria and diffuse mesangial IgA deposition. Although IgA nephropathy had previously been suggested to have a benign prognosis, long term follow-up of the patients revealed that it might lead to chronic renal failure. In this study, the association of the initial clinical and laboratory findings with the renal histological changes was evaluated in 14 cases with primary IgA nephropathy who were at follow-up with a mean duration of 43.07 +/- 16.88 months. Finally the correlation between the clinicopathological findings and prognosis was investigated. In 92.8% of the patients, macroscopic hematuria was the presenting complaint. Proteinuria was detected in 42.9% of the cases mild proteinuria in 14.3% and moderate in 28.6%. Renal biopsy specimens, evaluated according to Churg-Sobin's classification, showed grade 1 changes in 35.7% cases, grade 2 in 35.7%, grade 3 in 14.3% and grade 4 in 14.3%. Both the patients with grade 4 histology had moderate proteinuria, and developed chronic renal failure requiring hemodialysis. Prognosis was found to be associated with the degree of proteinuria and the severity of the histopathological findings.

Role of platelet-activating factor acetylhydrolase gene mutation in Japanese childhood IgA nephropathy

Platelet-activating factor (PAF) is a potent mediator of inflammatory injury in renal diseases. PAF is degraded to inactive products by PAF acetylhydrolase. Recently, a point mutation (G to T transversion) of the PAF acetylhydrolase gene was observed at position 994, and this mutation was found to contribute to the variability in plasma PAF levels, with undetectable plasma PAF acetylhydrolase activity occurring in homozygous patients (TT genotype) and reduced levels of activity in heterozygous patients (GT genotype). Therefore, we investigated the effect of the PAF acetylhydrolase gene mutation on the pathogenesis and progression of immunoglobulin A (IgA) nephropathy. Genomic DNA was obtained from 89 children with IgA nephropathy and 100 controls. We identified the PAF acetylhydrolase gene mutation (G994T) by polymerase chain reaction. There was no significant difference in genotypic frequency between patients and controls. However, urinary protein excretion at the time of biopsy was significantly greater in patients with the GT/TT genotypes than in those with the GG genotype. The percentage of glomeruli with mesangial cell proliferation was significantly greater in patients with the GT/TT genotypes than in those with the GG genotype. These results indicate the PAF acetylhydrolase gene mutation may influence the degree of proteinuria and the extent of mesangial proliferation in the early stage of childhood IgA nephropathy.

IgA nephropathy

Immunoglobulin A nephropathy results from the abnormal deposition of IgA immunoglobulin in the glomerulus, which leads to the characteristic presentation of painless hematuria. It is the most common glomerulonephritis worldwide. Originally described 30 years ago, it was thought to follow a benign course. We now know that IgA nephropathy leads to progressive renal destruction in about one third of affected patients. Alteration in glycosylation of circulating IgA may be an important pathophysiologic mechanism that predisposes to IgA deposition, although how this leads to parenchymal damage remains unclear. Hypertension, high-grade proteinuria, and elevated serum creatinine levels are known risk factors for progressive renal destruction. In addition to these well-recognized risk factors, there appear to be genetic variants, particularly within the angiotensin-converting enzyme gene, that portend a worse outcome.

A controlled trial of combined therapy for newly diagnosed severe childhood IgA nephropathy. The Japanese Pediatric IgA Nephropathy Treatment Study Group

The most appropriate treatment for patients with IgA nephropathy is controversial. Treatment with prednisolone, azathioprine, heparin-warfarin, and dipyridamole early in the course of disease may prevent immunologic renal injury in children with severe IgA nephropathy. To determine whether similar results can be obtained with a combination of just heparin-warfarin and dipyridamole, the effects of such treatment were compared to those of treatment with prednisolone, azathioprine, heparin-warfarin, and dipyridamole in 78 children with newly diagnosed IgA nephropathy showing diffuse mesangial proliferation. The patients were randomly assigned to receive either prednisolone, azathioprine, heparin-warfarin, and dipyridamole for 2 yr (group 1) or heparin-warfarin and dipyridamole for 2 yr (group 2). All of the 40 patients in group 1 and 34 of the 38 patients in group 2 completed the trial. The mean urinary protein excretion fell in group 1 patients (P < 0.0001), but remained unchanged in group 2 patients. The mean serum IgA concentration was reduced in group 1 patients (P = 0.0002), but was unchanged in group 2 patients. BP and creatinine clearance were normal at the end of the trial in all but one group 2 patient, who developed chronic renal insufficiency. The percentage of glomeruli showing sclerosis was unchanged in group 1 patients, but increased in group 2 patients (P = 0.006). The intensity of mesangial IgA deposits decreased in group 1 patients (P = 0.02), but remained unchanged in group 2 patients. In conclusion, the present study shows that treatment of children with severe IgA nephropathy with prednisolone, azathioprine, heparin-warfarin, and dipyridamole for 2 yr early in the course of disease reduces immunologic renal injury and prevents increase of sclerosed glomeruli.

Age-related histologic alterations after prednisolone therapy in children with IgA nephropathy

To examine whether the age of onset of clinical symptoms in childhood IgA nephropathy may affect changes of histologic alterations after receiving prednisolone therapy, an evaluation of glomerular lesions seen in biopsy specimen was done. Eighteen children with IgA nephropathy met study criteria. They received alternate-day prednisolone therapy within a month after the first renal biopsy. Renal biopsies were done at presentation and repeated at a mean interval of 23 months. The patients were grouped as follows: Group A, 8 cases which showed clinical symptoms at the age of 9 or under; Group B, 10 cases which showed the symptoms at the age of 10 or over. At the initial presentation, histologic indices including a percentage of mesangial area occupying glomeruli (the M/G ratio) in the 2 groups did not show a significant difference. The activity score and the M/G ratio in the group A decreased significantly at the second biopsies (4.6+/-0.9 vs. 1.8+/-1.0 and 25.7+/-6.1% vs. 21.4+/-2.7%, respectively), while in the group B did not. These observations may indicate the age of onset of clinical symptoms in childhood IgA nephropathy affects changes of histologic alterations after receiving prednisolone therapy.

IgA nephropathy: long-term prognosis for pediatric patients

OBJECTIVE

The determination of the ultimate prognosis for patients with IgA nephropathy diagnosed in childhood requires long-term follow-up of identified patients. The purpose of this study was to obtain such follow-up for patients from two centers where the disease has been diagnosed for more than 20 years.

METHODS

Clinical data at the apparent onset of symptoms and renal histologic data were obtained for 103 patients in whom IgA nephropathy was diagnosed before age 18 years. Clinical status at last follow-up was obtained from office records or from direct contact with the patient. Predicted kidney survival was determined by the Kaplan-Meier method. Follow-up of more than 10 years from the time of biopsy was available for 40 of the patients.

RESULTS

Fourteen of the patients have progressed to end-stage renal disease; three others have progressive chronic renal insufficiency as defined by an estimated creatinine clearance of less than 50 ml/min per 1.73 m2. Severity of the renal histologic findings and the degree of proteinuria at the time of biopsy were associated with poor outcome. For all patients, predicted kidney survival from the time of apparent onset was 94% at 5 years, 87% at 10 years, 82% at 15 years, and 70% at 20 years. Age at clinical onset and gender were not associated with poor outcome, but black race and severity of renal histologic findings were.

CONCLUSION

With follow-up into adulthood, the outcome for pediatric patients with IgA nephropathy appears to be as serious as that reported in adult patients. Follow-up of a pediatric patient with persistent clinical findings should be maintained after the patient's care is transferred to a physician caring for adults.

Long-term prognosis and prognostic factors of Japanese children with mesangial proliferative glomerulonephritis without IgA deposition

Mesangial proliferative glomerulonephritis without IgA deposition (non-IgA MesPGN) is commonly detected in biopsy specimens, but the clinicopathological correlation with the long-term prognosis still remains obscure. The aim of our study is to elucidate the long-term prognosis and the clinicopathological prognostic factors in patients with non-IgA MesPGN. We mailed questionnaires to 122 patients with primary glomerulonephritis who were biopsied between 1963 and 1975. Information was obtained from 109 of these 122 patients and 55 were histologically rediagnosed as having non-IgA MesPGN. The histological alterations of glomeruli and tubulointerstitium were classified into five grades. The mean period between the biopsy and the questionnaires was 20.5 years. Six of the 55 patients with non-IgA MesPGN developed end-stage renal failure and histopathological alterations of renal biopsies from these six patients were classified into grade IV or V. The presence of hypertension, heavy proteinuria of over 2+ or renal insufficiency at the biopsy was related to the severe histological changes, a grade of IV or V and to a poor prognosis. The renal survival rate of all the 55 patients was 88.3% at 20 years after the biopsy, while that of the 12 patients with severe histological changes was 48.6%. Although non-IgA MesPGN is considered to be a heterogeneous disease, we cannot ignore the incidence of this disease and thus consider it to be one of the important primary glomerulonephritides that occur in childhood.

Prognostic indicators in children with IgA nephropathy--report of the Southwest Pediatric Nephrology Study Group

Investigators in 13 pediatric nephrology centers reviewed clinical and pathological features in 218 children and adolescents with IgA nephropathy (IgAN), with particular emphasis on 80 patients who had follow-up periods of at least 4 years. Potential prognostic markers in the 80 children were compared between 12 (15%) who developed end-stage renal disease (ESRD) versus 68 who did not. The relationship between clinical and pathological features and the subsequent development of ESRD was examined using stepwise linear discriminant analysis in addition to standard univariate analysis. Seven variables were found to be predictive of ESRD: the presence of glomerular sclerotic changes, especially when this was associated with proliferation or sclerosis in 20% or more of the glomeruli; black race; hypertension at biopsy; proteinuria at biopsy; age at presentation; crescents; male sex. Using the resulting discriminant function, development of ESRD could be correctly predicted in 95% of the subjects. We conclude that ESRD is more common in American children with IgAN than was realized previously. Risk factors previously documented in adult studies have been confirmed, especially the presence of glomerular sclerosis, proteinuria, and hypertension.

Clinical features and prognosis in childhood IgA nephropathy

Clinical variables and laboratory and histologic findings were evaluated in 53 children with IgA nephropathy, of whom 44 were followed for a mean period of 6.2 years (range 1.2-14). At the end of the follow-up 8 patients (18.2%) had had no urinary anomalies for at least 1 year (stage A disease), 28 (63.6%) had microscopic hematuria with proteinuria < 1 g/m2/day (stage B), 5 (11.4%) had proteinuria > 1 g/m2/day (stage C), and 3 (6.8%) had chronic renal insufficiency (stage D). None of the patients in apparent remission presented with elevated serum IgA levels at disease onset. Gross or microscopic hematuria at onset correlated with stage A/B disease at the end of follow-up (p < .05) whereas the presence of proteinuria or nephritic syndrome at onset correlated with stage C/D disease after follow-up (p > .05). Presenting features of gross or microscopic hematuria without or with proteinuria (< 0.5 g/m2/day) correlated (p < .001) with minimal glomerular abnormalities at biopsy, whereas patients with nephritic syndrome had more severe histologic pictures. The presence of proliferative glomerulonephritis with crescents correlated (p < .0001) with poor outcome. The results demonstrate that the prognosis of IgA nephropathy in childhood must be viewed with caution and that outcome correlates with mode of onset and severity of the renal pathology.

The natural history of screening detected IgA glomerulonephritis in children

The clinical course of 43 children with IgA glomerulonephritis detected by mass urine screening was followed for a mean period of 8.1 years. Histological findings were graded according to the severity of glomerular and tubulointerstitial lesions. There was no correlation in the severity of histological grade and clinical outcome between subjects with microscopic hematuria and those with microscopic hematuria and proteinuria nor between those with and without one or more episodes of macroscopic hematuria during the follow-up period. None of the 35 children with proteinuria less than or equal to 1 g/m2/day had severe histological findings or developed renal impairment. In contrast, the 8 children with proteinuria greater than 1 g/m2/day had moderate and severe histological findings. Four of these 8 children developed hypertension or renal insufficiency during the follow-up period. Our study indicates that the outcome of screening detected IgA glomerulonephritis in children correlates with the level of proteinuria and the severity of renal pathology.

Asymptomatic constant isolated proteinuria in children

The clinical features, renal biopsy findings, and subsequent course in 53 children with asymptomatic constant isolated proteinuria were studied retrospectively (1) to determine the prevalence of renal pathologic abnormalities among these children, (2) to identify those clinical characteristics that may enable recognition of children with an increased likelihood of having renal pathologic abnormalities, and (3) to assess the clinical course. All biopsy specimens were examined by light, immunofluorescence, and electron microscopy. Twenty-five patients (47%) had significant glomerular changes (15 had focal segmental glomerulosclerosis, 4 IgA nephropathy, 3 diffuse mesangial proliferative glomerulonephritis without IgA deposition, and 3 membranous glomerulonephritis), and 28 had minimal glomerular changes. There were no differences between the patients with significant glomerular changes and those with minimal glomerular changes with regard to clinical and laboratory findings except for a predominance of boys in the former group. At the latest follow-up, seven patients with significant glomerular changes, but none with minimal glomerular changes, had chronic renal impairment. Because of the high incidence of significant glomerular changes and the high rate of progression to chronic renal impairment, we believe that a renal biopsy is indicated for a child with asymptomatic constant isolated proteinuria.

Course and long-term outcome of idiopathic IgA nephropathy in children

The long-term outcome of idiopathic IgA nephropathy (IgAN) in children was investigated with regard to clinical course and biopsy changes. All patients with biopsy-verified IgAN (diagnosed by kidney biopsy 1970-1985) at three children's clinics in Sweden were included in the study. Thirty-four (10 females, 24 males), out of a total of 72 patients, had a follow-up period of 8 years or more (10.7 +/- 1.9 years, range 8-14). After this duration of follow-up, urine abnormalities were found in 47% (group A), proteinuria in 35%, hypertension in 9%, and decreased glomerular filtration rate (GFR) in 3% of patients. However, 53% had no clinical signs of disease (group B). GFR depression at the time of clinical presentation of IgAN was more common in group A than in group B (P = 0.017). At the first renal biopsy, which was performed after the same duration of IgAN in both groups, focal segmental glomerular changes were more often found in group A (P = 0.017), while diffuse proliferative changes were more common in group B (P = 0.031). The course of the IgAN was thus often very protracted, with some children developing hypertension as well as decreased renal function. However, after a period of 8 years or more of follow-up half of the patients did not show any clinical signs of the disease, which may indicate low disease activity or, possibly, recovery.

An approach to the evaluation and treatment of microscopic hematuria

Persistent microscopic hematuria in children is most often benign or untreatable. The evaluation of microscopic hematuria in an otherwise healthy child need not require invasive and costly laboratory studies. The initial evaluation must look for signs of life-threatening causes of hematuria, i.e., hypertension, edema, oliguria, or significant proteinuria. If these are absent, a stepwise evaluation is suggested, which includes microscopic examination of the urine for red blood cell casts, a test for proteinuria, serum creatinine, and serial follow-up. Renal biopsy may establish a diagnosis but rarely changes the treatment in a child with asymptomatic isolated microscopic hematuria.

Screening for proteinuria and hematuria in school children--is it possible to reduce the incidence of chronic renal failure in children and adolescents?

In this study we evaluated the incidence of chronic renal failure in children with asymptomatic proteinuria and/or hematuria detected by a mass screening program in school and kindergarten. A total of four thousand and three children, aged from 2 to 18 years old was referred to our institute between 1977 and 1990. Of them, 4 cases were AGN, 8 cases Alports' syndrome, 7 cases FGN, 7 cases F(s)GS, 3 cases HSPN, 148 cases IgA nephropathy, 12 cases MN, 24 cases MPGN (including 7 cases of focal type MPGN), 1 case lupus nephritis, and others. Of these children 2 of 8 cases of Alports' syndrome, one of 7 cases of FGS, 6 of 148 cases of IgA nephropathy and none of 24 cases of MPGN developed chronic renal failure. It is true that the incidence of chronic renal failure in children with various kinds of renal disease detected by a mass screening program is lower than that of symptomatic children. However, since we do not have yet any specific treatment in most cases and also since the follow-up period is not long enough, the definite conclusion that a mass screening program can alter the prognosis of children with renal diseases cannot be drawn except for some particular lesions such as MPGN, especially the focal type. Further study including a much larger population of patients is necessary.

A quantitative analysis of the mesangium in children with IgA nephropathy: sequential study

Quantitative analysis of the mesangial matrix and cells was performed on serial renal biopsies from 41 children with IgA nephropathy. In the repeat renal biopsy, nine patients showed a significant increase of mesangial matrix, 29 showed no change and in three there was a significant decrease. Eight of the nine patients (89 per cent) with a matrix increase had persistent proteinuria at the second biopsy, whereas only 14 of the 32 (44 per cent) without a matrix increase had persistent proteinuria (P less than 0.05). Although the mesangial matrix increased in patients with persistent proteinuria, there was no decrease in patients with clinical remission. In contrast to the mesangial matrix, mesangial cells significantly decreased in 23 patients, did not change in 16, and significantly increased in only two in the second biopsy. These findings suggest that mesangial matrix increase is usually an irreversible change and that persistent proteinuria is associated with matrix increase with worsening in glomerular morphology and clinical outcome. This study indicates the importance of serial renal biopsy in children with IgA nephropathy with persistent proteinuria.

Asymptomatic haematuria and proteinuria: renal pathology and clinical outcome in 54 children

In a mass screening programme, 54 children with haematuria and proteinuria were detected and evaluated by clinical findings and renal histology. IgA glomerulonephritis (GN) occurred in 29 patients, diffuse mesangial proliferative GN (DPGN) in 16, membranous GN (MGN) in 4, membranoproliferative GN (MPGN) in 3, and focal segmental glomerular sclerosis (FSGS) was seen in 2. Of the 35 children with proteinuria less than or equal to 1 g/m2 per day, 21 with IgA GN and 14 with DPGN had only mild to moderate glomerular changes. None of these children had developed renal impairment after a mean period of 6.5 years (range 5-10 years). On the other hand, 8 children with IgA GN, 2 with DPGN, 4 with MGN, 3 with MPGN, and 2 with FSGS had proteinuria that exceeded 1 g/m2 per day. The biopsy specimens from these children showed moderate to severe glomerular changes, and 7 of these children had hypertension or renal impairment during the period of evaluation. This study suggests that a poor outcome correlates with the level of proteinuria and the severity of renal pathology in children with haematuria and proteinuria.

IgA nephropathy: clinical features and natural history--a pediatric perspective

This review describes the spectrum of clinical features observed in pediatric patients with IgA nephropathy (IgAN) in different parts of the world. The typical clinical presentation consists of an episode of macroscopic hematuria within 24 to 48 hours of an upper respiratory infection. However, many children who present with macroscopic hematuria are subjected to a battery of urologic studies before the appropriate procedure is performed. This sequence highlights the lack of awareness of IgAN among pediatricians, family practitioners, and urologists. The finding of microscopic hematuria or, less commonly, proteinuria, in a urinalysis carried out as part of a school screening program is the most frequent "presentation" of IgAN in Japanese children. However, it is possible that many children with IgAN expressed as microscopic hematuria and/or mild proteinuria remain undiagnosed in this country because routine urinalysis is not done and many pediatric nephrologists are reluctant to perform renal biopsies when such children are identified. It is now recognized that some patients with IgAN and nephrotic range proteinuria exhibit a state of steroid responsiveness. The renal biopsy in such patients often reveals "minimal change." Several recent studies have shown progressive deterioration in approximately 10% of all pediatric patients found to have IgAN and in 15% to 30% of the subset of patients with more severe histologic findings. Hypertension and proteinuria are observed frequently in patients who progress to chronic renal failure. It is proposed that multicenter collaborative studies be designed to evaluate proposed therapies for children with IgAN associated with proliferative glomerular lesions, particularly those in whom hypertension, proteinuria, and depressed glomerular filtration rate are found.

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.

Mesangial changes in IgA nephropathy in children

The mesangial changes in 92 renal biopsy specimens from 81 children with IgA nephropathy were correlated with the clinical and the other renal biopsy findings. Three types of mesangial changes were identified: mesangial hypercellularity was predominant compared with the increase in matrix in 34 biopsy specimens (type A), the degrees of mesangial hypercellularity and matrix increase were similar in 36 (type B) and matrix increase was predominant in 22 (type C). The interval between the onset of disease and biopsy was significantly shorter in biopsies with type A mesangial changes (P less than 0.01) and significantly longer in those with type C (P less than 0.01). Serial pathologic observations revealed that predominant mesangial hypercellularity was almost exclusively seen in the initial biopsy but predominant matrix increase was usually seen in the follow-up biopsy. The percentage of glomeruli showing sclerosis was significantly higher in biopsies with type C mesangial changes (P less than 0.05). At the latest follow-up, 58% of the patients showing type A and 57% showing type B lost their proteinuria, whereas only 9% showing type C lost their proteinuria (P less than 0.01). These findings suggest that predominant mesangial hypercellularity is characteristic of the early lesion of childhood IgA nephropathy, and progression of disease leads to gradual decrease of mesangial cellularity and increase of matrix with sclerosis.

Nonfamilial hematuria associated with glomerular basement membrane alterations characteristic of hereditary nephritis: comparison with hereditary nephritis

Characteristic ultrastructural alterations of the glomerular basement membrane (GBM) have been reported in hereditary nephritis and in children without a family history of renal disease. The clinical features, renal biopsy findings, and subsequent course were studied retrospectively in 48 children with such GBM changes to compare findings in those with and without a family history of nephritis and to determine the significance of the GBM changes in patients with nonfamilial disease. All 48 patients had hematuria. For 30, there was hematuria in at least one other member of the family (familial hematuria group); for 18, there was no familial incidence. There were no differences between the two groups with regard to clinical and pathologic findings. At the latest follow-up six boys with familial hematuria and three boys with nonfamilial hematuria had reduced renal function, and nine boys with familial hematuria and four boys and one girl with nonfamilial hematuria had neurosensory deafness. Our study results show that children with these GBM changes, with or without a family history of hematuria, tend to have a progressive course, with frequent occurrence of neurosensory deafness, and that the prognosis is more severe in boys. These observations suggest that such GBM changes in patients with nonfamilial hematuria may represent new mutations for hereditary nephritis.

Immunoelectron microscopic study of childhood IgA nephropathy and Henoch-Schönlein nephritis

Renal biopsy specimens from 11 children with Henoch-Schönlein nephritis and 14 with IgA nephropathy were examined by immunoelectron microscopy. The distribution of IgA reaction product (RP) was found to be similar to that of the electron-dense deposits seen with conventional electron microscopy. Deposits of IgA-RP were present in the mesangium and in the subendothelial region of the peripheral glomerular capillary wall in all patients. Subepithelial deposits of IgA-RP were seen in 12 patients. Deposits of IgG-RP were rare and no deposits of IgM-RP were observed. Deposits of C3-RP were found frequently, although they were smaller and less extensive than deposits of IgA-RP. There was no significant difference between Henoch-Schönlein nephritis and IgA nephropathy with regard to immunoelectron microscopy findings. These observations suggest that Henoch-Schönlein nephritis and IgA nephropathy are both forms of mesangiopathic glomerulo-nephritis caused by immune complexes, mainly composed of IgA.