Relationship between Gd-IgA1 and TNFR1 in IgA nephropathy and IgA vasculitis nephritis in children - multicenter study.

AIM OF THE STUDY: To evaluate the relationship between serum Gd-IgA1 (sGd-IgA1) and serum and urine TNFR1 (sTNFR1, uTNFR1) levels as possible prognostic factors in IgA nephropathy (IgAN) and IgA vasculitis nephritis (IgAVN). MATERIAL AND METHODS: From 299 patients from the Polish Registry of Pediatric IgAN and IgAVN, 60 children (24 IgAN and 36 IgAVN) were included in the study. The control group consisted of 20 healthy children. Proteinuria, haematuria, serum creatinine as well as IgA and C3 levels were measured and glomerular filtration rate (GFR) was calculated at onset and at the end of the follow-up. Kidney biopsy findings were evaluated using the Oxford classification. Serum Gd-IgA1 and serum and urine TNFR1 levels were measured at the end of follow-up. RESULTS: Serum Gd-IgA1 level was significantly higher in IgAN and IgAVN patients in comparison to the control group. Urine TNFR1 was significantly higher in IgAN than in IgAVN and the control group. We did not observe any differences in sTNFR1 level between IgAN, IgAVN and control groups. We found a positive correlation between Gd-IgA1 and creatinine (r = 0.34), and negative between Gd-IgA1 and GFR (r = -0.35) at the end of follow-up. We observed a negative correlation between uTNFR1/creatinine log and albumin level and protein/creatinine ratio. We did not find any correlations between Gd-IgA1 and TNFR1. CONCLUSIONS: The prognostic value of sGd-IgA1 in children with IgAN and IgAVN has been confirmed. TNFR1 is not associated with Gd-IgA1 and is not a useful prognostic marker in children with IgAN/IgAVN and normal kidney function.

The Role of Complement Component C3 Activation in the Clinical Presentation and Prognosis of IgA Nephropathy-A National Study in Children.

The aim of the study was to evaluate the influence of the intensity of mesangial C3 deposits in kidney biopsy and the serum C3 level on the clinical course and outcomes of IgAN in children. The study included 148 children from the Polish Pediatric IgAN Registry, diagnosed based on kidney biopsy. Proteinuria, creatinine, IgA, C3 were evaluated twice in the study group, at baseline and the end of follow-up. Kidney biopsy was categorized using the Oxford classification, with a calculation of the MEST-C score. The intensity of IgA and C3 deposits were rated from 0 to +4 in immunofluorescence microscopy. The intensity of mesangial C3 > +1 deposits in kidney biopsy has an effect on renal survival with normal GFR in children with IgAN. A reduced serum C3 level has not been a prognostic factor in children but perhaps this finding should be confirmed in a larger group of children.

[Influence of intensity, localization and type of deposits in renal biopsy for disease symptoms and follow up in children with IgA nephropathy]. / Wplyw nasilenia, lokalizacji i rodzaju zlogów w biopsji nerki na objawy kliniczne i rokowanie u dzieci z nefropatia IgA.

IgA nephropathy is the most common glomerulonephritis in the world. For diagnosis kidney biopsy is necessary. AIM: The aim of the study was assessment the significance of IgA, C3 and IgG deposits intensity and location in kidney childhood IgA nephropathy (IgAN) for the symptoms of the disease and the follow up. MATERIALS AND METHODS: Study population consisted of 81 children, average 11,45±3,99 years. IgAN was recognized based on renal biopsy, performed 1,2±1,84, median 0,5 years after the onset. We used Oxford classification (OC) to assess the severity of histopatological lesions. In renal biopsy IgA and C3 deposits were found in immunofluorescence in mesangium or in vessels of glomeruli or both, and intensity was defined 0 to +4. We analyzed: proteinuria (mg/kg/day), hematuria, creatinine, GFR (according to Schwartz formula) two times, at the onset of the disease (OOD) and at the follow up (FU). Patients were treated with: ACEI/ARB or steroids alone or with imunossupresion drugs: azathioprine (AZA), cyclophosphamide (CYC), cyclosporine A (CsA), mycopnenolate mophetil (MMF). The follow up was 3,31±2,88 years. We divided the patients into two groups, depending on the intensity of IgA deposits: G1 n=29 (+1/+2), G2 n=52 (+3/+4); depending on the localizations of these deposits, we analyzed 3 groups: A n= 39 (mesangium), B n= 15 (glomeruli vessels), C n=27 (both) and depending on the kind of deposits we analyzed 4 groups: gr. a - n=30 (only IgA), gr. b - n=37 (IgA+C3), gr. c - n=5 (IgA+IgG) gr. d - n= 9 (IgA+IgG+C3). RESULTS: At OOD and FU we not found any differences in G1 vs G2 for: age, proteinuria, GFR and OC in renal biopsy; at FU GFR<90 ml/ min/1,73 m2 FU was observed more frequently in G2 vs G1 (p=0,02). The differences in groups A,B,C and groups a,b,c,d were not found. CONCLUSIONS: Poor prognosis in childhood IgAN may also depend on the intensity of the deposits, irrespective of their location.

Long-Term Outcome of Steroid-Resistant Nephrotic Syndrome in Children.

We investigated the value of genetic, histopathologic, and early treatment response information in prognosing long-term renal outcome in children with primary steroid-resistant nephrotic syndrome. From the PodoNet Registry, we obtained longitudinal clinical information for 1354 patients (disease onset at >3 months and <20 years of age): 612 had documented responsiveness to intensified immunosuppression (IIS), 1155 had kidney biopsy results, and 212 had an established genetic diagnosis. We assessed risk factors for ESRD using multivariate Cox regression models. Complete and partial remission of proteinuria within 12 months of disease onset occurred in 24.5% and 16.5% of children, respectively, with the highest remission rates achieved with calcineurin inhibitor-based protocols. Ten-year ESRD-free survival rates were 43%, 94%, and 72% in children with IIS resistance, complete remission, and partial remission, respectively; 27% in children with a genetic diagnosis; and 79% and 52% in children with histopathologic findings of minimal change glomerulopathy and FSGS, respectively. Five-year ESRD-free survival rate was 21% for diffuse mesangial sclerosis. IIS responsiveness, presence of a genetic diagnosis, and FSGS or diffuse mesangial sclerosis on initial biopsy as well as age, serum albumin concentration, and CKD stage at onset affected ESRD risk. Our findings suggest that responsiveness to initial IIS and detection of a hereditary podocytopathy are prognostic indicators of favorable and poor long-term outcome, respectively, in children with steroid-resistant nephrotic syndrome. Children with multidrug-resistant sporadic disease show better renal survival than those with genetic disease. Furthermore, histopathologic findings may retain prognostic relevance when a genetic diagnosis is established.

Relationship between serum IgA/C3 ratio and severity of histological lesions using the Oxford classification in children with IgA nephropathy.

BACKGROUND: The aim of this study was to evaluate the usefulness of serum immunoglobulin A/complement factor 3 (IgA/C3) ratio for predicting histological severity of kidney lesions in children with IgA nephropathy (IgAN) based on World Health Organization (WHO) and the Oxford classification (OC). METHODS: We studied 89 children with IgAN with a mean age of 11.38 ± 4.1 years (range 2-18 years). Based on available medical records, we retrospectively evaluated clinical data, IgA/C3 ratio, and kidney biopsy findings using the five-grade WHO classification and the OC The mesangial hypercellularity (M), endocapillary hypercellularity (E), segmental sclerosis (S), tubular atrophy/interstitial fibrosis (T) (MEST) score (absent = 0, present = 1) calculated as the sum of M+E+S+T ranging from 0 to 4. RESULTS: Mean IgA/C3 ratio values were significantly higher (P < 0.05) in patients with M1, S1, and T1 compared with M0, S0, and T0, respectively (P < 0.05); there were no differences in the WHO classification. We found a significant positive correlation between the IgA/C3 ratio and proteinuria (r = 0.24) and determined optimal cutoff values of the IgA/C3 ratio, with a corresponding confidence interval for specific MEST scores. CONCLUSIONS: The IgA/C3 ratio in children with IgAN may be a useful marker of the severity of lesions found in kidney biopsy as evaluated using the OC.

Spectrum of steroid-resistant and congenital nephrotic syndrome in children: the PodoNet registry cohort.

BACKGROUND AND OBJECTIVES: Steroid-resistant nephrotic syndrome is a rare kidney disease involving either immune-mediated or genetic alterations of podocyte structure and function. The rare nature, heterogeneity, and slow evolution of the disorder are major obstacles to systematic genotype-phenotype, intervention, and outcome studies, hampering the development of evidence-based diagnostic and therapeutic concepts. To overcome these limitations, the PodoNet Consortium has created an international registry for congenital nephrotic syndrome and childhood-onset steroid-resistant nephrotic syndrome. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Since August of 2009, clinical, biochemical, genetic, and histopathologic information was collected both retrospectively and prospectively from 1655 patients with childhood-onset steroid-resistant nephrotic syndrome, congenital nephrotic syndrome, or persistent subnephrotic proteinuria of likely genetic origin at 67 centers in 21 countries through an online portal. RESULTS: Steroid-resistant nephrotic syndrome manifested in the first 5 years of life in 64% of the patients. Congenital nephrotic syndrome accounted for 6% of all patients. Extrarenal abnormalities were reported in 17% of patients. The most common histopathologic diagnoses were FSGS (56%), minimal change nephropathy (21%), and mesangioproliferative GN (12%). Mutation screening was performed in 1174 patients, and a genetic disease cause was identified in 23.6% of the screened patients. Among 14 genes with reported mutations, abnormalities in NPHS2 (n=138), WT1 (n=48), and NPHS1 (n=41) were most commonly identified. The proportion of patients with a genetic disease cause decreased with increasing manifestation age: from 66% in congenital nephrotic syndrome to 15%-16% in schoolchildren and adolescents. Among various intensified immunosuppressive therapy protocols, calcineurin inhibitors and rituximab yielded consistently high response rates, with 40%-45% of patients achieving complete remission. Confirmation of a genetic diagnosis but not the histopathologic disease type was strongly predictive of intensified immunosuppressive therapy responsiveness. Post-transplant disease recurrence was noted in 25.8% of patients without compared with 4.5% (n=4) of patients with a genetic diagnosis. CONCLUSIONS: The PodoNet cohort may serve as a source of reference for future clinical and genetic research in this rare but significant kidney disease.