IntroductionGDIgA1 (galactose deficient IgA1) plays a significant role in the pathogenesis of IgA nephropathy (IgAN) and Henoch-Schönlein nephritis (HSN).Aim of the studyThe aim of this study was to assess the relevance of serum GDIgA1 level as a prognostic marker in children with IgAN and HSN.Material and methods41 children were included to the study group (15 IgAN, 26 HSN) and 22 to the control group. The following parameters were evaluated at baseline and endpoint: proteinuria, erythrocyturia, serum creatinine, serum IgA, GFR. A kidney biopsy was performed in all patients and evaluated according to the Oxford Classification (1 – present, 0 – absent: M – mesangial hypercellularity; E– endocapillary hypercellularity; S – segmental sclerosis/adhesion; T – tubular atrophy/interstitial fibrosis), and was calculated as the total score (sum of M, E, S, T). At the end of follow-up, the serum GDIgA1 concentration was measured.ResultsThe serum GDIgA1 concentration in patients with IgAN and HSN was significantly higher than in the control group. No significant differences in mean proteinuria, erythrocyturia, GFR, MEST score, or GDIgA1 in serum, as well as the duration of follow-up between IgAN and HSN were observed. Baseline serum IgA concentration and time to kidney biopsy were significantly higher in children with IgAN than in children with HSN. We observed a positive correlation between GDIgA1 and IgA levels (r = 0.53), and GDIgA1 and serum creatinine levels (r = 0.5), as well as negative correlation between GDIgA1 and GFR (r = –0.37).ConclusionsSerum GDIgA1 level may have a prognostic value in children with IgAN and HSN; however, to fully elucidate its clinical potential further studies performed in larger patient cohorts are required.

The aim of this retrospective study was to assess the usefulness of potential predictors of poor prognosis in IgA nephropathy in children. The study population consisted of 55 children aged 11 ± 4 years, diagnosed on the basis of the Oxford classification and MEST score of kidney biopsy findings. Proteinuria, glomerular filtration rate (GFR), and the IgA/C3 serum ratio were assessed in all patients twice: at onset and at follow-up. The patients were treated with steroids, immunosuppressive drugs, and/or angiotensin-converting enzyme inhibitors. Follow-up was at 3.9 ± 2.9 (median 2.7) years. The patients were subdivided into two groups: with GFR <90 and ≥90 mL/min at follow-up. ROC AUC curves and logistic regression were used to evaluate the power of prognostic factors. The two groups did not differ regarding the level of proteinuria, MEST score, and the IgA/C3 ratio at onset of disease. There was a significant association between GFR reductions at onset and follow-up (AUC = 0.660; p < 0.05). In patients with nephrotic range proteinuria at onset, proteinuria at follow-up was more frequent compared with other patients (AUC = 0.760; p < 0.05), MEST score ≥3 tended to be associated with reduced GFR (AUC = 0.650; p = 0.07) but not with proteinuria (AUC = 0.608; p = 0.47), and the IgA/C3 ratio was higher (p < 0.05) at follow-up. No significant associations were found between the IgA/C3 ratio at onset and reduced GFR (AUC = 0.565; p = 0.46) or proteinuria at follow-up (AUC = 0.263; p = 0.20). We conclude that predictors of poor outcome in childhood IgAN include the following: GFR reduction, nephrotic range proteinuria at onset of disease, and high MEST score in Oxford classification of kidney biopsy. Despite a higher serum IgA/C3 ratio in children with impaired renal function in long-term follow-up, we failed to demonstrate a significant association between this ratio at onset of disease and reduced GFR or persistent proteinuria at follow-up. Thus, IgA/C3 ratio is not a good foreteller of progression of IgA nephropathy in childhood.

IgA nephropathy (IgAN) is the most common form of glomerulonephritis in pediatric population. The clinical presentation of the disease in children ranges from microscopic hematuria to end-stage kidney disease. The aim of the study was to retrospectively assess clinical and kidney biopsy features in children with IgAN. We assessed a cohort of 140 children, 88 boys, 52 girls with the diagnosis of IgAN in the period of 2000-2015, entered into the national Polish pediatric IgAN registry. The assessment included the following: proteinuria, hematuria, glomerular filtration rate (GFR), arterial blood pressure, and the renal pathological changes according to the Oxford classification and crescents formation, as modifiable and unmodifiable risk factors. The incidence of IgAN in Poland was set at 9.3 new cases per year. The mean age at onset of IgAN was 11.9 ± 4.3 years, and the most common presentation of the disease was the nephritic syndrome, recognized in 52 % of patients. Kidney biopsy was performed, on average, 1.3 ± 2.0 years after onset of disease. Based on the ROC analysis, a cut-off age at onset of disease for GFR <90 mL/min/1.73 m (risk factor of progression) was calculated as 13.9 years. Unmodifiable lesions: segmental sclerosis, tubular atrophy/interstitial fibrosis (S1, T1-2) in the Oxford classification and crescents in kidney biopsy were significantly more common in Gr 1 (>13.9 years) compared with Gr 2 (<13.9 years), despite a significantly shorter time to kidney biopsy in the former. We conclude that IgAN in children may be an insidious disease. A regular urine analysis, especially after respiratory tract infections, seems the best way for an early detection of the disease.

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.

Immunoglobulin A (IgA) vasculitis is the most common systemic vasculitis in the pediatric population. We present the case of a patient with IgA vasculitis with nephritis who developed cytomegalovirus (CMV) infection followed by Mycobacterium tuberculosis infection. In the literature, there are a few cases of IgA nephropathy accompanied by reactivation of CMV or tuberculosis. To the best of our knowledge, this is the first reported case of IgA vasculitis complicated by both CMV reactivation and tuberculosis. It is important to detect infections in patients with IgA vasculitis because they can induce and exacerbate the symptoms of the disease. Effective antimicrobial treatment facilitates the management of proteinuria and slows down the decline of renal function. Immunosuppressive therapy is a risk factor for reactivation of latent infections and makes patients more susceptible to its generalized and complicated course. This can be prevented by actively screening for hidden sites of infection.

The aim of the study was to investigate the relationship between the severity of typical clinical symptoms, severity of histopathological lesions in kidney biopsies in IgA vasculitis nephritis (IgAVN) and to propose indications for kidney biopsy in children. Material and methods This retrospective study enrolled 106 patients, included in the IgAVN registry of Polish children, diagnosed by kidney biopsy. Renal and extrarenal symptoms at onset of the disease were analyzed. Biopsy results were assessed using Oxford classifications (MEST-C). The patients were divided into 3 groups depending on the severity of proteinuria: A-nephrotic proteinuria with hematuria; B-non-nephrotic proteinuria with hematuria; C-isolated hematuria. Results The first symptoms of nephropathy were observed at the 0.7 (1–128.4) months from the onset of extrarenal symptoms. Kidney biopsy was performed on 39 (6–782) days after the onset of nephropathy symptoms. MEST-C score 4 or 5 was significantly more frequent in children from group A than in groups B and C. Significantly higher mean MEST-C score was found in patients with abdominal symptoms than without. In group A: S0 and T0 we found in significantly shorter time to kidney biopsy than in S1, T1–2 p < 0.05) and in group B the significantly shorter time in T0 compare to T1–2 p < 0.05). The ROC analysis shows that S1 changes appear in kidney biopsies in group A with cut off 21 days (AUC 0,702, p = 0.004, sensitivity 0.895 specificity 0.444) T1–2 changes after 35 days (AUC 0.685, p = 0.022, sensitivity 0.750, specificity 0.615), and in goupn B T1–2 cut off is 74 days (AUC 0,738, p = 0.002, sensitivity 0.667, specificity 0.833). Conclusions In childhood IgAVN, the severity of changes in the urine is clearly reflected in the result of a kidney biopsy. The biopsy should be performed in patients with nephrotic proteinuria no later than 3 weeks after the onset of this symptom in order to promptly apply appropriate treatment and prevent disease progression. Accompanying abdominal symptoms predispose to higher MESTC score.

This study aimed to evaluate the usefulness of vanin-1 and periostin in urine as markers of the autoimmune process in kidneys and renal fibrosis in IgA nephropathy (IgAN) and IgA vasculitis with nephritis (IgAVN). From a group of 194 patients from the Department of Pediatrics and Nephrology, who were included in the Polish Pediatric Registry of IgAN and IgAVN, we qualified 51 patients (20 with IgAN and 31 with IgAVN) between the ages of 3 and 17, diagnosed based on kidney biopsy, for inclusion in the study. All of the patients received glucocorticosteroids, immunosuppressive drugs, or renoprotective therapy. The control group consisted of 18 healthy individuals. The concentration of vanin was significantly higher in the IgAN and IgAVN groups than in the control group. The concentration of vanin/creatinine correlates positively with the level of IgA and negatively with the serum level of C3 at the end of the observation. Urinary vanin-1 concentration may be useful as a marker of the active autoimmune process in IgAN and IgAVN in children, but the study needs confirmation on a larger group of children, along with evaluation of the dynamics of this marker. Urinary periostin is not a good marker for children with IgAN and IgAVN, especially in stage 1 and 2 CKD.

The aim of the study was to determine whether an elevated IgA level at the time of the diagnosis of IgA nephropathy has an effect on the severity of kidney biopsy findings and long-term outcomes in children. We retrospectively studied 89 children with IgA nephropathy who were stratified into Group 1- elevated serum IgA and Group 2 - normal serum IgA at baseline. The level of IgA, proteinuria, hematuria, glomerular filtration rate (GFR) and hypertension (HTN) were compared at baseline and after the end of the follow-up period of 4.0 ± 3.1 years. Kidney biopsy findings were evaluated using the Oxford classification. The evaluation of treatment included immunosuppressive therapy and renoprotection with angiotensin converting-enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB), or no treatment. The elevated serum IgA was found in 46 (52 %) patients and normal serum IgA level was found in 43 (48 %) patients. No differences were found between the two groups regarding the mean age of patients, proteinuria, and the number of patients with reduced GFR or HTN at baseline. In kidney biopsy, mesangial proliferation and segmental sclerosis were significantly more common in Group 1 compared with Group 2 (p < 0.05). Immunosuppressive therapy was used in 67 % children in Group 1 and 75 % children in Group 2. The Kaplan-Meier survival curves for renal function (with normal GFR) and persistent proteinuria did not differ significantly depending on the serum IgA level at baseline. We conclude that in IgA nephropathy the elevated serum IgA at baseline may be associated with mesangial proliferation and segmental sclerosis contribute to glomerulosclerosis, but has no effect on the presence of proteinuria or on the worsening of kidney function during several years of disease course.