Early clinical course of biopsy-proven IgA vasculitis nephritis.

BACKGROUND: IgA vasculitis (IgAV) is the most common form of systemic vasculitis in childhood and frequently involves the kidney. A minority of patients with IgA vasculitis nephritis (IgAVN), especially those presenting with heavy proteinuria and/or kidney failure at onset, are at risk of chronic end-stage kidney disease. For deciding upon treatment intensity, knowledge of the short-term clinical course of IgAVN is needed to improve treatment algorithms. METHODS: For this retrospective multicenter study, the medical records of 66 children with biopsy-proven IgAVN were reviewed. Age, gender, medical history and therapeutic interventions were recorded. Laboratory data included serum creatinine, albumin, urinary protein excretion (UPE) and glomerular filtration rate (eGFR). Threshold values were determined for each parameter, full remission was defined as no proteinuria and eGFR > 90 ml/min/1.73m2. RESULTS: Median age at onset of IgAVN was 8.9 years. 14.1% of the children presented with nephrotic syndrome, 50% had an eGFR below 90 ml/min/1.73 m2 and 51.5% showed cellular crescents in renal histology. The treatment regimens varied notably. Forty-four patients were treated with immunosuppression; 17 patients with crescents or nephrotic syndrome were treated with corticosteroid (CS) pulse therapy. After 6 months, UPE had decreased from 3.7 to 0.3 g/g creatinine and the proportion of patients with a decreased eGFR had fallen from 50.0% to 35.5%. Thirteen children (26.5%) achieved full remission within 6 months. CONCLUSIONS: In most patients with IgAVN proteinuria decreases slowly and kidney function improves, but full remission is reached only in a minority after 6 months. Persistent heavy proteinuria in the first two months rarely developed into long-term proteinuria. Therefore, decisions for more intense treatment should take into account the course of UPE over time. For a comparison of treatment effects, patient numbers were too small. Prospective, randomized controlled trials are necessary to clarify risk factors and the effect of immunosuppressive therapies.

Febrile urinary tract infection after pediatric kidney transplantation: a multicenter, prospective observational study.

BACKGROUND: Febrile urinary tract infections (fUTIs) are common after kidney transplantation (KTx); however, prospective data in a multicenter pediatric cohort are lacking. We designed a prospective registry to record data on fUTI before and after pediatric KTx. METHODS: Ninety-eight children (58 boys and 40 girls) ≤ 18 years from 14 mid-European centers received a kidney transplant and completed a 2-year follow-up. RESULTS: Posttransplant, 38.7% of patients had at least one fUTI compared with 21.4% before KTx (p = 0.002). Before KTx, fUTI was more frequent in patients with congenital anomalies of kidneys and urinary tract (CAKUT) vs. patients without (38% vs. 12%; p = 0.005). After KTx, fUTI were equally frequent in both groups (48.7% vs. 32.2%; p = 0.14). First fUTI posttransplant occurred earlier in boys compared with girls: median range 4 vs. 13.5 years (p = 0.002). Graft function worsened (p < 0.001) during fUTI, but no difference was recorded after 2 years. At least one recurrence of fUTI was encountered in 58%. CONCLUSION: This prospective study confirms a high incidence of fUTI after pediatric KTx, which is not restricted to patients with CAKUT; fUTIs have a negative impact on graft function during the infectious episode but not on 2-year graft outcome.

B-Flow Sonography vs. Color Doppler Sonography for the Assessment of Vascularity in Pediatric Kidney Transplantation.

OBJECTIVE: To compare B-flow sonography (BFS) with color Doppler sonography (CDS) for imaging of kidney transplant vascularization in children. PATIENTS AND METHODS: All children receiving a kidney transplantation who underwent a protocol-based ultrasound examination (Loqiq 9, GE Medical Systems, Milwaukee, WI, USA) using the BFS and CDS technique with equal settings and probe position between January 2013 and January 2016 were retrospectively assessed (n = 40). The obtained datasets were visually graded according to the following criteria: (I) delineation of the renal vascular tree (Grade 1 - clear demarcation of interlobar, together with arcuate and interlobular vessels; Grade 2 - clear demarcation of interlobar and cortical vessels, but no distinction of interlobular from arcuate vessels; Grade 3 - only clear demarcation of interlobar vessels, Grade 4 - insufficient demarcation) (II) delineation of cortical vessel density in ventral, lateral, and dorsal part of the transplant, (III) smallest vessel-capsule distance, and (IV) maximum cortical vessel count. Comparison between methods was performed using Fisher's exact and paired sample t-tests. RESULTS: Applying a curved transducer (C1-6), BFS showed superior delineation of the renal vascular tree (p < 0.001), a lower vessel-capsule distance (p < 0.001), a higher cortical vessel count (p < 0.001), and a higher cortical vessel density in the superficial cortex (p = 0.01) than CDS. In the dorsal and lateral aspects of the transplant, cortical vessel density was lower with BFS (both p < 0.001). Using a linear high-resolution transducer (ML 6-15), no significant differences between the methods were found. CONCLUSION: Improved imaging of kidney transplant vascularization can be achieved in children by adding BFS to a standard protocol. The BFS technique is especially beneficial for overall assessment of the renal vascular tree together with the extent of cortical vascularization on curved array images. KEY POINTS: · Depiction of vascular tree and ventral cortical vessels is improved by BFS.. · The dorso-lateral cortex was better represented with CDS because of higher penetration.. · Additional monitoring with BFS improves the monitoring of transplant viability.. CITATION FORMAT: · Dammann E, Groth M, Schild R et al. B-Flow Sonography vs. Color Doppler Sonography for the Assessment of Vascularity in Pediatric Kidney Transplantation. Fortschr Röntgenstr 2021; 193: 49 - 60.

Treatment of Genetic Forms of Nephrotic Syndrome.

Idiopathic steroid-resistant nephrotic syndrome (SRNS) is most frequently characterized by focal segmental glomerulosclerosis (FSGS) but also other histological lesions, such as diffuse mesangial sclerosis. In the past two decades, a multitude of genetic causes of SRNS have been discovered raising the question of effective treatment in this cohort. Although no controlled studies are available, this review will discuss treatment options including pharmacologic interventions aiming at the attenuation of proteinuria in genetic causes of SRNS, such as inhibitors of the renin-angiotensin-aldosterone system and indomethacin. Also, the potential impact of other interventions to improve podocyte stability will be addressed. In this respect, the treatment with cyclosporine A (CsA) is of interest, since a podocyte stabilizing effect has been demonstrated in various experimental models. Although clinical response to CsA in children with genetic forms of SRNS is inferior to sporadic SRNS, some recent studies show that partial and even complete response can be achieved even in individual patients inherited forms of nephrotic syndrome. Ideally, improved pharmacologic and molecular approaches to induce partial or even complete remission will be available in the future, thus slowing or even preventing the progression toward end-stage renal disease.

Truncating Wilms Tumor Suppressor Gene 1 Mutation in an XX Female with Adult-Onset Focal Segmental Glomerulosclerosis and Streak Ovaries: A Case Report.

About 30% of children with nephrotic syndrome (NS) have inherited forms. Among them, mutations in Wilms tumor suppressor gene 1 (WT1) are a well characterized cause associated with steroid-resistant NS, Wilms tumor, and urogenital malformation in males. However, the role of WT1 mutations in adult-onset focal segmental glomerulosclerosis (FSGS) is unclear. We report the case of a 38-year-old female with FSGS. She had been diagnosed with streak ovaries during diagnostic workup for infertility. Mutational analysis identified the heterozygous mutation c.1372C>T (p.Arg458*) in WT1 and the heterozygous non-neutral polymorphism c.868G>A (p.Arg229Gln) in NPHS2. Chromosomal analysis revealed a normal 46,XX female karyotype. Our case highlights that WT1 mutations should be considered in XX females with adult-onset FSGS, especially if urogenital abnormalities are present.

Surgical complications after peritoneal dialysis catheter implantation depend on children's weight.

BACKGROUND: Surgical complications are estimated to be as high as 30%-40% during the first 8 weeks after implantation of peritoneal dialysis (PD) catheters. METHODS: 70 PD catheters which were implanted by transplant surgeons in 61 children (median age 3.3years, range 0.01-15.5years, 31 boys and 30 girls) in 2009-2014 were retrospectively reviewed. The incidence of complications and revisions during the first 6months after implantation was analyzed depending on children's weight and diagnosis. RESULTS: 17 out of 70 catheters needed a surgical revision within 6months after implantation (24.3%). Peritonitis was the most common complication affecting 18.6% of peritoneal dialysis catheters followed by obstruction and dislocation, which it occurred in 9 (12.9%) and 7 (10%) catheters, respectively. Leakage (n=5) only occurred in children with a weight of less than 10kg. The total proportion of complications was higher in children with less than 10kg of weight (P<0.001). CONCLUSION: PD is safe in children with acute renal failure and older children with chronic renal failure; however children with a weight of less than 10kg are more likely to develop complications.

Rat renal transplant model for mixed acute humoral and cellular rejection: Weak correlation of serum cytokines/chemokines with intragraft changes.

BACKGROUND: Acute renal allograft rejection remains a major cause of allograft dysfunction; especially for episodes with mixed humoral and cellular character which can be detrimental for graft survival. We established a rat RT model with exclusive and complete MHC-disparity to investigate pathomechanisms of acute rejection and evaluate serum multiplex assays as a diagnostic tool in this context. METHODS: LEW rats receive congeneic LEW.1W allografts (allo), no immunosuppression. Planned duration of the experiment was 4 weeks (n = 13 allo, n = 3 iso). To study kinetics of rejection, additional animals were sacrificed at day 7 (n = 6 allo and n = 3 iso) and day 21 (n = 3 allo). Serum cytokines and chemokine were longitudinally analyzed with multiplex assays in n = 5 allo and n = 5 controls. Allografts were assessed by histopathology, immunohisto-chemistry and PCR. RESULTS: Animals develop allograft dysfunction acute humoral rejection with additional cellular components. Donor-specific MHC-antibodies are already detectable at day seven (d7) after RT. Leukocytic graft infiltrates are dominated by macrophages and additionally consist of T-cells, B-cells and NK-cells. Increased intragraft expression of interleukin-2, interferon gamma, tumor necrosis factor alpha as well as B-cell activating factor and its receptor are observed. Of the 24 serum cytokines/chemokines, only CCL2 is significantly different (higher)in allo vs. controls at d7 (p = 0.02). CONCLUSIONS: Correlation of serum chemokines/cytokines with features of humoral and cellular rejection, as reproduced in our LEW.1W to LEW rat renal transplant model, is limited. Macrophages, B-cells and their signaling pathways deserve more attention in genesis and possibly also treatment of acute rejection.