A Genetic Risk Score Distinguishes Different Types of Autoantibody-Mediated Membranous Nephropathy

INTRODUCTION: Membranous nephropathy (MN) is the leading cause of nephrotic syndrome in adults and is characterized by detectable autoantibodies against glomerular antigens, most commonly phospholipase A2 receptor 1 (PLA2R1) and thrombospondin type-1 domain containing 7A (THSD7A). In Europeans, genetic variation in at least five loci, PLA2R1, HLA-DRB1, HLA-DQA1, IRF4, and NFKB1, affects the risk of disease. Here, we investigated the genetic risk differences between different autoantibody states. METHODS: 1,409 MN individuals were genotyped genome-wide with a dense SNV array. The genetic risk score (GRS) was calculated utilizing the previously identified European MN loci, and results were compared with 4,929 healthy controls and 422 individuals with steroid-sensitive nephrotic syndrome. RESULTS: GRS was calculated in the 759 MN individuals in whom antibody status was known. The GRS for MN was elevated in the anti-PLA2R1 antibody-positive (N = 372) compared with both the unaffected control (N = 4,929) and anti-THSD7A-positive (N = 31) groups (p < 0.0001 for both comparisons), suggesting that this GRS reflects anti-PLA2R1 MN. Among PLA2R1-positive patients, GRS was inversely correlated with age of disease onset (p = 0.009). Further, the GRS in the dual antibody-negative group (N = 355) was intermediate between controls and the PLA2R1-positive group (p < 0.0001). CONCLUSION: We demonstrate that the genetic risk factors for PLA2R1- and THSD7A-antibody-associated MN are different. A higher GRS is associated with younger age of onset of disease. Further, a proportion of antibody-negative MN cases have an elevated GRS similar to PLA2R1-positive disease. This suggests that in some individuals with negative serology the disease is driven by autoimmunity against PLA2R1

Vaccination Practices in Pediatric Dialysis Patients Across Europe. A European Pediatric Dialysis Working Group and European Society for Pediatric Nephrology Dialysis Working Group Study

Background: Data on the immunization practices in pediatric chronic kidney disease (CKD) patients are scarce. The purpose of this study was to evaluate current vaccination practices for children on dialysis across European pediatric nephrology centers. Methods: A total of 18 tertiary pediatric nephrology centers from 12 European countries were included in the study. The data on universal national immunization programs and immunization practices for children with chronic disease or risk were recorded from European Center for Disease Prevention and Control and the World Health Organization. The immunization practices and center protocols for monitoring antibody titers after vaccination in dialysis patients were obtained through a questionnaire. Results: All centers included in the study recommended immunization against hepatitis B virus (HBV), diphtheria, tetanus, pertussis, Hemophilus influenzae type b (Hib), poliomyelitis, measles, mumps, rubella (MMR), and streptococcus pneumonia in dialysis patients. In 16 centers, dialysis patients were vaccinated against influenza virus annually. HBV protective antibody titers were measured in 17 centers (during dialysis period in 14 centers, during pre-renal transplantation preparations in 14 centers or in both times in 11 centers). Hepatitis A virus (HAV) was reported to be followed in 13 centers, in 8 centers during dialysis period, and in 11 centers during pre-RTx preparations. MMR and varicella-zoster virus (VZV) protective antibody titers were measured during the dialysis period or before renal transplantation (RTx) in 12 and 15 centers, respectively, and in 6 centers both titers were checked both times. Conclusion: There are variations in vaccination practice across Europe. Children with CKD, those undergoing dialysis, and transplant candidates should receive age-appropriate vaccinations before RTx as well as before the transition to adult nephrology clinics and antibody levels should be monitored to evaluate the immunization status before and after RTx. (C) 2017 S. Karger AG, Basel.Peer reviewe

Hemodialysis in children with ventriculoperitoneal shunts: prevalence, management and outcomes

Peer reviewe

The genetic architecture of membranous nephropathy and its potential to improve non-invasive diagnosis

Membranous Nephropathy (MN) is a rare autoimmune cause of kidney failure. Here we report a genome-wide association study (GWAS) for primary MN in 3,782 cases and 9,038 controls of East Asian and European ancestries. We discover two previously unreported loci, NFKB1 (rs230540, OR = 1.25, P = 3.4 × 10-12) and IRF4 (rs9405192, OR = 1.29, P = 1.4 × 10-14), fine-map the PLA2R1 locus (rs17831251, OR = 2.25, P = 4.7 × 10-103) and report ancestry-specific effects of three classical HLA alleles: DRB1*1501 in East Asians (OR = 3.81, P = 2.0 × 10-49), DQA1*0501 in Europeans (OR = 2.88, P = 5.7 × 10-93), and DRB1*0301 in both ethnicities (OR = 3.50, P = 9.2 × 10-23 and OR = 3.39, P = 5.2 × 10-82, respectively). GWAS loci explain 32% of disease risk in East Asians and 25% in Europeans, and correctly re-classify 20-37% of the cases in validation cohorts that are antibody-negative by the serum anti-PLA2R ELISA diagnostic test. Our findings highlight an unusual genetic architecture of MN, with four loci and their interactions accounting for nearly one-third of the disease risk

Genome wide association study in steroid sensitive nephrotic syndrome

Steroid sensitive nephrotic syndrome (SSNS), the most common form of nephrotic syndrome in childhood is considered a complex disease with the immune system playing a critical role in its development. This is supported by recent molecular findings showing an association with classical human leukocyte antigen; yet, the exact nature of the disease, specifically the genetic architecture outside the HLA region, has not been elucidated. With this thesis we aimed to explore the genetics of SSNS by performing a genome-wide association study on a cohort of 422 European cases and 5642 ethnically matched controls with more than 5 million high-quality imputed genome-wide markers. Our results revealed three loci achieving genome-wide significance in association with the disease. The strongest association was found within the HLA-DR/DQ region (lead variant rs9273542, p=1.59×10-43, OR=3.39, 95%CI=2.86-4.03) confirming findings of previous GWAS. Moreover, we are the first reporting on two loci outside the HLA region on chromosome 6q22.1 and 4q13.3 that are associated with SSNS with genome-wide significance. The region on chromosome 6q contains the gene CALHM6, which has been implicated in the regulation of the immune system and is particularly expressed on CD4+ cells and naïve and memory B cells. The identified lead variant (rs2637678, p=1.27×10-17, OR=0.51, 95%CI=0.44-0.60) is a strong expression quantitative trait locus (eQTL) for CALHM6, with the risk allele predicting lower expression of CALHM6 on lymphocytes and hence possibly altered immune regulatory responses. The same variant is also an eQTL for the neighbouring gene DSE, which codes for an enzyme essential in the dermatan sulfate production. Overexpression of dermatan sulfate has been previously associated with glomerular diseases and could be a potential antigen involved in SSNS. These findings support the hypothesis that the immune system and its dysregulation play a critical role in the pathogenesis of SSNS

Epidemiology of paediatric renal stone disease: a 22-year single centre experience in the UK

Abstract Background Whilst still rare, the incidence of paediatric stone disease is increasing in developed countries and it is important to evaluate the aetiology. We set up a dedicated renal stone service for children combining medical and surgical expertise in 1993 and now have a large case series of children to investigate the epidemiology. Methods A retrospective hospital note review of children presenting with kidney stones during the last 22 years (1993–2015) was conducted. All patients had a comprehensive infective and metabolic screen and were classified as metabolic, infective or idiopathic stone disease. Results Five hundred eleven patients (322 male) were reviewed. The median age of presentation was 4.4y for males (1 m-16.6y) and 7.3y (1–18.5y) for females with a median height and weight on the 25th centile for male and on 10th and 25th for female, respectively. One hundred seventy five (34%) had an underlying metabolic abnormality, 112 (22%) had infective stones and 224 (44%) were classified as idiopathic. Of the 175 patients with a metabolic abnormality: 91 (52%) had hypercalciuria (76 persistent and 15 transient), 37 (21%) hyperoxaluria, 38 (22%) cystinuria, 3 (2%) abnormalities in the purine metabolism and the remainder other metabolic abnormalities. Bilateral stones occurred in 27% of the metabolic group compared to 16% in the non-metabolic group (OR 0.2, p < 0.05). Urinary tract infection was a common complication (27%) in the metabolic group. Conclusions In this paper, we present the largest cohort of paediatric stone disease reported from a developed country giving details on both, clinical and laboratory data. We show that in the majority of the patients there is an identifiable underlying metabolic and/or infective aetiology emphasizing the importance of a full work up to provide adequate treatment and prevent recurrence. Moreover, we show that stone disease in children, in contrast to the adult population, does not seem to be associated with obesity, as children have a weight below average at presentation

BILATERAL NEPHRECTOMY IN CHILDREN WITH CONGENITAL NEPHROTIC SYNDROME - IS IT STILL THE WAY TO GO

WOS: 000469797104069

Management of children with congenital nephrotic syndrome: challenging treatment paradigms

WOS: 000493307500019PubMed ID: 30215773Background. Management of children with congenital nephrotic syndrome (CNS) is challenging. Bilateral nephrectomies followed by dialysis and transplantation are practiced in most centres, but conservative treatment may also be effective. Methods. We conducted a 6-year review across members of the European Society for Paediatric Nephrology Dialysis Working Group to compare management strategies and their outcomes in children with CNS. Results. Eighty children (50% male) across 17 tertiary nephrology units in Europe were included (mutations in NPHS1, n = 55; NPHS2, n = 1; WT1, n = 9; others, n = 15). Excluding patients with mutations in WT1, antiproteinuric treatment was given in 42 (59%) with an increase in S-albumin in 70% by median 6 (interquartile range: 3-8) g/L (P< 0.001). Following unilateral nephrectomy, S-albumin increased by 4 (1-8) g/L (P = 0.03) with a reduction in albumin infusion dose by 5 (2-9) g/kg/week (P = 0.02). Median age at bilateral nephrectomies (n = 29) was 9 (7-16) months. Outcomes were compared between two groups of NPHS1 patients: those who underwent bilateral nephrectomies (n = 25) versus those on conservative management (n = 17). The number of septic or thrombotic episodes and growth were comparable between the groups. The response to antiproteinuric treatment, as well as renal and patient survival, was independent of NPHS1 mutation type. At final follow-up (median age 34months) 20 (80%) children in the nephrectomy group were transplanted and 1 died. In the conservative group, 9 (53%) remained without dialysis, 4 (24%; P< 0.001) were transplanted and 2 died. Conclusion. An individualized, stepwise approach with prolonged conservative management may be a reasonable alternative to early bilateral nephrectomies and dialysis in children with CNS and NPHS1 mutations. Further prospective studies are needed to define indications for unilateral nephrectomy.National Institute for Health Research Biomedical Research Centre at Great Ormond Street Hospital for Children National Health Service (NHS) Foundation Trust and University College, London; National Institute for Health Research (NIHR)National Institute for Health Research (NIHR)This work was supported by the National Institute for Health Research Biomedical Research Centre at Great Ormond Street Hospital for Children National Health Service (NHS) Foundation Trust and University College, London. R.S. holds a Career Development Fellowship with the National Institute for Health Research (NIHR)