A novel flow cytometry panel to identify prognostic markers for steroid-sensitive forms of idiopathic nephrotic syndrome in childhood

Introduction

The clinical evolution of steroid-sensitive forms of pediatric idiopathic nephrotic syndrome (INS) is highly heterogeneous following the standard treatment with prednisone. To date, no prognostic marker has been identified to predict the severity of the disease course starting from the first episode.

Methods

In this monocentric prospective cohort study we set up a reproducible and standardized flow cytometry panel using two sample tubes (one for B-cell and one for T-cell subsets) to extensively characterized the lymphocyte repertoire of INS pediatric patients. A total of 44 children with INS at disease onset were enrolled, sampled before and 3 months after standard induction therapy with prednisone and followed for 12 months to correctly classify their disease based on relapses. Age-matched controls with non immune-mediated renal diseases or with urological disorders were also enrolled. Demographical, clinical, laboratory and immunosuppressive treatment data were registered.

Results

We found that children with INS at disease onset had significantly higher circulating levels of total CD19+ and specific B-cell subsets (transitional, mature-naïve, plasmablasts/plasmacells, CD19+CD27+, unswitched, switched and atypical memory B cells) and reduced circulating levels of Tregs, when compared to age-matched controls. Prednisone therapy restored most B- and T-cell alterations. When patients were subdivided based on disease relapse, relapsing patients had significantly more transitional, CD19+CD27+ memory and in particular unswitched memory B cells at disease onset, which were predictive of a higher risk of relapse in steroid-sensitive patients by logistic regression analysis, irrespective of age. In accordance, B-cell dysregulations resulted mainly associated with steroid-dependence when patients were stratified in different disease severity forms. Of note, Treg levels were reduced independently from the disease subgroup and were not completely normalized by prednisone treatment.

Conclusion

We have set up a novel, reproducible, disease-specific flow cytometry panel that allows a comprehensive characterization of circulating lymphocytes. We found that, at disease onset, relapsing patients had significantly more transitional, CD19+CD27+ memory and unswitched memory B cells and those who are at higher risk of relapse had increased circulating levels of unswitched memory B cells, independently of age. This approach can allow prediction of clinical evolution, monitoring of immunosuppression and tailored treatment in different forms of INS.

Anti-nephrin antibodies in recurrence of focal segmental glomerulosclerosis: closer to discovering the Holy Grail?

Recurrent forms of primary focal segmental glomerulosclerosis (FSGS) pose an unmet challenge to nephrologists, both in terms of understanding the underlying pathophysiology and in terms of identifying an effective management strategy of this disease, which frequently leads to kidney graft loss. In the past few decades, experimental observations both in patients and in animal models have led to the hypothesis of the existence of circulating factors driving the loss of integrity of the glomerular filtration barrier in FSGS. Although different circulating factor candidates have been postulated, none has been unequivocally shown to be pathogenic. In the current study, Shirai et al. propose a new candidate for this role by identifying circulating anti-nephrin autoantibodies in a cohort of patients with post-transplant recurrence of primary FSGS. Recent evidence by Watts et al. has also identified anti-nephrin autoantibodies in the circulation and in the kidney biopsies of patients with minimal change disease. If confirmed, the identification of these autoantibodies would both contribute to identifying the elusive circulating factor in FSGS and increase our understanding of the spectrum of proteinuric glomerular lesions, spanning from minimal change disease to FSGS. The quest for the Holy Grail is perhaps closer to completion.

RadioLab project: knowledge of radon gas in Italy

RadioLab is an Italian project, addressed to school-age people, and designed for the dissemination of scientific culture on the theme of environmental radioactivity, with particular regards to the importance of knowledge of radon gas exposure. The project is a nationwide initiative promoted by the National Institute of Nuclear Physics- INFN. First tool used by the project, and of immediate impact to assess the public awareness on radon, is the administration of the survey "do you know the radon gas?". In the survey, together with the knowledge of radon and of its sources, information on personal, cultural and territorial details regarding the interviewees are also taken. Reasonably, the survey invests not only young people, but also their relatives, school workers and, gradually, the public. The survey is administrated during exhibitions or outreach events devoted to schools, but also open to the public. The survey is in dual form: printed and online. The online mode clearly leads RadioLab project even outside the school environment. Based on the results of the survey, several statistical analyses have been performed and many conclusions are drawn about the knowledge of the population on the radon risk. The RadioLab benefit and the requirement to carry on the project goals, spreading awareness of environmental radioactivity from radon, emerge. The dataset involves all twenty Italian regions and consists of 28,612 entries covering the 5-year period 2018-2022.

A child with semaphorin 3b-associated membranous nephropathy effectively treated with obinutuzumab after rituximab resistance

BACKGROUND

Membranous nephropathy is a glomerular disease characterized by the presence of immune-complexes deposited in the subepithelial space of the glomerular basement membrane. It is the main cause of nephrotic syndrome in adults, while in children it is very infrequent. Anti-CD20 monoclonal antibodies, mainly rituximab, represent a specific treatment for this disease.

CASE REPORT

We report the case of a child presenting at 2 years of age with steroid-resistant nephrotic syndrome diagnosed upon kidney biopsy as semaphorin 3B (SEMA3B)-associated primary membranous nephropathy. The patient responded to treatment with cyclosporine, but invariably relapsed upon tapering of this agent. Therefore, at age 9, he was successfully treated with rituximab to overcome cyclosporine dependence. However, after the second rituximab infusion, a rapid reconstitution of CD19 + B cells and a relapse of proteinuria occurred, requiring reintroduction of cyclosporine. Obinutuzumab, a type II anti-CD20 monoclonal antibody, was then infused inducing prolonged CD19 + B cell depletion and remission of proteinuria despite discontinuation of cyclosporine. A greater reduction in circulating anti-SEMA3B antibodies assessed by Western blot was observed after obinutuzumab compared with rituximab infusion.

DISCUSSION

Obinutuzumab was safe and well-tolerated, and may therefore represent an effective therapeutic alternative in children with primary MN and rituximab resistance.

A pediatric case of IgA nephropathy benefitting from targeted release formulation-budesonide

BACKGROUND

The best treatment for IgAN is still debated. The trials NEFIGAN and NEFIGARD have demonstrated that TRF-budesonide (Nefecon) efficiently and safely reduced proteinuria in adults, leading to FDA approval of Nefecon for adult IgAN. In pediatric IgAN, an etiological treatment does not yet exist, and the main therapies remain RAAS inhibitors and oral steroids. To our knowledge, this is one of the few pediatric reports of TRF-budesonide therapy.

CASE REPORT-DIAGNOSIS/TREATMENT

A 13-year-old boy underwent a kidney biopsy for recurrent macrohematuria and proteinuria, resulting in an IgAN diagnosis (MEST-C score M1-E1-S0-T0-C1). At admission, serum creatinine and UPCR were slightly increased. Three methylprednisolone pulses were performed, followed by prednisone and RAAS inhibitors therapy. However, after 10 months, macrohematuria became constant, and UPCR increased. A new kidney biopsy was performed, showing an increase in sclerotic lesions. Prednisone was discontinued, and a trial with IBD TRF-budesonide 9 mg/day started. One month later, macrohematuria episodes disappeared and UPCR decreased, with a stable kidney function. After 5 months, due to a reduction in morning cortisol levels and difficulty in drug provisioning, we started to wean TRF-budesonide by 3 mg every 3 months, with complete withdrawal after 1 year. During this period, episodes of macrohematuria dramatically decreased, and UPCR and kidney function were maintained stable.

CONCLUSION

Our case demonstrates that TRF-budesonide could be considered an effective second-line treatment in pediatric IgAN, particularly when a long course of steroids is necessary to control active inflammation. However, pediatric clinical trials to identify the correct dosage and tolerability of TRF-budesonide are urgently needed.

A phase I study of autologous mesenchymal stromal cells for severe steroid-dependent nephrotic syndrome

BACKGROUNDSevere forms of idiopathic nephrotic syndrome (INS) require prolonged immunosuppressive therapies and repeated courses of high-dose glucocorticoids. Mesenchymal stromal cells (MSCs) have promising immunomodulatory properties that may be employed therapeutically to reduce patient exposure to medications and their side effects.METHODSWe performed a phase I open-label trial assessing safety and feasibility of autologous bone marrow-derived MSCs (BM-MSCs) in children and young adults with severe forms of steroid-dependent nephrotic syndrome. Following autologous BM-MSC preparation and infusion, oral immunosuppression was tapered. Safety, efficacy, and immunomodulatory effects in vivo were monitored for 12 months.RESULTSSixteen patients (10 children, 6 adults) were treated. Adverse events were limited and not related to BM-MSC infusions. All patients relapsed during follow-up, but in the 10 treated children, time to first relapse was delayed (P = 0.02) and number of relapses was reduced (P = 0.002) after BM-MSC infusion, compared with the previous 12 months. Cumulative prednisone dose was also reduced at 12 months compared with baseline (P < 0.05). No treatment benefit was observed in adults.In children, despite tapering of immunosuppression, clinical benefit was mirrored by a significant reduction in total CD19+, mature, and memory B cells and an increase in regulatory T cells in vivo up to 3-6 months following BM-MSC infusionCONCLUSIONTreatment with autologous BM-MSCs is feasible and safely reduces relapses and immunosuppression at 12 months in children with severe steroid-dependent INS. Immunomodulatory studies suggest that repeating MSC infusions at 3-6 months may sustain benefit.TRIAL REGISTRATIONEudraCT 2016-004804-77.FUNDINGAIFA Ricerca Indipendente 2016-02364623.

Age and memory B cells at baseline are associated with risk of relapse and memory B-cell reappearance following anti-CD20 treatment in pediatric frequently-relapsing/steroid-dependent nephrotic syndrome

B-cell depleting anti-CD20 monoclonal antibodies, such as rituximab, have proven efficacy in children with frequently-relapsing/steroid-dependent nephrotic syndrome (FR/SDNS). However, drug-free remission is variable and specific baseline markers predictive of relapse after anti-CD20 treatment are still being defined. To clarify these, we performed a bicentric observational study in a large cohort of 102 children and young adults with FR/SDNS treated with anti-CD20 monoclonal antibodies (rituximab and ofatumumab). Sixty-two patients (60.8%) relapsed during a 24-month period (median [interquartile range] relapse-free survival, 14.4 months [7.9-24.0]). A lower risk of relapse was significantly associated with an older age (over 9.8 years, hazard ratio, 0.44; 95% confidence interval, 0.26-0.74) and a higher risk of relapse was significantly associated with higher circulating levels of memory B cells (1.14; 1.09-1.32) at time of anti-CD20 infusion, independent of time elapsed from onset, previous anti-CD20 treatment, type of administered anti-CD20 monoclonal antibodies, and previous or maintenance oral immunosuppression. Patients younger than 9.8 years at anti-CD20 infusion had a subsequent higher recovery of total, transitional, mature-naïve and memory B-cell subsets independent of previous anti-CD20 treatment and maintenance immunosuppression. Significantly, younger age and higher circulating levels of memory B cells at time of anti-CD20 infusion were also independently associated with the recovery of memory B cells by linear mixed-effects modelling. Thus, both younger age and higher circulating levels of memory B cells at time of infusion are independently associated with a higher risk of relapse and an earlier recovery of memory B cells following anti-CD20 treatment in children with FR/SDNS.

Multi-population genome-wide association study implicates immune and non-immune factors in pediatric steroid-sensitive nephrotic syndrome

Pediatric steroid-sensitive nephrotic syndrome (pSSNS) is the most common childhood glomerular disease. Previous genome-wide association studies (GWAS) identified a risk locus in the HLA Class II region and three additional independent risk loci. But the genetic architecture of pSSNS, and its genetically driven pathobiology, is largely unknown. Here, we conduct a multi-population GWAS meta-analysis in 38,463 participants (2440 cases). We then conduct conditional analyses and population specific GWAS. We discover twelve significant associations-eight from the multi-population meta-analysis (four novel), two from the multi-population conditional analysis (one novel), and two additional novel loci from the European meta-analysis. Fine-mapping implicates specific amino acid haplotypes in HLA-DQA1 and HLA-DQB1 driving the HLA Class II risk locus. Non-HLA loci colocalize with eQTLs of monocytes and numerous T-cell subsets in independent datasets. Colocalization with kidney eQTLs is lacking but overlap with kidney cell open chromatin suggests an uncharacterized disease mechanism in kidney cells. A polygenic risk score (PRS) associates with earlier disease onset. Altogether, these discoveries expand our knowledge of pSSNS genetic architecture across populations and provide cell-specific insights into its molecular drivers. Evaluating these associations in additional cohorts will refine our understanding of population specificity, heterogeneity, and clinical and molecular associations.

Use of Rituximab in Childhood Idiopathic Nephrotic Syndrome

Rituximab is an established therapy in children with idiopathic nephrotic syndrome to sustain short- to medium-term disease remission and avoid steroid toxicities. Recent trials focus on its use as a first-line agent among those with milder disease severity. Rituximab is used in multidrug refractory nephrotic syndrome and post-transplant disease recurrence, although the evidence is much less substantial. Available data suggest that the treatment response to rituximab depends on various patient factors, dosing regimen, and the concomitant use of maintenance immunosuppression. After repeated treatments, patients are found to have an improving response overall with a longer relapse-free period. The drug effect, however, is not permanent, and 80% of patients eventually relapse and many will require an additional course of rituximab. This underpins the importance of understanding the long-term safety profile on repeated treatments. Although rituximab appears to be generally safe, there are concerns about long-term hypogammaglobulinemia, especially in young children. Reliable immunophenotyping and biomarkers are yet to be discovered to predict treatment success, risk of both rare and severe side effects, e.g. , persistent hypogammaglobulinemia, and guiding of redosing strategy. In this review, we highlight recent advances in the use of rituximab for childhood nephrotic syndrome and how the therapeutic landscape is evolving.

FC066: Circulating Anti-Rituximab Antibodies Do Not Affect Response to Rituximab in Steroid-Dependent Nephrotic Syndrome

BACKGROUND AND AIMS

Previous studies reported that the chimeric anti-CD20 monoclonal rituximab may lead to the production of anti-rituximab antibodies (Anti-RTX-Abs), due to the chimeric nature, impairing the efficacy of further infusions. In the context of glomerulonephritis, recent findings have described that the incidence of anti-RTX-Abs development may affect the efficacy of rituximab in paediatric steroid dependent nephrotic syndrome (SDNS) [Fujinaga et al. Pediatr Nephrol. 2020 Oct; 35(10): 2003–2008] and in membranous nephropathy [Boyer-Suavet et al. Front Immunol. 2020 Jan 13; 10: 3069]. The improved patient outcomes and cost-effectiveness have led to the development of a new generation of fully human anti-B cell agents in haematological and autoimmune diseases [Klomjit et al. Am J Kidney Dis. 2020 Dec; 76(6): 883–888]. Therefore, elucidating the role of Anti-RTX-Abs with the aim to develop personalized therapies is mandatory. In a randomized clinical trial, we compared the efficacy of fully humanized anti-CD20 antibody ofatumumab versus rituximab in children and young adults with SDNS [Ravani et al. JASN Oct 2021, 32 (10) 2652–2663].

METHOD

We randomized 140 subjects to single infusion of rituximab or ofatumumab. Follow-up was of 24 months. We measured anti-rituximab IgG antibodies (LISA- TRACKER, Theradiag© Croissy Beaubourg, France) at the enrollment in 64/140 (46%) patients who previously received rituximab, regardless of the randomization arm, and at 6 months in 54/70 of the patients in the rituximab arm. (Fig. 1) Median time of last rituximab treatment was 36 months (13–54) before enrollment.

RESULTS

Anti-RTX-Abs were detected in none of the patients receiving more than or equal to one rituximab infusion before enrollment. At 6 months, Anti-RTX-Abs are detected in 14/54 patients (26%) who received rituximab (Fig. 2A). Patients developing anti-RTX-Abs or not had similar characteristics at enrollment. At T6, anti-RTX-Abs was not statistically different comparing who received rituximab before enrollment and who did not (Fig. 2B).

Of the 54 patients treated with rituximab, 35 (65%) relapsed in 12 months of follow-up. Incidence of patients with anti-RTX-Abs at T6 was not statistically different comparing who experienced relapse with who did not (Fig. 2C). Time to relapse is reported in Fig. 2D. According to the protocol study, the 35 relapsing received a further infusion of rituximab. In this subgroup, incidence of patients with anti-RTX-Abs at T6 was not statistically different comparing who experienced further relapses with who did not (Fig. 2E).

Both patients with and without anti-RTX-Abs had similar levels of total B-cell counts before rituximab therapy and at month 6 and 12 thereafter, showing similar B-cell reconstitution (Fig. 2F). We found similar percentages for memory B-cells comparing patients with and without Anti-RTX-Abs at enrollment, at month 6 and at month 12 of follow-up (Fig. 2G).

CONCLUSION

 We evaluated the impact of Anti-RTX-Abs in a prospective study considering a large cohort of SDNS patients who received additional rituximab in case of relapse after a single infusion (375 mg/m2). According to the literature, we reported the development of Anti-RTX-Abs after a single infusion, which seems to persist for limited time. However, in contrast to previous findings, the development of Anti-RTX-Abs does not represent an unfavourable factor, which may limit the efficacy and the safety of further infusions. The prospective design of our study, in contrast to previous ones, represents one of the major strength of the present work. Moreover, Anti-RTX-Abs did not affect total and memory B-cell reconstitution following rituximab treatment.

Long-term Efficacy and Safety of Repeated Rituximab to Maintain Remission in Idiopathic Childhood Nephrotic Syndrome: An International Study

Background: Long-term outcomes following multiple rituximab courses among children with frequently-relapsing, steroid-dependent nephrotic syndrome (FRSDNS) are unknown. Methods: A retrospective cohort study at 16 pediatric nephrology centers from 10 countries in Asia, Europe, and North America included children with FRSDNS who received ≥2 rituximab courses. Primary outcomes were relapse-free survival and adverse events. Results: 346 children (age 9.8 years, IQR 6.6-13.5; 73% boys) received 1149 rituximab courses. 145, 83, 50, 28, 22, and 18 children received 2, 3, 4, 5, 6 and ≥7 courses, respectively. Median follow-up was 5.9 years (IQR, 4.3-7.7). Relapse-free survival differed by treatment courses (clustered log-rank test p<0.001). Compared to the first course (10.0 months, 95% CI, 9.0-10.7), relapse-free period and relapse risk progressively improved following subsequent courses (12.0-16.0 months; HRadj, 0.03-0.13; 95% CI, 0.01-0.18; ps<0.001). B-cell depletion duration remained similar with repeated treatments (6.1 months, 95% CI, 6.0-6.3). Adverse events were mostly mild, most commonly hypogammaglobulinemia (50.9%), infection (4.5%), and neutropenia (3.7%). Side effects did not increase with more treatment courses nor higher cumulative dose. Only 78 of the 353 episodes of hypogammaglobulinemia were clinically significant. Younger age at presentation (2.8 vs 3.3 years; p=0.05) and at first rituximab (8.0 y vs 10.0 years; p=0.01) and history of steroid resistance (28% vs 18%; p=0.01) were associated with significant hypogammaglobulinemia. All 53 infective episodes resolved, except one patient with hepatitis B infection and another with EBV infection. There were 42 episodes of neutropenia, associated with history of steroid resistance (30% vs 20%, p=0.04). Upon last follow-up, 332 children (96%) had normal kidney function. Conclusion: Children receiving repeated rituximab for FRSDNS experience an improving clinical response. Side effects appear acceptable but significant complications can occur. These findings support repeated rituximab use in FRSDNS.

Belimumab for the treatment of children with frequently relapsing nephrotic syndrome: the BELNEPH study

BACKGROUND

Effectiveness of rituximab in pediatric idiopathic nephrotic syndrome suggests that B cells play a pathogenic role. We tested safety and efficacy of the B-cell-modulating agent belimumab in frequently relapsing nephrotic syndrome (FRNS).

METHODS

An open-label, prospective, single-arm pilot study (EUDRACT 2017-003839-11) was designed to treat 10 children with FRNS with i.v. belimumab for 12 months. Prednisone was tapered/stopped. Safety, number of relapses, cumulative prednisone dose and B-cell subset "levels" are referred to both B cell subset and immunoglobulin.

RESULTS

Five patients were enrolled, and four reached the primary 6-month endpoint. Of these, two completed the 12-month endpoint. Three patients experienced ≥2 relapses while on belimumab, requiring additional immunosuppression. Compared to the 6 months before belimumab treatment, the mean number of relapses (1.4 vs. 2, p=0.21) and the mean cumulative prednisone dose (1.86 vs. 2.62 g/m², p=0.17) were not significantly reduced during the 6 months on belimumab. This study was terminated by the steering committee after the interim evaluation because belimumab failed to show clear benefits to counterbalance the inconvenience of monthly i.v. infusion. During follow-up, total and mature-naïve B cells decreased, while no change in memory B-cells was observed. Serum immunoglobulins remained stable. No infusion reaction was observed.

CONCLUSIONS

Short-term treatment with belimumab in pediatric FRNS was well tolerated. The number of patients was too small to draw conclusions on efficacy. Nonetheless, we did not observe clear improvements. The burden of monthly in-hospital i.v. infusions outweighed potential benefits. Persistence of circulating memory B cells supports their pathogenic role in the disease. A higher resolution version of the Graphical abstract is available as Supplementary information.

B-Cell Dysregulation in Idiopathic Nephrotic Syndrome: What We Know and What We Need to Discover

The therapeutic efficacy of B-cell depletion by anti-CD20 treatment in pediatric and, more recently, in adult idiopathic nephrotic syndrome patients suggests a key role of B cells in the pathogenesis of the disease. However, their exact role is still unclear. B cells are able to secrete a large variety of antibodies that can protect against infections. However, B-cell dysregulation is well-established in a variety of autoimmune diseases. In parallel with their ability to produce antibodies, pathogenic B cells display altered effector functions by expressing activating surface molecules, which can strongly modify the immune homeostasis, or by producing specific cytokines, which can directly affect either podocyte structure and functions or modulate T-cell homeostasis. Herein, we report the most relevant clinical and experimental evidences of a pathogenic role of B cells in idiopathic nephrotic syndrome. We further highlight similarities and differences between children and adults affected by non-genetic forms of the disease and discuss what needs to be investigated in order to define the exact mechanisms underlying the pathogenic role of B cells and to identify more tailored therapeutic approaches.

Comprehensive phenotyping of human peripheral blood B lymphocytes in pathological conditions

Several diseases are associated with alterations of the B-cell compartment. Knowing how to correctly identify by flow cytometry the distribution of B-cell populations in the peripheral blood is important to help in the early diagnosis. In the accompanying article we describe how to identify the different B-cell subsets in the peripheral blood of healthy donors. Here we show a few examples of diseases that cause dysregulation of the B-cell compartment.

Randomised controlled trial comparing rituximab to mycophenolate mofetil in children and young adults with steroid-dependent idiopathic nephrotic syndrome: study protocol

INTRODUCTION

Glucocorticoids induce remission in 90% of children with idiopathic nephrotic syndrome (INS). Some become steroid-dependent (SD) and require the addition of steroid sparing drugs such as calcineurin-inhibitors (CNI) or cyclophosphamide, to maintain remission. Considering the toxicity of these drugs, alternative interventions are needed for long-term treatment. The anti-CD20 antibody rituximab has shown promising steroid-sparing properties, with conflicting results in complicated forms of SD-INS. Mycophenolate mofetil (MMF) resulted effective in maintaining free-steroid remission, however, studies are limited to few uncontrolled trials with reported different dose of MMF.

METHODS AND ANALYSIS

This open-label, two-parallel-arm, superiority controlled randomised clinical trial will enrol children with SD-INS maintained in remission with oral glucocorticoids or CNI. Children and young adults will be randomised to either MMF (1.200 mg/m²) or rituximab (375 mg/m²) infusion. After enrolment, glucocorticoids will be tapered until complete withdrawal. We will enrol 160 children and young adults to detect as significant at the two-sided p value of 0.01 with a power >0.8 a reduction in the risk of 1-year relapse (primary end-point). As secondary endpoints, we will compare the amount of glucocorticoids required to maintain complete remission at 6 and 24 months.

ETHICS AND DISSEMINATION

The trial was approved by the local ethics boards (Comitato Etico Regione Liguria CER Liguria https://www.portalericerca-liguria.it/). We will publish the study results at international scientific meetings.

TRIAL REGISTRATION NUMBERS

NCT004585152.

Benefits and Toxicity of Disulfiram in Preclinical Models of Nephropathic Cystinosis

Nephropathic cystinosis is a rare disease caused by mutations of the CTNS gene that encodes for cystinosin, a lysosomal cystine/H+ symporter. The disease is characterized by early-onset chronic kidney failure and progressive development of extra-renal complications related to cystine accumulation in all tissues. At the cellular level, several alterations have been demonstrated, including enhanced apoptosis, altered autophagy, defective intracellular trafficking, and cell oxidation, among others. Current therapy with cysteamine only partially reverts some of these changes, highlighting the need to develop additional treatments. Among compounds that were identified in a previous drug-repositioning study, disulfiram (DSF) was selected for in vivo studies. The cystine depleting and anti-apoptotic properties of DSF were confirmed by secondary in vitro assays and after treating Ctns-/- mice with 200 mg/kg/day of DSF for 3 months. However, at this dosage, growth impairment was observed. Long-term treatment with a lower dose (100 mg/kg/day) did not inhibit growth, but failed to reduce cystine accumulation, caused premature death, and did not prevent the development of renal lesions. In addition, DSF also caused adverse effects in cystinotic zebrafish larvae. DSF toxicity was significantly more pronounced in Ctns-/- mice and zebrafish compared to wild-type animals, suggesting higher cell toxicity of DSF in cystinotic cells.

CyTOF-Enabled Analysis Identifies Class-Switched B Cells as the Main Lymphocyte Subset Associated With Disease Relapse in Children With Idiopathic Nephrotic Syndrome

B cell depleting therapies permit immunosuppressive drug withdrawal and maintain remission in patients with frequently relapsing nephrotic syndrome (FRNS) or steroid–dependent nephrotic syndrome (SDNS), but lack of biomarkers for treatment failure. Post-depletion immune cell reconstitution may identify relapsing patients, but previous characterizations suffered from methodological limitations of flow cytometry. Time-of-flight mass cytometry (CyTOF) is a comprehensive analytic modality that simultaneously quantifies over 40 cellular markers. Herein, we report CyTOF-enabled immune cell comparisons over a 12-month period from 30 children with SDNS receiving B cell depleting therapy who either relapsed (n = 17) or remained stable (n = 13). Anti-CD20 treatment depleted all B cells subsets and CD20 depleting agent choice (rituximab vs ofatumumab) did not affect B cell subset recovery. Despite equal total numbers of B cells, 5 subsets of B cells were significantly higher in relapsing individuals; all identified subsets of B cells were class-switched. T cell subsets (including T follicular helper cells and regulatory T cells) and other major immune compartments were largely unaffected by B cell depletion, and similar between relapsing and stable children. In conclusion, CyTOF analysis of immune cells from anti-CD20 antibody treated patients identifies class-switched B cells as the main subset whose expansion associates with disease relapse. Our findings set the basis for future studies exploring how identified subsets can be used to monitor treatment response and improve our understanding of the pathogenesis of the disease.

Human or Chimeric Monoclonal Anti-CD20 Antibodies for Children with Nephrotic Syndrome: A Superiority Randomized Trial

BACKGROUND

The chimeric anti-CD20 monoclonal antibody rituximab is effective in steroid-dependent and calcineurin inhibitor-dependent forms of nephrotic syndrome, but many patients relapse at 1 year. Because ofatumumab, a fully human anti-CD20 monoclonal antibody, has a more extended binding site and higher affinity to CD20 compared with rituximab, it might offer superior efficacy in these patients.

METHODS

We designed a single-center randomized clinical trial to compare the long-term efficacy of ofatumumab versus rituximab in children and young adults with nephrotic syndrome maintained in remission with prednisone and calcineurin inhibitors. We randomized 140 children and young adults (aged 2-24 years) to receive intravenous ofatumumab (1.50 mg/1.73 m²) or rituximab (375 mg/m²). After infusions, oral drugs were tapered and withdrawn within 60 days. The primary outcome was relapse at 1 year, which was analyzed following the intent-to-treat principle. The secondary endpoint was relapse within 24 months from infusion, on the basis of urine dipstick and confirmed by a urine protein-to-creatinine ratio <200.

RESULTS

At 12 months, 37 of 70 (53%) participants who received ofatumumab experienced relapse versus 36 of 70 (51%) who received rituximab (odds ratio [OR], 1.06; 95% confidence interval [95% CI], 0.55 to 2.06). At 24 months, 53 of 70 (76%) participants who received ofatumumab experienced relapse, versus 46 of 70 (66%) who received rituximab (OR, 1.6; 95% CI, 0.8 to 3.3). The two groups exhibited comparable B cell subpopulation reconstitution and did not differ in adverse events.

CONCLUSIONS

A single dose of ofatumumab was not superior to a single dose of rituximab in maintaining remission in children with steroid-dependent and calcineurin inhibitor-dependent nephrotic syndrome.

CLINICAL TRIAL REGISTRATION NUMBERS

ClinicalTrials.gov (NCT02394119) and https://www.clinicaltrialsregister.eu/ctr-search/search (2015-000624-28).

FC 131OFATUMUMAB OR RITUXIMAB FOR CHILDREN WITH STEROID-DEPENDENT NEPHROTIC SYNDROME. A RANDOMIZED CONTROLLED TRIAL

Background and Aims

The chimeric anti-CD20 monoclonal antibody rituximab has been successfully used in steroid-dependent forms of nephrotic syndrome (SDNS) to maintain oral-drug-free remission, but relapses at one year occur in almost half of the patients. Ofatumumab, a fully human anti-CD20 monoclonal antibody, may be superior to rituximab in maintaining remission of SDNS. We compared the efficacy and safety of ofatumumab vs. rituximab in children and young adults with SDNS (NCT02394119) and evaluated the risk of relapse following steroid and calcineurin-inhibitor tapering and withdrawal.

Method

We randomly assigned 140 children and younger adults (age 2-24 years) with SDNS maintained in remission with steroids and calcineurin-inhibitors to receive intravenous ofatumumab (1.500 mg/1.73 m2; intervention) or rituximab (375 mg/m2; control). Following infusions, oral drugs were tapered and withdrawn. Participants were followed for 24 months. The primary outcome was relapse at one year, defined by protein-creatinine ratio ≥2000 mg/g or &gt;3+ protein on urine dipstick for 3 consecutive days. Cellular and safety data were also assessed.

Results

At 12 months, 36 patients (51.4%) relapsed in the rituximab arm and 37 (52.8%) in the ofatumumab arm (Odds Ratio [OR] 1.06; 95% confidence interval [CI] 0.55 to 2.06). At 24 months, 46 children relapsed in the rituximab arm (65.7%) and 53 in the ofatumumab arm (75.7%). In both arms, circulating B cell levels declined following treatment and recovered between 3 and 9 months. Higher pretreatment levels and faster recovery after decline of memory B cells predicted relapse.

Conclusion

In children and younger adults with SDNS, ofatumumab is not superior to the chimeric anti-CD20 antibody rituximab. Immune phenotyping data indicate that anti-CD20 therapies alter the course of the disease by interfering with memory B cell populations and can be used to predict response to anti-CD20 treatment.

Evaluation of Immune and Vaccine Competence in Steroid-Sensitive Nephrotic Syndrome Pediatric Patients

Idiopathic nephrotic syndrome is a childhood renal disease characterized by a damage of the glomerular filtration barrier leading to an intense leakage of proteins into the urine. This severe proteinuria causes a transient but strong reduction of serum IgG. Therefore, evaluation of vaccine competence by measuring serum levels of protective antibodies can be misleading in nephrotic syndrome, especially during the active phase of disease. To overcome this issue, in parallel to measuring serum antigen-specific IgG, we quantified by ELISPOT the number of antigen-specific memory B cells induced by previous immunization with tetanus and hepatitis B virus (HBV) in 11 steroid-sensitive nephrotic syndrome (SSNS) pediatric patients at onset before any immunosuppressive treatment (mean age 5.1±0.9 years). Five age-matched children with non-immunomediated nephro-urologic disorders were also enrolled as controls (mean age 6.9±2.3 years). Low total serum IgG levels (<520 mg/dl) were found in all the analyzed SSNS patients. In parallel, median levels of anti-tetanus and anti-HBV IgG were significantly reduced compared to controls [0.05 (0.03–0.16) vs. 0.45 (0.29–3.10) IU/ml and 0.0 (0.0–0.5) vs. 30.3 (5.5–400.8) mIU/ml, respectively; p = 0.02 for both], with serum IgG titers below protective threshold in 7/11 SSNS patients for tetanus and in 9/11 SSNS patients for HBV. In contrast, all SSNS patients had a competent B-cell response, showing an amount of total IgG-secreting B cells >1,000 counts/10⁶ stimulated cells. The amount of anti-tetanus and anti-HBV IgG-secreting B cells was also comparable to that of controls (p = 0.24, p = 0.32, respectively), with a frequency of memory anti-tetanus and anti-HBV IgG secreting B cells >0.1% of total IgG secreting B cells. In conclusion, SSNS children at disease onset pre-immunosuppressive therapy showed a competent immune and vaccine response against tetanus and HBV, which can be correctly evaluated by quantification of antigen-specific memory B cells rather than by measuring serum IgG levels. This approach allows early identification of the impairment of immune and vaccine competence, which may derive from protracted use of different immunosuppressive drugs during disease course.

Prolonged Impairment of Immunological Memory After Anti-CD20 Treatment in Pediatric Idiopathic Nephrotic Syndrome

Anti-CD20 therapy is effective in idiopathic nephrotic syndrome (INS). However, transient or sustained hypogammaglobulinemia predisposing to an increased risk of infectious diseases can follow treatment in some patients. We analyzed the long-term effects of anti-CD20 therapy on immunological memory in 27 frequently-relapsing/steroid-dependent INS pediatric patients after more than 4 years from the first and at least 2 years from the last anti-CD20 infusion. Twenty-one INS children, never treated with anti-CD20 and under an intense oral immunosuppression with prednisone, mycophenolate mofetil, and calcineurin inhibitors were also included as control group. Levels of circulating B-cell subpopulations, total serum immunoglobulins and IgG and memory B cells directed against hepatitis B virus (HBV) and tetanus were determined and correlated with clinical characteristics. Nine patients never relapsed after more than 2 years from the last anti-CD20 administration (5 after the first, 3 after the second, and 1 after the fifth infusion). At last follow-up, most patients showed a complete recovery and normalization of total (27/27), transitional (27/27), and mature-naïve B cells (25/27). However, a sustained and significant reduction of total memory (20/27) and switched memory (21/27) B cells was found in most patients. 11/27 patients showed hypogammaglobulinemia at last follow-up and, among these, four presented with a severe hypogammaglobulinemia (IgG < 160 mg/dl). In contrast, no patient in the control group developed a severe hypogammaglobulinemia. Age at the time of first anti-CD20 administration was positively associated with IgG levels at last follow-up (p = 0.008); accordingly, younger patients had an increased risk of hypogammaglobulinemia (p = 0.006). Furthermore, severe hypogammaglobulinemia and delayed switched memory B-cell reconstitution were more frequent in non-relapsing patients. Reduced IgG levels against HBV and tetanus were observed at baseline and further declined at last follow-up. Antigen-specific memory B-cells were induced by re-immunization, but specific IgG titers remained low. In conclusion, anti-CD20 therapy can be disease-modifying in some INS patients. However, a prolonged impairment of immunological memory occurs frequently, independently from the number of anti-CD20 infusions, particularly in younger patients. Re-immunization may be necessary in these patients.

Consecutive episodes of heart and kidney failure in an "otherwise" healthy young man

BACKGROUND

Acute renal failure is a rare occurrence in a patient with an unremarkable past medical history and should always lead to an in depth clinical study. The occurrence in the same healthy young subject, of consecutive episodes of heart failure and of acute renal failure is an even rarer event and should prompt diagnostic tests and restrict the diagnostic hypotheses.

CASE PRESENTATION

We present the case of a 28 year-old man who, while waiting to undergo assessment for a mild chronic kidney disease, was diagnosed with decompensated dilated cardiomyopathy and placed on diuretics and β-blockers. After few weeks he developed a non oligoanuric acute renal failure with a slight elevation of serum calcium. Renal biopsy proved suggestive for renal sarcoidosis; thus the hypothesis of systemic sarcoidosis with cardiac and renal involvement was possible avoiding further delay in initiation of therapy.

CONCLUSIONS

Cardiac sarcoidosis is usually silent but the majority of cases are diagnosed when cardiac symptoms are present in a patient with systemic sarcoidosis. Renal involvement with granulomatous interstitial nephritis is also quite rare and can be an unexpected finding at kidney biopsy. This case highlights the need to evaluate thoroughly clinical problems that do not fit in a specific scenario and emphasizes the importance of performing a kidney biopsy in case of kidney failure of unknown etiology.

B cell phenotype in pediatric idiopathic nephrotic syndrome

BACKGROUND

A pathogenic role of B cells in non-genetic nephrotic syndrome has been suggested by the efficacy of rituximab, a B cell depleting antibody, in maintaining a prolonged remission. However, little information is available on B cell homeostasis in nephrotic syndrome patients.

METHODS

We retrospectively analyzed by flow cytometry the distribution of different B cell subpopulations in 107 steroid-sensitive and in 6 genetic steroid-resistant nephrotic syndrome pediatric patients, compared with age- and sex-matched controls.

RESULTS

Fifty-one steroid-sensitive patients at disease onset, before starting immunosuppression, presented significantly increased levels of total, transitional, memory, and switched memory B cells compared to controls. Oral immunosuppression strongly affected transitional and mature B cell levels in 27 patients in relapse and also in 29 patients in remission, whereas memory B cells were significantly higher compared to controls during relapse, despite the immunosuppressive treatment, and were normalized only in patients in remission. Children with genetic forms of steroid-resistant nephrotic syndrome presented no differences in B cell profile from controls.

CONCLUSIONS

Our study indicates that memory B cells, more than other B cell subsets, are increased and appear to be pathogenically relevant in steroid-sensitive nephrotic syndrome pediatric patients.

Inhibitory Effect of Retinoids on the Generation of Procoagulant Activity by Blood Mononuclear Phagocytes

Retinoids are known to modulate several functions of mononuclear phagocytes. We have studied the effect of retinyl acetate (RAc) and retinoic acid (RA) on the production of procoagulant activity (PCA) by human peripheral blood mononuclear cells stimulated with endotoxin (1 εg/ml, 4 or 20 h at 37°C). Both compounds caused a dose-dependent reduction in the expression of cell-associated PCA (from 86 to <10% of control in the range of concentration comprised between 0.1 and 100 εM). This effect was also observed when the cells were exposed to retinoids for 10 min and washed before challenge with endotoxin, indicating that it is rapid and irreversible. In contrast, incubation of RAc or RA for 3 h at 37° C with cells that have been already stimulated with endotoxin (20 h at 37° C) remained without influence on cell PCA. The inhibitory action of retinoids was also observed when monocyte-enriched (>85%) preparations or highly purified monocyte-derived macrophages (>99%) were used instead of whole mononuclear cells. BW755C, an inhibitor of cyclo-oxygenase and lipoxygenase, reversed the inhibitory effect of retinoids, whereas acetylsalycilic acid, an inhibitor of cyclo-oxygenase, was inactive, suggesting the involvement of a lipoxygenase product. The inhibition of monocyte/macrophage PCA production and the subsequent reduction of cell potential for fibrin deposition might represent one of the mechanisms whereby retinoids exert their antiinflammatory and immunomodulatory activities.

Properties of Chimeric (Tissue-Type/Urokinase-Type) Plasminogen Activators Obtained by Fusion at the Plasmin Cleavage Site

Two hybrid plasminogen activators (K2tu-PA and FK2tu-PA), linking the kringle 2 domain or the finger plus the kringle 2 domains of tissue-type plasminogen activator (t-PA) to the catalytic domain of single-chain urokinase-type plasminogen activator (scu-PA) were studied. At variance with similar constructs previously reported, they were obtained by fusion of the t-PA and scu-PA derived portions at their plasmin cleavage site (between Arg275 of t-PA and Ile159 of scu-PA), thus eliminating from scu-PA the two peptide bonds (Glu143-Leu144 and Arg156-Phe157) that lead to low molecular weight scu-PA and to thrombin-inactivated tcu-PA. The specific activities of K2tu-PA and FK2tu-PA, as measured by fibrin plate were 2.5 × 106 and 1.0 × 106 t-PA equivalent units/mg, respectively. Activation of plasminogen by hybrid PAs was stimulated by both CNBr-digested fibrinogen (40- and 80-fold) and Des-A-fibrin monomers (6- and 12-fold). The relatively weak stimulation of chimeric PAs by minimally degraded fibrin monomers was consistent with their reduced fibrin binding capacity. Like scu-PA, the chimeric PAs, in the single-chain form, were insensitive to inhibition, as they retained full activity after prolonged incubation in plasma and did not interact with SDS-reactivated recombinant PAI-1. The concentration producing 50% lysis of blood clots in 3 h was 0.5 μg/ml for K2tu-PA and 1 μg/ml for FK2tu-PA, as compared to 0.5 μg/ml and >2 μg/ml for t-PA and scu-PA, respectively. Plasminogen and α2-antiplasmin consumption induced by the hybrid PAs in clot-free plasma was comparable to (K2tu-PA) or lower than (FK2tu-PA) that induced by either t-PA or scu-PA. When exposed to plasmin, the hybrids were completely converted into two-chain molecules with full enzymatic activity. At variance with u-PA, however, the two-chain recombinant activators still required fibrin for full expression of activity. These data indicate that the products of such “artificial” fusion behave like true chimeras without loss of biological activity. The insensitivity to thrombin inactivation and to the proteolytic cleavage leading to low molecular weight scu-PA might confer enhanced stability to the molecules, especially at thrombus level. Moreover, if the thrombolytic activity observed in vitro is maintained in vivo, the prolonged half life of these hybrids should result in higher plasma levels of activator and thus in more extensive and rapid lysis.

Unbalanced Coagulation-Fibrinolysis Potential during L-Asparaginase Therapy in Children with Acute Lymphoblastic Leukaemia

Treatment of acute lymphoblastic leukaemia (ALL) with L-asparaginase (L-asp) may be associated with thrombotic complications, but the pathogenetic mechanisms of thrombus formation and persistence remain unclear. We studied the procoagulant activity (PCA) of peripheral blood mononuclear cells and some components of the plasma fibrinolytic system in L0 children with ALL undergoing remission induction therapy which includes L-asp. Mononuclear cells obtained 14 days after starting L-asp treatment generated significantly higher amounts of PCA (identified as tissue factor) than cells isolated before the first dose of L-asp and 7 days after the cessation of L-asp administration (p <0.01). Augmented PCA coincided with an increase in the plasma D-dimer. The plasma levels of type 1- plasminogen activator inhibitor were found signiticantly elevated during L-asp therapy (p <0.05), whereas plasminogen levels were markedly decreased (p <0.05). These findings suggest that, during the course of L-asp treatment, the coagulation-fibrinolysis balance is shifted towards promotion of fibrin formation and deposition. Although it remains to be conclusively established whether Lasp per se or the concurrent administration of multiple chemotherapeutic agents is responsible for these changes, the latter could contribute to the thrombotic complications associated with remission induction therapy for ALL.

Increased Mononuclear Cell Tissue Factor and Type-2 Plasminogen Activator Inhibitor and Reduced Plasma Fibrinolytic Capacity in Children with Lymphoma

Blood clotting activation and fibrin deposition are common findings in lymphoma patients. We evaluated the capacity of peripheral blood mononuclear cells to produce procoagulant activity (PCA) and plasminogen activator inhibitor (PAI) in 12 children with newly diagnosed lymphoma (8 non-Hodgkin’s, 4 Hodgkin’s) and in 12 matched healthy donors. In the same subjects we also measured plasma antigen levels of tissue-type PA (t-PA), urokinase-type PA (u-PA), PAI-1, PAI-2, and D-dimer. PCA generated by mononuclear cells after incubation for 20 h at 37° C was significantly higher in patients than in controls (p = 0.027). In all samples it was identified as tissue factor by functional criteria (dependence on factor VII). Moreover, culture medium obtained from patients’ mononuclear cells after incubation for 20 h at 37° C contained significantly higher amounts of PAI activity and PAI-2 antigen than control samples (p <0.001). Plasma PAI-1 and t-PA antigens were significantly augmented in patients (p <0.005), the mean increase of PAI-I being about 5 times higher than that of t-PA. Plasma levels of D-dimer wete markedly increased in the patients’ group (p <0.001), whereas u-PA and PAI-2 antigens did not differ from controls. It is suggested that monocytes from lymphoma patients are endowed with functional abnormalities leading to the simultaneous expression of tissue factor and antifibrinolytic activity. These abnormalities, coupled with a reduced plasma fibrinolytic potential, could play an important pathogenetic role in blood clotting activation and fibrin deposition associated with lymphoma.

Complement-Dependent and Complement-Independent Interactions of Bacterial Lipopolysaccharides and Mucopeptides with Rabbit and Human Platelets

The effect of 10 commercial lipopolysaccharides (LPS) and of 5 highly purified LPS with variable but defined polysaccharide content, two LPS from anaerobic bacteria, two mucopeptides and two meningococcal polysaccharides, was studied on rabbit and human platelets. All the LPS preparations induced aggregation in rabbit heparinized platelet-rich plasma (PRP) but to differing degrees. However, a preparation consisting essentially of lipid A (from Salmonella minnesota Re 595) was one of the most active. The mucopeptides were very potent whereas the meningococcal polysaccharides had no effect. The activity was abolished by inactivation of complement. The lack of ability of LPS and mucopeptides to aggregate rabbit platelets in ethyleneglycol tetraacetic acid (EGTA) – PRP suggests that the mechanism depends on activation of the classical pathway of complement. None of the bacterial products induced aggregation of human platelets.

When washed rabbit platelets are mixed with complement-depleted rabbit serum and calcium chloride, generation of thrombin occurs. Washed platelets contribute to thrombin generation by providing factor V, a factor X activating activity, and possibly phospholipid (Brit. J. Haemat. 36: 107, 1977). All the LPS preparations but not the mucopeptides or meningococcal polysaccharides enhanced the rate of thrombin formation by enhancing the factor X activating activity of rabbit or human platelets.

It is concluded that LPS affect rabbit platelets both by complement-dependent and complement-independent mechanisms, but human platelets only by the complement- independent pathway. Mucopeptides react with platelets only by the complement-dependent way and have no effect on human platelets.

Therapeutic Effect of a Low Molecular Weight Dermatan Sulphate (Desmin 370) in Rat Venous Thrombosis - Evidence for an Anticoagulant-Independent Mechanism

We evaluated the capacity of a low molecular weight dermatan sulphate (D370) to prevent thrombus formation and to induce a reduction of a stabilized thrombus in a rat venous thrombosis model. Injection of D370, 10 min before induction of venous stasis (prevention model), prevented thrombus formation in a dose-dependent way (ED50: 2.3 mg/kg). When given to rats 6 h after induction of venous stasis (therapeutic model), D370 caused a time- and dose-dependent reduction in thrombus size (60% to 70% reduction 2 h after injection of 10 mg/kg). At comparable antithrombotic dosages (i.e. minimum dose giving complete inhibition of thrombus formation), heparin (0.5 mg/kg) only caused 40% reduction of a preformed thrombus while hirudin (1 mg/kg) was virtually ineffective (less than 10% reduction in weight). All three compounds inhibited 125I-fibrin(ogen) deposition on 6-h aged thrombi by more than 85%, suggesting that D370 and, to a lesser extent, heparin reduce thrombus size via mechanisms other than inhibition of thrombus accretion. The involvement of a fibrinolysis-mediated mechanism in the D370-induced effect is suggested by the following. EACA (1 g/kg), when given to thrombus-bearing control animals, did not influence thrombus weight. However, when administered before D370 treatment, it prevented the expected reduction in thrombus weight by more than 80%, without influencing the effect of D370 on 125I-fibrin(ogen) accumulation onto preexisting thrombi. D370 injection caused neither an enhancement of fibrinolytic activity nor a reduction of PAI in plasma. In vitro, D370 (200 μg/ml) was unable to potentiate the spontaneous or PA-induced lysis of 125I-fibrinogen labelled blood, plasma, or purified fibrin clots. It is suggested that prevention of thrombus formation by D370 is related mainly to inhibition of blood coagulation, whereas reduction of the weight of aged thrombi is primarily due to an anticoagulant-independent mechanism, most probably involving local enhancement of the fibrinolytic process. D370 may represent an alternative pharmacologic agent both in the prevention and in the therapy of venous thrombosis.

Transethnic, Genome-Wide Analysis Reveals Immune-Related Risk Alleles and Phenotypic Correlates in Pediatric Steroid-Sensitive Nephrotic Syndrome

Background Steroid-sensitive nephrotic syndrome (SSNS) is a childhood disease with unclear pathophysiology and genetic architecture. We investigated the genomic basis of SSNS in children recruited in Europe and the biopsy-based North American NEPTUNE cohort.Methods We performed three ancestry-matched, genome-wide association studies (GWAS) in 273 children with NS (Children Cohort Nephrosis and Virus [NEPHROVIR] cohort: 132 European, 56 African, and 85 Maghrebian) followed by independent replication in 112 European children, transethnic meta-analysis, and conditional analysis. GWAS alleles were used to perform glomerular cis-expression quantitative trait loci studies in 39 children in the NEPTUNE cohort and epidemiologic studies in GWAS and NEPTUNE (97 children) cohorts.Results Transethnic meta-analysis identified one SSNS-associated single-nucleotide polymorphism (SNP) rs1063348 in the 3' untranslated region of HLA-DQB1 (P=9.3×10-23). Conditional analysis identified two additional independent risk alleles upstream of HLA-DRB1 (rs28366266, P=3.7×10-11) and in the 3' untranslated region of BTNL2 (rs9348883, P=9.4×10-7) within introns of HCG23 and LOC101929163 These three risk alleles were independent of the risk haplotype DRB1*07:01-DQA1*02:01-DQB1*02:02 identified in European patients. Increased burden of risk alleles across independent loci was associated with higher odds of SSNS. Increased burden of risk alleles across independent loci was associated with higher odds of SSNS, with younger age of onset across all cohorts, and with increased odds of complete remission across histologies in NEPTUNE children. rs1063348 associated with decreased glomerular expression of HLA-DRB1, HLA-DRB5, and HLA-DQB1.Conclusions Transethnic GWAS empowered discovery of three independent risk SNPs for pediatric SSNS. Characterization of these SNPs provide an entry for understanding immune dysregulation in NS and introducing a genomically defined classification.

Impaired Fibrinolysis in Obstructive Jaundice - Evidence from Clinical and Experimental Studies

Microvascular thrombosis is considered an important pathogenetic factor in renal failure associated with obstructive jaundice but the mechanisms leading to fibrin deposition are still unknown. The plasma levels of plasminogen activator inhibitor (PAI) in 29 patients with obstructive jaundice were found significantly increased as compared to 20 nonjaundiced patients. Fibrin autography of plasma supplemented with tissue plasminogen activator (t-PA) revealed that in icteric samples most of the added activator migrated with an apparent Mr of 100 kDa, corresponding to t-PA-PAI complex, whereas in control samples virtually all t-PA migrated as free enzyme. PAI activity detected in icteric samples is similar to the endothelial type PAI since it is neutralized by a monoclonal antibody against PAI-1.

Venous stasis in jaundiced patients was neither associated with an increase in blood fibrinolytic activity nor with a decrease in PAI activity. Immunologic assay showed that t-PA release was impaired in 3 out of 4 patients. In controls, venous occlusion induced an increase in both fibrinolytic activity and t-PA antigen and a reduction in PAI activity. Bile duct recanalization in jaundiced patients subjected to surgery was accompanied by a decrease in plasma PAI activity which paralleled the decrease in serum bilirubin levels. In nonjaundiced patients, surgical treatment did not cause significant changes in either parameter. Rabbits made icteric by bile duct ligation showed an early and progressive increase in plasma PAI activity indicating that obstructive jaundice itself causes the elevation of circulating PAI. It is concluded that obstructive jaundice is associated with a severe impairment of fibrinolysis which might contribute to microvascular thrombosis and renal failure.

Nephrotic-Range Proteinuria and Peripheral Edema in a Child: Not Only Idiopathic Nephrotic Syndrome

Hemolytic uremic syndrome (HUS) is defined by the simultaneous occurrence of hemolytic anemia, thrombocytopenia, and acute kidney injury due to thrombotic microangiopathy (TMA) mainly occurring in renal and cerebral microvessels. Although the most common cause of HUS in children is Shiga toxin-producing Escherichia coli, atypical forms in which Shiga toxin is not the trigger may occur. Research over the last few years has shown that complement dysregulation secondary to mutations of genes coding for proteins involved in the regulation of the alternative pathway of complement account for most forms of atypical HUS (aHUS). Among these, thrombomodulin (THBD) gene mutations, representing 3–5% of all alternative pathway complement component abnormalities, correlate with early disease onset and rapid evolution to end-stage renal failure. aHUS onset is generally sudden, but occasionally the only manifestations of renal TMA are arterial hypertension, proteinuria, and a progressive increase in serum creatinine. Nephrotic syndrome at disease onset is exceptional. We describe the case of an adolescent female who presented with peripheral edema due to nephrotic-range proteinuria with bioptic evidence of TMA. Study of the alternative complement pathway showed a heterozygous missense THBD gene mutation (P501L variant) consistent with aHUS diagnosis. One year later she developed clinical signs of hemolytic anemia. Eculizumab, an anti-C5 monoclonal antibody, was started with rapid improvement. This case report highlights the phenotypic variability in aHUS due to THBD gene mutation. Early diagnosis by renal biopsy followed by genetic screening is required to optimize management in such a rare disease with a severe prognosis.

Reduced fibrinolytic resistance in patients with factor XI deficiency. Evidence of a thrombin-independent impairment of the thrombin-activatable fibrinolysis inhibitor pathway

Essentials Plasma of factor XI-deficient patients (FXI-dp) displays enhanced fibrinolysis. We investigated the role of thrombin activatable fibrinolysis inhibitor (TAFI) in 18 FXI-dp. FXI-dp generated less activated TAFI (TAFIa) on clotting challenge and were resistant to TAFIa. TAFI activation and TAFIa resistance correlated with bleeding score and bleeding phenotype.

SUMMARY

Background Factor XI (FXI) deficiency, a rare disorder with unpredictable bleeding, has been associated with reduced fibrinolytic resistance as a result of abnormal fibrin density. Objective We investigated the involvement of thrombin-activatable fibrinolysis inhibitor (TAFI) in the increased lysability of FXI-deficient (FXI-def) clots and the role of thrombin. Patients/Methods Eighteen patients with FXI deficiency (1-58%) and 17 matched controls were investigated for fibrinolytic resistance to t-PA, thrombin generation, TAFI activation and response to TAFIa. Results When clotting was induced by 0.5 pm tissue factor (TF), FXI-def plasmas displayed less thrombin and TAFIa generation and shorter lysis time than controls. A 100-fold higher TF concentration (to bypass FXI) abolished the difference in thrombin generation but not in lysis time between patients and controls. Normalization of FXI levels by a FXI concentrate increased thrombin generation but had no effect on the lysis time of FXI-def plasma. Moreover, when clots were induced by purified thrombin and high concentrations of FXa inhibitor, FXI-def plasma still generated less TAFIa and displayed a shorter lysis time than controls. Finally, upon TAFIa addition, the lysis time of FXI-def plasma was prolonged significantly less than that of control plasma, suggesting a TAFIa resistance. TAFIa generation and TAFIa resistance were correlated with the bleeding score, displaying a considerable capacity to discriminate between patients with and without bleeding. Conclusions TAFI pathway impairment, largely caused by a hitherto unknown TAFIa resistance, appears to be one main cause of decreased fibrinolytic resistance in FXI deficiency and might be clinically useful for assessing the bleeding risk of FXI-def patients.

The 14-3-3 protein in multiple sclerosis: a marker of disease severity

Context: In multiple sclerosis (MS) axonal damage is an early event and is probably to be considered the most relevant cause of permanent and progressive disability. Objectives: To investigate the value of the increase of 14-3-3 and tau proteins in the cerebrospinal fluid (CSF) as peripheral markers of axonal pathology and predictors of disease evolution. Patients and methods: In the CSF samples obtained from 63 patients with demyelinating diseases (DD), including 20 clinically isolated syndromes (CIS) and 43 clinically defined MS, as well as from 56 controls, we analysed the presence of 14-3-3 reactivity by immunoblot analysis along with the concentration of tau protein by sandwich ELISA. Results: The percentage of DD subjects showing a positive 14-3-3 protein CSF reactivity (38%) was significantly higher than the one previously detected, and was correlated in the MS patients with a more severe clinical phenotype in terms of degree of disability and rate of disease progression, during a 10-month mean clinical follow-up. On the contrary, the levels of the CSF-tau protein were highly variable in DD and control subjects, and the mean CSF-tau concentration was similar in both groups. Conclusions: The immunoblot analysis of 14-3-3 protein in the CSF could be a useful marker to identify a subgroup of DD patients with high risk of developing severe disability.

B Cell Reconstitution after Rituximab Treatment in Idiopathic Nephrotic Syndrome

The pathogenesis of nephrotic syndrome is unclear. However, the efficacy of rituximab, a B cell-depleting antibody, in nephrotic syndrome suggests a pathogenic role of B cells. In this retrospective study, we determined by flow cytometry levels of B and T cell subpopulations before and after rituximab infusion in 28 pediatric patients with frequently relapsing or steroid-dependent nephrotic syndrome. At baseline, patients had lower median percentages of transitional and mature B cells than age-matched healthy controls (P<0.001). Rituximab induced full depletion of B cells (<1% of lymphocytes). At 1 year, most patients exhibited complete total and mature B cell recovery, whereas memory B cell subsets remained significantly depleted. Total T cell concentration did not change with rituximab, whereas the CD4(+)/CD8(+) T cell ratio tended to increase. Fourteen patients relapsed within 24 months, with a median follow-up of 11.2 months (interquartile range, 8-17.7 months). We observed no difference at baseline between nonrelapsing and relapsing patients in several clinical parameters and cell subset concentrations. Reconstitution of all memory B cell subpopulations, number of immunosuppressive drugs, and dose of tacrolimus during the last 4 months of follow-up were predictive of relapse in univariate Cox regression analysis. However, only delayed reconstitution of switched memory B cells, independent of immunosuppressive treatment, was protective against relapse in multivariate (P<0.01) and receiver operator characteristic (P<0.01 for percentage of lymphocytes; P=0.02 for absolute count) analyses. Evaluation of switched memory B cell recovery after rituximab may be useful for predicting relapse in patients with nephrotic syndrome.

Sialylation of N-linked glycans influences the immunomodulatory effects of IgM on T cells

Human serum IgM Abs are composed of heavily glycosylated polymers with five glycosylation sites on the μ (heavy) chain and one glycosylation site on the J chain. In contrast to IgG glycans, which are vital for a number of biological functions, virtually nothing is known about structure-function relationships of IgM glycans. Natural IgM is the earliest Ig produced and recognizes multiple Ags with low affinity, whereas immune IgM is induced by Ag exposure and is characterized by a higher Ag specificity. Natural anti-lymphocyte IgM is present in the serum of healthy individuals and increases in inflammatory conditions. It is able to inhibit T cell activation, but the underlying molecular mechanism is not understood. In this study, to our knowledge, we show for the first time that sialylated N-linked glycans induce the internalization of IgM by T cells, which in turn causes severe inhibition of T cell responses. The absence of sialic acid residues abolishes these inhibitory activities, showing a key role of sialylated N-glycans in inducing the IgM-mediated immune suppression.

[Improving vaccination social marketing by monitoring the web]

Immunisation is one of the most important and cost- effective interventions in Public Health because of their significant positive impact on population health.However, since Jenner's discovery there always been a lively debate between supporters and opponents of vaccination; Today the antivaccination movement spreads its message mostly on the web, disseminating inaccurate data through blogs and forums, increasing vaccine rejection.In this context, the Società Italiana di Igiene (SItI) created a web project in order to fight the misinformation on the web regarding vaccinations, through a series of information tools, including scientific articles, educational information, video and multimedia presentations The web portal (http://www.vaccinarsi.org) was published in May 2013 and now is already available over one hundred web pages related to vaccinations Recently a Forum, a periodic newsletter and a Twitter page have been created. There has been an average of 10,000 hits per month. Currently our users are mostly healthcare professionals. The visibility of the site is very good and it currently ranks first in the Google's search engine, taping the word "vaccinarsi" The results of the first four months of activity are extremely encouraging and show the importance of this project; furthermore the application for quality certification by independent international Organizations has been submitted.

Monoclonal antibodies targeting the antifibrinolytic activity of activated thrombin-activatable fibrinolysis inhibitor but not the anti-inflammatory activity on osteopontin and C5a

BACKGROUND

Recently, anti-thrombin-activatable fibrinolysis inhibitor (TAFI) mAbs selectively inhibiting plasmin-mediated TAFI activation were shown to stimulate fibrinolysis in vitro and in vivo, suggesting, in contrast to other findings, that plasmin-mediated TAFI activation plays an important role in fibrinolysis regulation.

OBJECTIVE

To further characterize the effects of two plasmin-specific anti-TAFI mAbs (MA-TCK11A9 and MA-TCK26D6) on TAFI-dependent inhibition of fibrinolysis.

METHODS AND RESULTS

Both mAbs inhibited plasmin-mediated but not thrombin/thrombomodulin-mediated TAFI activation, whereas neither inhibited the cleavage of hippuryl-arginine by activated TAFI (TAFIa). They stimulated tissue-type plasminogen activator-induced fibrinolysis in different clot lysis models through a TAFI-dependent mechanism, especially in the presence of thrombomodulin (TM), a condition in which TAFI is largely activated by the thrombin-TM complex. In a fibrinolysis-based TAFIa activity assay, both mAbs inhibited TAFIa, whereas other mAbs targeting thrombin-TM-mediated TAFI activation did not. The inhibition of TAFIa activity, however, was substrate-specific, because neither mAb inhibited the cleavage of thrombin-activated osteopontin and C5a by TAFIa, thus sparing the anti-inflammatory activity of TAFIa.

CONCLUSIONS

Our anti-TAFI mAbs, by selectively inhibiting TAFIa activity on fibrin, may represent the prototype of a new class of TAFI inhibitors with improved pharmacologic activity.

Effect of warfarin treatment on thrombin activatable fibrinolysis inhibitor (TAFI) activation and TAFI-mediated inhibition of fibrinolysis

BACKGROUND

Severe clotting deficiencies are associated with enhanced in vitro fibrinolysis due to insufficient thrombin activatable fibrinolysis inhibitor (TAFI) activation. Because oral anticoagulant therapy (OAT) with warfarin causes a partial deficiency of vitamin K-dependent factors, its effect on clot lysability remains unclear.

OBJECTIVES

To evaluate plasma and blood fibrinolytic capacity in patients under stable OAT (n = 221) as compared with controls (n = 132).

METHODS

Fibrinolysis resistance of plasma (turbidimetry) and blood (thromboelastography) clots was calculated as the lysis time of tissue factor-induced clots exposed to 30 and 100 ng mL(-1) t-PA, respectively.

RESULTS

Plasma PAI-1 was similar in the two groups, whereas TAFI was slightly lower in patients. OAT plasma clots lysed faster than controls (P = 0.001). The addition of the TAFIa inhibitor PTCI reduced lysis time by 14% in OAT and 34% in controls, and the difference between the groups disappeared. Similar data were obtained with blood clots. Thrombin and TAFIa generation in OAT plasma amounted to roughly 50% of controls, supporting a reduced thrombin-dependent TAFI activation. Clot resistance of OAT plasma was normalized by Ba-citrate plasma eluate or prothrombin but not by BaSO(4) serum eluate, rFVIIa or FX. Surprisingly, circulating levels of TAFIa and its inactive derivative TAFIai were higher in warfarin patients (P < 0.0001) and correlated with plasmin-antiplasmin (P = 0.0001) but not with prothrombin F(1) (+) (2) .

CONCLUSIONS

OAT enhances both plasma and blood fibrinolysis by reducing thrombin-dependent TAFI activation, a phenomenon largely determined by low prothrombin levels. At variance with in vitro data, 'basal' in vivo TAFIa/ai levels seem related to plasmin rather than thrombin generation.

Factors associated with access to antiviral treatment in a multicentre cross-sectional study of patients with chronic hepatitis B in Italy

A multicentre cross-sectional survey was performed to provide an accurate picture of patients with chronic hepatitis B (CHB) cared for by Italian Infectious Diseases Centers (IDCs). This analysis describes factors associated with access to the treatment of CHB in a country where barriers to treatment are not expected to exist because of comprehensive coverage under the National Health System (NHS). The study was performed in 74 IDCs. The analysis focused on 3305 patients with CHB of 3760 HBsAg-positive patients enrolled from March to September, 2008. To account for missing values, a Multiple Imputation method was used. Treatment was reported in 2091 (63.3%) patients. In the multivariate analysis, an increased chance of getting treatment was independently associated with 10 years increase of age at diagnosis (adjusted odds ratio [aOR] 1.2, 95% confidence interval [CI] 1.1-1.3, P < 0.001), HBeAg positivity (aOR 1.8, 95% CI 1.1-2.8, P < 0.001), cirrhosis (aOR 3.6, 95% CI 2-6.3, P = 0.012), HDV (aOR 1.6, 95% CI 1.02-2.5, P = 0.042) and HIV positivity (aOR 6.5, 95% CI 4-10.8, P < 0.001). Conversely, a decreased chance was associated with female gender (aOR 0.6, 95% CI 0.5-0.7, P < 0.001), immigration (aOR 0.6, 95% CI 0.5-0.9, P = 0.009), alcohol consumption (aOR 0.7, 95% CI 0.5-0.98, P = 0.04) and HCV positivity (aOR 0.5, 95% CI 0.3-0.8, P = 0.005). Our study shows that Italian IDCs treat a high percentage of patients with CHB. Nevertheless, disparities exist which are not related to the severity of disease limiting access to antiviral therapy of CHB, even in a country with a universal healthcare system.

Protein glutathionylation in cellular compartments: a constitutive redox signal

Glutathione provides means of regulating protein function by the process of glutathionylation. Despite the role of oxidative stress biomarkers assumed recently by glutathionylated proteins in human diseases, so far no information is available on the intracellular distribution of glutathionylated proteins in human cell lines. In this study, we combined the specificity of monoclonal antibody labeling for protein-bound glutathione (GS-Pro) with the ability of confocal microscopy to localize molecules with high spatial resolution. We performed immunofluorescence analysis on dermal fibroblasts, both in steady state than in proliferative conditions, and on in situ extracted matrix samples. For the first time, we report the compartmentalization of constitutively glutathionylated proteins in different subcellular districts and we found a tight association between glutathione, nuclear lamina, and cytoskeleton. In proliferating cells, total GS-Pro fluorescence increases in the early phases of growth and significantly drops when cells reach confluence. Interestingly, a nuclear shift of GS-Pro was observed between 6 and 48 hours after plating, becoming homogeneous with the cytoplasm when growth slows. The ability to visualize a detailed intracellular distribution of this critical marker of protein oxidation may provide an additional tool to highlight pathways in turns 'redox-activated' and to identify new pathogenic pathways in human diseases.

Rituximab in a childhood-onset idiopathic refractory chronic inflammatory demyelinating polyneuropathy

Childhood-onset chronic inflammatory demyelinating polyneuropathy (CIDP) are generally responsive to conventional immunosuppressant treatments. However about 20% of patients may be refractory to several treatments and the disease has poor outcome. Rituximab is becoming a promising treatment in selected adult cases of severe CIDPs. We report the effectiveness of Rituximab in a refractory childhood-onset CIDP and we suggest this treatment as an effective choice in unresponsive childhood CIDP.

Evaluation of immediate impact of cane use on energy expenditure during gait in patients with knee osteoarthritis

PURPOSE

The aim of the present study was to assess the immediate impact of cane use on energy expenditure during gait in patients with knee OA analyzing VO(2).

METHODS

An observational, cross-sectional study was carried out on 64 symptomatic patients with a diagnosis of knee OA. The assessment of energy expenditure was performed through an analysis of expired gases using the portable K4 apparatus (Cosmed, Model K4 b2, Italy) during the six-min walk test (6MWT). Two tests were performed with a cane and two without a cane on two different days within a seven-day period.

RESULTS

The patients walked farther on the test without the cane (p<0.001). Oxygen expenditure (VO(2)) and the O(2) cost of walking at the end of the 6MWT increased approximately 50% and 80% during cane-assisted gait when compared to gait without the use of a cane (p<0.001). Pain (Borg scale) decreased approximately 20% at the end of the 6MWT with cane-assisted gait in comparison to gait without a cane (p<0.001).

CONCLUSION

Cane use causes an immediate increase in energy expenditure (VO(2)) during gait and O(2) cost of walking and an immediate decrease of pain during gait. It is necessary to do a more prolonged follow up in order to assess the impact of daily cane use on energy expenditure among these patients and determine whether adaptation occurs. Furthermore, it is necessary to study whether daily cane use has a positive impact on important parameters in these patients, such as pain, function and quality of life.