Maintenance of remission of ANCA vasculitis by rituximab based on B cell repopulation versus serological flare: a randomised trial

OBJECTIVE

To compare two long-term remission maintenance strategies for antineutrophil cytoplasmic antibody (ANCA) vasculitis.

METHODS

We conducted a prospective, single-centre, open-label, randomised controlled trial of patients with ANCA vasculitis in remission after completing at least 2 years of fixed-schedule rituximab. In the B cell arm, rituximab was reinfused upon B cell repopulation; in the ANCA arm, rituximab was reinfused upon significant rise in ANCA level. Evaluations were conducted every 3 months. The primary endpoint was clinical relapse, defined as a modified BVAS/WG >0 by 36 months. Secondary endpoints included serious adverse events (SAEs) and rituximab exposure.

RESULTS

115 patients were enrolled. Median follow-up time was 4.1 years (IQR 2.5-5.0). By Kaplan-Meier analysis, 4.1% (95% CI 1.0 to 15.6) of patients had a clinical relapse in the B cell arm, compared with 20.5% (95% CI 11.9 to 34.1) in the ANCA arm, at 3 years after study entry (log-rank p=0.045). Total SAEs, including infectious SAEs, and deaths did not differ. The number of SAEs due to COVID-19 was higher in the B cell arm (p=0.049). In the B cell arm, patients received a mean of 3.6 (SD 2.4) infusions (3.6 g) per person over the median study follow-up time of 4.1 years, compared with 0.5 (SD 1.4) infusions (0.5 g) per patient in the ANCA arm (p<0.001).

CONCLUSIONS

Rituximab dosed for B cell repopulation results in fewer clinical relapses than when dosed for a rise in ANCA level in maintenance of remission for ANCA vasculitis. Overall safety was equivalent; SAEs due to COVID-19 and rituximab exposure were higher with the B cell strategy.

TRIAL REGISTRATION NUMBER

NCT02749292.

Nephrotic-range proteinuria: a potential risk factor for failure of tixagevimab-cilgavimab prophylaxis

BACKGROUND

Pre-exposure prophylaxis with tixagevimab-cilgavimab has been shown to reduce the incidence of SARS-CoV-2 infection in immunocompromised individuals. Individuals with nephrotic-range proteinuria can lose immunoglobulins such as tixagevimab-cilgavimab in the urine and, therefore, may derive less benefit from tixagevimab-cilgavimab. There are no published studies evaluating the association of nephrotic-range proteinuria with failure of tixagevimab-cilgavimab prophylaxis.

METHODS

We conducted a retrospective observational cohort study of all individuals at our center who received tixagevimab-cilgavimab while they had nephrotic-range proteinuria. Each individual in the nephrotic group was matched 1:3 with controls who were matched for B cell depletion therapy in addition to the total dose and date of first tixagevimab-cilgavimab administration. The primary outcome was the development of breakthrough SARS-CoV-2 infection after receiving tixagevimab-cilgavimab.

RESULTS

Sixteen patients received tixagevimab-cilgavimab between January 1st, 2022, and June 30th, 2022, at a time when they had nephrotic-range proteinuria. Proteinuria levels and serum creatinine levels were higher while serum albumin levels were lower in the nephrotic group compared to the control group. At a median follow-up of 251 days, 38% of individuals in the nephrotic group had developed breakthrough SARS-CoV-2 infections, compared to only 13% in the control group at a median follow-up of 238 days. Nephrotic-range proteinuria was associated with a higher incidence of breakthrough infection (log-rank P = 0.04).

CONCLUSIONS

Nephrotic-range proteinuria may increase the risk of failure of tixagevimab-cilgavimab pre-exposure prophylaxis. Prospective studies to validate these findings and to evaluate the optimal dosing strategy of antibody-based prophylaxis in this group of patients are needed.

Small fiber neuropathy associated with ANCA positivity: a case series and brief literature review

INTRODUCTION

Small fiber neuropathy [SFN] is a common peripheral neurologic disorder with a vast array of implicated etiologies. It has previously been proposed that some forms of immune-mediated small fiber neuropathy are driven by vasculitis, though antinuclear cytoplasmic antibodies [ANCA] antibodies have not commonly been reported in association with SFN, thus far. We present this case series to discuss the observation of a possible novel association between ANCA and SFN.

METHODS

This is a retrospective case series of 6 patients with SFN and ANCA positivity, with and without systemic manifestations. Patients included were diagnosed with SFN by skin biopsy or autonomic function testing and were seropositive for ANCA by ELISA.

RESULTS

Six patients are outlined, including 4 females and 2 males. Antigen specific antibodies were MPO alone in 4 cases, PR3 alone in 1 case and both MPO and PR3 in 1 case. Systemic vasculitis was noted in 2 patients. Five patients received immunosuppression. Three patients experienced partial improvement, while symptoms stabilized in 3 patients.

DISCUSSION

This is the first series of patients with suspected immune-mediated SFN and ANCA antibody positivity, raising the possibility of ANCA mediated isolated SFN. This is in contradistinction to the more typical ANCA-mediated peripheral neuropathy manifestations of mononeuropathy multiplex or axonal sensorimotor neuropathy. We cannot unequivocally prove ANCA-associated vasculitis [AAV] causality in these cases; however, the stabilization in SFN symptomatology and associated improvement in ANCA antibody titer, after AAV treatment, may be indicative of an association.

Humanistic and Economic Burden of IgA Nephropathy: Systematic Literature Reviews and Narrative Synthesis

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is a progressive inflammatory kidney disease requiring long-term treatment to reduce the risk of progression to kidney failure. Here, we present two systematic literature reviews (SLRs) to identify and summarize literature reporting the humanistic and economic burden of IgAN.

METHODS

Electronic literature databases (Ovid Embase, PubMed, and Cochrane) were searched for relevant literature on 29 November 2021, supplemented with gray literature searches. Studies reporting any health-related quality of life (HRQoL) or health state utility outcomes in IgAN patients were included in the humanistic impact SLR, and studies reporting the costs and healthcare resource utilization associated with or economic models of IgAN disease management were included in the economic burden SLR. Narrative synthesis was used to discuss the heterogeneous studies included in the SLRs. Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and Cochrane guidelines were followed, and all included studies were assessed for risk of bias using the Center for Evidence-Based Management tool for Critical Appraisal of a Survey or the Drummond Checklist.

RESULTS

A total of 876 and 1122 references were identified from electronic and gray literature searches for humanistic and economic burden, respectively. Three studies reporting humanistic impact and five studies reporting economic burden met criteria for inclusion in these SLRs. The included humanistic studies reported patient preferences in the USA and China, HRQoL for patients with IgAN in Poland, and impact of exercise on HRQoL for patients with IgAN in China. The five economic studies reported costs of IgAN treatment in Canada, Italy, and China, along with two economic models from Japan.

DISCUSSION

Current literature suggests IgAN is associated with substantial humanistic and economic burdens. However, these SLRs demonstrate the paucity of research conducted to specifically describe the humanistic or economic burden of IgAN and highlight the need for further research.

Paraneoplastic Glomerular Diseases

Paraneoplastic glomerular diseases (GNs) are rare manifestations in patients with underlying hematologic and solid organ malignancies and can occur before or after the detection of cancer. In the absence of established algorithms for investigation and reliable tests, they remain difficult to diagnose. Given the heterogeneity and infrequency of cases, the pathogenesis of most paraneoplastic GNs is poorly understood. Most of our recent understanding of paraneoplastic GNs has emerged from the discovery of target antigens in membranous nephropathy such as thrombospondin type-1 domain-containing protein 7A and neural epidermal growth factor-like 1 protein that appear to be promising in differentiating a primary vs paraneoplastic cause of membranous nephropathy. Treatment of paraneoplastic GNs is usually directed at the underlying malignancy. This review will focus on the epidemiology, pathogenesis, and diagnosis of paraneoplastic glomerular processes.

Association of renal transplantation with reduced risk of myocardial infarction and ischemic stroke in ANCA-associated vasculitis: An observational cohort study

OBJECTIVE

Myocardial infarction and ischemic stroke are leading causes of cardiovascular (CV) morbidity and mortality in ANCA-associated vasculitis (AAV), especially for the 20% with end-stage renal disease (ESRD). We assessed the impact of renal transplantation on the risk of myocardial infarction and stroke among patients with ESRD due to AAV.

METHODS

We identified patients from the United States Renal Data System with ESRD due to AAV between 2000 and 2016. We examined the association between renal transplantation and the risk of non-fatal and fatal myocardial infarction or ischemic stroke among waitlisted patients using Medicare claims and death data through 2017. We used time-varying Cox proportional hazards models with age as the time scale to estimate hazard ratios (HR) and 95% confidence intervals (CIs) for myocardial infarction and ischemic stroke events among patients who received a renal transplant compared to those who remained on the waitlist.

RESULTS

Of 1029 waitlisted patients, 593 (58%) were transplanted over a mean of 5.7 years. There were 17 events (4.6/1,000 person-years) in the transplanted group and 40 events (13.7/1,000 person-years) in the group that remained waitlisted. A renal transplant was associated with a 78% lower risk of myocardial infarction or ischemic stroke (HR=0.22, 95% CI 0.11 to 0.47). These findings persisted across sex and age groups and when censoring patients after living donor transplantation.

CONCLUSIONS

Among AAV patients with ESRD, renal transplantation can substantially reduce the risk of myocardial infarction and ischemic stroke. Improving access to transplantation for this population may further improve outcomes.

Combination of Rituximab, Low-Dose Cyclophosphamide, and Prednisone for Primary Membranous Nephropathy: A Case Series With Extended Follow Up

RATIONALE & OBJECTIVE

B-cell depletion with rituximab has emerged as a first-line therapy for primary membranous nephropathy (MN). However, most patients do not achieve complete remission with rituximab monotherapy. In this case series, we report longer-term remission and relapse rates, anti-phospholipase A₂ receptor (PLA₂R) antibody levels, B-cell levels, and serious adverse events in patients with primary MN who received rituximab combined with an initial short course of low-dose oral cyclophosphamide and a course of rapidly tapered prednisone.

STUDY DESIGN

Single-center retrospective case series.

SETTING & PARTICIPANTS

60 consecutive patients with primary MN treated with the combination of rituximab, low-dose cyclophosphamide, and prednisone at the Vasculitis and Glomerulonephritis Center at the Massachusetts General Hospital.

FINDINGS

After treatment initiation, median follow-up was 38 (interquartile range [IQR], 25-62) months; 100% of patients achieved partial remission, defined as a urinary protein-creatinine ratio (UPCR) < 3 g/g and a 50% reduction from baseline, at a median of 3.4 months. By 2 years after treatment initiation, 83% achieved complete remission, defined as a UPCR < 0.3 g/g. The median time to complete remission was 12.4 months. Immunologic remission (defined by an anti-PLA₂R titer < 14 RU/mL) was achieved by 86% and 100% of anti-PLA₂R seropositive patients (n = 29) at 3 and 6 months, respectively, after treatment initiation. After 1 year, the median UPCR fell from 8.4 (IQR, 5.0-10.7) to 0.3 (IQR, 0.2-0.8) g/g (P < 0.001). No patient relapsed throughout the duration of B-cell depletion. Relapse occurred in 10% of patients at 2 years after the onset of B-cell reconstitution following the last rituximab dose. Over a combined follow-up time of 228 patient-years, 18 serious adverse events occurred. One death occurred unrelated to treatment or primary MN, and 1 patient progressed to kidney failure requiring kidney replacement therapy.

LIMITATIONS

Absence of a comparison group.

CONCLUSIONS

All patients with primary MN treated with combination therapy achieved partial remission and most achieved a durable complete remission with an acceptable safety profile.

Rituximab in Membranous Nephropathy

Membranous nephropathy (MN) is the most common cause of primary nephrotic syndrome among adults. The identification of phospholipase A2 receptor (PLA2R) as target antigen in most patients changed the management of MN dramatically, and provided a rationale for B-cell depleting agents such as rituximab. The efficacy of rituximab in inducing remission has been investigated in several studies, including 3 randomized controlled trials, in which complete and partial remission of proteinuria was achieved in approximately two-thirds of treated patients. Due to its favorable safety profile, rituximab is now considered a first-line treatment option for MN, especially in patients at moderate and high risk of deterioration in kidney function. However, questions remain about how to best use rituximab, including the optimal dosing regimen, a potential need for maintenance therapy, and assessment of long-term safety and efficacy outcomes. In this review, we provide an overview of the current literature and discuss both strengths and limitations of "the new standard."

COVID-19 Recovery Without B Cells or Antibodies in Patients Receiving Rituximab for Autoimmune Disease

No Abstract.

Rituximab in adult minimal change disease and focal segmental glomerulosclerosis - What is known and what is still unknown?

Primary forms of minimal change disease and focal segmental glomerulosclerosis are rare podocytopathies and clinically characterized by nephrotic syndrome. Glucocorticoids are the cornerstone of the initial immunosuppressive treatment in these two entities. Especially among adults with minimal change disease or focal segmental glomerulosclerosis, relapses, steroid dependence or resistance are common and necessitate re-initiation of steroids and other immunosuppressants. Effective steroid-sparing therapies and introduction of less toxic immunosuppressive agents are urgently needed to reduce undesirable side effects, in particular for patients whose disease course is complex. Rituximab, a B cell depleting monoclonal antibody, is increasingly used off-label in these circumstances, despite a low level of evidence for adult patients. Hence, critical questions concerning drug-safety, long-term efficacy and the optimal regimen for rituximab-treatment remain unanswered. Evidence in the form of large, multicenter studies and randomized controlled trials are urgently needed to overcome these limitations.

Maternal gene expression profiling during pregnancy and preeclampsia in human peripheral blood mononuclear cells

Preeclampsia is a major obstetrical complication affecting maternal and fetal health. While it is clear that there is a substantial placental contribution to preeclampsia pathogenesis, the maternal contribution is less well characterized. We therefore performed a genome-wide transcriptome analysis to explore disease-associated changes in maternal gene expression patterns in peripheral blood mononuclear cells (PBMCs).

METHODS

Preeclampsia was defined as gestational hypertension, proteinuria and hyperurecimia. Total RNA was isolated from PBMCs obtained from women with uncomplicated pregnancies (n = 5) and women with preeclamptic pregnancies (n = 5). Gene expression analysis was carried out using Agilent oligonucleotide microarrays. Biological pathway analysis was undertaken using Ingenuity Pathway Analysis software. Quantitative real-time PCR (QRTPCR) was performed to validate the gene expression changes of selected genes in normotensive and preeclamptic patients (n = 12 each).

RESULTS

We identified a total of 368 genes that were differentially expressed in women with preeclampsia compared to normal controls with false discovery rate (FDR) controlled at 10%. In follow up experiments we further analyzed the expression levels of a number of genes that were identified as altered by the microarray data including survivin (BIRC5), caveolin (CAV1), GATA binding protein-1 (GATA1), signal tranducer and activator of transcription 1 (STAT1), E2F transcription factor-1 (E2F1), fibronectin-1 (FN1), interleukin-4 (IL-4), matrix metalloprotease-9 (MMP-9) and WAP four disulfide domain protein (WFDC-1) by QRTPCR. Additionally we performed immuno blot analysis and zymography to verify some of these candidate genes at the protein level. Computational analysis of gene function identified an anti-proliferative and altered immune function cellular phenotype in severe preeclamptic samples.

CONCLUSIONS

We have characterized the genome-wide mRNA expression changes associated with preeclampsia-specific genes in circulating maternal blood cells at the time of delivery. In addition to providing information relating to the biological basis of the preeclampsia phenotype, our data provide a number of potential biomarkers for use in the further characterization of this disease.

Altered global gene expression in first trimester placentas of women destined to develop preeclampsia

BACKGROUND

Preeclampsia is a pregnancy-specific disorder that remains a leading cause of maternal, fetal and neonatal morbidity and mortality, and is associated with risk for future cardiovascular disease. There are no reliable predictors, specific preventative measures or treatments other than delivery. A widely held view is that the antecedents of preeclampsia lie with impaired placentation in early pregnancy. Accordingly, we hypothesized dysregulation of global gene expression in first trimester placentas of women who later manifested preeclampsia.

METHODS

Surplus chorionic villus sampling (CVS) tissues were collected at 10-12 weeks gestation in 160 patients with singleton fetuses. Four patients developed preeclampsia, and their banked CVS specimens were matched to 8 control samples from patients with unaffected pregnancies. Affymetrix HG-U133 Plus 2.0 GeneChips were utilized for microarray analysis. Naïve Bayes prediction modeling and pathway analysis were conducted. qRT-PCR examined three of the dysregulated genes.

RESULTS

Thirty-six differentially expressed genes were identified in the preeclampsia placentas. qRT-PCR verified the microarray analysis. Thirty-one genes were down-regulated. Many were related to inflammation/immunoregulation and cell motility. Decidual gene dysregulation was prominent. No evidence was found for alterations in hypoxia and oxidative stress regulated genes.

CONCLUSIONS

To our knowledge, this is the first study to show dysregulation of gene expression in the early placentas of women approximately 6 months before developing preeclampsia, thereby reinforcing a placental origin of the disorder. We hypothesize that placentation in preeclampsia is compromised in the first trimester by maternal and fetal immune dysregulation, abnormal decidualization, or both, thereby impairing trophoblast invasion. Several of the genes provide potential targets for the development of clinical biomarkers in maternal blood during the first trimester. Supplementary materials are available for this article via the publisher's online edition.

Novel soluble Flt-1 isoforms in plasma and cultured placental explants from normotensive pregnant and preeclamptic women

Pregnant women who develop preeclampsia exhibit higher circulating levels of the soluble VEGF receptor-1 (sFlt-1). Recent findings suggest that soluble Flt-1 may contribute to the pathogenesis of preeclampsia by binding and neutralizing vascular endothelial growth factors (VEGF) and placental growth factor (PlGF). Existing literature identifies sFlt-1 as a 100 kDa glycoprotein, a product of an mRNA splice variant. We hypothesized that sFlt-1 expression may be more complex with multiple variants of sFlt-1 as well as multiple sources during normal pregnancy and preeclampsia. Using a combination of affinity purification of sFlt-1 by heparin-agarose and epitope specific antibodies, we performed Western blot analysis with epitope specific antibodies for sFlt-1. Plasma of preeclamptic women exhibits significantly higher amounts of a novel 145 kDa variant of sFlt-1, along with the 100 kDa isoform. We identified sFlt-1 variants in the conditioned medium from placental explant cultures that are hypoxia responsive with varying sizes, including 185, 145,100 and 60 kDa forms, as well as antigenicity. The 145 kDa was similar in antigenicity to the 100 kDa found in plasma whereas the 185 and 60 kDa sFlt-1 demonstrated different epitopes. Deglycosylation studies also confirm that there are multiple sFlt-1 polypeptides. Co-immunoprecipitation with VEGF suggests that these different sFlt isoforms can bind VEGF and therefore, may be of functional importance. Finally, comparison of sFlt-1 in the conditioned medium obtained from cultured cytotrophoblasts, peripheral blood mononuclear cells (PBMCs) and human uterine microvascular cells (HUtMVECs) exhibit mainly the100 kDa sFlt-1. Collectively these data suggest the presence of multiple isoforms of sFlt-1 in the circulation of women with preeclampsia as well as in uncomplicated pregnancies and the possibility of multiple sources. Placental hypoxia may contribute to sFlt-1 over expression but other regulatory mechanisms cannot be ruled out.

Circulating and placental endoglin concentrations in pregnancies complicated by intrauterine growth restriction and preeclampsia

Inadequate trophoblast invasion and spiral artery remodeling leading to poor placental perfusion and hypoxia are believed to underlie preeclampsia (PE) and intrauterine growth restriction (IUGR). Recent studies implicate increased circulating endoglin as a contributor to the pathogenesis of PE. The objective of this study was to determine whether placental and circulating endoglin concentrations are altered in pregnancies complicated by intrauterine growth restricted (IUGR) infants and to address the role of hypoxia on the regulation of placental endoglin. We analyzed 10 placentas each from normal pregnant (NP), PE, and IUGR subjects. Endoglin levels were 2.5-fold higher in preeclamptic placentas compared to NP (15.4+/-2.6 versus 5.7+/-1.0, p<0.01). In contrast, endoglin levels were similar in NP and IUGR placentas (5.7+/-1.0 vs 5.9+/-1.1, p=NS). Placentas from pregnancies with both PE and IUGR exhibited endoglin levels comparable to the PE group and significantly different from normotensive pregnancies with and without IUGR pregnancies (mean 14.9+/-4.0, n=9, p=0.013). Soluble endoglin concentrations in maternal plasma were comparable in NP and IUGR, but higher in women with PE (n=10 per group, p<0.05). Despite a 2-fold increase in hypoxia inducible factor, HIF-1alpha, we did not observe endoglin upregulation in NP, PE, or IUGR placental villous explants exposed to hypoxia (2% oxygen). In contrast to PE, placental or circulating endoglin is not increased in normotensive women delivering small, asymmetrically grown (IUGR) infants at term. The placentas of women with IUGR appear to be fundamentally different from PE women with respect to endoglin, despite the proposed common pathology of deficient trophoblast invasion/spiral artery remodeling and poor placental perfusion.

Mechanisms of renal vasodilation and hyperfiltration during pregnancy: current perspectives and potential implications for preeclampsia

A thorough understanding of the renal and cardiovascular adaptations to normal gestation is essential for proper diagnosis and management of hypertensive disorders and renal diseases during pregnancy. Here, we briefly review the renal hemodynamic changes of normal pregnancy. In addition, we present new findings and current concepts related to the underlying hormonal and molecular mechanisms. Finally, we speculate on the potential contribution of these insights from normal pregnancy to the pathogenesis of preeclampsia.