Management of adult patients with podocytopathies: an update from the ERA Immunonephrology Working Group.

The histopathological lesions, minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) are entities without immune complex deposits which can cause podocyte injury, thus are frequently grouped under the umbrella of podocytopathies. Whether MCD and FSGS may represent a spectrum of the same disease remains a matter of conjecture. Both frequently require repeated high-dose glucocorticoid therapy with alternative immunosuppressive treatments reserved for relapsing or resistant cases and response rates are variable. There is an unmet need to identify patients who should receive immunosuppressive therapies as opposed to those who would benefit from supportive strategies. Therapeutic trials focusing on MCD are scarce, and the evidence used for the 2021 Kidney Disease: Improving Global Outcomes (KDIGO) guideline for the management of glomerular diseases largely stems from observational and pediatric trials. In FSGS, the differentiation between primary forms and those with underlying genetic variants or secondary forms further complicates trial design. This article provides a perspective of the Immunonephrology Working Group (IWG) of the European Renal Association (ERA) and discusses the KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases focusing on the management of MCD and primary forms of FSGS in the context of recently published evidence, with a special emphasis on the role of rituximab, cyclophosphamide, supportive treatment options and ongoing clinical trials in the field.

Avacopan for ANCA-associated vasculitis with hypoxic pulmonary haemorrhage.

BACKGROUND AND HYPOTHESIS: Pulmonary haemorrhage with hypoxia caused by ANCA-associated vasculitis (AAV) has a high early mortality. Avacopan, an oral C5a receptor antagonist, is an approved treatment for AAV, but patients with pulmonary haemorrhage requiring invasive pulmonary ventilation support were excluded from the ADVOCATE trial. METHODS: A retrospective, observational, multicentre case series of AAV patients with hypoxic pulmonary haemorrhage, requiring oxygen support or mechanical ventilation, who received avacopan. RESULTS: Eight patients (62.5% female), median age 64 years (range 17-80), seven with kidney involvement, median glomerular filtration rate (GFR) 11 (range 5-99) ml/min per 1.73m2, were followed for a median of 6 months from presentation. Seven were newly diagnosed (87.5%), five were MPO-ANCA and three PR3-ANCA positive. All had hypoxia, four requiring mechanical ventilation (three invasive and one non-invasive). Intensive care unit (ICU) stay for the four patients lasted a median of 9 days (range 6-60). Four received rituximab and cyclophosphamide combination, three rituximab and one cyclophosphamide. Four underwent plasma exchange and one received two months of daily extracorporeal membrane oxygenation (ECMO) therapy. Following the initiation of avacopan after a median of 10 days (range 2-40), pulmonary haemorrhage resolved in all patients, even two who had one month of refractory pulmonary haemorrhage prior to avacopan. Additionally, after one month, the median prednisolone dose was 5 mg/day (range 0-50), with three patients successfully discontinuing steroid use. Two patients suffered serious infections, two discontinued avacopan, one permanently due to a rash and one temporarily after three months due to neutropenia. All patients survived and no re-hospitalization occurred. CONCLUSION: We report the use of avacopan as a component of the treatment for pulmonary haemorrhage with hypoxia in AAV. Despite the life-threatening presentations all patients recovered, but attribution of the positive outcomes to avacopan is limited by the concomitant therapies and retrospective observational design.

Randomized Trial on the Effect of an Oral Spleen Tyrosine Kinase Inhibitor in the Treatment of IgA Nephropathy.

Introduction: We reported increased spleen tyrosine kinase (SYK) expression in kidney biopsies of patients with IgA nephropathy (IgAN) and that inhibition of SYK reduces inflammatory cytokines production from IgA stimulated mesangial cells. Methods: This study was a double-blind, randomized, placebo-controlled phase 2 trial of fostamatinib (an oral SYK inhibitor) in 76 patients with IgAN. Patients were randomized to receive placebo, fostamatinib at 100 mg or 150 mg twice daily for 24 weeks on top of maximum tolerated dose of renin-angiotensin system inhibitors. The primary end point was reduction of proteinuria. Secondary end points included change from baseline in estimated glomerular filtration rate (eGFR) and kidney histology. Results: Although we could not detect significant reduction in proteinuria with fostamatinib overall, in a predetermined subgroup analysis, there was a trend for dose-dependent reduction in median proteinuria (from baseline to 24 weeks by 14%, 27%, and 36% in the placebo, fostamatinib 100 mg, and 150 mg groups, respectively) in patients with baseline urinary protein-to-creatinine ratios (UPCR) more than 1000 mg/g. Kidney function (eGFR) remained stable in all groups. Fostamatinib was well-tolerated. Side effects included diarrhea, hypertension, and increased liver enzymes. Thirty-nine patients underwent repeat biopsy showing reductions in SYK staining associated with therapy at low dose (-1.5 vs. 1.7 SYK+ cells/glomerulus in the placebo group, P < 0.05). Conclusions: There was a trend toward reduction in proteinuria with fostamatinib in a predefined analysis of high risk patients with IgAN despite maximal care, as defined by baseline UPCR greater than 1000 mg/g. Further study may be warranted.

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."

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.

Effect of belimumab on proteinuria and anti-phospholipase A2 receptor autoantibody in primary membranous nephropathy.

BACKGROUND: Immunosuppressant drugs reduce proteinuria and anti-phospholipase A2 receptor autoantibodies (PLA2R-Ab) in primary membranous nephropathy (PMN) with varying success and associated toxicities. This study aimed to evaluate the effect of belimumab on proteinuria and PLA2R-Ab in participants with PMN. METHODS: In this prospective, open-label, experimental medicine study, 14 participants with PMN and persistent nephrotic-range proteinuria received up to 2 years belimumab monotherapy (10 mg/kg, every 4 weeks). Changes in proteinuria (urinary protein:creatinine ratio), PLA2R-Ab, albumin, cholesterol, B-cell subsets and pharmacokinetics were analysed during treatment and up to 6 months after treatment. RESULTS: Eleven participants completed to the primary endpoint (Week 28) and nine participants completed the study. In the intention-to-treat population population, baseline proteinuria of 724 mg/mmol [95% confidence interval (CI) 579-906] decreased to 498 mg/mmol (95% CI 383-649) and 130 mg/mmol (95% CI 54-312) at Weeks 28 and 104, respectively, with changes statistically significant from Week 36 (n = 11, P = 0.047). PLA2R-Ab decreased from 174 RU/mL (95% CI 79-384) at baseline to 46 RU/mL (95% CI 16-132) and 4 RU/mL (95% CI 2-6) at Weeks 28 and 104, respectively, becoming statistically significant by Week 12 (n = 13, P = 0.02). Nine participants achieved partial (n = 8) or complete (n = 1) remission. Participants with abnormal albumin and/or cholesterol at baseline gained normal/near normal levels by the last follow-up. Adverse events were consistent with those expected in this population. CONCLUSIONS: Belimumab treatment in participants with PMN can reduce PLA2R-Ab and subsequently proteinuria, important preludes to remission induction.

Visual loss in giant cell arteritis 3 weeks after steroid initiation.

Giant cell arteritis (GCA) is the most common vasculitis in adults and blindness is a common complication if left untreated. Oral glucocorticoids are the mainstay of treatment and if started promptly, loss of vision can usually be prevented. We present the case of a 77-year-old man who developed irreversible bilateral blindness after a confirmed diagnosis of GCA and oral steroid treatment. The roles of diagnostic delay, steroid dosing, significance of visual symptoms at diagnosis and after commencing oral glucocorticoids, and interpretation of ophthalmological signs are reviewed.

Long-term follow-up of patients who received repeat-dose rituximab as maintenance therapy for ANCA-associated vasculitis.

OBJECTIVE: ANCA-associated vasculitis (AAV) is characterized by a chronic relapsing course. Rituximab (RTX) is an effective maintenance treatment; however, the long-term outcomes after its discontinuation are unclear. The aim of this study was to explore the long-term outcomes of AAV patients treated with repeat-dose RTX maintenance therapy. METHODS: AAV patients receiving a RTX treatment protocol consisting of an induction and maintenance phase were included. For initial remission induction, RTX was dosed at 1 g every 2 weeks or 375 mg/m(2) weekly for 4 consecutive weeks and for remission maintenance at 1 g every 6 months for 24 months. At the first RTX administration, ongoing immunosuppressives were withdrawn. RESULTS: Sixty-nine patients were identified, 67 of whom were failing other therapies. Nine relapsed during the RTX treatment protocol; however, all 69 were in remission at the end of the maintenance phase on a median prednisolone dose of 2.5 mg/day and 9% were receiving additional immunosuppression. During subsequent observation, 28 patients relapsed a median of 34.4 months after the last RTX infusion. Risk factors for relapse were PR3-associated disease (P = 0.039), B cell return within 12 months of the last RTX infusion (P = 0.0038) and switch from ANCA negativity to positivity (P = 0.0046). Two patients died and two developed severe hypogammaglobulinaemia. CONCLUSION: This study supports the efficacy and safety of a fixed-interval RTX maintenance regimen in relapsing/refractory AAV. Relapses after discontinuation of maintenance therapy did occur, but at a lower rate than after a single RTX induction course. PR3-associated disease, the switch from ANCA negative to positive and the return of B cells within 12 months of the last RTX administration were risk factors for further relapse.

The immunopathology of ANCA-associated vasculitis.

The small-vessel vasculitides are a group of disorders characterised by variable patterns of small blood vessel inflammation producing a markedly heterogeneous clinical phenotype. While any vessel in any organ may be involved, distinct but often overlapping sets of clinical features have allowed the description of three subtypes associated with the presence of circulating anti-neutrophil cytoplasmic antibodies (ANCA), namely granulomatosis with polyangiitis (GPA, formerly known as Wegener's Granulomatosis), microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (eGPA, formerly known as Churg-Strauss syndrome). Together, these conditions are called the ANCA-associated vasculitidies (AAV). Both formal nomenclature and classification criteria for the syndromes have changed repeatedly since their description over 100 years ago and may conceivably do so again following recent reports showing distinct genetic associations of patients with detectable ANCA of distinct specificities. ANCA are not only useful in classifying the syndromes but substantial evidence implicates them in driving disease pathogenesis although the mechanism by which they develop and tolerance is broken remains controversial. Advances in our understanding of the pathogenesis of the syndromes have been accompanied by some progress in treatment, although much remains to be done to improve the chronic morbidity associated with the immunosuppression required for disease control.

Defunctioning polymorphism in the immunoglobulin G inhibitory receptor (FcγRIIB-T/T232) does not impact on kidney transplant or recipient survival.

BACKGROUND: There is an increasing appreciation of the deleterious effects of antibody and B cells on acute and chronic transplant outcomes. Many effector functions of antibody are mediated by a family of receptors (FcγRs) that are expressed on most immune cells, including neutrophils, natural killer cells, and B cells. Most FcγRs are activating and controlled by a single inhibitory receptor, FcγRIIB (CD32B), which also regulates some aspects of B-cell activation and antibody production. FcγRIIB-deficient mice develop severe chronic arteriopathy in a murine cardiac allograft model. A single nucleotide polymorphism in human FcγRIIB (rs1050501) results in profound receptor dysfunction and is associated with systemic lupus erythematosus. The frequency of this FcγRIIB-I/T232 polymorphism also shows significant racial variation. METHODS: In the present study, we sought to determine whether the FcγRIIB-I/T232 single nucleotide polymorphism rs1050501 affected susceptibility to renal allograft rejection or loss and transplant recipient survival. FcγRIIB-I/T232 genotype was determined in 2,851 Caucasian and 570 Afro-Caribbean renal transplant recipients, and in 236 transplant recipients with a primary diagnosis of systemic lupus erythematosus, all of whom were enrolled into the Collaborative Transplant Study. RESULTS: We found no significant difference in pretransplant panel reactive antibodies, acute rejection at 1-year nor in 10-year transplant or patient survival in individuals with differing FcγRIIB-I/T232 genotype. CONCLUSION: This negative result is surprising, given the importance of this receptor in modulating antibody effector function.

Venous thromboembolism with concurrent pulmonary haemorrhage in systemic vasculitis.

BACKGROUND: Pulmonary haemorrhage (PH) is a serious manifestation of systemic vasculitis with high mortality rates yet vasculitis is associated with an increased prevalence of venous thromboembolism (VTE). The concurrent presentation of severe PH and VTE poses a challenge in terms of therapeutic management. METHODS: This is a retrospective case review of the clinical manifestations and response to treatment in vasculitis patients presenting with concurrent pulmonary haemorrhage and VTE (pulmonary embolism and/or deep venous thrombosis). RESULTS: Of 35 patients with severe PH due to systemic vasculitis, 7 (20%) had concurrent VTE. The most common cause was anti-neutrophil cytoplasm antibody-associated vasculitis, followed by anti-glomerular basement membrane disease. Vasculitis responded to conventional therapies and VTE treatment with anticoagulation was uncomplicated in five of six cases. In one case, anticoagulation precipitated the PH and another was not anticoagulated and developed recurrent VTE. All patients survived without further complications after a mean follow-up of 46 months (3-98). CONCLUSIONS: Concurrent VTE occurred in one-fifth of cases with severe PH due to vasculitis. Management of VTE with anticoagulation was effective but led to pulmonary haemorrhage in one patient.