Diagnosis and management of ANCA-associated vasculitis.

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis consists of two main diseases, granulomatosis with polyangiitis and microscopic polyangiitis, and remains among the most devastating and potentially lethal forms of autoimmune inflammatory disease. Granulomatosis with polyangiitis and microscopic polyangiitis are characterised by a necrotising vasculitis that can involve almost any organ, and have generally been studied together. The diseases commonly affect the kidneys, lungs, upper respiratory tract, skin, eyes, and peripheral nerves. Granulomatous inflammation and multinucleated giant cells are key pathological hallmarks of granulomatosis with polyangiitis, but are absent in microscopic polyangiitis. Many immune system events are essential to disease aetiopathogenesis, such as activation of the alternative complement pathway, neutrophil activation via complement receptors, and the influx of inflammatory cells, including monocytes and macrophages. These cells perpetuate inflammation and lead to organ damage. During the 21st century, the management of ANCA-associated vasculitis has moved away from reliance on cytotoxic medications and towards targeted biological medications for both the induction and maintenance of disease remission. Earlier diagnosis, partly the result of more reliable ANCA testing, has led to improved patient outcomes and better survival. Reductions in acute disease-related mortality have now shifted focus to long-term morbidities related to ANCA-associated vasculitis and their treatments, such as chronic kidney disease and cardiovascular disease. Therapeutic approaches in both clinical trials and clinical practice still remain too reliant on glucocorticoids, and continued efforts to reduce toxicity from glucocorticoids remain a priority in the development of new treatment strategies.

The Improved Kidney Risk Score in ANCA-Associated Vasculitis for Clinical Practice and Trials.

SIGNIFICANCE STATEMENT: Reliable prediction tools are needed to personalize treatment in ANCA-associated GN. More than 1500 patients were collated in an international longitudinal study to revise the ANCA kidney risk score. The score showed satisfactory performance, mimicking the original study (Harrell's C=0.779). In the development cohort of 959 patients, no additional parameters aiding the tool were detected, but replacing the GFR with creatinine identified an additional cutoff. The parameter interstitial fibrosis and tubular atrophy was modified to allow wider access, risk points were reweighted, and a fourth risk group was created, improving predictive ability (C=0.831). In the validation, the new model performed similarly well with excellent calibration and discrimination ( n =480, C=0.821). The revised score optimizes prognostication for clinical practice and trials. BACKGROUND: Reliable prediction tools are needed to personalize treatment in ANCA-associated GN. A retrospective international longitudinal cohort was collated to revise the ANCA renal risk score. METHODS: The primary end point was ESKD with patients censored at last follow-up. Cox proportional hazards were used to reweight risk factors. Kaplan-Meier curves, Harrell's C statistic, receiver operating characteristics, and calibration plots were used to assess model performance. RESULTS: Of 1591 patients, 1439 were included in the final analyses, 2:1 randomly allocated per center to development and validation cohorts (52% male, median age 64 years). In the development cohort ( n =959), the ANCA renal risk score was validated and calibrated, and parameters were reinvestigated modifying interstitial fibrosis and tubular atrophy allowing semiquantitative reporting. An additional cutoff for kidney function (K) was identified, and serum creatinine replaced GFR (K0: <250 µ mol/L=0, K1: 250-450 µ mol/L=4, K2: >450 µ mol/L=11 points). The risk points for the percentage of normal glomeruli (N) and interstitial fibrosis and tubular atrophy (T) were reweighted (N0: >25%=0, N1: 10%-25%=4, N2: <10%=7, T0: none/mild or <25%=0, T1: ≥ mild-moderate or ≥25%=3 points), and four risk groups created: low (0-4 points), moderate (5-11), high (12-18), and very high (21). Discrimination was C=0.831, and the 3-year kidney survival was 96%, 79%, 54%, and 19%, respectively. The revised score performed similarly well in the validation cohort with excellent calibration and discrimination ( n =480, C=0.821). CONCLUSIONS: The updated score optimizes clinicopathologic prognostication for clinical practice and trials.

Ultrastructural Examination of Glomerular Fibrillary Deposits in Diabetic Nephropathy.

Glomerular fibrillary deposits have occasionally been reported in diabetic nephropathy, but no large-scale, ultrastructural evaluation of these deposits has been reported so far. Here, we report our study of glomerular non-Congophilic, DnaJ homolog subfamily B member 9 negative fibrillary deposits in diabetic nephropathy as characterized by transmission electron microscopy. Clinical data from 55 patients with biopsy-confirmed diabetic nephropathy and 18 healthy living donors were reviewed, and their biopsies were evaluated by light microscopy, immunofluorescence, and electron microscopy. Small fibrillary structures with a diameter of 10 ± 1 nm were present in all cases with diabetic nephropathy, regardless of the histologic class. In addition, glomerular fibrillary structures with a diameter of 23 ± 5 nm or 30 ± 7 nm were present in 35 cases. Interestingly, especially the small- and medium-sized fibrils, usually without apparent organization, were comparable with fibrils in fibrillary glomerulopathy. We conclude that glomerular fibrillary deposits occur far more commonly in renal biopsies of patients with diabetic nephropathy than generally considered. This is an important finding because their similarity to fibrils in fibrillary glomerulonephritis may complicate the histologic diagnostic process, especially in cases of overlapping clinical manifestations. Therefore, when encountering fibrillary deposits on electron microscopy, it is important to consider diabetic nephropathy as an alternative diagnosis.

Long-term outcome of kidney function in patients with ANCA-associated vasculitis.

BACKGROUND: Kidney involvement is common in ANCA associated vasculitis (AAV) and prognosis determined by the severity of kidney damage. This study focused on long-term kidney outcomes, defining possible risk factors and comparing the performance of three different histological classifications to predict outcomes for patients with AAV. METHODS: The dataset included 848 patients with newly diagnosed AAV who participated in 7 RCTs (1995-2012). Follow up information obtained from questionnaires sent to the principal investigators of the original RCTs. RESULTS: The cumulative incidence of end-stage kidney disease (ESKD) at 5 and 10 years was 17% and 22%, respectively. Patients who developed ESKD had reduced patient survival compared to those with preserved kidney function (HR: 2.8, P-value < 0.001). Comparing patients with AAV and kidney involvement to a matched general population, patients with AAV had poor survival outcomes, even in early stages of CKD. The main cause of death was infection followed by cardiovascular disease in patients developing ESKD and malignancy in those who did not. 34% of patients with initial need for dialysis recovered kidney function after treatment. 35 out of 175 in need of kidney replacement therapy (KRT) during follow up received a kidney transplant with good outcome; 86% patient survival at 10 years.In the subcohort of 214 patients with available kidney biopsies, three scoring systems were tested: the Berden classification, the Renal Risk Score (RRS), and the Mayo Clinic Score (MCCS). The scores highlighted the importance of normal glomeruli and severe glomerulosclerosis on kidney survival (P < 0.001 and P = 0.001, respectively). The RRS demonstrated a moderate prediction of kidney survival (AUC: 0.79; SE: 0.03, 95% CI: 0.71-0.83). CONCLUSIONS: Early diagnosis is extremely important. Even milder forms of kidney involvement have an impact on the prognosis. Patients in need of KRT had the lowest survival rates, but kidney transplantation has shown favorable outcomes for eligible AAV patients. The three histologic scoring systems were all identified as independent prognostic factors for kidney outcome.

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.

Proteinuria and hematuria after remission induction are associated with outcome in ANCA-associated vasculitis.

In anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), hematuria and proteinuria are biomarkers reflecting kidney involvement at diagnosis. Yet, the prognostic value of their persistence after immunosuppressive induction therapy, reflecting kidney damage or persistent disease, remains uncertain. To study this, our post hoc analysis included participants of five European randomized clinical trials on AAV (MAINRITSAN, MAINRITSAN2, RITUXVAS, MYCYC, IMPROVE). Urine protein-creatinine ratio (UPCR) and hematuria of spot urine samples collected at the end of induction therapy (four-six months after treatment initiation) were correlated with the occurrence of a combined end point of death and/or kidney failure, or relapses during follow-up. Among 571 patients (59% men, median age 60), 60% had anti-proteinase 3-ANCA and 35% had anti-myeloperoxidase-ANCA, while 77% had kidney involvement. After induction therapy, 157/526 (29.8%) had persistent hematuria and 165/481 (34.3%) had UPCR of 0.05 g/mmol or more. After a median follow-up of 28 months (interquartile range 18-42), and adjustment for age, ANCA type, maintenance therapy, serum creatinine and persistent hematuria after induction, a UPCR of 0.05 g/mmol or more after induction was associated with significant risk of death/kidney failure (adjusted Hazard Ratio [HR] 3.06, 95% confidence interval 1.09-8.59) and kidney relapse (adjusted subdistribution HR 2.22, 1.16-4.24). Persistent hematuria was associated with significant kidney relapse (adjusted subdistribution HR 2.16, 1.13-4.11) but not with relapse affecting any organ nor with death/kidney failure. Thus, in this large cohort of patients with AAV, persistent proteinuria after induction therapy was associated with death/kidney failure and kidney relapse, whereas persistent hematuria was an independent predictor of kidney relapse. Hence, these parameters must be considered to assess long-term kidney prognosis of patients with AAV.

Novel aspects in the pathophysiology and diagnosis of glomerular diseases.

Immune deposits/complexes are detected in a multitude of tissues in autoimmune disorders, but no organ has attracted as much attention as the kidney. Several kidney diseases are characterised by the presence of specific configurations of such deposits, and many of them are under a 'shared care' between rheumatologists and nephrologists. This review focuses on five different diseases commonly encountered in rheumatological and nephrological practice, namely IgA vasculitis, lupus nephritis, cryoglobulinaemia, anti-glomerular basement membrane disease and anti-neutrophil cytoplasm-antibody glomerulonephritis. They differ in disease aetiopathogenesis, but also the potential speed of kidney function decline, the responsiveness to immunosuppression/immunomodulation and the deposition of immune deposits/complexes. To date, it remains unclear if deposits are causing a specific disease or aim to abrogate inflammatory cascades responsible for tissue damage, such as neutrophil extracellular traps or the complement system. In principle, immunosuppressive therapies have not been developed to tackle immune deposits/complexes, and repeated kidney biopsy studies found persistence of deposits despite reduction of active inflammation, again highlighting the uncertainty about their involvement in tissue damage. In these studies, a progression of active lesions to chronic changes such as glomerulosclerosis was frequently reported. Novel therapeutic approaches aim to mitigate these changes more efficiently and rapidly. Several new agents, such as avacopan, an oral C5aR1 inhibitor, or imlifidase, that dissolves IgG within minutes, are more specifically reducing inflammatory cascades in the kidney and repeat tissue sampling might help to understand their impact on immune cell deposition and finally kidney function recovery and potential impact of immune complexes/deposits.

Long-term outcomes and prognostic factors for survival of patients with ANCA-associated vasculitis.

BACKGROUND: Despite newer treatments with immunosuppressive agents, there still exists a considerable morbidity and mortality risk among patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Since 1994 the European Vasculitis Society (EUVAS) has aimed for an improved outcome for patients with AAV, conducting several prospective randomized controlled trials (RCTs). The aim for the present study was to further evaluate the long-term survival of patients with AAV included in seven RCTs conducted by the EUVAS as well as to identify potential prognostic factors. METHODS: Long-term follow-up data were collected from questionnaires sent to the principal investigators of the original RCTs (1995-2012): MEPEX, NORAM, CYCAZAREM, CYCLOPS, IMPROVE, RITUXVAS and MYCYC, comprising 848 patients, all newly diagnosed with AAV. Relative survival estimates are presented for the study cohorts. Demographic, clinical and laboratory characteristics at trial entry were studied as potential prognostic factors in multivariable models. RESULTS: A total of 478 (56%) patients had granulomatosis with polyangiitis (GPA) and 370 (44%) had microscopic polyangiitis (MPA) with a mean age at diagnosis of 58 ± 14 years. The median follow-up time was 8 years (interquartile range 2.9-13.6). During the observation period there were 305 deaths and the main causes were infections (26%), cardiovascular disease (14%) and malignancies (13%). When compared with a matched cohort (regarding country, age group and sex) from the background population there were 14.2% more deaths among our cohort of AAV patients at 5 years, 19.9% at 10 years, 28.8% at 15 years and 36.3% at 20 years. The excess mortality occurred in all age groups. The estimated median survival time (from diagnosis) was 17.8 years (95% confidence interval 15.7-20). Among variables measured at baseline, advanced age, male sex, low estimated glomerular filtration rate and low platelet count were identified as predictors of death in a multivariate Cox model. CONCLUSIONS: Patients with AAV still have an increased risk of mortality compared with the general population despite newer therapeutic regimens. Treatment complications and organ damage are the main causes of limited survival and infections remain the leading cause of mortality among patients with AAV.

Complement activation and regulation in rheumatic disease.

Complement is a key component of the innate immune defence and in addition forms a bridge to the adaptive immune responses. As such complement is of vital importance for efficient protection against infections. However, the activity of the complement system can also aberrantly be directed against the tissues of the body itself and contribute to organ damage in a variety of diseases. In several rheumatic diseases complement activation is suggested to play a pronounced role. This review will highlight the role of both complement activation and complement regulation in rheumatic disease. A contribution of complement to the disease process is often suggested based on the presence of complement activation fragments in the target tissues or the presence of complement activation fragments in the circulation. The role that complement plays in different rheumatic diseases is often unknown but is thought to contribute to tissue damage as a consequence of autoantibody mediated immune complex formation and deposition. In addition reduced complement inhibition mediated by endogenous complement regulators can also enhance complement activity and tissue damage. In observational studies, it is difficult to distinguish whether complement activation is a result of enhanced activation or decreased regulation. Until recently, strong conclusions on the relative importance of complement activation to the pathology were largely restricted to animal experiments. Usage of complement targeting therapeutics in humans will hopefully give us the opportunity to study the actual contribution of complement activation towards disease progression and tissue damage in rheumatic disease into more detail.

Endopeptidase Cleavage of Anti-Glomerular Basement Membrane Antibodies in vivo in Severe Kidney Disease: An Open-Label Phase 2a Study.

BACKGROUND: The prognosis for kidney survival is poor in patients presenting with circulating anti-glomerular basement membrane (GBM) antibodies and severe kidney injury. It is unknown if treatment with an endopeptidase that cleaves circulating and kidney bound IgG can alter the prognosis. METHODS: An investigator-driven phase 2a one-arm study (EudraCT 2016-004082-39) was performed in 17 hospitals in five European countries. A single dose of 0.25 mg/kg of imlifidase was given to 15 adults with circulating anti-GBM antibodies and an eGFR <15 ml/min per 1.73m2. All patients received standard treatment with cyclophosphamide and corticosteroids, but plasma exchange only if autoantibodies rebounded. The primary outcomes were safety and dialysis independency at 6 months. RESULTS: At inclusion, ten patients were dialysis dependent and the other five had eGFR levels between 7 and 14 ml/min per 1.73m2. The median age was 61 years (range 19-77), six were women, and six were also positive for anti-neutrophil cytoplasmic antibodies. Then 6 hours after imlifidase infusion, all patients had anti-GBM antibodies levels below the reference range of a prespecified assay. At 6 months 67% (ten out of 15) were dialysis independent. This is significantly higher compared with 18% (nine out of 50) in a historical control cohort (P<0.001, Fisher's exact test). Eight serious adverse events (including one death) were reported, none assessed as probably or possibly related to the study drug. CONCLUSIONS: In this pilot study, the use of imlifidase was associated with a better outcome compared with earlier publications, without major safety issues, but the findings need to be confirmed in a randomized controlled trial.Clinical Trial registration number: EUDRACT 2016-004082-39 https://www.clinicaltrialsregister.eu/ctr-search/trial/2007-001377-28/results.

Dissecting the histological features of lupus nephritis highlights new common patterns of injury in class III/IV.

OBJECTIVE: The International Society of Nephrology/Renal Pathology Society classification is the gold standard for the characterisation of lupus nephritis (LN) on renal biopsy, with therapeutic repercussions. Its recent revision simplified the current class subdivisions, eliminating the S/G forms of class IV, although data on a possible pathogenetic/clinical value of this subdivision are still contradictory. METHODS: 353 renal biopsies from Belimumab International Study in LN were assessed through central pathology review. Univariate logistic models and a decision tree were performed on 314 adequate biopsies to evaluate the impact of histological features on focal/diffuse classes. Removing class I/II (n=6) and 'pure' class V (n=34), principal component analysis (PCA) and heatmap were used to explore similarities among III, IVS and IVG biopsies either incorporating or not the mixed classes (+V, n=274). Finally, a method aimed at partitioning the cases into k clusters based on their similarity (KMeans), was used to study features from the cohort of 'pure' class III/IVS/IVG cases (n=214) to determine alternative subdivisions based on phenotypic data. RESULTS: Segmental endocapillary hypercellularity (EH) was prevalent in class III, global EH, wire loops, hyaline thrombi and double contours were hallmarks of class IVG, with IVS cases showing intermediate characteristics. Heatmap and PCA confirmed the segregation of these features among classes, showing better segregation for focal/diffuse LN as compared with the mixed classes (+V). KMeans revealed the presence of two main clusters, membranoproliferative-like (n=83) or vasculitis-like (n=131). CONCLUSIONS: This study reveals new phenotypic forms of LN surpassing the traditional classes as determined by the current classification. Future validation and confirmation are required to confirm these findings.

Reduced Glomerular Endothelial Thrombomodulin Is Associated with Glomerular Macrophage Infiltration in Diabetic Nephropathy.

The endothelial glycoprotein thrombomodulin regulates coagulation, inflammation, and apoptosis. In diabetic mice, reduced thrombomodulin function results in diabetic nephropathy (DN). Furthermore, thrombomodulin treatment reduces renal inflammation and fibrosis. Herein, thrombomodulin expression was examined in human kidney samples to investigate the possibility of targeting thrombomodulin in patients with DN. Glomerular thrombomodulin was analyzed together with the number of glomerular macrophages in 90 autopsied diabetic cases with DN, 55 autopsied diabetic cases without DN, and 37 autopsied cases without diabetes or kidney disease. Thrombomodulin mRNA was measured in glomeruli microdissected from renal biopsies from patients with DN and nondiabetic controls. Finally, glomerular thrombomodulin was measured in diabetic mice following treatment with the selective endothelin A receptor (ETAR) blocker, atrasentan. In diabetic patients, glomerular thrombomodulin expression was increased at the mRNA level, but decreased at the protein level, compared with nondiabetic controls. Reduced glomerular thrombomodulin was associated with an increased glomerular influx of macrophages. Blocking the ETAR with atrasentan restored glomerular thrombomodulin protein levels in diabetic mice to normal levels. The reduction in glomerular thrombomodulin in diabetes likely serves as an early proinflammatory step in the pathogenesis of DN. Thrombomodulin protein may be cleaved under diabetic conditions, leading to a compensatory increase in transcription. The nephroprotective effects of ETAR antagonists in diabetic patients may be attributed to the restoration of glomerular thrombomodulin.

Increased microchimerism in peripheral blood of women with systemic lupus erythematosus: relation with pregnancy.

OBJECTIVES: We aimed to determine the presence, amount and origin of microchimerism in peripheral blood of pregnant and non-pregnant parous women with systemic lupus erythematosus (SLE) as compared to control subjects. METHODS: We performed a comparative study in which peripheral blood was drawn from eleven female non-pregnant SLE-patients and 22 control subjects, and from six pregnant SLE-patients and eleven control subjects during gestation and up to six months postpartum. Quantitative PCR for insertion-deletion polymorphisms and null alleles was used to detect microchimerism in peripheral blood mononuclear cells and granulocytes. RESULTS: Microchimerism was detected more often in non-pregnant SLE-patients than control subjects (54.4% vs. 13.6%, respectively; p=0.03). When present, the median total number of foetal chimeric cells was 5 gEq/106 in patients and 2.5gEq/106 in control subjects (p=0.048). Microchimerism was mostly foetal in origin; maternal microchimerism was detected in one patient and one control subject. In control subjects, microchimerism was always derived from only one source whereas in 50% of patients it originated from multiple sources. The pregnant patients had a significantly higher median number of foetal chimeric cells in the granulocyte fraction just after delivery than control subjects (7.5 gEq/106 vs. 0 gEq/106, respectively; p=0.02). CONCLUSIONS: Just after delivery, SLE-patients had more microchimerism than control subjects. Three months post-partum, microchimerism was no longer detectable, only to reappear many years after the last pregnancy, more often and at higher levels in SLE-patients than in control subjects. This suggests that these chimeric cells may originate from non-circulating foetal chimeric stem cells.

Reappraisal of Renal Arteritis in ANCA-associated Vasculitis: Clinical Characteristics, Pathology, and Outcome.

BACKGROUND: Renal involvement in ANCA-associated vasculitis (AAV) is associated with poor outcomes. The clinical significance of arteritis of the small kidney arteries has not been evaluated in detail. METHODS: In a multicenter cohort of patients with AAV and renal involvement, we sought to describe the clinicopathologic characteristics of patients with AAV who had renal arteritis at diagnosis, and to retrospectively analyze their prognostic value. RESULTS: We included 251 patients diagnosed with AAV and renal involvement between 2000 and 2019, including 34 patients (13.5%) with arteritis. Patients with AAV-associated arteritis were older, and had a more pronounced inflammatory syndrome compared with patients without arteritis; they also had significantly lower renal survival (P=0.01). In multivariable analysis, the ANCA renal risk score, age at diagnosis, history of diabetes mellitus, and arteritis on index kidney biopsy were independently associated with ESKD. The addition of the arteritis status significantly improved the discrimination of the ANCA renal risk score, with a concordance index (C-index) of 0.77 for the ANCA renal risk score alone, versus a C-index of 0.80 for the ANCA renal risk score plus arteritis status (P=0.008); ESKD-free survival was significantly worse for patients with an arteritis involving small arteries who were classified as having low or moderate risk, according to the ANCA renal risk score. In two external validation cohorts, we confirmed the incidence and phenotype of this AAV subtype. CONCLUSIONS: Our findings suggest AAV with renal arteritis represents a different subtype of AAV with specific clinical and histologic characteristics. The prognostic contribution of the arteritis status remains to be prospectively confirmed.

Forever Connected: The Lifelong Biological Consequences of Fetomaternal and Maternofetal Microchimerism.

BACKGROUND: Originally studied as a mechanism to understand eclampsia-related deaths during pregnancy, fetal cells in maternal blood have more recently garnered attention as a noninvasive source of fetal material for prenatal testing. In the 21st century, however, intact fetal cells have been largely supplanted by circulating cell-free placental DNA for aneuploidy screening. Instead, interest has pivoted to the ways in which fetal cells influence maternal biology. In parallel, an increasing appreciation of the consequences of maternal cells in the developing fetus has occurred. CONTENT: In this review, we highlight the potential clinical applications and functional consequences of the bidirectional trafficking of intact cells between a pregnant woman and her fetus. Fetal cells play a potential role in the pathogenesis of maternal disease and tissue repair. Maternal cells play an essential role in educating the fetal immune system and as a factor in transplant acceptance. Naturally occurring maternal microchimerism is also being explored as a source of hematopoietic stem cells for transplant in fetal hematopoietic disorders. SUMMARY: Future investigations in humans need to include complete pregnancy histories to understand maternal health and transplant success or failure. Animal models are useful to understand the mechanisms underlying fetal wound healing and/or repair associated with maternal injury and inflammation. The lifelong consequences of the exchange of cells between a mother and her child are profound and have many applications in development, health, and disease. This intricate exchange of genetically foreign cells creates a permanent connection that contributes to the survival of both individuals.

"In my beginning is my end": usefulness of repeat kidney biopsies in lupus nephritis.

Malvar et al. report the results of a study on protocolized repeat renal biopsies in 76 patients with class III or IV (± class V) lupus nephritis. They show that managing maintenance therapy in patients with lupus nephritis through protocolized repeat kidney biopsies results in a lower flare rate. Provided that these results can be replicated in other studies, there is an argument for protocolized repeat kidney biopsies to become the standard of care.

Consensus definitions for glomerular lesions by light and electron microscopy: recommendations from a working group of the Renal Pathology Society.

Over the past 2 decades, scoring systems for multiple glomerular diseases have emerged, as have consortia of pathologists and nephrologists for the study of glomerular diseases, including correlation of pathologic findings with clinical features and outcomes. However, one important limitation faced by members of these consortia and other renal pathologists and nephrologists in both investigative work and routine practice remains a lack of uniformity and precision in clearly defining the morphologic lesions on which the scoring systems are based. In response to this issue, the Renal Pathology Society organized a working group to identify the most frequently identified glomerular lesions observed by light microscopy and electron microscopy, review the literature to capture the published definitions most often used for each, and determine consensus terms and definitions for each lesion in a series of online and in-person meetings. The defined lesions or abnormal findings are not specific for any individual disease or subset of diseases, but rather can be applied across the full spectrum of glomerular diseases and within the context of the different scoring systems used for evaluating and reporting these diseases. In addition to facilitating glomerular disease research, standardized terms and definitions should help harmonize reporting of medical kidney diseases worldwide and lead to more-precise diagnoses and improved patient care.

Human leukocyte antigen selected allogeneic mesenchymal stromal cell therapy in renal transplantation: The Neptune study, a phase I single-center study.

Mesenchymal stromal cells (MSC) hold promise as a novel immune-modulatory therapy in organ transplantation. First clinical studies have used autologous MSCs; however, the use of allogeneic "off-the-shelf" MSCs is more sustainable for broad clinical implementation, although with the risk of causing sensitization. We investigated safety and feasibility of allogeneic MSCs in renal transplantation, using a matching strategy that prevented repeated mismatches. Ten patients received two doses of 1.5 × 106 /kg allogeneic MSCs 6 months after transplantation in a single-center nonrandomized phase Ib trial, followed by lowering of tacrolimus (trough level 3 ng/mL) in combination with everolimus and prednisone. Primary end point was safety, measured by biopsy proven acute rejection (BPAR) and graft loss 12 months after transplantation. Immune monitoring was performed before and after infusion. No BPAR or graft loss occurred and renal function remained stable. One patient retrospectively had DSAs against MSCs, formed before infusion. No major alterations in T and B cell populations or plasma cytokines were observed upon MSC infusion. Administration of HLA selected allogeneic MSCs combined with low-dose tacrolimus 6 months after transplantation is safe at least in the first year after renal transplantation. This sets the stage to further explore the efficacy of third-party MSCs in renal transplantation.

2019 Update of the Joint European League Against Rheumatism and European Renal Association-European Dialysis and Transplant Association (EULAR/ERA-EDTA) recommendations for the management of lupus nephritis.

OBJECTIVE: To update the 2012 EULAR/ERA-EDTA recommendations for the management of lupus nephritis (LN). METHODS: Following the EULAR standardised operating procedures, a systematic literature review was performed. Members of a multidisciplinary Task Force voted independently on their level of agreeement with the formed statements. RESULTS: The changes include recommendations for treatment targets, use of glucocorticoids and calcineurin inhibitors (CNIs) and management of end-stage kidney disease (ESKD). The target of therapy is complete response (proteinuria <0.5-0.7 g/24 hours with (near-)normal glomerular filtration rate) by 12 months, but this can be extended in patients with baseline nephrotic-range proteinuria. Hydroxychloroquine is recommended with regular ophthalmological monitoring. In active proliferative LN, initial (induction) treatment with mycophenolate mofetil (MMF 2-3 g/day or mycophenolic acid (MPA) at equivalent dose) or low-dose intravenous cyclophosphamide (CY; 500 mg × 6 biweekly doses), both combined with glucocorticoids (pulses of intravenous methylprednisolone, then oral prednisone 0.3-0.5 mg/kg/day) is recommended. MMF/CNI (especially tacrolimus) combination and high-dose CY are alternatives, for patients with nephrotic-range proteinuria and adverse prognostic factors. Subsequent long-term maintenance treatment with MMF or azathioprine should follow, with no or low-dose (<7.5 mg/day) glucocorticoids. The choice of agent depends on the initial regimen and plans for pregnancy. In non-responding disease, switch of induction regimens or rituximab are recommended. In pure membranous LN with nephrotic-range proteinuria or proteinuria >1 g/24 hours despite renin-angiotensin-aldosterone blockade, MMF in combination with glucocorticoids is preferred. Assessment for kidney and extra-renal disease activity, and management of comorbidities is lifelong with repeat kidney biopsy in cases of incomplete response or nephritic flares. In ESKD, transplantation is the preferred kidney replacement option with immunosuppression guided by transplant protocols and/or extra-renal manifestations. Treatment of LN in children follows the same principles as adult disease. CONCLUSIONS: We have updated the EULAR recommendations for the management of LN to facilitate homogenization of patient care.

Glomerular C4d deposition can precede the development of focal segmental glomerulosclerosis.

Recent studies suggest that complement plays a role in the pathogenesis of focal segmental glomerulosclerosis (FSGS). Moreover, co-localization of IgM and C3 deposits with FSGS lesions has frequently been reported. Here, we investigated whether glomerular complement deposition precedes the development of FSGS and whether it represents local complement activation. Renal biopsies from 40 patients with primary FSGS, 84 patients with minimal change disease, and 10 healthy individuals were stained for C4d, C1q, and mannose-binding lectin. C4d deposits were also measured in renal allograft biopsies from 34 patients with native primary FSGS, 18 of whom subsequently developed recurrent FSGS. Lastly, we measured C4d deposits in the Munich Wistar Frömter rat model of FSGS. The prevalence of C4d-positive glomeruli was significantly higher among patients with FSGS (73%) compared to patients with minimal change disease (21%) and healthy individuals (10%). Moreover, segmental sclerosis was absent in 42% of C4d-positive glomeruli. Glomerular C1q was significantly more prevalent in FSGS compared to minimal change disease or healthy individuals, while mannose-binding lectin was infrequently observed. C4d deposition was significantly more prevalent in recurrent FSGS (72%) before the development of sclerotic lesions compared to control transplant samples (27%). Finally, at the onset of albuminuria but before the development of FSGS lesions, Munich Wistar Frömter rats had a significantly higher percentage of C4d-positive glomeruli (31%) compared to control rats (4%). Thus, glomerular C4d deposition can precede the development of FSGS, suggesting that complement activation may play a pathogenic role in the development of FSGS.