ANCA-associated vasculitis with renal involvement

An Autopsy Case of Renal-Limited Granulomatosis With Polyangiitis Presenting With Acute Renal Failure and Initial Delirium

Granulomatosis with polyangiitis (GPA) has three clinicopathological features, namely, necrotizing granulomatosis of the upper respiratory tract and lungs, focal segmental necrotizing glomerulonephritis of the kidney, and necrotizing vasculitis of small vessels throughout the body. A 92-year-old man with clinically diagnosed probable Alzheimer's disease (AD) exhibited subacute deterioration in cognitive function. On admission, he was diagnosed with acute renal failure with an elevated creatinine level (5.48 mg/dL) as well as severe disturbance of consciousness. Antineutrophil cytoplasmic antibodies (ANCAs) directed against proteinase 3 (PR3-ANCA) were highly positive with ≥ 350 U/mL. The patient was diagnosed with GPA and was managed with steroid pulse therapy. However, he died without any improvement in renal function. As a result of the autopsy, the patient was diagnosed with definite AD, and his impaired consciousness was found not to be caused by central nervous system involvement due to GPA. As necrotizing crescentic glomerulonephritis was observed, the cause of the acute progressive renal failure was found to be PR3-ANCA-positive GPA. The autopsy revealed no GPA-related lesions in other parts of the body aside from the kidneys. It is rare to encounter cases of PR3-ANCA-positive GPA with renal-limited vasculitis and acute renal failure as the initial manifestation, as in the present case. Making an accurate clinical diagnosis of older patients suffering from various diseases in multiple organs is challenging. Although autopsy has the limitation of a terminal image, it is extremely useful in elucidating the pathophysiology of the older patient in this case.

Recurrent Coronary Vasospasm in a 50-Year-Old Woman with Granulomatous Polyangiitis: A Case Report

Granulomatosis with polyangiitis (GPA) is a necrotizing granulomatous vasculitis classified as an autoimmune small-vessel vasculitis. Clinically, approximately 80% of affected organs in GPA involve the upper/lower respiratory tract and kidneys, with cardiovascular system involvement being rare. Here, we report a case of a 50-year-old female patient who presented with sudden-onset chest pain lasting for 1 hour. The patient had normal body temperature, and markers of infection such as C-reactive protein and erythrocyte sedimentation rate were within normal limits. Electrocardiography revealed ST-segment elevation in inferior, precordial, and posterior leads. Emergency coronary angiography showed no significant obstructive disease, prompting consideration of vasospastic angina given the patient's recurrent chest pain symptoms and findings on laboratory and imaging studies. The patient underwent treatment including coronary vasospasm antagonists and immunomodulation, resulting in clinical improvement and subsequent discharge. During a 7-month follow-up period, the patient did not experience any further adverse cardiovascular events.

Causes of Oral Granulomatous Disorders: An Update and Narrative Review of the Literature

Granulomatous diseases include a diverse range of chronic inflammatory disorders with a wide variety of pathologies and clinical characteristics. In particular, the orofacial region can be affected by granulomatous conditions-whether as an isolated disease or as part of a systemic disorder. Regardless of the nature of the disease or its mechanism of development, precise diagnosis can be challenging, as etiopathogenesis may be driven by several causes. These include reactions to foreign bodies, infections, immune dysregulation, proliferative disorders,, medications, illicit drugs, and hereditary disorders. Granulomas can be identified using histopathological assessment but are not pathognomonic of a specific disease, and therefore require correlation between clinical, serological, radiographical, and histopathological findings. The purpose of this review is to provide a summary of the etiopathogenesis, clinical and histopathologic characteristics, and treatment of oral granulomatous disorders.

Lymphatic vessels in patients with crescentic glomerulonephritis: association with renal pathology and prognosis

BACKGROUND

Various immune cells, including T cells, B cells, macrophages, and neutrophils contribute to the development of crescentic glomerulonephritis. Previous animal studies have suggested that lymphangiogenesis is involved in the migration of inflammatory cells and the activation of adaptive immunity. However, the extent of the association between lymphatic vessels and crescentic glomerulonephritis severity and prognosis remains unknown.

METHODS AND RESULTS

In this study, we assessed lymphatic vessel density in 71 patients with crescentic glomerulonephritis who underwent renal biopsies between June 2017 and June 2022. By immunohistochemistry and immunofluorescence, we identified increased lymphatic vessel density in the kidneys of patients with crescentic glomerulonephritis compared to controls. Lymphatic vessels were categorized as total, periglomerular, and interstitial. Spearman's rank correlation analysis showed a positive correlation between total and periglomerular lymphatic vessel density and glomerular crescent proportion. High lymphatic vessel density (total and periglomerular) correlated with declining kidney function, increased proteinuria, and severe glomerular and interstitial pathology. Interstitial lymphatic vessel density had minimal relationship with renal lesions. After a median duration of 13 months of follow-up, higher total and periglomerular lymphatic vessel density was associated with poorer prognosis. Transcriptomic analysis revealed increased immune cell activation and migration in crescentic glomerulonephritis patients compared to healthy controls. Periglomerular lymphatic vessels might play a significant role in immune cell infiltration and renal injury.

CONCLUSION

Elevated lymphatic vessel density in patients with crescentic glomerulonephritis is associated with poor prognosis and may serve as a predictive factor for adverse outcomes in these patients.

The correlation of interstitial change with renal prognosis in patients with myeloperoxidase-ANCA-associated glomerulonephritis: a single-center retrospective analysis

OBJECTS

We aim to explore the correlation between active/chronic tubulointerstitial injury and renal survival, and to compare their predictive value in patients with myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (AAGN).

METHOD

A total of 225 patients with MPO-AAGN diagnosed between February 2004 and December 2020 were included. Survival and univariate/multivariate Cox regression analyses were used to analyze the prognostic value of interstitial inflammation and interstitial fibrosis/tubular atrophy (IF/TA).

RESULTS

Of the 225 patients, 73 (32.4%) patients developed end-stage renal disease (ESRD) requiring maintenance dialysis. Interstitial inflammation>50% and IF/TA>50% were important predictors for ESRD in MPO-AAGN in multivariate Cox regression analysis adjusted by age, gender, estimated glomerular filtration rate (eGFR)≤15 ml/min/1.73m2, and normal glomeruli% (classified by <25%, 25-50%, >50%). Furthermore, we conducted stratified Cox regression analysis and found different results in the subgroups of eGFR>15 ml/min/1.73m2 and eGFR≤15 ml/min/1.73m2. Interstitial inflammation>50% and IF/TA>50% were significant risk factors for ESRD in the subgroup of eGFR>15 ml/min/1.73m2, but not or less significant in the subgroup of eGFR≤15 ml/min/1.73m2. Similarly, the survival analysis according to interstitial inflammation>50%/≤50% and IF/TA>50%/≤50% showed significant differences in the subgroup of eGFR>15 ml/min/1.73m2, but not or less significant in the subgroup of eGFR≤15 ml/min/1.73m2.

CONCLUSIONS

Interstitial inflammation>50% and IF/TA>50% were prognostic factors for renal survival in MPO-AAGN. In particular, interstitial inflammation and IF/TA had a better predictive ability in the subgroup of eGFR>15 ml/min/1.73m2. Key Points • Interstitial inflammation>50% and IF/TA>50% can help to predict renal survival in MPO-AAGN. • Both interstitial inflammation and IF/TA had a better predictive ability in the subgroup of eGFR>15 ml/min/1.73m2 than those in the subgroup of eGFR≤15 ml/min/1.73m2.

Clinical phenotypes and prognoses of microscopic polyangiitis based on kidney biopsies

BACKGROUND

To classify the different clinical phenotypes and compare the distinct prognoses of microscopic polyangiitis (MPA).

METHODS

A retrospective analysis of 436 patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) from 2015 to 2022 was conducted in our center, of which 90 patients were diagnosed with MPA and underwent renal biopsy.

RESULTS

Among the 90 MPA patients, 63% were female, and the median age at onset was 63 years (25th-75th percentile: 58-68). The median follow-up time was 26 months (25th-75th percentile: 10-53). We identified four subtypes: renal impairment type (cluster 1, 39%), pure type (cluster 2, 22%), systemic inflammation type (cluster 3, 26%), and rapid progress type (cluster 4, 13%). Cluster 1, characterized by renal dysfunction at onset (80%), demonstrated poor prognoses with only 26% achieved complete remission (CR), 11% dying, and 19% developing renal failure. In contrast, patients in cluster 2, exclusively female, most had only kidney involvement showed the best prognoses with 55% achieving CR and none experiencing death or renal failure within 10 years. Cluster 3 mostly consisted of males; high fever and C-reactive protein levels were the primary characteristics. These cases exhibited moderate prognoses with 53% achieving CR, 9% dying, and 4% developing renal failure. Finally, patients in cluster 4, which was characterized by rapidly progressive glomerulonephritis, had the worst prognoses, with none achieving CR, 8% dying, and 75% developing renal failure despite aggressive treatment.

CONCLUSIONS

MPA is classified into four subtypes with distinct clinical manifestations and prognoses.

Efficacy of protein A immunoadsorption and therapeutic plasma exchange in ANCA-associated vasculitis with severe renal involvement: a retrospective study

BACKGROUND

Severe renal impairment is a common complication of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and is associated with poor prognosis and shorter survival. It is urgent to find effective treatments to improve the prognosis of AAV patients. This study was designed to assess the efficacy and safety of protein A immunoadsorption (PAIA) and therapeutic plasma exchange (TPE) for AAV with severe renal involvement.

METHODS

A total of 48 AAV patients with renal involvement admitted to the Second Xiangya Hospital from January 2018 to February 2021 were selected. Clinical data, myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA), remission at 6 months, and outcomes were evaluated. The primary outcomes of interest were death and renal survival as defined by the occurrence of end-stage renal disease (ESRD).

RESULTS

PAIA was effective in the removal of MPO-ANCA and IgG, and showed superior over TPE in the clearance of MPO-ANCA within 1 month after treatment. After a median follow-up of 14.5 months, PAIA therapy showed an advantage in reducing mortality over TPE. There was no difference in the development of ESRD between the two groups. Multivariate Cox regression analysis indicated that higher serum creatinine (SCr) and lower haemoglobin level were independent risks of ESRD. Age > 60, lower serum albumin (ALB), and failure to achieve remission at 6 months were independent risks of death.

CONCLUSIONS

PAIA treatment reduces MPO-ANCA and IgG as well as mortality in AAV patients, and may be beneficial for severe AAV in clinical practice. Higher SCr, lower serum ALB or haemoglobin levels, age > 60, and failure to achieve remission at 6 months independently predict the ESRD or death of AAV patients with severe renal involvement.KEY MESSAGESCompared with therapeutic plasma exchange, protein A immunoadsorption treatment eliminates myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA) and IgG better and reduces mortality in ANCA-associated vasculitis (AAV) patients with severe renal involvement.Higher serum creatinine, lower serum albumin or haemoglobin levels, age > 60, and failure to achieve remission at 6 months independently predict the end-stage renal disease (ESRD) or death of AAV patients with severe renal involvement.

Overlapping drug-induced vasculitis, ANCA-associated vasculitis, and lupus nephritis caused by low-dose hydralazine

INTRODUCTION

We present a case of drug-induced vasculitis secondary to low-dose hydralazine with overlapping features of antineutrophil cytoplasmic antibody-associated vasculitis and drug-induced lupus nephritis.

CASE PRESENTATION

A 52-year-old Hispanic woman with a medical history of resistant hypertension treated with hydralazine 10 mg twice daily for 1 year presented with generalized weakness, dizziness, nausea, vomiting, and gross hematuria. There was fever, tachycardia, leukocytosis, lactic acidosis, hyperkalemia, renal failure, and anemia. Chest computed tomography and bronchoscopy revealed a left lower lobe infiltrate and diffuse alveolar hemorrhage. Serologic testing was positive for anti-double-stranded DNA, anti-Smith, lupus anticoagulant, anti-histone, anti-cardiolipin IgM antibodies, and antineutrophil cytoplasmic antibodies (myeloperoxidase and proteinase 3). A kidney biopsy revealed crescentic glomerulonephritis with an overlapping finding of membranous nephropathy. Broad-spectrum antibiotics, immunosuppressants, corticosteroids, and plasmapheresis were initiated. The patient survived but required continuous hemodialysis.

CONCLUSIONS

Although a few cases of simultaneous antibody-associated vasculitis and drug-induced lupus nephritis secondary to hydralazine use have been reported, this case is singular. Similar findings were previously reported with doses of 50-100 mg two to three times daily over 1-5 years. In our patient, a dose of only 10 mg twice daily for a year caused a severe disease presentation. This brings to light the combination of different vasculitides that can coexist and the potentially life-threatening adverse effects of low-dose hydralazine that should be kept in mind.

Changing Phenotypes and Clinical Outcomes Over Time in Microscopic Polyangiitis

Introduction

Diagnosis and management of microscopic polyangiitis (MPA) have evolved considerably over the past decades, but it is unknown whether clinical and histological presentation and patient and renal outcomes have changed accordingly.

Methods

We compared clinical and histopathological characteristic at diagnosis, risk of death, end-stage kidney disease (ESKD), and relapse rate in patients diagnosed with MPA between 1980 and 2022, after grouping them in 2 periods (p): p1980-2001 and p2002-2022. We compared the mortality rate between the 2 periods using Kaplan-Meier estimator and Cox-regression, and competing risks of ESKD and death using the Aalen-Johansen estimator, Fine-Gray multiple regression, and multistate models.

Results

Out of 187 patients, 77 were in p1980-2001 and 110 in p2002 to 2022. Patients in p2002 to 2022 were older (66.2 ± 14.0 SD vs. 57.7 ± 15.8; P < 0.001), had a better kidney function (estimated glomerular filtration rate [eGFR] 25.9 ± 24.8 vs. 21.5 ± 28.2 ml/min per 1.73 m2; P = 0.011) and a lower prevalence of the Berden sclerotic class (5.9 vs. 20.9%; P = 0.011). Despite a similar crude and adjusted patient survival, the risk of ESKD decreased during p2002 to 2022 (subdistribution hazard ratio [HR] 0.30, 95% confidence interval [CI]: 0.16-0.57; P < 0.001). The results remained significant after accounting for death after ESKD and after adjusting for potential confounders (HR 0.33 [95% CI: 0.18-0.63; P < 0.001]). The risk of relapse was numerically higher during p2002 to 2022 (subdistribution-HR 1.64 [95% CI: 0.95-2.83; P = 0.075]).

Conclusion

MPA kidney involvement has become less severe over the past decades, leading to a reduced risk of ESKD and a higher relapse rate, despite a comparable risk of death.

Occurrence and localization of FOXP3 + cells in kidney biopsies in lupus nephritis and ANCA-associated vasculitis

The study aims to increase the understanding regarding the role of regulatory T cells (Tregs) in lupus nephritis (LN) and ANCA-associated vasculitis (AAV) by comparing their localization in renal tissue and changes following immunosuppressive therapy. Kidney biopsies from 12 patients with LN and 7 patients with AAV were examined. Kidney biopsies had been performed both at active disease and following immunosuppressive treatment. Clinical data was collected at both biopsy occasions. Expression of Forkhead Box P 3 (Foxp3) in renal tissue was assessed by immunohistochemistry. An arbitrary scale was used to estimate the number of Foxp3+ cells. In LN, 8/12 (67%) had positive tissue staining for Foxp3 at baseline, most pronounced in inflammatory infiltrates, but also interstitially and in a peri-glomerular pattern. At second biopsies, after immunosuppressive treatment, 4/12 (33%) still had detectable Foxp3+ cells, found in persisting inflammatory infiltrates and some in the interstitium. Patients with a good clinical response to treatment had high grade of Foxp3+ cells in first biopsies. In AAV, only 2/7 (29%) had positive staining for Foxp3 at baseline, in inflammatory infiltrates and to a lesser extent in the interstitium, despite large areas of inflammatory infiltrates in all patients. At follow-up, 2/7 (29%) biopsies were positive for Foxp3. Our data show a higher presence of Foxp3+ cells in renal tissue from LN patients compared to AAV, suggesting that Tregs may be differently involved in the control of inflammatory mechanisms in these diseases. These findings could have further implication for therapeutic approaches aiming at restoring the immunological tolerance. Key Points • Foxp3+-cells are present in larger amount in renal tissue in lupus nephritis vs. ANCA-associated vasculitis. • Our data suggest that Foxp3+ regulatory T cells are involved in the control of inflammatory processes in lupus nephritis.

Soluble triggering receptor expressed on myeloid cell-1 reflects the cross-sectional activity of microscopic polyangiitis and granulomatosis with polyangiitis

Objectives

We investigated whether soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) reflects cross-sectional activity of microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA).

Methods

Forty-seven MPA and 32 GPA patients with well-documented clinical records and stored sera were enrolled. sTREM-1 levels were evaluated using Magnetic Luminex® assay, and disease activity was assessed using Birmingham vasculitis activity score (BVAS). Patients were divided into two groups according to the upper and lower halves of BVAS. Receiver operator characteristic (ROC) curve analysis was used to identify cut-off for determining upper half of BVAS. Linear and binary logistic regression was performed to evaluate the association between sTREM-1 and disease activity and status.

Results

The median age of patients was 67.0 years, and 58.2 % were women. The median BVAS and sTREM-1 were 12.0 and 467.1 pg/mL. sTREM-1 was significantly correlated with BVAS along with five-factor score, Short-Form 36-Item Health Surveys, and C-reactive protein. In multivariable linear regression analysis, erythrocyte sedimentation rate (standardised β 0.241), and sTREM-1 (standardised β 0.288) were correlated with BVAS. ROC analysis revealed that the cut-off of sTREM-1 for the upper half of BVAS was 474.1 pg/mL. MPA and GPA patients with sTREM-1 ≥474.1 pg/mL exhibited a significantly higher risk for the upper half of BVAS than those without (relative risk 5.932). Multivariable logistic regression analysis demonstrated sTREM-1 ≥474.1 pg/mL (odds ratio 5.662) was associated with the upper half of BVAS.

Conclusion

sTREM-1 reflects the activity of MPA and GPA, suggesting its role as a potential biomarker for assessing disease severity.

Longitudinal Patterns of Renal Function in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

OBJECTIVE

A spectrum of chronic kidney disease (CKD) and end-stage renal disease (ESRD) may occur in antineutrophil cytoplasmic antibody-associated vasculitis (AAV). The longitudinal trajectory of renal function in AAV is poorly understood.

METHODS

Patients with ≥2 creatinine measurements, including at baseline (±30 days of treatment initiation), were included from the Mass General Brigham AAV Cohort. We calculated estimated glomerular filtration rate (eGFR). We incorporated longitudinal changes in eGFR into a group-based trajectory model to identify patients with similar patterns of change in renal function. The chi-square test and the Kruskal-Wallis test were used to evaluate differences between groups in categorical variables and non-normally distributed continuous variables, respectively.

RESULTS

In 255 AAV patients, we identified 4 renal trajectory groups: rapid decline (n = 20), impaired (n = 82), preserved (n = 129), and recovery (n = 24). The rapid decline and impaired groups had greater baseline comorbidity (P = 0.01) and lower prevasculitis eGFR (P = 0.02). Clinically significant CKD (eGFR <60 ml/minute/1.73 m2 ) persisted over 5 years in >75% of the impaired group, compared to <40% of patients in the preserved group (P < 0.001). ESRD occurred most frequently in the rapid decline (100%), followed by the impaired and preserved groups (7% each). Baseline AAV renal involvement was present prior to 95% of ESRD. However, ESRD etiology varied, with 90% of rapid-onset ESRD attributed to vasculitis, versus 17-44% in impaired or preserved groups (P = 0.001).

CONCLUSION

We identified 4 longitudinal patterns of renal function after AAV diagnosis. Our findings highlight the burden of CKD in AAV and provide a framework for future research into personalized care in this vulnerable population.

Prognostic value of proteinuria monitoring in anti-neutrophil cytoplasmic antibody-associated vasculitis

OBJECTIVE

To determine the prognostic significance of proteinuria monitoring in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV).

METHODS

We retrospectively analyzed the data of kidney biopsy-confirmed patients with AAV. Proteinuria was evaluated by a urine dipstick test. Poor renal outcome was defined as stage 4/5 chronic kidney disease (CKD) (estimated glomerular filtration rate < 30 mL/min/1.73 m2).

RESULTS

We enrolled 77 patients with a median follow-up duration of 36 months (interquartile range, 18-79) in this study. Excluding 8 patients on dialysis at 6 months, 59/69 (85.5%) achieved remission after induction therapy. Patients were then divided into two groups according to the presence of proteinuria at 6 months after induction therapy (n = 29 with proteinuria, 40 without proteinuria). There was no significant difference in the rate of relapse or death according to the presence of proteinuria (p = 0.304 relapse, 0.401 death). In contrast, patients with proteinuria had significantly lower kidney function than those without proteinuria (41 vs. 53.5 mL/min/1.73 m2, p = 0.003). Multivariate analysis revealed that eGFR values at 6 months (hazard ratio [HR] 0.925; 95% CI 0.875-0.978, p = 0.006) and proteinuria at 6 months (HR 4.613; 95% CI 1.230-17.298, p = 0.023) were significantly associated with stage 4/5 CKD.

CONCLUSION

The presence of proteinuria at 6 months after induction therapy and low renal function was significantly associated with a higher risk of stage 4/5 CKD in patients with AAV. Monitoring for proteinuria after induction therapy may help predict poor renal outcomes in patients with AAV.

Enhancer of zeste homolog 2 promotes renal fibrosis after acute kidney injury by inducing epithelial-mesenchymal transition and activation of M2 macrophage polarization

Long-term follow-up data indicates that 1/4 patients with acute kidney injury (AKI) will develop to chronic kidney disease (CKD). Our previous studies have demonstrated that enhancer of zeste homolog 2 (EZH2) played an important role in AKI and CKD. However, the role and mechanisms of EZH2 in AKI-to-CKD transition are still unclear. Here, we demonstrated EZH2 and H3K27me3 highly upregulated in kidney from patients with ANCA-associated glomerulonephritis, and expressed positively with fibrotic lesion and negatively with renal function. Conditional EZH2 deletion or pharmacological inhibition with 3-DZNeP significantly improved renal function and attenuated pathological lesion in ischemia/reperfusion (I/R) or folic acid (FA) mice models (two models of AKI-to-CKD transition). Mechanistically, we used CUT & Tag technology to verify that EZH2 binding to the PTEN promoter and regulating its transcription, thus regulating its downstream signaling pathways. Genetic or pharmacological depletion of EZH2 upregulated PTEN expression and suppressed the phosphorylation of EGFR and its downstream signaling ERK1/2 and STAT3, consequently alleviating the partial epithelial-mesenchymal transition (EMT), G2/M arrest, and the aberrant secretion of profibrogenic and proinflammatory factors in vivo and vitro experiments. In addition, EZH2 promoted the EMT program induced loss of renal tubular epithelial cell transporters (OAT1, ATPase, and AQP1), and blockade of EZH2 prevented it. We further co-cultured macrophages with the medium of human renal tubular epithelial cells treated with H₂O₂ and found macrophages transferred to M2 phenotype, and EZH2 could regulate M2 macrophage polarization through STAT6 and PI3K/AKT pathways. These results were further verified in two mice models. Thus, targeted inhibition of EZH2 might be a novel therapy for ameliorating renal fibrosis after acute kidney injury by counteracting partial EMT and blockade of M2 macrophage polarization.

Diagnostic accuracy of ultrasound-based multimodal radiomics modeling for fibrosis detection in chronic kidney disease

OBJECTIVES

To predict kidney fibrosis in patients with chronic kidney disease using radiomics of two-dimensional ultrasound (B-mode) and Sound Touch Elastography (STE) images in combination with clinical features.

METHODS

The Mindray Resona 7 ultrasonic diagnostic apparatus with SC5-1U convex array probe (bandwidth frequency of 1-5 MHz) was used to perform two-dimensional ultrasound and STE software. The severity of cortical tubulointerstitial fibrosis was divided into three grades: mild interstitial fibrosis and tubular atrophy (IFTA), fibrotic area < 25%; moderate IFTA, fibrotic area 26-50%; and severe IFTA, fibrotic area > 50%. After extracting radiomics from B-mode and STE images in these patients, we analyzed two classification schemes: mild versus moderate-to-severe IFTA, and mild-to-moderate versus severe IFTA. A nomogram was constructed based on multiple logistic regression analyses, combining clinical and radiomics. The performance of the nomogram for differentiation was evaluated using receiver operating characteristic (ROC), calibration, and decision curves.

RESULTS

A total of 150 patients undergoing kidney biopsy were enrolled (mild IFTA: n = 74; moderate IFTA: n = 33; severe IFTA: n = 43) and randomized into training (n = 105) and validation cohorts (n = 45). To differentiate between mild and moderate-to-severe IFTA, a nomogram incorporating STE radiomics, albumin, and estimated glomerular filtration (eGFR) rate achieved an area under the ROC curve (AUC) of 0.91 (95% confidence interval [CI]: 0.85-0.97) and 0.85 (95% CI: 0.77-0.98) in the training and validation cohorts, respectively. Between mild-to-moderate and severe IFTA, the nomogram incorporating B-mode and STE radiomics features, age, and eGFR achieved an AUC of 0.93 (95% CI: 0.89-0.98) and 0.83 (95% CI: 0.70-0.95) in the training and validation cohorts, respectively. Finally, we performed a decision curve analysis and found that the nomogram using both radiomics and clinical features exhibited better predictability than any other model (DeLong test, p < 0.05 for the training and validation cohorts).

CONCLUSION

A nomogram based on two-dimensional ultrasound and STE radiomics and clinical features served as a non-invasive tool capable of differentiating kidney fibrosis of different severities.

KEY POINTS

• Radiomics calculated based on the ultrasound imaging may be used to predict the severities of kidney fibrosis. • Radiomics may be used to identify clinical features associated with the progression of tubulointerstitial fibrosis in patients with CKD. • Non-invasive ultrasound imaging-based radiomics method with accuracy aids in detecting renal fibrosis with different IFTA severities.

Prognostic factors associated with advanced chronic kidney disease in a cohort of patients with ANCA vasculitis and renal involvement

OBJECTIVE

The aim of this study was to evaluate prognostic factors associated with advanced chronic kidney disease (ACKD) in a cohort of patients with ANCA-associated vasculitis and renal involvement.

METHODS

Observational retrospective study. We included patients with biopsy-proven ANCA glomerulonephritis (GN) diagnosed between 2001 and 2016, with at least 1-year follow-up. Data were recorded at diagnosis, end of induction, after 12 months of treatment, and at the end of follow-up. We analysed clinical-analytical data and renal histopathology, as well as treatments, dialysis requirement, relapses and death. Univariate analysis was performed to identify factors associated with long-term ACKD (eGFR < 30 ml/min). Multivariate analysis using an alternative outcome (eGFR at the end of follow-up) was performed. Diagnostic accuracy for ACKD of each predictor variable was compared using AUC of ROC curves.

RESULTS

Sixty patients were included: 17 GPA, 14 MPA, 5 EGPA, and 24 RLV. Forty-six patients were women (76.7%). Mean age at diagnosis was 67.8 years (SD 13.1), and median follow-up time was 4.2 years (IQR 2.2-6.8). At the end of follow-up, 12 patients (20.0%) had an eGFR < 30 ml/min. Univariate analysis showed a statistically significant association of ACKD with sclerotic class biopsy (OR 7.17, 95% CI 1.34-38.31), 12-month proteinuria (OR 5.16, 95% CI 1.16-22.87), and creatinine at diagnosis (OR 1.24, 95% CI 1.02-1.52), end of induction (OR 15.40, 95% CI 2.41-98.28), and after 12 months (OR 19.25, 95% CI 2.75-134.92). In the multivariate analysis, eGFR at baseline (< 0.001), after 6 months (< 0.001) and 12 months of treatment (< 0.001), remained statistically associated with eGFR at the end of follow-up. The best diagnostic accuracy in ROC curves was shown by serum creatinine at the end of induction treatment (AUC 0.93) and after 12 months (AUC 0.94).

CONCLUSION

In this cohort of patients with ANCA GN, creatinine and eGFR at baseline and after 6 and 12 months of treatment were the best predictors of ACKD at the end of follow-up.

Oral manifestations of anti-neutrophil cytoplasmic antibody-associated vasculitis: an update and narrative review of the literature

Anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) is a multisystem disorder of small blood vessels subdivided into granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). Oral manifestations (OMs) have been reported to include mucosal ulceration, gingival enlargement, alveolar bone necrosis, tooth loss, oro-antral communication, palatal perforation, parotitis, and candidal infection mainly in GPA. They may appear during the course of the disease, as a disease flare-up, or as the presenting sign. These OMs are often nonspecific and can mimic an array of conditions, therefore formulating a differential diagnosis can be challenging. This review updates the OMs of GPA, and, for the first, time includes OMs of other AAVs. It provides recommendations for the overall assessment and the diagnosis and management of all AAV OMs with considerations for treatment coordination. The role of oral health care providers in multidisciplinary care is highlighted.

Metabolomics combined with clinical analysis explores metabolic changes and potential serum metabolite biomarkers of antineutrophil cytoplasmic antibody-associated vasculitis with renal impairment

Background

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is an autoimmune systemic disease, and the majority of AAV patients have renal involvement presenting as rapid progressive glomerulonephritis (GN). Currently, the clinically available AAV markers are limited, and some of the newly reported markers are still in the nascent stage. The particular mechanism of the level changes of various markers and their association with the pathogenesis of AAV are not well defined. With the help of metabolomics analysis, this study aims to explore metabolic changes in AAV patients with renal involvement and lay the foundation for the discovery of novel biomarkers for AAV-related kidney damage.

Methods

We performed liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based on serum samples from patients with AAV (N = 33) and healthy controls (N = 33) in order to characterize the serum metabolic profiling. The principal component analysis (PCA) and orthogonal partial least-squares-discriminant analysis (OPLS-DA) were used to identify the differential metabolites. Least Absolute Shrinkage and Selection Operator (LASSO) and eXtreme Gradient Boosting (XGBoost) analysis were further conducted to identify the potential diagnostic biomarker. A receiver operating characteristic (ROC) curve analysis was conducted to evaluate the diagnostic performance of the identified potential biomarker.

Results

A total of 455 metabolites were detected by LC-MS analysis. PCA and OPLS-DA demonstrated a significant difference between AAV patients with renal involvement and healthy controls, and 135 differentially expressed metabolites were selected, with 121 upregulated and 14 downregulated. Ninety-two metabolic pathways were annotated and enriched based on the KEGG database. N-acetyl-L-leucine, Acetyl-DL-Valine, 5-hydroxyindole-3-acetic acid, and the combination of 1-methylhistidine and Asp-phe could accurately distinguish AAV patients with renal involvement from healthy controls. And 1-methylhistidine was found to be significantly associated with the progression and prognosis of AAV with renal impairment. Amino acid metabolism exhibits significant alternations in AAV with renal involvement.

Conclusion

This study identified metabolomic differences between AAV patients with renal involvement and non-AAV individuals. Metabolites that could accurately distinguish patients with AAV renal impairment from healthy controls in this study, and metabolites that were significantly associated with disease progression and prognosis were screened out. Overall, this study provides information on changes in metabolites and metabolic pathways for future studies of AAV-related kidney damage and lays a foundation for the exploration of new biomarkers of AAV-related kidney damage.

Evaluation of a renal risk score for Japanese patients with ANCA-associated glomerulonephritis in a multi-center cohort study

Background

In patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis, prediction of renal survival should guide the choice of therapy, but a prediction of the histological classification has inconsistencies.

Objectives

To evaluate the usefulness of renal risk score (RRS) for Japanese patients with ANCA-associated glomerulonephritis (AAGN) and compare the prediction for end-stage renal disease (ESRD) between RRS and the histological classification.

Methods

We retrospectively analyzed 96 patients with AAGN who underwent a renal biopsy. Renal survival was categorized by RRS, and the histological classification was assessed separately. We compared the predictive values for RRS and the histological classification.

Results

The median observational period was 37.5 (interquartile range [IQR] 21.5-77.0) months. The median RRS point at the time of renal biopsy was 2 (IQR 0-7.8), and the patients were categorized into low- (n = 29), medium- (n = 43), and high-risk groups (n = 24) using RRS. As expected, the renal prognosis was the worst in the "high-risk" group and the best in the "low-risk" group. In the histological classification, the survival deteriorated progressively from "focal" (best) to "mixed," "crescentic," and "sclerotic" (worst) classes, different from the order in the original proposal for this system. Multivariable Cox regression analysis revealed that RRS was independently associated with ESRD. The difference in prediction for renal survival between RRS and the histological classification was not significant using area under receiver-operating-characteristic curves.

Conclusion

We evaluated the usefulness of RRS in Japanese patients with AAGN and found it a stable predictor of renal survival in such patients.

Predictors of relapse in granulomatosis with polyangiitis: a multi-center study

Background

Granulomatosis with polyangiitis (GPA) is a rare systemic vasculitis. Its severity ranges from indolent disease to fulminant that may cause death. With treatment, remission is seen in more than 80% of cases, although relapse is still common. There have been studies showing that there may be factors to predict relapse in GPA. Based on relapses, the decision to start treatment and/or to monitor the patients more closely is made. Therefore, predicting the relapse of GPA can be effective in controlling the disease. Our aim was to investigate possible factors for relapse in GPA.

We recruited 254 patients diagnosed with GPA who were under treatment at Alzahra hospital affiliated to Isfahan University of Medical Sciences (from 2013 to 2020) and Amir Alam Hospital affiliated to Tehran University of Medical Sciences (from 2020 to 2022) to plan a retrospective study. Chi-squared or Fisher’s exact tests were performed to compare categorical variables, while the Mann–Whitney U test was used to compare continuous variables.

Results

Analysis of our patients (aged 20–80,122 females) showed that 147 patients (57.9%) experienced relapse. Mean age in relapse group was 43.8 ± 16.6 and in no-relapse group was 45.6 ± 15.1 (P > 0.05). Among many potential predictors, we observed in multivariate analysis that positive PR3-ANCA (proteinase 3-antineutrophilic cytoplasmic antibodies) (P = 0.007, OR:2.62,CI:1.29–5.31),nose manifestations (P = 0.004, OR 3.00, CI 1.43–6.26), mucosal membranes involvement (P = 0.009, OR 4.21, CI 1.43–12.38), and gastrointestinal tract (GI) complications (P = 0.03, OR 5.64, CI 1.14–27.90) were significant predictors of GPA relapse.

Conclusion

Among clinical and laboratory features we studied, positive PR3-ANCA, nose manifestations, mucosal membranes involvement, and GI complications were independent predictors of relapse in patients with GPA.

CD206+CD68+ mono-macrophages and serum soluble CD206 level are increased in antineutrophil cytoplasmic antibodies associated glomerulonephritis

Background

Antineutrophil Cytoplasmic Antibodies (ANCA) associated glomerulonephritis (AGN) is a group of autoimmune diseases and mono-macrophages are involved in its glomerular injuries. In this study, we aim to investigate the role of CD206⁺ mono-macrophages in AGN.

Methods

27 AGN patients (14 active AGN, 13 remissive AGN) together with healthy controls (n = 9), disease controls (n = 6) and kidney function adjusted controls (n = 9) from Department of Nephrology, Ruijin hospital were recruited. Flow cytometry was used to study proportion of CD206⁺ cells in peripheral blood. Immunohistochemistry for CD206 staining was performed and CD206 expression was scored in different kidney regions. Serum soluble CD206 (sCD206) was measured by enzyme-linked immunosorbent assay (ELISA). We also generated murine myeloperoxidase (MPO) (muMPO) ANCA by immunizing Mpo^−/− mice. Mouse bone marrow-derived macrophages (BMDMs) from wild C57BL/6 mice and peripheral blood mononuclear cell (PBMC) derived macrophages from healthy donors were treated with MPO ANCA with or without its inhibitor AZD5904 to investigate the effects of MPO-ANCA on CD206 expression.

Results

The proportion of peripheral CD206⁺CD68⁺ cells in active AGN patients were significantly higher than that in remissive patients (p < 0.001), healthy controls (p < 0.001) and kidney function adjusted controls (p < 0.001). Serum sCD206 level in active AGN patients was higher than that in healthy controls (p < 0.05) and remissive patients (p < 0.01). Immunohistochemistry showed CD206 was highly expressed in different kidney regions including fibrinoid necrosis or crescent formation, glomeruli, periglomerular and tubulointerstitial compartment in active AGN patients in comparison with disease controls. Further studies showed MPO ANCA could induce CD206 expression in BMDMs and PBMC derived macrophages and such effects could be reversed by its inhibitor AZD5904.

Conclusion

ANCA could induce CD206 expression on mono-macrophages and CD206⁺ mono-macrophages are activated in AGN. CD206 might be involved in the pathogenesis of AAV and may be a potential target for the disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-022-00529-w.

Diagnosing and treating ANCA-associated vasculitis: an updated review for clinical practice

ANCA-associated vasculitides (AAV) are a group of rare, primary, systemic necrotizing small-vessel vasculitides. Granulomatosis with polyangiitis and microscopic polyangiitis account for ∼80–90% of all AAV. Exposure to silica dust, farming and chronic nasal Staphylococcus aureus carriage are associated with increased risk of developing AAV. When a diagnosis of AAV is suspected, as in patients with multisystem organ dysfunction or those with features such as chronic recurrent rhinosinusitis, cavitated lung nodules, palpable purpura or acute kidney injury, then appropriate further investigations are needed, including ANCA testing. In this scenario, a structured clinical assessment should be conducted, evaluating all the organs possibly involved, and tissue biopsy may be necessary for confirmation of the diagnosis. Therapeutic algorithms vary based on the severity of AAV, the clinical diagnosis/ANCA specificity, and the patient’s age, weight, comorbidities and prognosis. Recent data favour rituximab as a preferable option for both induction and maintenance of remission. In addition, regimens with less glucocorticoids are equally effective and safer in inducing remission compared with conventional regimens, and avacopan is an effective glucocorticoid-sparing option. In contrast, there is not compelling evidence to support the routine use of plasma exchange in addition to standard remission-induction therapy in AAV. ANCA and other biomarkers can be helpful in association with clinical assessment to guide diagnosis and treatment decisions. Patients should be frequently evaluated during follow-up for possible disease relapses or treatment-related morbidity, and for monitoring damage accrual, especially metabolic and cardiovascular damage.

Type of ANCA May Be Indispensable in Distinguishing Subphenotypes of Different Clinical Entities in ANCA-Associated Vasculitis

The traditional nomenclature system for classifying antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) based on clinical phenotype describes granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA) and microscopic polyangiitis (MPA) as distinct clinical entities. This classification has proved its expedience in clinical trials and everyday clinical practice; yet, a substantial overlap in clinical presentation still exists and often causes difficulties in prompt definition and clinical distinction. Additionally, new insights into the AAV pathogenesis point out that PR3 and MPO-AAV may not represent expressions of the same disease spectrum but rather two distinct disorders, as they display significant differences. Thus, it is supported that a classification based on ANCA serotype (PR3-ANCA, MPO-ANCA or ANCA-negative) could be more accurate and also closer to the nature of the disease compared to the phenotype-based one. This review aims to elucidate the major differences between PR3 and MPO-AAV in terms of epidemiology, pathogenesis, histological and clinical manifestations and response to therapeutic approaches.

Relationship Between Gender and 1-Year Mortality in ANCA-Associated Vasculitis Patients: A Single-Center Retrospective Analysis and Meta-Analysis

Objective

The relationship between gender and short-term prognosis of patients with anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) is unclear, hence single-center retrospective analysis and meta-analysis were conducted to determine the relationship.

Methods

Initially treated patients with AAV were retrospectively enrolled. Data of clinical manifestation, laboratory indicators, Birmingham vasculitis activity score (BVAS), therapeutic treatments, and the patients' situations within 1 year were recorded. First, we compared the basic characteristics between male and female patients. Second, the risk factors associated with a 1-year mortality rate of patients with AAV were evaluated. Finally, a meta-analysis was performed to explore the effect of gender on 1-year mortality in patients with AAV.

Results

The study involved 84 patients with AAV, including 33 female and 51 male participants. In total, 14 people died (12 males and 2 females) and 70 survived in the 1st year. Statistical differences were noted in the age of onset, the course of the disease, WBC, HB, N, ESR, CRP, BUN, ALT and ALB, BVAS, and 1-year mortality rate between male and female participants. In male patients, elevated Scr, NLR, PLT, and RDW-CV were associated with poor AAV (P < 0.05) prognosis. The meta-analysis verified that male gender was an independent risk factor for the 1-year mortality of patients with AAV(OR = 1.54).

Conclusion

Significant sex-specific differences were found in patients with AAV. Male patients contributed to 1.54-fold of 1-year mortality risk in patients with AAV by meta-analysis. More attention should be paid to the mortality risk of male patients with AAV in the early stage.

BVAS version 3 and BVAS/GPA: standing on the same line?

INTRODUCTION/OBJECTIVES

Birmingham vasculitis activity score (BVAS) version 3 (BVAS 3.0) and BVAS/granulomatosis with polyangiitis (BVAS/GPA) are used as indicators of disease activity in anti-neutrophil cytoplasmic antibody-associated vasculitis. We evaluated the association between these indices and the significance in patients with GPA and microscopic polyangiitis (GPA/MPA).

METHODS

We retrospectively reviewed the records of 203 patients with GPA/MPA in our hospital. The correlation between BVAS 3.0 and BVAS/GPA with the five-factor score (FFS) and laboratory data was investigated. The episodes of all-cause mortality, end-stage renal disease, and disease relapse were counted as adverse clinical outcomes. Multivariate Cox hazard analyses were performed to assess the relationships between both indices and patient outcomes.

RESULTS

Sixty-five (32.0%) and 138 (68.0%) patients with GPA and MPA were included. The median BVAS 3.0 was significantly higher in patients with MPA than in those with GPA (13.0 vs. 11.0, p = 0.015), whereas BVAS/GPA was higher in patients with GPA (4.0 vs. 3.0, p = 0.001). BVAS 3.0 and BVAS/GPA correlated significantly (r = 0.670, p < 0.001); both BVAS 3.0 and BVAS/GPA were shown to be associated with the outcomes investigated in separate Cox models. However, the correlation between BVAS 3.0 and BVAS/GPA was especially higher in a subgroup of patients with MPA than in those with GPA (MPA: r = 0.817, p < 0.001 vs. GPA: r = 0.570, p < 0.001) and with renal involvement (r = 0.676, p < 0.001).

CONCLUSIONS

Although both BVAS 3.0 and BVAS/GPA significantly correlated and predicted outcomes well in those with GPA/MPA, a discord was observed based on disease subtypes and organ involvement. Key Points • BVAS 3.0 and BVAS/GPA significantly correlated and predicted outcomes in those with GPA/MPA. • A discordance was also observed based on disease subtypes and organ involvement.

Practice patterns and outcomes for pediatric ANCA vasculitis transplant recipients in a national cohort

BACKGROUND

Anti-neutrophil cytoplasmic autoantibody (ANCA) vasculitis is a rare condition in pediatric patients. Little is known about practice patterns and outcomes of pediatric transplant patients. The purpose of our study was to examine differences in patient characteristics, immunosuppression, and long-term graft outcomes between ANCA and non-ANCA vasculitis recipients.

METHODS

We used the Scientific Registry of Transplant Recipients to evaluate pediatric ANCA vasculitis recipients between the ages of 1 and 22 years old from 1991 to 2017 and compared them to non-ANCA vasculitis patients during the same time cohort in the USA.

RESULTS

A total of 26,431 transplant recipients were identified, of these, 337 with ANCA vasculitis. Mean 1-year eGFR was 62.46 and 64.92 ml/min/1.73 m² (p = 0.002), and mean 5-year eGFR was 57.95 and 59.38 ml/min/1.73 m² (p = 0.18) between the non-ANCA and ANCA groups, respectively. Five-year graft survival was similar in both groups (non-ANCA 75.5 vs. ANCA 78.6%; p = 0.19). Of those with graft loss within the ANCA group, only 0.6% was secondary to disease recurrence (p = 0.14).

CONCLUSIONS

Kidney transplant is a safe treatment modality for children with ANCA-related kidney failure. ANCA patients have comparable graft survival when compared to the general transplant population with a low risk of recurrence. Thymoglobulin was used in a higher proportion within the ANCA group compared to the non-ANCA group. Tacrolimus, mycophenolate mofetil/mycophenolic acid, and steroids were the predominant maintenance immunosuppression used in both groups. A higher resolution version of the Graphical abstract is available as Supplementary information.

Endothelial Dysfunction Induced by Extracellular Neutrophil Traps Plays Important Role in the Occurrence and Treatment of Extracellular Neutrophil Traps-Related Disease

Many articles have demonstrated that extracellular neutrophil traps (NETs) are often described as part of the antibacterial function. However, since the components of NETs are non-specific, excessive NETs usually cause inflammation and tissue damage. Endothelial dysfunction (ED) caused by NETs is the major focus of tissue damage, which is highly related to many inflammatory diseases. Therefore, this review summarizes the latest advances in the primary and secondary mechanisms between NETs and ED regarding inflammation as a mediator. Moreover, the detailed molecular mechanisms with emphasis on the disadvantages from NETs are elaborated: NETs can use its own enzymes, release particles as damage-associated molecular patterns (DAMPs) and activate the complement system to interact with endothelial cells (ECs), drive ECs damage and eventually aggravate inflammation. In view of the role of NETs-induced ED in different diseases, we also discussed possible molecular mechanisms and the treatments of NETs-related diseases.

[Granulomatosis with polyangiitis with head and neck symptoms as the first clinical manifestation: clinical analysis of 28 cases]

Objective:To investigate the early clinical features and diagnosis of granulomatous polyangiitis（GPA） with head and neck symptoms as the first presentation. Methods:The data of 28 patients with GPA diagnosed in the Second Hospital of Shanxi Medical University from 2014 to 2021, whose first symptoms appeared on the head and neck, were collected. All patients underwent relevant imaging examinations, laboratory tests, endoscopy, and pathological tissue biopsies. Systemic glucocorticoid or combined immunosuppressive therapy was administered and followed up for 1-5 years. Results:Two patients refused treatment and were lost to follow-up; 26 patients were discharged with improved symptoms, complaining of nasal ventilation, resolution of supraorbital swelling, reduced dyspnoea, and renal symptoms. Five patients were repeatedly admitted to the hospital due to recurrent renal involvement. Conclusion:Although GPA often begins with head and neck symptoms, it is non-specific and can easily be confused with chronic inflammatory disease, leading to misdiagnosis. If suspicious cases are identified, they should be combined with endoscopy, pathological tissue biopsy, and special laboratory tests as early as possible to shorten the time to diagnosis, and obtain early diagnosis and treatment.

Clinical and Renal Histology Findings and Different Responses to Induction Treatment Affecting the Long-Term Renal Outcomes of Children With ANCA-Associated Vasculitis: a Single-Center Cohort Analysis

Introduction

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is relatively rare in children. This article aimed to analyze clinical and renal histology findings and different responses to induction treatment associated with the long-term renal outcomes in children with AAV in a single center.

Methods

All pediatric patients with AAV admitted to Tongji Hospital from January 2002 to January 2021 were included in the study. The demographic, clinical, pathological, laboratory, and treatment data and outcomes were collected and analyzed to identify predictors associated with response to induction treatment and progression to end-stage renal disease (ESRD).

Results

In total, 48 children with AAV were included in this cohort; 81.25% of them were women, and 91.7% were microscopic polyangiitis (MPA). Kidney involvement was found in 45 patients (93.75%). The most common histopathological subtype was crescentic form in this cohort according to Berden's classification. In total, 34 patients (70.8%) showed eGFR <60 ml/min/1.73 m2 at the time of diagnosis. Complete and partial remission was achieved in 8 patients (16.7%) and 19 patients (39.6%), respectively, following 6-month induction treatment. Half of the patients eventually progressed to ESRD at a mean time of (13.04 ± 15.83) months after diagnosis. The independent predictors of nonremission following induction treatment and progression to ESRD were baseline eGFR <60 ml/min/1.73 m2 and hypertension at diagnosis. Renal survival significantly decreased over time in patients with renal sclerotic subtypes or those with nonremission following induction treatment by Kaplan-Meier curve estimation.

Conclusions

Our study demonstrates that women, MPA, and crescentic subtypes are predominant in pediatric AAV in China. Initial renal failure (eGFR <60 ml/min/1.73 m2), hypertension, sclerotic pathological subtype, and nonremission following induction treatment are predictive of long-term renal outcomes.

Assessment of Renal Risk Score and Histopathological Classification for Prediction of End-Stage Kidney Disease and Factors Associated With Change in eGFR After ANCA-Glomerulonephritis Diagnosis

Introduction

The “Renal Risk Score” (RRS) and the histopathological classification have been proposed to predict the risk of end-stage kidney disease (ESKD) in ANCA-associated glomerulonephritis (ANCA-GN). Besides, factors associated with kidney function recovery after ANCA-GN onset remain to be more extensively studied. In the present study, we analyzed the value of the RRS and of the histopathological classification for ESKD prediction. Next, we analyzed factors associated with eGFR change within the first 2 years following ANCA-GN diagnosis.

Materials and Methods

We included patients from the Maine–Anjou ANCA-associated vasculitis registry with at least 6 months of follow-up. The values of ANCA-GN, histopathological classification, and RRS, and the factors associated with eGFR variations between ANCA-GN diagnosis and 2 years of follow-up were assessed.

Results

The predictive values of the histopathological classification and RRS were analyzed in 123 patients. After a median follow-up of 42 months, 33.3% patients developed ESKD. The predictive value of RRS for ESKD was greater than that of the histopathological classification. Determinants of eGFR variation were assessed in 80/123 patients with complete eGFR measurement. The median eGFR increased from ANCA-GN diagnosis to month 6 and stabilized thereafter. The only factor associated with eGFR variation in our study was eGFR at ANCA-GN diagnosis, with higher eGFR at diagnosis being associated with eGFR loss (p<0.001).

Conclusion

The RRS has a better predictive value for ESKD than the histopathological classification. The main determinant of eGFR variation at 2 years was eGFR at ANCA-GN diagnosis. Thus, this study suggests that eGFR recovery is poorly predicted by histological damage at ANCA-GN diagnosis.

Atlantoaxial instability and cervical noninfectious spondylodiscitis in a patient with Wegener's granulomatosis: A case report

A 61-year-old male patient with Wegener's granulomatosis was admitted due to neck pain and quadriparesis. Clinical evaluation showed severe cervical noninfectious spondylodiscitis, myelopathy, sagittal imbalance, and atlantoaxial instability. A combined anterior and posterior approach was implemented. Postoperative clinical evaluation showed improved neurologic status.

Identification of diagnostic markers and immune cell infiltration characteristics in antineutrophil cytoplasmic antibody-associated vasculitis by weighted gene co-expression network analysis

Background

Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) is a group of life-threatening systemic autoimmune diseases. The aim of this study was to determine the relationship between the AAV hub gene and immune cell infiltration, and its value for clinical disease treatment.

Methods

We downloaded the microarray information of 37 AAV patients and 27 controls from Gene Expression Omnibus (GEO). Genes were classified into totally different modules exploitation weighted gene co-expression network analysis (WGCNA). AAV diagnostic indicators were screened and then assessed immune cell infiltration by the least absolute shrinkage and selection operator (LASSO) and CIBERSORT. Finally, Connectivity Map analysis was applied to predict possible AAV glomerulus injury improvement therapies.

Results

WGCNA was developed and differentially expressed genes were classified into 6 modules, the black module was most tightly correlated to AAV. Among them, TIMP1 and FCER1G were most closely related to clinical features. Resting mast cells and monocytes emerged as having the foremost distinguished variations in AAV. C3AR1 and FCER1G were involved in AAV development by immune regulation. Connectivity Map analysis indicated the most significant compound was fisetin.

Conclusions

The present study is that the initial to spot immune cell infiltration with microarray data of glomeruli in AAV, which provides novel proof and clues for additional analysis of the molecular mechanisms.

Clinical Characteristics and Outcomes of Patients With ANCA-Associated Vasculitides in a Colombian Hospital

BACKGROUND/OBJECTIVE

Antineutrophil cytoplasmic antibody-associated vasculitides (AAVs) are uncommon systemic autoimmune diseases, of which few reports exist in Latin America. Our aim was to examine AAV evaluated in a high-complexity hospital in southwestern Colombia, with emphasis in severe forms.

METHODS

A medical records review study of 67 patients was performed, and data were collected from electronic registries. Moderate and severe AAVs were defined as the presence of life-threatening complications, unfavorable Birmingham Vasculitis Activity Score outcomes, and hospitalization requirements at the time of diagnosis and by the last follow-up, between 2011 and 2019. Clinical manifestations, treatment, and outcomes were evaluated. The AAV subtypes were compared.

RESULTS

A total of 67 cases were included. The majority were female (n = 44, 65.67%), and the median age was 52 (40-64) years. Granulomatosis with polyangiitis (GPA) was the most frequent with 42 patients (62.68%), followed by microscopic polyangiitis (MPA) and eosinophilic GPA, with 15 patients (22.38%) and 10 patients (14.92%), respectively. Forty-four patients (65.67%) presented pulmonary symptoms. The highest Birmingham Vasculitis Activity Score corresponded to MPA, with 21 (12-25) points. Fifteen patients (22.4%) were admitted to the intensive care unit throughout the course of the disease, of whom 10 had GPA. The longest stay and duration of mechanical ventilation were seen in MPA. The principal treatments were corticosteroids and cyclophosphamide, and the main outcome was end-stage renal disease.

CONCLUSIONS

In this cohort of AAV, most of cases corresponded to GPA, and pulmonary manifestations were the most common. Microscopic polyangiitis was the more severe subtype as it showed worse impairment in clinical characteristics and intensive care unit requirements.

Patient Survival Between Hemodialysis and Peritoneal Dialysis Among End-Stage Renal Disease Patients Secondary to Myeloperoxidase-ANCA-Associated Vasculitis

BACKGROUND

A significant proportion of anti-neutrophil cytoplasmic antibody (ANCA) associated glomerulonephritis eventually progresses to end-stage renal disease (ESRD) thus requiring long-term dialysis. There is no consensus about which dialysis modality is more recommended for those patients with associated vasculitis (AAV-ESRD). The primary objective of this study was to compare patient survival in patients with AAV-ESRD treated with hemodialysis (HD) or peritoneal dialysis (PD).

METHODS

This double-center retrospective cohort study included dialysis-dependent patients who were treated with HD or PD. Clinical data were collected under standard format. The Birmingham vasculitis activity score (BVAS) was used to evaluate disease activity at diagnosis and organ damage was assessed using the vasculitis damage index (VDI) at dialysis initiation.

RESULTS

In total, 85 patients were included: 64 with hemodialysis and 21 with peritoneal dialysis. The patients with AAV-PD were much younger than the AAV-HD patients (48 vs. 62, P < 0.01) and more were female (76.2 vs. 51.6%, P = 0.05). The laboratory data were almost similar. The comorbidities, VDI score, and immuno-suppressive therapy at dialysis initiation were almost no statistical difference. Patient survival rates between HD and PD at 1 year were 65.3 vs. 90% (P = 0.062), 3 year were 59.6 vs. 90% (P < 0.001), and 5 years were 59.6 vs. 67.5% (P = 0.569). The overall survival was no significant difference between the two groups (P = 0.086) and the dialysis modality (HD or PD) was not shown to be an independent predictor for all-cause death (hazard ratio (HR) 0.73; 95% confidence interval (CI) 0.31-1.7; P = 0.473). Cardio-cerebrovascular events were the main cause of death among AAV-HD patients while infection in patients with AAV-PD.

CONCLUSION

These results provide real-world data that the use of either hemodialysis or peritoneal dialysis modality does not affect patient survival for patients with AAV-ESRD who need long-term dialysis.

Understanding the Gut-Kidney Axis in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: An Analysis of Gut Microbiota Composition

Increasing evidence suggested that gut microbiota played critical roles in developing autoimmune diseases. This study investigated the correlation between gut microbiota and antineutrophil cytoplasmic antibody-associated vasculitis (AAV) with kidney injury. We analyzed the fecal samples of 23 AAV patients with kidney injury using a 16s RNA microbial profiling approach. The alpha-diversity indexes were significantly lower in AAV patients with kidney injury than healthy controls (Sobs P &lt; 0.001, Shannon P &lt; 0.001, Chao P &lt; 0.001). The beta-diversity difference demonstrated a significant difference among AAV patients with kidney injury, patients with lupus nephritis (LN), and health controls (ANOSIM, p = 0.001). Among these AAV patients, the Deltaproteobacteria, unclassified_o_Bacteroidales, Prevotellaceae, Desulfovibrionaceae Paraprevotella, and Lachnospiraceae_NK4A136_group were correlated negatively with serum creatinine, and the proportion of Deltaproteobacteria, unclassified_o_Bacteroidales, Desulfovibrionaceae, Paraprevotella, and Lachnospiraceae_NK4A136_group had a positive correlation with eGFR. In conclusion, the richness and diversity of gut microbiota were reduced in AAV patients with kidney injury, and the alteration of gut microbiota might be related with the severity of kidney injury of AAV patients. Targeted regulation of gut microbiota disorder might be a potential treatment for AAV patients with kidney injury.

Granulomatous Polyangiitis With Renal Involvement: A Case Report and Review of Literature

Granulomatosis with polyangiitis (GPA), formerly named Wegner’s granulomatosis is an antineutrophilic cytoplasmic antibody (ANCA) associated vasculitis of the small vessels. GPA can affect several organ systems even though predominantly affects respiratory and renal systems. Pathogenesis is initiated by activation of the immune system to produce ANCA, Cytoplasmic (C-ANCA) antibody, which thereby leads to widespread necrosis and granulomatous inflammation. Multisystem involvement with varied symptomatology makes GPA diagnosis more challenging. Early diagnosis and management are vital and can alter the prognosis of the disease. We present a literature review and a clinical scenario of a 26-year-old male with a history of chronic sinusitis, testicular carcinoma in remission, recent onset of worsening cough, epistaxis, hoarseness of voice, weight loss, and dark-colored urine. Workup revealed high titers of C-ANCA, C-reactive protein, procalcitonin, CT chest evidence of mass-like consolidation, and bronchoscopy findings of friable tissue that was not amenable for biopsy. Methylprednisolone and rituximab (RTX) were administered, which resulted in marked clinical improvement. Therefore, a keen eye for details is necessary to diagnose GPA early, which can improve disease outcomes dramatically.

Cutaneous manifestations of acute kidney injury

Acute kidney injury (AKI) is a common medical problem with a multitude of aetiologies. Prompt diagnosis and management is key in the prevention of complications. Cutaneous signs can often give diagnostic clues of underlying systemic diseases causing AKI.

This review summarises cutaneous findings of diseases causing AKI in adults. Knowledge of such cutaneous signs could lead to earlier diagnosis of underlying kidney disease and facilitate management strategies in a timely manner.

Acute interstitial nephritis, polyarteritis nodosa, Kawasaki's disease, granulomatosis with polyangiitis (previously Wegener's granulomatosis), microscopic polyangiitis, eosinophilic granulomatosis with polyangiitis (previously Churg-Strauss syndrome), Henoch-Schonlein purpura, cryoglobulinaemia, Sjogren's Syndrome, systemic sclerosis, nephrogenic systemic fibrosis, dermatomyositis, systemic lupus erythematosus, amyloidosis, and cholesterol embolisation syndrome were highlighted as diseases causing AKI with cutaneous manifestations.

Plasma Exchange in ANCA-Associated Vasculitis: A Narrative Review

Therapeutic plasma exchange (TPE) is an adjunctive intervention to immunosuppression for the treatment of severe renal involvement or lung hemorrhage in patients with ANCA-associated vasculitis (AAV). Patients with AAV have an increased risk for progression to end-stage kidney disease (ESKD) or death despite advances in immunosuppressive therapy. The potential pathogenicity of ANCA makes TPE a reasonable treatment approach for the life-threatening complications of AAV. The efficacy of intensive TPE in rapidly progressive glomerulonephritis was originally described in small studies almost four decades ago. Further randomized trials examined the addition of TPE to standard of care, exhibiting mixed results in both patient and renal survival. The largest clinical trial to date, PEXIVAS, failed to demonstrate a clear benefit for TPE in severe AAV. In light of new evidence, the role of TPE remains controversial across the vasculitis medical community. The purpose of this review is to summarize the clinical indications and the current available data for the use of TPE in patients with severe AAV.

The Pathogenesis of End-Stage Renal Disease from the Standpoint of the Theory of General Pathological Processes of Inflammation

Chronic kidney disease can progress to end-stage chronic renal disease (ESRD), which requires the use of replacement therapy (dialysis or kidney transplant) in life-threatening conditions. In ESRD, irreversible changes in the kidneys are associated with systemic changes of proinflammatory nature and dysfunctions of internal organs, skeletal muscles, and integumentary tissues. The common components of ESRD pathogenesis, regardless of the initial nosology, are (1) local (in the kidneys) and systemic chronic low-grade inflammation (ChLGI) as a risk factor for diabetic kidney disease and its progression to ESRD, (2) inflammation of the classical type characteristic of primary and secondary autoimmune glomerulonephritis and infectious recurrent pyelonephritis, as well as immune reactions in kidney allograft rejection, and (3) chronic systemic inflammation (ChSI), pathogenetically characterized by latent microcirculatory disorders and manifestations of paracoagulation. The development of ChSI is closely associated with programmed hemodialysis in ESRD, as well as with the systemic autoimmune process. Consideration of ESRD pathogenesis from the standpoint of the theory of general pathological processes opens up the scope not only for particular but also for universal approaches to conducting pathogenetic therapies and diagnosing and predicting systemic complications in severe nephropathies.

Clinicopathological Characteristics and Influencing Factors of Renal Vascular Lesions in Anti-neutrophil Cytoplasmic Autoantibody-Related Renal Vasculitis

The purpose of this study was to evaluate the clinicopathological features of different degrees of extraglomerular renal vascular lesions (RVLs) in patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated renal vasculitis and explore their clinical determinants. This is a retrospective study of 186 patients with ANCA-associated renal vasculitis diagnosed at the First Affiliated Hospital of Zhengzhou University from January 2014 to April 2019. The patients who met the inclusion criteria were divided into non-renal RVLs, mild RVLs, moderate RVLs, and severe RVLs. It was found that there were significant differences in serum creatinine (SCR), estimated glomerular filtration rate (eGFR), erythrocyte sedimentation rate (ESR), high-density lipoprotein (HDL), systolic blood pressure (SBP), the prevalence rate of hypertension, the proportion of normal glomeruli, and the proportion of sclerotic glomeruli and interstitial fibrosis integral. SCR and ESR are independent risk factors for RVLs. The participants were followed up for 1 year, and the progression to end-stage renal disease (ESRD) and death was defined as endpoint events. We found that the survival rate of patients without RVLs was significantly higher than that of patients with RVLs and that the RVLs were an independent risk factor for ESRD or death. Early intervention in the progression of RVLs can improve the prognosis.

Evaluating a Living Donor With Rheumatoid Arthritis for a Recipient With End-Stage Renal Disease From Antineutrophil Cytoplasmic Antibodies Associated Vasculitis

A 60-year-old Caucasian female with sero-positive rheumatoid arthritis (RA) was evaluated as a potential kidney donor for her brother-in-law with end-stage kidney disease (ESKD) secondary to c-antineutrophil cytoplasmic antibody (c-ANCA) associated vasculitis (AAV) and membranous nephropathy (MN). With little to no data supporting or contradicting this unique scenario, in addition to the varying viewpoints expressed by the different specialists, our multidisciplinary transplant committee encountered a difficult decision of whether to approve a candidate with RA for a living kidney donation or not. As a result, we carried out a careful literature review addressing aspects of recipients' outcomes following kidney transplants from a living donor with RA, especially when the recipient has AAV, living donor's short- and long-term outcomes post kidney donation, renal disease in AAV and RA, and maintenance of disease remission.

Recent advances in Extracellular Vesicles and their involvements in vasculitis

Systemic vasculitis is a heterogeneous group of multisystem autoimmune disorders characterized by inflammation of blood vessels. Although many progresses in diagnosis and immunotherapies have been achieved over the past decades, there are still many unanswered questions about vasculitis from pathological understanding to more advanced therapies. Extracellular vesicles (EVs) are double-layer phospholipid membrane vesicles harboring various cargoes. EVs can be classified into exosomes, microvesicles (MVs), and apoptotic bodies depending on their size and origin of cellular compartment. EVs can be released by almost all cell types and may be involved in physical and pathological processes including inflammation and autoimmune responses. In systemic vasculitis, EVs may have pathogenic involvement in inflammation, autoimmune responses, thrombosis, endothelium injury, angiogenesis and intimal hyperplasia. EV-associated redox reaction may also be involved in vasculitis pathogenesis by inducing inflammation, endothelial injury and thrombosis. Additionally, EVs may serve as specific biomarkers for diagnosis or monitoring of disease activity and therapeutic efficacy, i.e. AAV-associated renal involvement. In this review, we have discussed the recent advances of EVs, especially their roles in pathogenesis and clinical involvements in vasculitis.

Investigating the forensic pathological characteristics of systemic vasculitis: A retrospective study of 20 deaths caused by systemic vasculitis

Systemic vasculitis (SV) is a condition characterized by vascular inflammatory disease that often involves the medium and small arteries of various organs throughout the body. SV is difficult to diagnose due to the diversity of clinical symptoms and manifestations, and only tissue biopsy is of great significance. Even so, complications or secondary lesions of SV can also lead to death. In forensic medicine, we can often observe multiple vasculitis in histological observations, which is easily overlooked as a primary cause of death in the final diagnosis. Twenty SV cases were registered in our institution from a total of 1088 completed autopsies, which represents 1.83% of the total autopsies. The ages of these 20 SV patients ranged from 16 to 73 years, and the mean age was 41.1 ± 15.9 years. SV usually involves multiple organs, such as the heart, lung, liver, kidney, gastrointestinal system and brain, simultaneously. The intensity of the lesions in the heart and kidney seemed to be more severe than the lesion intensity in other organs in most cases. The causes of death were identified as acute myocarditis (8 cases), acute heart failure (3 cases), cerebral artery rupture (3 cases), cardiovascular artery rupture (2 cases), acute interstitial pneumonia (2 cases), aortic aneurysm rupture (1 case) and acute renal failure (1 case). The typical histopathological changes (smooth muscle degeneration, fibrinoid necrosis, inflammatory cell infiltration and microthrombosis) of arteries observed in this study were of great significance for diagnosing SV. In this article, we try to analyse and summarize the lesion characteristics in cases of death caused by SV in order to provide some help for forensic workers in identifying such cases.

Tubulointerstitial nephritis without glomerular crescent formation as an underestimated subgroup of renal involvement among microscopic polyangiitis patients: A case report

Although extra-glomerular involvement of microscopic polyangiitis is not regarded as a characteristic finding of the disease, tubulointerstitial nephritis should be considered as a new subclass of renal involvement.

Characterization of a Rat Model of Myeloperoxidase-Anti-Neutrophil Cytoplasmic Antibody-Associated Crescentic Glomerulonephritis

BACKGROUND/AIM

Necrotizing crescentic glomerulonephritis (GN) associated with anti-neutrophil cytoplasmic antibodies (ANCA) against myeloperoxidase (MPO) is a devastating disease that quickly progresses to kidney failure. Current therapies are broadly immunosuppressive and associated with adverse effects. We wanted to set up a model that could be suitable for testing narrowly targeted therapies.

METHODS

The model was constructed in male Wistar Kyoto rats through injections of human MPO (hMPO) and pertussis toxin, followed by a sub-nephritogenic dose of sheep anti-rat glomerular basement membrane (GBM) serum to boost the disease. Rats were monitored for 35 days. Rats given hMPO alone, saline, or human serum albumin with or without anti-GBM serum were also studied.

RESULTS

Rats receiving hMPO developed circulating anti-hMPO and anti-rat MPO antibodies. Challenging hMPO-immunized rats with the anti-GBM serum led to more glomerular neutrophil infiltration and MPO release, and severe haematuria, heavy proteinuria, and higher blood urea nitrogen than hMPO alone. Pauci-immune GN developed with crescents, affecting 25% of glomeruli. The majority of crescents were fibrocellular. Necrotizing lesions and Bowman capsule ruptures were detected. Cells double positive for claudin-1 (a marker of parietal epithelial cells [PECs]) and neural cell adhesion molecule (NCAM; progenitor PECs) were present in crescents. Double staining for NCAM and Ki-67 established proliferative status of progenitor PECs. Podocyte damage was associated with endothelial and GBM changes by electron microscopy. Monocyte/macrophages and CD4+ and CD8+ T cells accumulated in glomeruli and the surrounding area and in the tubulointerstitium. Lung haemorrhage also manifested.

CONCLUSION

This model reflects histological lesions of human ANCA-associated rapidly progressive GN and may be useful for investigating new therapies.

Renal dysfunction in systemic sclerosis beyond scleroderma renal crisis

Research regarding renal involvement in SSc has almost exclusively focused on scleroderma renal crisis (SRC). There are relatively limited data regarding renal impairment in SSc beyond SRC. We performed an electronic search using the key words systemic sclerosis or scleroderma combined with each of the following: renal dysfunction, kidney, glomerular filtration rate (GFR), proteinuria and hematuria. We searched for reports relevant to renal dysfunction in SSc beyond SRC. In 796 SSc patients recruited in five studies. 251 (31.5%) had GFR < 90 ml/min whereas 155(19.5%) patients had GFR < 60 ml/min. Most data indicate that the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula should be considered as the most suitable tool for assessing renal function in SSc pts, since it provides similar results to measured GFR. These data indicate that renal dysfunction in SSc in not uncommon and therefore patients with SSc should have their renal function assessed by GFR estimation on a regular basis.

Renal Involvement in Granulomatosis With Polyangiitis Increases Economic Health Care Burden: Insights From the National Inpatient Sample Database

Background This study aims to compare outcomes of hospitalizations of granulomatosis with polyangiitis (GPA) with and without renal involvement. The primary outcome was inpatient mortality, whereas secondary outcomes were hospital length of stay (LOS) and total hospital charge. Methods Data were abstracted from the National Inpatient Sample (NIS) 2016 and 2017 databases. The NIS was searched for GPA hospitalizations with and without renal involvement as the principal or secondary diagnosis using International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10) codes. GPA hospitalizations for adult patients from the above groups were identified. Multivariate logistic and linear regression analyses were used to adjust for possible confounders for the primary and secondary outcomes, respectively. Results There were more than 71 million discharges included in the combined 2016 and 2017 NIS database, of which 23,670 were for adult patients who had either a principal or secondary ICD-10 code for GPA, and 8,265 (34.92%) of these GPA hospitalizations had renal involvement. Hospitalizations for GPA with renal involvement had similar inpatient mortality (3.8% vs. 3.7%; adjusted OR: 1.14; 95% CI: 0.84-1.56; p=0.406) compared to those without renal involvement. GPA with renal involvement hospitalizations had an increase in adjusted mean LOS of 1.36 days (95% CI: 0.82-1.91; p=0.0001) compared to those without renal involvement. GPA with renal involvement hospitalizations had an increase in adjusted total hospital charges of $18,723 (95% CI: 9,595-27,852; p=0.0001) compared to those without renal involvement. Conclusions GPA with renal involvement hospitalizations had similar inpatient mortality compared to those without renal involvement. However, LOS and total hospital charges were greater in those with renal involvement.

A Case of Myeloma Kidney with Perinuclear Anti-Neutrophil Cytoplasmic Antibody and Anti-Myeloperoxidase Positivity: The Importance of Determining the True Cause of Renal Impairment

Acute kidney injury (AKI) is a common presentation which can result from a number of different underlying pathological processes. Haematological malignancies, particularly multiple myeloma (MM), are known to frequently present with AKI. Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a rare condition which can cause crescentic glomerulonephritis (GN), resulting in AKI. We present the case of a 60-year-old man who presented with clinical features suggestive of AAV in the context of blood tests which demonstrated AKI and positive perinuclear ANCA (p-ANCA) and anti-myeloperoxidase (anti-MPO) titres. Further investigations demonstrated an underlying diagnosis of MM. A renal biopsy was ultimately required to determine the cause of AKI, a cast nephropathy. This case is the first to our knowledge which demonstrates a rare situation in which myeloma kidney is associated with positive p-ANCA and anti-MPO titres, without any evidence of a crescentic GN. It highlights the importance of following up on all investigations sent in the context of AKI, even when a potential diagnosis seems evident. Furthermore, it demonstrates the role of renal biopsy in confirming a diagnosis in the context of AKI with multiple differential diagnoses.

Efficacy of Rituximab and Plasma Exchange in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis with Severe Kidney Disease

BACKGROUND

Treatment of patients with ANCA-associated vasculitis (AAV) and severe renal involvement is not established. We describe outcomes in response to rituximab (RTX) versus cyclophosphamide (CYC) and plasma exchange (PLEX).

METHODS

A retrospective cohort study of MPO- or PR3-ANCA-positive patients with AAV (MPA and GPA) and severe kidney disease (eGFR <30 ml/min per 1.73 m²). Remission, relapse, ESKD and death after remission-induction with CYC or RTX, with or without the use of PLEX, were compared.

RESULTS

Of 467 patients with active renal involvement, 251 had severe kidney disease. Patients received CYC (n=161) or RTX (n=64) for remission-induction, and 51 were also treated with PLEX. Predictors for ESKD and/or death at 18 months were eGFR <15 ml/min per 1.73 m² at diagnosis (IRR 3.09 [95% CI 1.49 to 6.40], P=0.002), renal recovery (IRR 0.27 [95% CI 0.12 to 0.64], P=0.003) and renal remission at 6 months (IRR 0.40 [95% CI 0.18 to 0.90], P=0.027). RTX was comparable to CYC in remission-induction (BVAS/WG=0) at 6 months (IRR 1.37 [95% CI 0.91 to 2.08], P=0.132). Addition of PLEX showed no benefit on remission-induction at 6 months (IRR 0.73 [95% CI 0.44 to 1.22], P=0.230), the rate of ESKD and/or death at 18 months (IRR 1.05 [95% CI 0.51 to 2.18], P=0.891), progression to ESKD (IRR 1.06 [95% CI 0.50 to 2.25], P=0.887), and survival at 24 months (IRR 0.54 [95% CI 0.16 to 1.85], P=0.330).

CONCLUSIONS

The apparent benefits and risks of using CYC or RTX for the treatment of patients with AAV and severe kidney disease are balanced. The addition of PLEX to standard remission-induction therapy showed no benefit in our cohort. A randomized controlled trial is the only satisfactory means to evaluate efficacy of remission-induction treatments in AAV with severe renal involvement.