Propylthiouracil-induced Antineutrophil Cytoplasmic Antibody (ANCA)-associated Renal Vasculitis Versus Primary ANCA-associated Renal Vasculitis: A Comparative Study

Objective.Renal involvement is frequently present in primary antineutrophil cytoplasmic antibody-associated small-vessel vasculitis (AAV) as well as propylthiouracil (PTU)-induced AAV. We analyzed the characteristics of patients with PTU-induced AAV with renal involvement and investigated the differences of the 2 diseases.Methods.Thirty-six patients with PTU-induced AAV, diagnosed from 1997 to 2010, were enrolled for study. Their data were compared with those of 174 patients with primary AAV diagnosed at the same time. Renal involvement was present in all patients.Results.There was a prominent proportion of young women with PTU-induced AAV (p < 0.01). They had lower levels of proteinuria and serum creatinine and higher estimated glomerular filtration rate (p < 0.01, p < 0.01, and p < 0.01, respectively). Clinical immunological abnormalities were less severe in patients with PTU-induced AAV. Patients with PTU-induced AAV had less organ involvement and lower Birmingham Vasculitis Assessment Score than patients with primary AAV (p < 0.01). Renal biopsies showed a lower proportion of glomeruli with crescents (p < 0.01). Interstitial inflammation was less severe in patients with PTU-induced AAV (p < 0.05). Similarly, interstitial fibrosis and tubular atrophy were less severe in patients with PTU-induced AAV (p < 0.01, p < 0.05, respectively). Renal survival and total survival were better in patients with PTU-associated vasculitis (p < 0.05, p = 0.01).Conclusion.Clinical and histopathological abnormalities were less severe in patients with PTU-induced AAV and most of them had a good prognosis.

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Electron microscopy study of 496 cases of lupus nephritis: A single-center experience

Lupus ◽

10.1177/0961203320984539 ◽

2021 ◽

pp. 096120332098453

Author(s):

Bahar Bagheri ◽

Seyed Mohammad Owji ◽

Simin Torabinezhad ◽

Hadi Raeisi Shahraki ◽

Amirhossein Kamalinia ◽

...

Keyword(s):

Electron Microscopy ◽

Lupus Nephritis ◽

Light Microscopy ◽

Lupus Erythematosus ◽

Interstitial Fibrosis ◽

Renal Involvement ◽

Correct Classification ◽

Tubular Atrophy ◽

Diagnosis And Classification

Introduction Renal involvement is seen in about 40-82% of systemic lupus erythematosus (SLE) Asian patients. The exact diagnosis and classification of lupus nephritis are important for treatment and prognosis. This study aimed to investigate the value of electron microscopy (EM) in the diagnosis and classification of lupus nephritis compared with light microscopy. Method In this cross-sectional referral-center 16-year study of lupus nephritis, the final diagnosis was based on the EM study. Primary light microscopy findings were compared with EM diagnosis. Moreover, Immunofluorescence patterns distribution was assessed. Results From 496 patients diagnosed with lupus nephritis based on EM, 225(45.4%) of patients were categorized in class IV, followed by 98(19.7%), 93(18.8%), 46(9.3%), and 14(2.8%) who were categorized into classes of II, III, V, and VI respectively. Only 1(0.2%) patient belonged to class I, and 19(3.8%) cases were diagnosed with mixed two classes. Using EM was essential for diagnosing 25.6% of cases taking the correct classification by light microscopy into account; however, disregarding correct classification, this could change to a 7.4% contribution rate of EM. The most common cause of misdiagnosis, disregarding incorrect classification, was inadequate or wrong tissue. Positive associations were detected between tubular atrophy and interstitial fibrosis of both electron and light microscopy with different classes (P < 0.001). Conclusion While light microscopy is highly accurate for diagnosing lupus nephritis regardless of correct classification, EM contributes substantially to the correct classification of lupus nephritis types.

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P0456LONG TERM PATIENT SURVIVAL AND RELAPSE RATE IN ANCA ASSOCIATED PATIENTS WITH RENAL INVOLVMENET - DATA FROM CROATIAN REFERRAL CENTER

Nephrology Dialysis Transplantation ◽

10.1093/ndt/gfaa142.p0456 ◽

2020 ◽

Vol 35 (Supplement_3) ◽

Author(s):

Matija Crnogorac ◽

Ana Brechelmacher ◽

Ivica Horvatić ◽

Patricia Kacinari ◽

Miroslav Tišljar ◽

...

Keyword(s):

Relapse Rate ◽

Interstitial Fibrosis ◽

Renal Involvement ◽

Induction Treatment ◽

Tubular Atrophy ◽

Free Survival ◽

Acute Dialysis ◽

Significant Difference ◽

Stage Renal Disease

Abstract Background and Aims The aim of the research was to evaluate patient and renal as well as relapse free survival in ANCA associated vasculitis (AAV) patients in our center. Despite the advances in understanding pathogenesis of AAVs and advances in treatment, the outcomes of AAV patient differ in various centers. Method This study included 106 consecutive AAV patients with renal involvement in the period from 2007-2017. We performed renal biopsy on patients using automatic 16 Gauge needle. Light, immunofluorescent and electronic microscopy were performed. All the patients were treated with cyclophosphamide and steroids in induction treatment with adjuvant PLEX and dialysis depending on renal function and lung manifestations. Primary outcomes were combined outcome progression to end-stage renal disease, defined as persistent (more than three months) need for renal replacement therapy or permanent reduction of EGFR to <15ml/minute (according to CKD EPI formula) and/or death (ESRDD), death (D) and ESRD alone, and disease relapse. Kaplan Meyer survival analysis and multivariate Cox proportional hazard regression analysis were used to explore difference between phenotypes and finding significant predictors regarding outcomes. Out of 106 patients (55,6% female, median age 61; IQR 51-70) there were 66 (61,1%) microscopic poliangitiis (MPA), 20 (18,5%) granulomatosis with angitiis and 20 (18,5%) with renal limited vasculitis (RLV),There were 14 (13%) PR3-ANCA positive patients, 57 (52,8%) MPO ANCA positive, 5 (4,6%) PR3-ANCA+MPO-ANCA positive and 32 (29,6%) ANCA negative patients. Histologically (Berden classification) 43 (39,8%) patients had crescentic, 19 (17,6%) focal, 34 (31,5%) mixed and 12 (11,1%) sclerotic class. Follow up time ranged from 1 to 127 months. Median follow up time was 21 months (IQR = 7-44). Median time to diagnosis was 3 months (IQR 2,0-6,0). Results During follow up 21 (19,8%) patients died, 26 (24,5%) patients reached ESRD and 10 (9,4%) patients relapsed. There was no significant difference in outcomes between clinical, serological or histological phenotypes. In multivariant analysis independent predictors for death were age (HR = 1,059, 95% CI =1,001-1,120; p = 0,046), anemia (HR = 0,952, 95% CI =0,908-0,998; p = 0,040) and BVAS (HR = 1,093, 95% CI =1,030-1,159; p = 0,003), for ESRD. the need for acute dialysis (HR = 4,674, 95% CI =1,996-10,946; p = < 0,001), and interstitial fibrosis and tubular atrophy (IFTA) percentage over 50% (HR = 2,652, 95% CI =1,157-6,081; p = 0,021). and for relapse rate younger age (HR = 0,924, 95% CI = 0,870-0,981; p =0,010), lower serum creatinine levels (HR = 0,996, 95% CI = 0,992-1,000; p = 0,033), and the need for acute dialysis (HR = 59,545, 95% CI =3,467-1022,665; p = 0,005). Event free survival after 12, 24, 36 and 60 months was for death 83,9, 81,2, 79 and 74,7%, for ESRD 80,6, 77,9, 76,1 and 71% and for relapse 95,3, 88,4, 88,4 and 85%. Conclusion Timely diagnosis and treatment can ensure better outcomes in AAV patients. Though there is an overlap in predictive factors between different cohorts, there are still distinctive differences especially between cohorts from clinical trials and those from observational studies. Our study is among few to show significance of anemia as clinical predictor and IFTA percentage as pathohistological predictor.

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P0136COMPARISON OF SECONDARY IGA NEPHROPATHY OF ANKYLOSING SPONDYLITIS AND PRIMARY IGA NEPHROPATHY IN CLINICAL AND PATHOLOGICAL FEATURES

Nephrology Dialysis Transplantation ◽

10.1093/ndt/gfaa142.p0136 ◽

2020 ◽

Vol 35 (Supplement_3) ◽

Author(s):

Qin Xue ◽

Guang Li Zhang ◽

Zebo Tian

Keyword(s):

Retrospective Study ◽

Ankylosing Spondylitis ◽

Iga Nephropathy ◽

Interstitial Fibrosis ◽

Renal Involvement ◽

Control Group ◽

Pathological Features ◽

Tubular Atrophy ◽

The Difference ◽

Clinical And Pathological Features

Abstract Background and Aims Renal involvement is one of the most common extra-articular complications caused by ankylosing spondylitis (AS). The main pathological manifestation is secondary IgA nephropathy(SIgAN) in Chinese AS patients. The difference between SIgAN and primary IgAN (PIgAN) remains unclear due to the lack of cases. Therefore, the aim of this retrospective study was to compare the clinical and pathological features of SIgAN of AS (SIgAN-AS) and PIgAN, to detect the pathogenesis of SIgAN Method Clinical characteristics and pathological data were collected in patients who were diagnosed with IgAN by renal biopsy in our hospital from Jan 2008 to Oct 2018. Patients with SIgAN-AS were recruited by the ratio 1:5 of patients with primary IgAN as the control group in the study. Fifteen patients with SIgAN-AS and Seventy-five patients with PIgAN were enrolled in this retrospective study. Results There were 15 cases in AS group, including 13 male and 2 female. The cohort of 75 patients with PIgAN included 34 male and 41 female. There were more males in AS group 13/15 (86.7%) vs 37/75(49.3%) ,P < 0.05. Compared with PIgAN patients, SIgAN-AS patients had higher incidences of hematuria( 13/15(86.7%)vs 44/75 (58.7%) , P < 0.05), lower levels of 24-hour urinary protein(0.85±0.68 vs 1.57±1.54g, P < 0.05), but higher levels of eGFR (CKD-MDRD formula) (117.60±37.33 vs 85.35±31.36, P < 0.05),eGFR (CKD-EPI formula) (128.01±41.58 vs 92.75±36.09, P < 0.05), Albumin (44.67±3.48 vs 41.09±7.07 g/L, P < 0.05) ESR (43.20 ±33.94 vs 18.79±16.26mm/h, P < 0.001) , and CRP (21.19±30.61 vs 2.11±4.58mg/L, P < 0.001) . From the perspective of renal pathology of PIgAN, SIgA-AS patients had fewer incidences of renal tubular atrophy / interstitial fibrosis of nephropathy (P <0.05). The immunohistostaining analysis showed higher incidences of dominant deposits of single IgA in mesangial cell area (P < 0.05). Conclusion Patients with SIgAN-AS is more common in male and display a milder progression than those with primary IgAN. Majority of the SIgAN-AS can be improved with early intervention.

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Systematic Scoring of Tubular Injury Patterns Reveals Interplay between Distinct Tubular and Glomerular Lesions in ANCA-Associated Glomerulonephritis

Journal of Clinical Medicine ◽

10.3390/jcm10122682 ◽

2021 ◽

Vol 10 (12) ◽

pp. 2682

Author(s):

Samy Hakroush ◽

Désirée Tampe ◽

Peter Korsten ◽

Philipp Ströbel ◽

Björn Tampe

Keyword(s):

Medical Center ◽

Renal Involvement ◽

Disease Onset ◽

Antineutrophil Cytoplasmic Antibody ◽

Small Vessel Vasculitis ◽

Glomerular Sclerosis ◽

Tubular Injury ◽

Injury Patterns ◽

Renal Biopsies ◽

Glomerular Lesions

Background: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a small vessel vasculitis, most frequently presenting as microscopic polyangiitis (MPA) or granulomatosis with polyangiitis (GPA). Acute tubular injury with the presence of tubulitis was previously reported to be of prognostic value in ANCA glomerulonephritis (GN). In particular, distinct tubular injury lesions were associated with the deterioration of kidney function at AAV disease onset, as well as renal resistance to treatment, and higher risk of progression to composite outcome in patients with AAV. To expand our knowledge regarding distinct tubular lesions in AAV, we aimed to describe acute tubular injury patterns in association with glomerular lesions in ANCA GN by systematic histological scoring. Methods: A total number of 48 renal biopsies with confirmed renal involvement of AAV admitted to the University Medical Center Göttingen from 2015 to 2020 were retrospectively examined. By systematic scoring of tubular injury lesions, the association between clinical parameters, laboratory markers, and histopathological findings was explored. Results: We have shown that cellular casts in renal biopsies were frequently observed in the majority of cases with ANCA GN. Furthermore, we showed that tubular epithelial simplification with dilatation correlated with MPA and MPO subtypes, C3c hypocomplementemia, severe renal involvement, and uACR. Red blood cell (RBC) casts were associated with increased levels of C-reactive protein (CRP), leukocyturia, and hematuria. Finally, we found that hyaline casts were associated with an increased fraction of glomeruli with global glomerular sclerosis. Conclusions: Acute tubular injury patterns were correlated with active ANCA GN, whereas tubular injury lesions reflecting the later stages of kidney disease correlated with chronic glomerular lesions. These results suggest an interplay between different renal compartments.

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Noninvasive Assessment of Interstitial Fibrosis and Tubular Atrophy in Renal Transplant by Combining Point-Shear Wave Elastography and Estimated Glomerular Filtration Rate

Diagnostics ◽

10.3390/diagnostics12010018 ◽

2021 ◽

Vol 12 (1) ◽

pp. 18

Author(s):

Chi Qin ◽

Hailong Jin ◽

Haixiang Zhang ◽

Yun Zhang ◽

Zhaojie Guan ◽

...

Keyword(s):

Glomerular Filtration Rate ◽

Glomerular Filtration ◽

Shear Wave ◽

Filtration Rate ◽

Estimated Glomerular Filtration Rate ◽

Interstitial Fibrosis ◽

Shear Wave Elastography ◽

Optimal Cutoff ◽

Tubular Atrophy ◽

Significant Difference

The purpose of this study was to evaluate the feasibility of the combination of point-shear wave elastography (p-SWE) and estimated glomerular filtration rate (eGFR) for assessing different stages of interstitial fibrosis and tubular atrophy (IF/TA) in patients with chronic renal allograft dysfunction (CAD). From September 2020 to August 2021, 47 patients who underwent renal biopsy and p-SWE examinations were consecutively enrolled in this study. The areas under the receiver operating characteristic curves (AUCs) were calculated to evaluate overall accuracy and to identify the optimal cutoff values for different IF/TA stages. A total of 43 patients were enrolled in this study. The renal cortical stiffness and eGFR showed a significant difference between IF/TA Grade 0–1 and Grade 2–3 (p < 0.001). Additionally, renal stiffness and eGFR were independent predictors for moderate-to-severe IF/TA (Grade ≥ 2) according to multiple logistic regression analysis. The combination of p-SWE and eGFR, with an optimal cutoff value of −1.63, was superior to eGFR alone in assessing moderate-to-severe interstitial fibrosis (AUC, 0.86 vs. 0.72, p = 0.02) or tubular atrophy (AUC, 0.88 vs. 0.74, p = 0.02). There was no difference between p-SWE and eGFR in assessing moderate-to-severe IF/TA (AUC, 0.85 vs. 0.79, p = 0.61). Therefore, combining p-SWE and eGFR is worthy of clinical popularization and application.

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Serum uromodulin as an early biomarker of tubular atrophy and interstitial fibrosis in patients with glomerulopathies

Terapevticheskii arkhiv ◽

10.26442/terarkh201890641-47 ◽

2018 ◽

Vol 90 (6) ◽

pp. 41-47 ◽

Cited By ~ 1

Author(s):

A V Smirnov ◽

M Khasun ◽

I G Kayukov ◽

O V Galkina ◽

V G Sipovski ◽

...

Keyword(s):

Filtration Rate ◽

Renal Damage ◽

Estimated Glomerular Filtration Rate ◽

Renal Excretion ◽

Interstitial Fibrosis ◽

Stone Formation ◽

Tubular Atrophy ◽

Daily Excretion ◽

Early Biomarker ◽

Healthy Persons

Aim. To assess the significance of the serum uromodulin (Tamm-Horsfall protein - THP) concentration (Sumo) as an early biomarker of tubular atrophy (TA) and interstitial renal fibrosis (IF) in patients with glomerulopathies. Materials and methods. 84 patients with glomerulopathy and 11 practically healthy persons (control) were examined. Uromodulin concentrations in serum and urine (Uumo) were measured, renal excretion of this protein and the estimated glomerular filtration rate (eGFR) were established. A semi-quantitative assessment of nephrobioptates was performed. Results and discussion. Sumo decreases with a minimum expression of tubular atrophy (TA) or interstitial fibrosis (IF), when the values of eGFR still remain normal. Variations of such excretory parameters of THP as Uumo, daily excretion, and ratio: urinary uromodulin / urinary creatinine, did not manifest a similar trend. Conclusion. Sumo is promising as an early biomarker of fibrotic and atrophic renal damage. The parameters of renal excretion of THP do not seem to have this property. The reason for the delay in the decline of Uumo in the progression of CKD as compared to the decrease in Sumo seems to be the need to maintain a sufficient Uumo to counteract urinary tract infection and stone formation.

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P0282SARCOIDOSIS WITH RENAL INVOLVEMENT: APPROACH TO DIAGNOSIS AND MANAGEMENT

Nephrology Dialysis Transplantation ◽

10.1093/ndt/gfaa142.p0282 ◽

2020 ◽

Vol 35 (Supplement_3) ◽

Author(s):

Imen Chemli ◽

Meriem Ben salem ◽

Ahmed Letaief ◽

Mouna Hammouda ◽

Sabra Aloui ◽

...

Keyword(s):

Renal Failure ◽

Renal Function ◽

Interstitial Fibrosis ◽

Single Case ◽

Renal Involvement ◽

Membranous Glomerulonephritis ◽

Reticuloendothelial System ◽

Tubular Atrophy ◽

Tubulointerstitial Nephropathy

Abstract Background and Aims Renal involvement in sarcoidosis is rare. It is most often the consequence of calcium metabolism disorders, interstitial granulomatous damage or secondary glomerular damage. It can progress to kidney failure in around 3% of cases. In this study, we determined the clinical presentation of sarcoidosis with renal involvement and we described the histological lesions. We report our experience about the management and the follow-up. Method we analyzed all cases of renal failure caused by sarcoidosis in our department during the period of 13 years (2006-2019). There were five patients (one man and four women) at the time of diagnosis. The middle age was 53.8 years. Results The renal involvement was revealing in 60% of the cases. The extrarenal localizations were: pulmonary (100%), cutaneous (knotty erythema 20%), ocular (dry eye syndrome (60%) and anterior uveitis (20%)), the reticuloendothelial system (adenitis (20%) and medullary (20%)), exocrine glands (sialadenitis (40%), nasal (20%), nervous (optic neuritis 20%)). The middle renal clearance (eGFR) at the time of diagnosis of renal involvement was 33ml / min / 1.73 m. Moderate proteinuria was observed in four patients (median: 0.99 g / 24 hours), aseptic leukocyturia in one patient. No patient had microscopic hematuria. Hypercalcemia was noted in 60% of patients with hyper calciuria (median: 3 mmol / kg / 24 hours). Nephrolithiasis was noted in only one patient. No cases of nephrocalcinosis was noted. Renal biopsy showed tubulointerstitial nephropathy with granulomatous in 2 cases (40%), absence of granuloma in one case, extra-membranous glomerulonephritis in one patient and moderate interstitial fibrosis with tubular atrophy in two patients, fibrous andarteritis in a single case. A granuloma without caseous necrosis was objectified on the osteo-medullary biopsy in a single case. All patients received oral corticosteroids (Prednisone: 1 mg / kg / day for 4 patients; 0.5 mg / kg / day for one patient) associated with the treatment of hypercalcemia (hydration and diuretics). The follow-up varied from 2 to 156 months with an median of 56.4 months. 3 patients improved their renal function with a middle clearance : M0: 29 ml / min, M1: 42 ml / min, M3: 68 ml / min, M6: 67 ml / min, M12: 95 ml / min. A non-recovery of renal function was noted in only one patient. An end-stage renal disease was observed in two patients. A renal and extrarenal (lymph node) relapse was noted in a single patient with an interval of 7 years after the initial presentation. Conclusion Renal involvement in sarcoidosis is probably underestimated. Treatment is based on corticosteroid, which must be introduced early to prevent progression to renal failure.

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Pulmonary fibrosis presenting as an early manifestation of microscopic polyangiitis

Monaldi Archives for Chest Disease ◽

10.4081/monaldi.2012.149 ◽

2015 ◽

Vol 77 (3-4) ◽

Author(s):

D. Eleftheriou ◽

S. Katsenos ◽

S. Zorbas ◽

I. Griveas ◽

K. Psathakis

Keyword(s):

Pulmonary Fibrosis ◽

Microscopic Polyangiitis ◽

Interstitial Fibrosis ◽

Renal Involvement ◽

Pulmonary Involvement ◽

Alveolar Haemorrhage ◽

Clinical Feature ◽

Small Vessel Vasculitis ◽

Radiographic Evidence ◽

Pulmonary Interstitial Fibrosis

Microscopic polyangiitis (MPA) is a systemic small vessel vasculitis that is included in the pulmonary-renal syndromes. Although glomerulonephritis represents the major clinical feature of MPA indicative of renal involvement, diffuse alveolar haemorrhage is the classic manifestation of pulmonary involvement. However, pulmonary fibrosis is a less frequently reported pulmonary manifestation. Herein we describe a patient who was diagnosed with MPA presenting with radiographic evidence of pulmonary interstitial fibrosis as an early clinical manifestation accompanied by constitutional symptoms such as fever and weight loss. We also include a short literature review focusing on the association between pulmonary fibrosis and MPA.

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Pathology of Antineutrophil Cytoplasmic Antibody–Associated Pulmonary and Renal Disease

Archives of Pathology & Laboratory Medicine ◽

10.5858/arpa.2016-0098-ra ◽

2017 ◽

Vol 141 (2) ◽

pp. 223-231 ◽

Cited By ~ 2

Author(s):

Maxwell L. Smith

Keyword(s):

Differential Diagnosis ◽

Renal Disease ◽

Clinical Laboratory ◽

Tissue Injury ◽

Renal Involvement ◽

Antineutrophil Cytoplasmic Antibody ◽

Small Vessel Vasculitis ◽

Antibody Testing ◽

Anca Associated Vasculitis ◽

Histopathologic Diagnosis

Context.—Antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis commonly presents with pulmonary and renal involvement that may present diagnostic challenges. Objectives.—To highlight the updates in the classification of small vessel vasculitis, present the patterns of pulmonary and renal pathology in which ANCA-associated vasculitis is included in the differential diagnosis, analyze the screening and specific antineutrophil cytoplasmic antibody testing methods in the clinical laboratory, compare and contrast the 3 major ANCA-associated vasculitis diseases, and review the pathophysiologic mechanisms of tissue injury in this setting. Data Sources.—Data are derived from published literature and clinical experience. Conclusions.—Although rare, ANCA-associated vasculitis diseases are often considered in the differential diagnosis of many pathologic patterns of pulmonary and renal disease. Histopathologic diagnosis of specific entities in this context nearly always requires correlation of the pathology with clinical and serologic data.

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Kidney biopsy chronicity grading in antineutrophil cytoplasmic antibody-associated vasculitis

Nephrology Dialysis Transplantation ◽

10.1093/ndt/gfab250 ◽

2021 ◽

Author(s):

Marta Casal Moura ◽

Fernando C Fervenza ◽

Ulrich Specks ◽

Sanjeev Sethi

Keyword(s):

Renal Function ◽

Kidney Biopsy ◽

Interstitial Fibrosis ◽

Antineutrophil Cytoplasmic Antibody ◽

Response To Treatment ◽

Remission Induction ◽

Induction Treatment ◽

Tubular Atrophy ◽

Renal Outcomes ◽

The Impact

Abstract Background Kidney biopsy is valuable for prognostic assessment of renal outcomes in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) with glomerulonephritis (AAV-GN) but the impact of chronic changes is not determined. Methods We conducted a retrospective cohort study of myeloperoxidase (MPO)- or proteinase 3 (PR3)-ANCA-positive patients with AAV and active renal disease. We applied the Mayo Clinic Chronicity Score (MCCS) and validated and evaluated its implications on outcome prediction in AAV-GN. Results We analyzed 329 patients with kidney biopsies available to score. The extent of chronicity was graded by MCCS as minimal [102 (31.0%)], mild [106 (32.2%)], moderate [86 (26.1%)] and severe [35 (10.6%)]. The MCCS grades correlated with the degree of renal function impairment at presentation [mean estimated glomerular filtration rate (eGFR) 48.3 versus 29.2 versus 23.7 versus 18.5 mL/min/1.73 m2, respectively; P < 0.0001]. Higher degrees of the individual components of the MCCS (glomerulosclerosis, interstitial fibrosis, tubular atrophy and arteriosclerosis) were associated with lower median eGFR (P < 0.0001) and decreased event-free [kidney failure (KF) and death] survival (P = 0.002, P < 0.0001, P < 0.0001 and P = 0.017, respectively). Patients with lower MCCS grades recovered renal function more frequently (P < 0.0001). Increasing MCCS grades were associated with decreased renal recovery (P = 0.001), more frequent events and shorter time to KF (P < 0.0001), KF and death (P < 0.0001) and death (P = 0.042), independent of the remission induction treatment used (cyclophosphamide or rituximab). The MCCS stratified renal outcomes for each MCCS grade and can be used in clinical practice as a cutoff for KF prediction (MCCS ≥4). Conclusions Chronic changes on kidney histology independently predict renal function, outcomes and response to treatment in AAV-GN.

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