A predictive mortality score in ANCA-associated renal vasculitis.

BACKGROUND: Several scores have been developed to predict mortality at anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) diagnosis. Their prognostic value in Caucasian patients with kidney involvement (AAV-GN) remains uncertain as none has been developed in this specific population. We aimed to propose a novel and more accurate score specific for them. METHODS: This multicentric study included patients diagnosed with AAV-GN since January 2000 in four nephrology centers (recorded in the Maine-Anjou AAV-GN Registry). Existing scores and baseline characteristics were assessed at diagnosis before any therapeutic intervention. A multivariable analysis was performed to build a new predictive score for death. Its prognosis performance (area under receiving operating curve and C-index) and accuracy (Brier score) was compared with existing scores. One hundred and eighty-five patients with AAV-GN from the RENVAS registry were used as a validation cohort. RESULTS: A total of 228 patients with AAV-GN from the Maine-Anjou registry were included to build the new score. It included the four components most associated with death: age, history of hypertension or cardiac disease, creatinine and hemoglobin levels at diagnosis. Overall, 194 patients had all the data available to determine the performance of the new score and existing scores. The new score performed better than the previous ones in the development and in the validation cohort. Among the scores tested, only Five-Factor Score and Japanese Vasculitis Activity Score had good performance in predicting death in AAV-GN. CONCLUSIONS: This original score, named DANGER (Death in ANCA Glomerulonephritis-Estimating the Risk), may be useful to predict the risk of death in AAV-GN patients. Validation in different populations is needed to clarify its role in assisting clinical decisions.

Early Renal Recovery after the First Flare of Pauci-Immune Glomerulonephritis.

INTRODUCTION: Renal involvement is a severe manifestation of antineutrophil cytoplasmic antibody-associated vasculitis. Patients often progress to end-stage renal disease. The potential for renal recovery after the first flare has seldom been studied. Our objectives were to describe the evolution of the estimated glomerular filtration rate (eGFR) and identify factors associated with the change in the eGFR between diagnosis and the follow-up at 3 months (ΔeGFRM0-M3). METHODS: This was a retrospective study over the period 2003-2018 of incident patients in the Nord-Pas-de-Calais (France). The primary outcome was the ΔeGFRM0-M3. RESULTS: One hundred and seventy-seven patients were included. The eGFR at 3 months was significantly higher than at diagnosis (mean ± standard deviation, 40 ± 24 vs. 28 ± 26 mL/min/1.73 m2, p < 0.001), with a ΔeGFRM0-M3 of 12 ± 19 mL/min/1.73 m2. The eGFR at 12 months was higher than at 3 months (44 ± 13 vs. 40 ± 24 mL/min/1.73 m2, p = 0.003). The factors significantly associated with the ΔeGFRM0-M3 in multivariate analysis were the percentage of cellular crescents and neurological involvement. The mean increase in the eGFR was 2.90 ± 0.06 mL/min/1.73 m2 for every 10-point gain in the percentage of cellular crescents. CONCLUSIONS: Early renal recovery after the first flare of pauci-immune glomerulonephritis occurred mainly in the first 3 months of treatment. The percentage of cellular crescents was the main independent predictor of early renal recovery.

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

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

Prognostic Value of Microscopic Hematuria after Induction of Remission in Antineutrophil Cytoplasmic Antibodies-Associated Vasculitis.

BACKGROUND: Pauci-immune glomerulonephritis (PIGN) is a major prognostic factor in antineutrophil cytoplasmic antibodies-associated vasculitis (AAV). Renal remission is usually defined as improvement or stabilization of serum creatinine and proteinuria levels but the significance of hematuria is unclear. We evaluated the prognostic value of microscopic hematuria in patients in remission from a first flare of PIGN. METHODS: A multicenter retrospective study was conducted of all patients with histologically proven PIGN in northern France who presented a first renal flare of AAV between 2003 and 2013. All patients received conventional induction treatment and were considered in remission. Two groups were defined by the presence (H+) or absence (H-) of hematuria (dipstick 1+ and/or cytology ≥10,000 erythrocytes/mL). The primary outcome measure was the occurrence of renal relapse (RR) and/or end-stage renal disease (ESRD). RESULTS: Eighty-six patients were included: 41 (48%) had hematuria at remission. The median follow-up time was 44 ± 34 months. There was no significant difference between the groups in terms of the primary endpoint or the number of RR. However, the survival rate without RR was significantly lower in the H+ group (p = 0.002). In multivariate analysis, risk factors for RR were hematuria at remission for relapses within 44 months (hazard ratio [HR] 4.15; 95% CI 1.15-15.01; p = 0.03) and the duration of maintenance immunosuppressive therapy (HR 0.96 per additional month; 95% CI 0.94-0.99; p = 0.002). CONCLUSION: Hematuria at remission after a first PIGN flare was not associated with ESRD but with the occurrence of RR within 44 months of remission.

Tacrolimus-induced nephrotoxicity in mice is associated with microRNA deregulation.

Although Tacrolimus is an immunosuppressive drug widely used in renal transplantation, its chronic use paradoxically induces nephrotoxic effects, in particular renal fibrosis, which is responsible for chronic allograft dysfunction and represents a major prognostic factor of allograft survival. As molecular pathways and mechanisms involved in Tacrolimus-induced fibrogenic response are poorly elucidated, we assessed whether miRNAs are involved in the nephrotoxic effects mediated by Tacrolimus. Treatment of CD-1 mice with Tacrolimus (1 mg/kg/d for 28 days) resulted in kidney injury and was associated with alteration of a gene expression signature associated with cellular stress, fibrosis and inflammation. Tacrolimus also affected renal miRNA expression, including miRNAs previously involved in fibrotic and inflammatory processes as "fibromirs" such as miR-21-5p, miR-199a-5p and miR-214-3p. In agreement with in vivo data, Renal Proximal Tubular Epithelial cells exposed to Tacrolimus (25 and 50 µM) showed upregulation of miR-21-5p and the concomitant induction of epithelial phenotypic changes, inflammation and oxidative stress. In conclusion, this study suggests for the first time that miRNAs, especially fibromiRs, participate to Tacrolimus-induced nephrotoxic effects. Therefore, targeting miRNAs may be a new therapeutic option to counteract Tacrolimus deleterious effects on kidney.

Tubulointerstitial damage and interstitial immune cell phenotypes are useful predictors for renal survival and relapse in antineutrophil cytoplasmic antibody-associated vasculitis.

The aims of this study were to determine whether tubulointerstitial damage in the form of interstitial fibrosis/tubular atrophy and total interstitial inflammation predicted progression to end stage renal disease (ESRD) and/or renal relapse (RR) in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV). One hundred thirteen patients with AAV from six French centers with an index biopsy performed between 2003 and 2013 were included. Histological assessments using the AAV glomerular classification and the kidney allograft Banff classification were performed on pathological review. Biopsy tissues were also investigated by CD3, CD20, CD68, CD163, FOXP3 and RORγt immunohistochemical staining. Competing risks models were calculated. Of the 113 patients, 26 (23.0%) died during follow-up and 29 (25.6%) developed ESRD. Among the 94 patients who achieved remission by the end of induction therapy without developing ESRD, 26 (27.6%) experienced RR. The two independent prognostic factors for ESRD were the estimated glomerular filtration rate at presentation (HR 0.35; 95% CI 0.23-0.51; P < 0.0001) and IF/TA > 25% (HR 2.27; 95% CI 1.18-4.37; P = 0.014). When the distribution of interstitial immune cell phenotypes was included in a second multivariable model, the organization of lymphocytic infiltrates was also an independent predictor of ESRD (HR 2.86; 95% CI 1.35-6.1, P = 0.006). The independent risk factors for RR were a higher CD3/CD20 ratio (HR 1.39; 95% CI 1.05-1.85; P = 0.02) and the presence of RORγt positive cells (HR 2.70; 95% CI 1.11-6.54; P = 0.02). Our results highlight the prognostic value of initial histological evaluations in AAV. Measurements of tubulointerstitial damage and interstitial immune cell phenotype distributions should be considered to improve risk assessments for ESRD and RR.