Résumé
ANCA-associated vasculitis is a rare and severe autoimmune disease, particularly in cases of renal involvement. In addition to immunosuppressants, plasma exchanges are used to treat severe forms of vasculitis. International guidelines recommend renal biopsies for their diagnostic and prognostic roles. The Berden, ARRS, and AKRiS classifications show that certain histological lesions, such as interstitial fibrosis, tubular atrophy, and the percentage of normal glomeruli, negatively impact renal prognosis.The objective is to evaluate the renal response of patients with severe forms of ANCA-associated vasculitis who underwent renal biopsy and plasma exchanges, identifying the histological determinants favorable to renal recovery. Method: this is a retrospective multicenter study of 34 patients with ANCA-associated vasculitis with severe renal involvement who received plasma exchanges. The primary endpoint was death, the need for dialysis, or persistent renal dysfunction (eGFR < 30 ml/min/1.73m² for 3 months) at one year. Results: among the 34 patients (56% men), 19 (55%) met the primary endpoint. The 15 patients with an eGFR > 30 ml/min/1.73m² at one year were younger (60 vs. 70 years), mostly male (73% vs. 42%), and had higher CRP levels (107 vs. 32 mg/l). Histologically, this group had more normal glomeruli (25% vs. 11%), less glomerulosclerosis (15% vs. 22%), and more cellular and partial crescents.Conclusion: patients treated with plasma exchanges who had a better renal prognosis had more normal glomeruli, less glomerulosclerosis, and predominantly cellular and partial crescents. These results support the systematic use of renal biopsies in severe forms of ANCA-associated vasculitis to better tailor treatments.