ANCA-associated vasculitides: what nephrologists need to know

Renal involvement in ANCA vasculitides (AAV) is frequent and often severe, leading to end-stage kidney disease either immediately, in the follow-up or after episodes of relapses. Renal involvement is associated with other organ involvement in granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (PAM), but may also be isolated in vasculitis limited to the kidney. It is less common in eosinophilic granulomatosis with polyangiitis (GEPA). The classical clinical presentation is one of rapidly progressive glomerulonephritis, associated with the presence of PR3-ANCA or MPO-ANCA. Kidney biopsy (showing pauci-immune extra-capillary glomerulonephritis) is not essential for the diagnosis of VAA, but it does have a prognostic value, can rule out other causes of glomerulonephritis (especially in renal-limited forms of AAV) and can help for the decision of plasma exchange use. Treatment of AAV with renal involvement is based on a combination of corticosteroids and immunosuppressants (rituximab or cyclophosphamide). Avacopan may also be proposed as a cortisone-sparing treatment. This review sets out the various recommended therapeutic protocols and their scope of application. The role of plasma exchange is also discussed.