Renal vasculitis in 2012: reclassification and the introduction of biologicals.

2012 saw the classification of the systemic vasculitides revised. Genetic studies showed that granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) are different diseases with aberrant immune responses to different autoantigens. B-cell depletion with rituximab also acquired a primary role in the treatment of GPA and MPA, as well as in cryoglobulinaemic vasculitis.