Keywords: AAV, antineutrophil cytoplasmic antibody–associated vasculitis; ACR, American College of Rheumatology; ANA, antinuclear antibody; ANCA, antineutrophil cytoplasmic antibody; MCTD, mixed connective tissue disease; RNP, ribonucleoprotein; SLE/AAV, systemic lupus erythematosus antineutrophil cytoplasmic antibody–associated vasculitis overlap syndrome; anti-MPO, antimyeloperoxidase; antineutrophil cytoplasmic antibody; p-ANCA, perinuclear antineutrophil cytoplasmic antibody; renal failure; systemic lupus erythematosus; vasculitis.