MPO-ANCA necrotizing glomerulonephritis related to rheumatoid arthritis.

Two patients with rheumatoid arthritis (RA) developed necrotizing crescentic glomerulonephritis with high titers of anti-myeloperoxidase antibodies (MPO) in the absence of overt extrarenal vasculitis. We therefore suggest that in some patients with RA, MPO-ANCA necrotizing glomerulonephritis (GN) may occur as a kidney-limited form of rheumatoid vasculitis, and that RA should be added to the list of diseases potentially associated with necrotizing GN with anti-MPO antibodies. These observations also point out the importance of repeatedly evaluating titers of anti-MPO antibodies in the course of RA, especially if renal impairment or abnormal urinary sediment are present.