Antineutrophil cytoplasmic antibody-associated necrotizing crescentic glomerulonephritis in a patient receiving treatment with etanercept for severe rheumatoid arthritis

Etanercept is a tumor necrosis factor inhibitor used in the treatment of rheumatoid arthritis and, increasingly, in a range of other diseases. We report a case of necrotizing crescentic glomerulonephritis, associated with a positive antineutrophil cytoplasmic antibody, causing acute renal failure in a woman receiving treatment with etanercept for severe rheumatoid arthritis. Our patient was treated with steroids and cyclophosphamide following withdrawal of etanercept, with a good clinical response. Although reports of vasculitis in patients receiving treatment with etanercept are rare, this drug has been shown to up-regulate some aspects of immune function, and the possibility that this agent may precipitate or exacerbate vasculitis in some individuals has to be considered.