Anti-CTLA4 Antibody–Induced Lupus Nephritis

To the Editor: A 64-year-old man with a history of metastatic melanoma was admitted to our hospital for the nephrotic syndrome in 2006. In 2005, subcutaneous metastases had been diagnosed, which were resistant to conventional chemotherapy. The patient then received monotherapy with ipilimumab (investigational agent, Bristol-Myers Squibb), a monoclonal antibody against cytotoxic T-lymphocyte–associated antigen 4 (CTLA4), at a dose of 3 mg per kilogram of body weight given intravenously every 3 weeks. Proteinuria was not present before the protocol was initiated, and the nephrotic syndrome was diagnosed after two injections. Physical examination showed only a 3-cm inguinal lymphadenopathy on the . . .