Antineutrophil cytoplasmic autoantibody specific for proteinase 3 in a patient with shunt nephritis induced by Gemella morbillorum

A 17-year-old girl had been placed with ventriculoperitoneal, then ventricu loatrial shunts for congenital hydrocephalus since birth. The patient origi nally was diagnosed as having a lupus like disease, but later turned out to have shunt nephritis, presenting with fever, proteinuria, pancytopenia, an d hypocomplementemia. Antineutrophil cytoplasmic autoantibody specific for proteinase 3 (PR3-ANCA) was detected in her serum. The patient received ora l prednisolone and repeated methylprednisolone pulses, with essentially no beneficial affects. A gram positive coccus, Gemella morbillorum, was recove red from her blood as well as cerebrospinal fluid, and the culture of the s hunt catheter established the diagnosis of shunt nephritis. Removal of the shunt catheter improved symptoms dramatically and decreased PR3-ANCA in ser um to an undetectable level. Because steroids had no effects and the contro l of bacterial infection lowered PR3-ANCA levels, the antibody would have b een induced by continuous infection with G morbillorum. (C) 2001 by the Nat ional Kidney Foundation, Inc.