Acute renal failure in a neonate caused by the transplacental transfer of a nephrotoxic paraprotein: Successful resolution by exchange transfusion

Acute renal failure was diagnosed within 6 days of birth in a full-term neo nate, The mother was known to have a monoclonal gammopathy, immunoglobulin G (IgG) lambda, discovered a year before pregnancy on being investigated fo r hematuria and proteinuria. Her renal function was intact. Maternal renal biopsy performed at the time showed a focal proliferative glomerulonephriti s with nonfibrillary homogeneous mesangial and intramembranous electron-den se deposits. Immunoperoxidase staining was positive for IgG and lambda and kappa light chains along the glomerular and tubular basement membranes. Pre gnancy was uneventful, Protein electrophoresis and immunofixation of the in fant girl's serum and urine samples showed the presence of a paraprotein el ectrophoretically identical to that found in the mother. Exchange transfusi on :resulted in a rapid improvement of renal function in parallel to the di sappearance of the monoclonal component. (C) 1999 by the National Kidney Fo undation, Inc.