Gold nephropathy.

Nephropathy with proteinuria is an occasional complication of gold therapy for rheumatoid arthritis and is considered to be due to an immune hypersensitivity reaction. Three patients are described in whom the structural changes typical of gold nephropathy were demonstrated by electron microscopy of renal biopsies. There was early membranous glomerular nephropathy with multiple sub-epithelial deposits of immune complexes. In one case these were shown by immunofluorescence to contain IgG and complement. Proximal tubules contained characteristic dense granular intracytoplasmic gold inclusions, best demonstrated by electron microscopy of unstained sections.