Gold nephropathy. Ultrastructural, fluorescence, and microanalytic studies of two patients.

Renal biopsy specimens from two patients with gold nephropathy showed two distinctly different types of alterations. The first demonstrated lesions suggestive of immunologic injury primarily to the glomerulus and identical with membranous glomerulonephritis. The second had no evidence of immunologic injury, but contained extensive vacuolar degeneration of proximal tubular epithelial cells. Ultrastructurally, the vacuoles contained lipid materials and occupied the basal portion of the cells. Other tubular cells contained numerous "gold-containing" cytosegresomes. In this second specimen, it appeared that the filtered gold had a direct toxic effect on the tubular epithelium and perhaps also on the glomerular capillary wall. These findings suggest that gold nephropathy may indeed be a spectrum of a combination of both direct toxic and immunologic injury to glomeruli and tubules.