[Conspicuous accumulation of membranous glomerulonephritis following gold therapy in chronic polyarthritis--a side effect of a new preparation?].

The development of severe proteinuria or nephrotic syndrome as an adverse reaction to gold therapy in rheumatoid arthritis is well known. Morphologic examination reveals membranous glomerulonephritis in almost all cases. Since the beginning of 1978 there has been a striking increase in the number of such cases seen at this institute. 5 patients aged from 17 to 65 years who had been treated with sodium aurothiomalate for rheumatoid arthritis developed severe proteinuria. In all cases only minimal glomerular changes were observable by light microscopy. Electron microscopy demonstrated multiple electrondense, subepithelial deposits which were confirmed by fluorescence microscopy. In all cases characteristic lysosomes ("aurosomes") were demonstrated in the cytoplasm, mainly of the epithelial glomerular cells. This unusual accumulation of almost identical cases coincides with the introduction of a new gold preparation, Na-aurothiomalate (Tauredon), containing 46% metallic gold.