Abstract
Twenty patients with rheumatoid arthritis developing proteinuria when being treated with penicillamine have been studied. In 5 the proteinuria was mild and resolved rapidly. Eleven of the remaining patients have undergone renal biopsy. One was found to have amyloidosis, and in the other 10 there was evidence of an immune complex type of injury, manifested by a granular immunoglobulin deposition within glomerular capillary walls associated with subepithelial deposits, found on electron microscopy. The proteinuria associated with this was mild (mean 2.6 g per 24 h) and occurred on average some eight months after commencing therapy (range 6 weeks to 60 months).