[Kidney complications in chronic polyarthritis].

50 patients with definite rheumatoid arthritis treated with D-penicillamine were studied every 4 weeks by disk electrophoresis of the urine to make an early record of the glomerular proteinuria of the immune complex nephritis, which has been described as a side effect of this treatment. In 30 of these patients we found, however, a tubular proteinuria which correlated well with the disease activity and which disappeared after successful basic treatment. This finding indicates interstitual renal involvement due to the basic disease.