Copper and zinc status in rheumatoid arthritis: studies of plasma, erythrocytes, and urine, and their relationship to disease activity markers and pharmacological treatment.

We studied the status of copper and zinc in rheumatoid arthritis (RA). The aims of the work were to ascertain whether or not RA is associated with copper and/or zinc deficiency, to establish the relationship between these trace metals and the main biohumoral and clinical indices of the disease, and to examine the effect on copper and zinc of the drugs normally used by RA patients. Metal levels were measured by atomic absorption spectroscopy in the plasma, whole blood cells and 24 hr urine of 120 RA patients; 70 patients suffering from primary osteoarthritis were used as the control group. In the plasma of RA patients copper and ceruloplasmin levels were found to be significantly increased whereas zinc levels were significantly decreased. No major variations were observed in the blood cell and 24 hr urine copper and zinc levels. Plasma copper was significantly correlated with some of the biohumoral markers of RA, but did not correlate with any of the clinical indices of the disease. Plasma zinc was significantly correlated with numerous of the biohumoral as well as clinical markers of RA. With the exception of an increased urinary excretion of copper in D-penicillamine treated RA patients, drug therapy did not influence the copper status in RA. Conversely, plasma zinc was found to be lower in RA patients taking NSAIDs and/or steroids. These results suggest the following conclusions: i) RA patients do not seem to be deficient in either copper or zinc; ii) plasma copper appears to be a poor index of RA severity; iii) plasma zinc could have some practical value in defining the overall severity of the disease.