Serum zinc, copper and selenium in rheumatoid arthritis.

Rheumatoid arthritis (RA) is characterized by low serum Zn and high serum Cu. In multiple linear regression both were explained by disease activity parameters. It is suggested that interleukin-1 causes both changes by 1) increasing the metallothionein-mediated hepatic uptake to serum Zn and 2) upregulating ceruloplasmin (acute phase reactant) gene and synthesis in liver and subsequently the level of ceruloplasmin-Cu complexes in the blood. Cu absorption was diminished by zinc intake. Cu- and Zn-dependent erythrocyte SOD was increased in RA. In contrast to plasma GSHPx serum selenium was low in RA and this was associated with disease activity parameters.