The importance of iron in rheumatoid disease.

The hypothesis is that iron, which accumulates in rheumatoid synovial membrane and fluid contributes to the variable expression of rheumatoid disease in two ways. Firstly, it catalyses oxidative radical reactions which lead to the formation of the hydroxyl radical and subsequent lipid peroxidation. Hydroxyl radicals and lipid peroxidation cause extensive disruption of cellular and organelle membranes and promote inflammatory tissue damage. Secondly, the infiltration of the rheumatoid synovium by chronic inflammatory cells may be due not to an antigenic process but to the tendency for these cells, which have receptors for iron-binding proteins, to migrate towards deposits of iron.