Suppressive Effect of Iron on Concanavalin A‐Induced Multinucleated Giant Cell Formation by Human Monocytes

Immune dysfunction in patients with iron overload has been reported. Iron disturbed CD2 expression on T‐cells, cell‐mediated immunity by Th1 cells and monocyte functions including phagocytosis and natural killer activity. In the present study, we examined the effects of iron and desferrioxamine (DFX, an iron chelator) on generation of multinucleated giant cells (MGC) by human monocytes in vitro. Human monocytes were isolated from venous blood and cultured with concanavalin A (Con A) stimulation with additives, ferric citrate (Fe‐citrate) or sodium citrate (Na‐citrate) or DFX for 4 days. The cells were fixed and subjected to Wright staining. MGC formation was observed under light microscopy. Con A induced MGC formation in a dose‐dependent manner, and reached a plateau after 3 days of incubation. MGC formation was suppressed when Con A‐stimulated monocytes were cultured with the co‐addition of Fe‐citrate but not Na‐citrate only in the early phase of culture (less than 24 hours). DFX also suppressed MGC form...