If I'm reading this correctly, serum ferritin is a benign substance in our bodies, as long as it's bound to iron molecules. Without iron it is hypothesized that it becomes toxic. I guess doctors see this in chronic disease states. I know from other articles that when our bodies feel they are under attack they release a substance called hepcidin. Hepcidin shuts down the ingress of iron from the GI Tract and the egress of iron from our bodily stores in an effort to kill the enemy. Every living organism (with the exception of two microbes) love and need iron. So by shutting down the iron, our bodies can sometimes thwart the enemy.
Bottom line is, for anyone who has high serum ferritin (but not hemochromatosis) then make sure to get those blood tests that can actually tell if that ferritin is bound to iron.