Iron storage in human disease: Fractionation of hepatic and splenic iron into ferritin and haemosiderin with histochemical correlations.

The hepatic and splenic storage iron, including the relative distribution between ferritin and haemosiderin, was estimated in 130 necropsies including normal accident cases and cases with a variety of diseases. The storage iron was also examined histochemically. It was found that in the normal subjects, on the average, approximately 400 mg. of iron was stored in these two organs, somewhat more than half being present as ferritin iron. Increased storage iron was found in some cases of infection, malignancy, and in blood and hepatic diseases, while low stores were present in other cases with malignancy and in polycythaemia vera. Although there was a slight tendency in infections and malignant diseases for more of the storage iron to be present as haemosiderin than normally, the most important factor affecting the distribution of iron between ferritin and haemosiderin was the total storage iron concentration. With total storage iron less than 500 mug. per gram of tissue, more iron was stored as ferritin than haemosiderin, and with values above 1,000 mug. per gram more was stored as haemosiderin. The behaviour of storage iron in this respect was very similar both in the liver and in the spleen. Although the histological and chemical estimates of the storage iron showed a general agreement there was much variation and histological examination of the tissues gave only a very approximate idea of the storage iron levels.