Absence of macrophage and presence of plasmacellular iron storage in the terminal duodenum of patients with hereditary haemochromatosis.

Biopsy specimens of the terminal duodenum obtained from 11 patients with hereditary haemochromatosis were examined by light and electron microscopy. Stainable iron was found in the lamina propria of the terminal duodenum in only 4 patients, all of whom were in an advanced stage of the disease. The iron was localized in the basal parts of the villi, sparing their tips, and between the crypts of Lieberkühn. The iron-storing cells could be identified as plasma cells, in which ferritin and haemosiderin were localized within lysosomes and ferritin molecules scattered in the cell sap. There was no storage of iron in macrophages. These observations demonstrate the impaired iron-storing capacity of macrophages in hereditary haemochromatosis, which may be related to the increased iron absorption in this iron storage disease.