Ultrastructural Localization of Iron in the Human Jejunum in Iron Overload (Bantu Siderosis)



Summary. Light and electron microscopical studies of intestinal biopsies from 22 patients with advanced Bantu siderosis revealed that ferritin-iron was deposited in dense membrane-bound ferritin bodies, in apical vesicles and in Golgi vesicles of the jejunal absorptive cells. Acid phosphatase was demonstrated within the ferritin bodies and it was concluded that these bodies were lysosomes. Ferritin molecules were also observed in the intercellular space between epithelial cells and cells of the lamina propria, and within the lumen of capillaries.

Electron-dense material, presumably ‘haemosiderin’ occurred in the Golgi cisternae of the concave face of the Golgi complex of jejunal epithelial cells. In the lamina propria, iron in the form of ferritin and haemosiderin was observed mainly in macrophages, but ferritin was also deposited within fibroblasts.