Ouchterlony double immunodiffusion method demonstrates absence of ferritin immunoreactivity in visceral organs from nine patients with Niemann-Pick disease type C.

Ouchterlony double immunodiffusion clearly demonstrated absence of ferritin, the principal iron storage protein, in spleen and/or liver extracts from nine patients with Niemann-Pick disease type C (NPC). The patients died from different clinical forms of this disease of still unknown etiology. The absence of ferritin immunoreactivity was shown using two different antisera raised in rabbits against ferritin from human spleen or liver, organs which predominantly contain light chain subunits (L-ferritin). A diagnostic double immunodiffusion assay of ferritin is, therefore, feasible with small amounts of NPC liver tissue, e.g., needle biopsy specimens. Furthermore, SDS–polyacrylamide gel electrophoresis after Coomassie blue staining revealed an almost complete absence of the L-ferritin protein band in crude spleen heat extracts from two NPC patients. The absence of visceral ferritin in all nine patients studied is suggestive of a biochemical abnormality that is as characteristic as the known impairment of cellular trafficking of LDL-derived cholesterol in this complex lysosomal storage disorder. According to recent data a relationship exists between ferritin-dependent lipid peroxidation and oxidative modification of LDL. We suggest that deficiency of the antioxidant ferritin—whatever the nature of this deficiency might be–could lead to uncontrolled LDL oxidation with subsequent multisubstrate lipidosis in NPC disease.