IRON STORAGE IN PORPHYRIA CUTANEA TARDA

. Iron stores have been quantitated by several methods in 30 patients with porphyria cutanea tarda (PCT). Twenty-seven had clinically manifest and three had latent disease. There were twenty-three men and seven women. The mean non-hemin iron concentration in liver biopsy specimens related either to dry weight or to protein content was significantly higher in PCT than in control male subjects. In patients with manifest PCT, iron stores mobilizable for hemoglobin formation by frequent phlebotomy showed a mean value of 1.8 g and a highest value of 4.4 g. The desferrioxamine-induced urinary iron excretion was above the normal range for males in 2/3 of the patients with manifest PCT, and the mean of the PCT group was significantly higher than that of the controls. All determinations of iron stores in porphyrics, however, showed wide variations between individuals and an appreciable overlap with controls. Although the size of the iron stores was definitely higher in the porphyric group, values within the range of idiopathic hemochromatosis were not encountered. Histochemical examination of the liver showed significantly greater amounts of stainable iron in parenchymal and in Kupffer cells in patients with PCT as compared with control subjects. All patients with manifest PCT had stainable iron in both parenchymal and Kupffer cells. Only a few in the control group had stainable iron in Kupffer cells. The porphyric group also had a higher amount of reticular iron in bone marrow sections. The mean serum iron concentration, the percentage saturation of transferrin and the percentage of sideroblasts were significantly higher in PCT as compared with the controls. The possible mechanisms which might be responsible for the increased iron stores in PCT are discussed.