Circulating Siderocytes in Human Subjects

The number of circulating erythrocytes containing reticulum and no siderotic granules (R cells), both reticulum and siderotic granules (R-S cells), and siderotic granules and no reticulum (S cells) was determined in 80 normal adults, 7 normal newborns and 486 patients with hematologic disorders.

Few R-S cells (maximum 0.3 per cent) or S cells (maximum 0.2 per cent) were observed in the blood of normal adults. The number of siderocytes as observed in the direct Prussian blue method (direct-total siderocytes) did not exceed 0.7 per cent. R-S cells greater than 1.0 per cent and direct-total siderocytes greater than 2.0 per cent were observed in each of 7 normal newborns.

Among the 486 patients, R-S cells more numerous than 1.0 per cent, S cells greater than 1.0 per cent, or direct-total siderocytes greater than 2.0 per cent were observed only in four conditions. Increases in R-S cells were seen in patients with severe hemolytic anemia and in patients with sideroblastic anemia associated with mild hemolysis. Increases in S cells were seen in splenectomized patients in the absence of hemolysis. Increases both in R-S cells and S cells were seen in patients with splenic atrophy or replacement and in splenectomized patients in the presence of hemolysis.