Observations on the Foam Cell in Thalassemia

Histologic and histochemical study of the foam cell in the spleen in thalassemia has shown that the foamy appearance is due to the accumulation of an acidic mucopolysaccharide of the chondroitin sulfuric acid type in the cytoplasm of this histiocytic cell. This polysaccharide shows intense red coloration with the periodic acid Schiff reaction, which is thus of great value in demonstrating the foam cell in tissue sections. The possible sources of this mucopolysaccharide have been discussed.