Ultrastructural Study on the Spleens of 28 Patients with ITP：Platelet Phagocytosis of Cordal Macrophages

Spleens of 28 patients with idiopatic thrombocytopenic purpura have been observed histologically, immunohistologically and electron microscopically. Spleens of fifteen patients had the foamy cells in the red pulp. Some foamy cells had positive materials for anti-human platelet antibody, using the unlabelled immunoperoxidase method. Electorn microscopically, many platelets in varying stages of intracellular digestion from intact-appearing platelets to myelinlike materials were disclosed in the foamy cells. We suggest that there are two types of the macrophage in the spleen from patients with ITP. One does not reveal foamy cytoplasm, because phagocytized are immediately digested by the lysosomal enzyme within cytoplasm of macrophages. The other has foamy cytoplasm, because phagocytized platelets are incompletely digested and remain as myelinlike materials within cytoplasm of macrophages.

ITP

Ultrastructure

Spleen

Platelet

Cordal macrophage