Splenic function in chronic myelogenous leukemia

Spleen function was evaluated by measurement of the clearance of autologous heat-damaged 99mTc-labelled erythrocytes from the circulation and into the spleen and the enumeration of pitted erythrocytes by interference contrast microscopy, and the spleen area was determined by scintillation scanning. All measurements were performed on 12 patients with chronic myelogenous leukemia and compared with 10 controls with apparently normal spleens, 6 splenectomized subjects and 9 patients with a reactive splenomegaly. Patients with CML had spleen function test results similar to normal controls in spite of having enlarged spleens whose projection area did not differ from that of the patients with reactive splenomegaly. Thus, patients with CML have a decreased spleen function per unit volume and signs of splenic hypofunction in the peripheral blood. The reduction of spleen function per unit volume in CML is the result of a severe decrease of the splenic blood perfusion which could result from the combined effects of the myeloid metaplasia and the increased whole-blood viscosity due to high white-cell counts.