Erythroblastic Islands and Extra-Medullary Erythropoiesis in Chronic Myeloid Leukaemia

Abstract

Aspirates from bone marrow, spleen and liver were morphologically analysed in 15 untreated patients with chronic myeloid leukaemia. Megaloblastic changes of the erythroblasts were found to be more common in the spleen and liver than in the bone marrow. A significant increase of ‘erythroblastic islands’, i.e. erythroblasts in contact with reticulum cells, were recorded in the leukaemia patients compared to 15 healthy controls. It is suggested that the presence of such formations may indicate an increased death rate of defective erythroblasts followed by phagocytosis into reticuloendothelial cells.

Different Composition of the Erythropoietic Tissue in Bone Marrow, Spleen and Liver in Myelofibrosis

“…There is little information of the function and the composition of the erythropoietic tis sue in the liver in myeloproliferative disorders and the present work was undertaken to investigate whether or not the morphology and the mitotic activity of erythroblasts of the spleen and the liver might indicate some abnormalities in the extramedullary production of red cells in MF. Com parisons with earlier investigations of CML patients [10][11][12][13] may also give some information on the influence of the microenvironment on the erythroblasts.…”

“…There are also more erythroblasts among the precursor cells in the liver and the same results have been found in CML patients [10][11][12][13]. The higher proportion of erythroblasts in the liver and the spleen could be due to sampling errors, because erythroblasts may be more readily aspirated [18] and/or the true prevalence of myelopoiesis may be underrated due to rupture of the myelocytes [16].…”

“…A rather high incidence of megaloblastic anemia due to folate deficiency among the MF patients has also been reported [5], Studies of red cell kinetics have shown that the splenic erythropoiesis in MF is considerably insufficient [3,9,14,18] and often combined with a striking hemolysis. Pure morphologic investigations of the spleen erythro poiesis have also given evidence of an ineffective production of erythroblasts in MF [15,16] and in other myeloproliferative disorders such as CML [10][11][12][13] and polythemia vera [15,16].…”

“…(I) 15 untreated patients with a recent diagnosis of CML. Detailed de scriptions have been given elsewhere [11][12][13]. (II) 7 male and 10 female probands without perceivable hematologic disorders and with clinical diagnoses such as spon dylolisthesis, cervical disc prolapse, adipositas, psychiatric disorders and unverified hypogonadismus served as normals.…”

Morphologic Studies of the Erythropoietic Part of the Bone Marrow in Myeloid Leukaemias

“…An increase of 'erythroblastic islands', i.e. erythroblasts in contact with bone marrow macrophages has been reported not only in cases with megaloblastic anaemia due to vitamin Biz deficiency (Sjogren & Brandt 1974c) but also in patients with acute myeloid leukaemias (Sjogren 1975) and CML (Sjogren 1976). In all these cases the number of erythroblastic islands was correlated to the percentage of basophilic erythroblasts within the erythropoietic pool.…”