Decreased ribosomal RNA content and in vitro RNA synthesis in purified bone marrow erythroblasts of patients with idiopathic ineffective erythropoiesis and DiGuglielmo disease

Haematological features of primary myelodysplastic syndromes (PMDS) at initial presentation: a study of 118 cases

The haematological features of 118 cases of primary myelodysplastic syndromes (PMDS) were reviewed to see how these could be related and classified according to the recent FAB proposals. A majority of the cases were elderly who presented with a macrocytic or normocytic anaemia and reticulocytopenia. Cases of acquired idiopathic sideroblastic anaemia (AISA) usually had normal leucocyte and platelet counts, erythroid hyperplasia, marked dyserythropoiesis and more than 20% ringed sideroblasts. Cases of refractory anaemia with excess of blasts (RAEB) had frequent neutropenia and thrombopenia usually with prominent dysgranulopoiesis and dysthrombopoiesis. Refractory anaemia or refractory cytopenia appeared morphologically to be a heterogeneous group. Leukaemic transformation did not occur in any of these 16 cases of AISA whereas six of the 34 cases of RAEB transformed into acute leukaemia. It appears that the cases of PMDS present with well defined haematological features which permit recognition of different groups; these latter groups appear to be morphologically and prognostically distinct.

Quantitation of globin mRNA in individual human erythroblasts by in situ hybridization

In situ hybridization of globin mRNA was performed in four human bone marrows using a 3H-cDNA derived from rat globin messenger. Erythroblasts were classified according to nuclear area as well as to morphological appearance after Giemsa staining. Grains over individual erythroblasts and reticulocytes were counted by incident light microphotometry. Reticulocytes from phenyl hydrazine-treated rats served as internal standards in order to allow a comparison of different experiments. The preliminary results from one normal bone marrow, one of stress erythropoiesis and two of aplastic anemia revealed the major content of globin mRNA in the states of basophilic erythroblasts or proerythroblasts. In all cases there was a tendency of decreasing globin mRNA content towards orthochromatic erythroblasts, and even more so, towards reticulocytes. The results show some differences between normal and diseased erythropoiesis which are under study on a larger scale now in order to ascertain their significance.