Erythropoietic Cell Proliferation in Different Clinical States of <i>β</i>-Thalassaemia

Abstract

Erythropoietic cell proliferation of 6 cases of different clinical states of β--thalassaemia (thal) was studied by a combined method using Feulgen-cytophotometry and autoradiography after in vitro labelling with ³H-TdR. An abnormal distribution of the DNA content and ³H-TdR incorporation was found, which was more pronounced in the one patient with thal major than in the 3 patients with thal minor and was not provable in the subclinical form (minima), indicating a direct relationship to the ineffective erythropoiesis and the states of anaemia in this disease. This proliferation disturbance consisted of an accumulation of cells in G₁, a decreased proportion of cells in S and a decreased S/G₂ ratio, and was limited to the early polychromatic cell compartment. In the basophilic erythroblasts, a decreased proportion of cells in G₁ was observed revealing a shortening of the G₁ period in this cell compartment

Some Characteristics of the Proliferative Activity of Erythroblasts in Untreated and Treated Acute Leukaemia

“…A similar proliferation defect has also been observed in preleukaemic acute leukaemia [8] and in other conditions showing ineffective erythropoiesis as thalassaemia [7,12] and congenital dyserythropoietic anaemia type II [6], Therefore ineffective erythropoiesis, showing an accumulation of diploid resting cells in the early polychromatic cell compartment, is regarded as a common patho-physiological mechanism, resting on quite different aetiological factors.…”

Cell Proliferation in the ‘Preleukaemic’ Phase of Acute Leukaemia

“…A similar proliferation defect in erythropoiesis has been recently de scribed in cases of untreated acute leukaemia [7] and in other clinical manifestations of ineffective erythropoiesis as sideroblastic anaemia [25], congenital dyserythropoietic anaemia type II [18] and homozygous and heterozygous /1-thalassaemia [16,26], Therefore, the proliferation defect showing an increased G,/S ratio in the early polychromatic ery throblasts refers to a common pathophysiological mechanism, resting on different etiological factors.…”

Proliferation of Erythroblasts in Refractory Anaemia

“…This result suggests, that either the presynthetic phase is prolonged or a part of the proliferating erythroblasts do not enter the In studies of erythropoietic cell proliferation with in vivo and in vitro methods in diseases with erythropoietic insufficiency, similar results are obtained. The reports concern /f-thalassaemia [11,16], congenital dy serythropoietic anaemia [10], acute leukaemia [6,13], erythroleukae mia' [5,15], 3 cases of refractory anaemia [7], one case of 'preleukaemia' [12] and sideroblastic anaemia [15]. With exception of the inherited di seases it is a matter of erythropoietic insufficiency in leukaemia with or without hyperplastic erythropoiesis and furthermore diseases, which often represent preleukaemic states.…”