An Electron Microscopic Study of the Nuclear Abnormalities in Erythroblasts in Beta-Thalassaemia Major

Summary. Erythroblasts in the peripheral blood of 20 splenectomized patients with β-thalassaemia were examined by electron microscopy. A number of alterations in the structure and integrity of the nucleus and nuclear membrane was noted and these included apparent widening of the nuclear pores, partial absence and areas of reduplication of the nuclear membrane. Intranuclear inclusions were found, some identical to the electron-dense inclusions (Heinz bodies) present in the cytoplasm, while others contained aggregates of finer particles, probably iron micelles. Some erythroblast nuclei appeared to contain portions of cytoplasm with similar inclusions. Nuclear alterations were most prominent when inclusion bodies were abundant in the cytoplasm and when they were in close approximation to or in contact with nuclear material. These nuclear abnormalities may be related to the recognized disturbance in proliferation of thalassaemic erythroblasts and the ineffective erythro-poiesis encountered in this disease.