The Ultrastructure of Dyserythropoiesis in Aplastic Anaemia

Abstract

Electron microscopy of erythropoiesis in aplastic anaemia has demonstrated some unique features of dyserythropoiesis at the ultrastructural level, which contribute to understanding of the morphological features which are seen in the light microscope. The findings provide further evidence for the presence of qualitative defects in erythropoiesis in aplastic conditions. The alterations seen included bi- and multinucleated cells, intercellular bridges containing microtubules, internuclear chromatin bridges, irregular nuclear shapes, juxta-nuclear and peripheral cisternal structures, ringed sideroblasts, a diversity of intranuclear inclusions, nuclear clefts in both eu- and heterochromatin, and a variety of anomalies of the nuclear membrane. The significance of the occurrence of these anomalies in aplastic anaemia is considered and the role of the nuclear membrane and of endoplasmic reticulum in the pathogenesis of aplastic anaemia is discussed.

Emperipolesis and Annulate Lamellae in Erythroleukaemia

“…Nuclear blebs or clefts were also revealed in many of the erythroblasts reported by Huhn et al (1973). It is said that this nuclear abnormality is most probably responsible for the derangement of DNA metabolism (Ahearn et al 1974), or of nuclear membrane formation and fusion during mitosis (Frisch et al 1975). It is considered that these derangements exist in the present cases.…”

Junctional Structures in Haemopoiesis: a Study of Bone Marrow using Freeze‐Fracture and Lanthanum Impregnation Techniques

“…We believe that the submembranous densities seen without delineation of corresponding intercellular structures (Fig 8) could represent zonula or fascia adherens. By the use of FF and extracellular tracer methods, we have been unable to identify junctional structures similar to those described in diseases associated with dyshaemopoiesis (Breton-Gorius et al, 1973Flandrin et al, 1974;Lewis & Verwilghen, 1973;Frisch & Lewis, 1974;Frisch et al, 1975Frisch et al, , 1976Sane1 & Serpick, 1970;Blom, 1977;Frisch & Lewis, 1978). Haemopoiesis is a proliferating cell system with relatively rapid turnover rate.…”

“…Although no references have been made to the presence of intercellular junctions involving haemopoietic cells in normal marrow, the occurrence of specialized membrane regions has been reported or suggested in marrow cells from a variety of diseases associated with dyshaemopoiesis (Lewis & Verwilghen, 1973;Frisch & Lewis, 1974;Frisch et al, 1975Frisch et al, , 1976Breton-Gorius et al, 1973Sane1 & Serpick, 1970;Blom, 1977;Frisch & Lewis, 1978). Modifications of cell membranes are believed to be responsible for their formation.…”

Congenital Hypoplastic Anaemia Refractory to Corticosteroids but Responding to Cyclophosphamide and Antilymphocytic Globulin

“…Dyserythropoiesis of greater or lesser severity occurs in a wide range of condi tions [18,19]; it is quite frequent in aplastic anaemia [8,9], but has not been described neither in PRCA nor in CHA, although a condition 'inter mediate' between the latter and the congenital dyserythropoietic anaemias has also been described recently [26]. Dyserythropoiesis has been report ed in fetal hepatic erythropoiesis [29] and in early post-transplantation haematopoiesis [22], and has been considered, together with the produc tion of fetal haemoglobin [3], as a partial and accelerated recapitulation of ontogeny.…”