Mituoki Eguchi

Composition of the intra-erythroblastic precipitates in thalassaemia and congenital dyserythropoietic anaemia (CDA): identification of a new type of CDA with intra-erythroblastic precipitates not reacting with monoclonal antibodies to α- and β-globin chains

Ultrathin sections of bone marrow cells from two patients with homozygous β‐thalassaemia, two patients with haemoglobin H (HbH) disease, a patient with congenital dyserythropoietic anaemia (CDA) type III and two patients with severe congenital dyserythropoietic anaemia of an unusual type were reacted with mouse monoclonal antibodies against various globin chains and the reaction visualized using a gold‐labelled goat antibody against mouse IgG. The multiple rounded intra‐erythroblastic inclusions found in homozygous β‐thalassaemia reacted with the monoclonal antibody against α‐globin chains but not β‐globin chains, thus confirming that they consisted of precipitated α‐globin chains. The branching intra‐erythroblastic inclusions found in HbH disease and CDA type III reacted with the monoclonal antibody against β‐globin chains but not α‐globin chains, indicating that they consisted of precipitated β‐globin chains. The two patients with severe CDA had been transfusion‐dependent since infancy, had a normal α:β globin chain synthesis ratio or parents with normal red cell indices, displayed prominent dysplastic changes in their erythroblasts, and had intra‐erythroblastic inclusions resembling those seen in homozygous β‐thalassaemia. However, unlike those in β‐thalassaemia, the inclusions in these two patients did not react with the monoclonal antibody against either α‐ or β‐globin chains. The inclusions reacted with antibody against ζ‐globin chains, but detailed studies in one of the patients indicated that the antigen involved was not ζ‐globin. These patients have features not reported in the condition known as dominantly inherited inclusion body β‐thalassaemia and appear to suffer from a novel type of CDA in which the intra‐erythroblastic inclusions may consist of some non‐globin protein or structurally‐abnormal α‐globin chains.

Myeloid and erythroid lineage expression of haemopoietic progenitors derived from an abnormal clone in erythroleukaemia

Summary. To clarify the lineage involvement of haemopoietic progenitor cells in erythroleukaemia, the morphology and chromosomes of single colonies from a patient with erythroleukaemia were analysed simultaneously. The cytogenetic analysis of bone marrow cells revealed two clones; 44.XY, −7, −12, −17, del (5)(q31),+ Mar and 43,XY, −7, −12, −17, −19,del(5)(q31),+ Mar. Of 40 metaphases examined, there were 34 and six of these clones, respectively. Bone marrow mononuclear cells were plated at 5 × 104/ml in methylcellulose medium containing phytohaemagglutinin‐stimulated leucocyte conditioned medium and erythropoietin. Seventeen colonies, i.e. nine blast cell colonies, four myeloid (Sudan black B‐positive) colonies, and four erythroid (benzidine‐positive) colonies contained analysable metaphases, yielding 102 metaphases in total. Except for chromosome random loss, the karyotype within a colony remained constant. All three types of colonies showed an abnormal clone; 44.XY, − 7, −12, − 17,del(5)(q31),+Mar. From these findings, it is concluded that myeloid and erythroid lineages in erythroleukaemia were derived from the same abnormal clone.