The pattern of reactivated fetal erythropoiesis in bone marrow disorders of childhood.

The expression of fetal characteristics of erythropoiesis (haemoglobin F concentration, haemoglobin A2 concentration, haemoglobin F cells, globin chain synthesis, carboanhydrase isoenzyme B, hexokinase isoenzymes, erythrocyte membrane antigens of the iI- and the ABH-system) was examined in red cells of twelve patients with different bone marrow disorders (juvenile chronic myeloid leukaemia (JCML), erythroleukaemia (EL), acute myelogenous leukaemia (AML), aplastic anaemia (AA) and Diamond-Blackfan anaemia (DB)). In JCML and EL all red cell parameters studied appeared to be fetal including the distribution of hexokinase isoenzymes. No fetal signs could be found in red cells of patients with AML. In two patients with DB who were treated by transfusion no fetal erythropoiesis could be detected. In one patient with DB under cortisone treatment i-antigen, ABH-antigens, haemoglobin F concentration, globin chain synthesis and hexokinase isoenzyme distribution were of the fetal or mixed type. In patients with AA only slight elevations of haemoglobin F were detectable. The nearly total reversion to fetal erythropoiesis in JCML and EL seems to be a part of the disorder itself, whereas in the other disorders the reactivation of fetal erythropoiesis could be the result of an erythropoietic stress.