Electron microscope and high resolution autoradiographic studies of the erythroblasts in haemoglobin H disease.

Electron microscope studies of bone marrow from a patient with haemoglobin H (HbH) disease have revealed the presence of highly condensed branching intracytoplasmic inclusions within a proportion of the early and late polychromatic erythroblasts and reticulocytes. Intraerythroblastic inclusions of this type have not yet been described in any other haematological disorder and may well be a specific feature of HbH disease. Electron microscope autoradiographic studies of the marrow cells from the patient with HbH disease revealed that (1) active protein synthesis continues in inclusion-containing erythroblasts and (2) there is a rapid precipitation of a considerable proportion of the newly synthesized free beta chains onto the surfaces of preformed inclusions, presumably after conversion to HbH. These electron microscope and electron microscope autoradiographic findings are quite different from the findings previously reported in homozygous beta thalassaemia using the same techniques.