Light microscopical aspect of the erythroblasts cultured from patient 2 bone marrow. (a) In the presence of autologous serum: The erythroblasts are closely apposed to each other with occasional nonbasophilic areas present at their junction, mimicking the morphology of the bone marrow smears. (b) In the presence of a control serum: The grown erythroblasts are scattered and individually disposed on this cytospun preparation and do not display the characteristic abnormalities of the disease.