Aplastic anemia with circulating erythroblasts.

Since the presence of erythroblasts (Ebl) in the peripheral blood of patients suspected to have aplastic anemia (AA) has been thought to suggest an error in diagnosis, such patients may not receive appropriate therapy promptly, with potentially fatal results. However, we recently experienced patients who had the typical features of AA except for circulating Ebl, and responded well to therapy for AA. In this study, we examined 55 untreated AA patients for the presence of circulating Ebl. Seven patients (12.7%) had circulating Ebl (at least one Ebl per 200 leukocytes counted). These seven patients showed the typical features of AA. There were no significant differences in age or hematologic parameters, including the morphology of bone marrow Ebl, between the AA patients having circulating Ebl (Ebl(+) AA) and the AA patients without Ebl. All but one of the Ebl(+) AA patients responded well to the therapy for AA. During 12.0-110.4 months of follow-up, transformation to other diseases did not occur, and all seven patients were alive. We conclude that circulating Ebl are not rare in patients who have otherwise typical features of AA, and that if such Ebl(+) AA patients are severely cytopenic, they should receive treatment for AA without delay.