Acute Erythroblastopenia in Sickle-Cell Anemia and Infectious Mononucleosis

AN ACUTE transitory cessation of red-blood-cell production in hereditary spherocytosis was reported by Owren,¹who applied the term "aplastic crisis" to the precipitous drop in red-blood-cell count and hemoglobin levels noted in his patients. Similar observations have also been made by Dameshek and Bloom,²Horne and co-workers,³and others⁴on persons with familial hemolytic jaundice. Dameshek and Bloom²suggested that the aplastic crisis was secondary to increased splenic activity, which produced a maturation arrest of the red-cell apparatus at the pronormoblast level. Recently, Singer and associates⁵described the development of an aplastic crisis in a patient with sickle-cell anemia. The pathophysiologic mechanisms responsible for the development of such an event in the hemolytic syndromes have been extensively discussed by both Owren¹and Singer and others.⁵No evidence of hypersplenism, either in inhibiting the marrow or in causing increased hemolysis of the red