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,¹ who 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,² Horne and co-workers,³ and others⁴ on persons with familial hemolytic jaundice. Dameshek and Bloom² suggested 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 associates⁵ described 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 Owren¹ and Singer and others.⁵ No evidence of hypersplenism, either in inhibiting the marrow or in causing increased hemolysis of the red