Sickle-Cell Disease: The Aplastic Crisis and Erythroid Maturation Defect Occurring Simultaneously in Three Members of a Family

It is now recognized that bone-marrow failure rather than hyperhemolysis underlies the crises in sickle-cell disease.1,2Bonemarrow failure has been reported in Cooley's hemolytic anemia,3hereditary spherocytosis,4and paroxysmal nocturnal hemoglobinuria.5Maturation arrest of the neutrophil polymorphonuclear leukocytes has been noted in sickle-cell disease.6Infection has been thought to precipitate bone-marrow aplasia in sickle-cell disease1,2and in hereditary spherocytosis.7The occurrence of "aplastic crisis" in several members of a family has been recorded in hereditary spherocytosis7and in sickle-cell disease.17Erythroblastopenia has been noted during the course of viral pneumonia in patients without hemolytic blood diseases,8and the same communication records eosinophilia in patients who had erythrocytic aplasia after exposure to allergens. The association of chronic hemolytic anemias with megaloblastic arrest of the bone marrow has been documented. Some of these responded to vitamin B12therapy,9some were associated with pregnancy,10and in others dietary deficiency of folie acid