Erythropoiesis during recovery from macrocytic anemia: macrocytes, normocytes, and microcytes

Abstract

In seven patiens with markd megaloblastic anemia (MCV > 110 fl), red cell size distribution curves (erythrograms) demonstrated the size of red cells produced after therapy. In six, the new red cells were normocytic throughout recovery. In the seventh patient, folate repletion alone produced a new population of microcytes, due to unsuspected iron deficiency; after iron repletion normocytes were produced. Three patients with autoimmune hemolytic anemia had macrocytosis (MCV > 110 fl) witout folate or vitamin B12 deficiency. During recovery with prednisone therapy, instead of a discrete new normocytic population appearing, the entire population progressively returned to normal size. Normal rather than 'stress' reticulocytes, and remodeled stress reticulocytes remaining, may explain this different pattern of recovery. Two patients initially had minor subpopulations of smaller red cells that disappeared soon after therapy. These probably reflected the dyserythropoiesis of severe megaloblastic anemia.