Studies on red-cell aplasia: IX. Ferrokinetics during remission of the disease.

Ferrokinetic studies and external organ measurements of radioiron were performed on five patients with pure red-cell aplasia (PRCA) in remission. One patient with PRCA in relapse was also studied. Of those in remission, one patient had erythroid hyperplasia and ineffective erythropoiesis after the remission occurred. This was indicated by a very short 59Fe clearance rate and reduced red-cell 59Fe incorporation, a marked increase of the erythron iron turnover over the fixed red-cell iron turnover, and a prolonged marrow transit time. These indices were normal three years later. Four patients had normal effective erythropoiesis while in remission. Two patients had an extended marrow distribution. These studies indicate that some cases of PRCA evolve into a state of ineffective erythropoiesis with erythroid hyperplasia. It is possible that in some patients, primary refractory anemia with ineffective erythropoiesis may be related to PRCA because of the evolution from one state into the other. Alternatively, a second pathologic process may have been acquired between the PRCA and normal hematopoiesis.