Cortisone and ACTH in Hypoplastic Anemia *

For many years hypoplastic or aplastic anemia has been identified with a confusing group of pancytopenias which are refractory to treatment. Recently The Committee for Clarification of the Nomenclature of Cells and Diseases of the Blood and Blood-forming Organs has redefined the term hypoplastic anemia and discarded the term aplastic anemia."3 Hypoplastic anemia is defined by this committee as a pancytopenia caused by actual hypocellularity of the bone marrow. This definition probably embraces many diseases with different etiologies but it does place in a single category all cases of pancytopenia due to hypocellularity of the bone marrow. In most reports of pancytopenias which are refractory to treatment no clear differentiation has been made between cases with hypocellularity and those with hypercellularity of the marrow. This fact makes it hard to draw conclusions concerning the etiology and prognosis of true hypoplastic anemia. There seem to be two distinct types of hypoplastic anemia. One is acute and fulminating and usually is associated with a definite history of exposure to an agent toxic for bone marrow. Avoidance of exposure to this agent not infrequently is followed by spontaneous recovery. The other type is chronic and slowly progressive over a period of months or years. In most of the chronic cases it is not possible to obtain a history of significant exposure to toxins. Recovery from the chronic type of hypoplastic anemia occurs only rarely and unpredictably and apparently is spontaneous rather than due to any specific treatment. No agent has been found which will induce regeneration of the bone marrow in acute or chronic hypoplastic anemia. Soon after the introduction of cortisone and ACTH in the treatment of a variety of diseases it was discovered that they would often correct a complicating anemia or leukopenia. These findings suggested that cortisone and ACTH had a stimulatory effect on hematopoiesis and might be useful in the treatment of hypoplastic anemia.2 The response of normal bone marrow to cortisone and ACTH has not been fully evaluated. Hills"0 and Forsham7 reported a moderate neutrophilic leukocytosis in normal individuals four hours after a single dose of ACTH but this observation can hardly be interpreted as evidence for stimulation of bone marrow. Administration of ACTH over a period of several days,