Plasma Erythropoietic Factor in Anemic Human Patients

By T. C. PRENTICE AND E. A. MIIIAND T HE EXISTENCE of a humoral erythropoietic stimulating factor which controls red cell productiomi has been suspected for mnamiy years. Carmiot amid I)eulamidre’ postulated in 1906 that such might be true. Imi 1950 Reissmanm, usimig paral)iotic rats, published convincing experimnental evidemice of a circubatimig erythropoietic factor imiduced by placimig one member of the pair in a hypoxic atniosphere. Iii 1952 au excellent. review concerning the fundamental stimulus for erythropoiesis was written by Gramit amid Root.3 A blood-borne substance capable of stimulatimig erythropoiesis was stromigly suggested. Subsequemitly many laboratories have takemi up amid expanded this concept, using several different methods of study. Thus plasma, or a “deproteinized” extract of plasma, obtamed front amiimals rendered anemic by bleedimig4’#{176} was showmi to have the ability to stimulate imicreased erythropoiesis in recipiemit animuabs. Simuilar material from animals with phenybhydrazimie-immduced hemolytic aneniia”’5 possessed the same properties, though somewhat more potemit. Plasma froni animals kept in a low oxygemi atmosphere has exerted sigmiificamit erythropoietic activity.’6’ Also t.here is evidence’s that. a substamice may be present iii the milk of amioxic rats and mice which produces au imicreased hemoglobin content of the miursimig young. As studies with experimemital amiimabs have progressed, increasimig imiterest has beemi cemitered omi the sigmiificance of these fimidimigs imi patients with various types of anemia amid polycythemnia. This phase, the study of human patiemits, has been aided tremuemidously by the denionstrat ion’2 ‘ that boiled extracts of human plasma retain their erythropoietic stimubatimig properties. This discovery enabled imivestigators to test the erythropoietic stimulatimig properties of extracts of human plasma imi other animal species without detectable reactions due t.o foreign protein. Also smaller amiioumits of plasma were then adequate, simice the extract could be assayed imi small amiimals. Reports of such studies, using plasma extracts from human patielits with varied fornis of anemia amid polycythemia, are now begimining to appear.’9’ 20 They have imidicated, in general, marked increases of erythropoietimi in plasma from patiemits with Cooley’s amiemia, less comisistent increases in Sickle cell anemia, hO imicrease in one case of hypoplastic anemia amid increased amounts in patients with polycythemia vera and secomidary pobycythemia. The present study is a report of 9 further patiemits with anemia of varied etiology imi whom plasma erythropoiet.imi has been assayed. Ancillary st.udies have been done in sonic of these cases in au effort to further clarify the significance of this factor in the particular individual.