EVIDENCE FOR THE PRESENCE OF CFU-E WITH INCREASED INVITRO SENSITIVITY TO ERYTHROPOIETIN IN SICKLE-CELL-ANEMIA

  • 1 January 1984
    • journal article
    • research article
    • Vol. 63  (5) , 1168-1171
Abstract
To investigate the cellular events that accompany erythroid hyperplasia, several effects of erythropoietin (Epo) on marrow CFU-E [erythrocyte colony forming unit] in sickle cell anemia (SCA) were studied. CFU-E number, CFU-E growth as a function both of Epo exposure time and of Epo concentration, and suppression of Epo-induced CFU-E formation by anti-Epo antiserum were measured. With 0.5 U Epo/ml, the number of CFU-E was elevated in SCA (1087 .+-. 520) compared to normal (430 .+-. 130). CFU-E were formed even when Epo was immediately neutralized by a 1/150 dilution of anti-Epo. After 40 h of Epo exposure, only 2% total CFU-E were expressed in normal marrow, whereas 12%-40% of CFU-E were expressed in SCA. Inhibition of CFU-E growth required at least 1/50 dilution of anti-Epo in SCA and a 1/300 dilution in normal marrow. In contrast to normal, a small number (5%-20%) of CFU-E were expressed in the absence of added Epo in SCA, and this pool required a 1/150 dilution of anti-Epo for inhibition. The Epo dose-response curve in SCA revealed a peak in colony formation around 0.1 U Epo/ml and 0.5 U Epo/ml, whereas only 1 peak at 0.5 U Epo/ml was seen in normals. In response to the demands of chronic erythroid hyperplasia in SCA, a pool of CFU-E is present characterized by increased in vitro sensitivity to Epo.