Quantitative expression of erythropoietin receptor (EPO-R) on acute leukaemia cells: relationships between the amount of EPO-R and CD phenotypes, in vitro proliferative response, the amount of other cytokine receptors and clinical prognosis

Expression of erythropoietin (EPO) receptor (EPOR) was analysed in leukaemi a cells from 150 patients with acute myeloid leukaemia (AML) or acute lymph oblastic leukaemia (ALL). EPO-R was expressed in 81 (60%) out of 136 AML, a nd in vitro treatment with EPO led to proliferation of leukaemia cells in 1 3 (16%) out of 81 AML examined. EPO-R expression and in vitro response to E PO were observed in all subtypes of AML according to the French-American-Br itish (FAB) classification. All eight patients with FAB-M6 expressed EPO-R, and one out of four showed an in vitro response to EPO. Although there was no significant correlation (r = 0.2522) between the amount of EPO-R and th e in vitro response to EPO, all of the AML patients who showed in vitro res ponse expressed EPO-R. Stern cell factor significantly enhanced both EPO-R expression and in vitro response to EPO. Interleukin-3 tended to;increase i n vitro response to EPO. CD phenotypes, the amount of granulocyte colony-st imulating factor (G-CSF) receptors and the amount of TPO receptors had no s ignificant relationship with the amount of EPO-R. Patients with both EPO-R expression and in vitro response to EPO had shorter duration of complete re mission than those without EPO-R (P = 0.0053). EPO-R was expressed in four (29%) out of 14 ALL. and none out of Eve ALL showed in vitro response to EP O.