Background: In patients with terminal renal failure, the most frequentlynoted hematological change is normocytic normochromic anemia. As not all anemic patients respond in thesame way to treatment with human erythropoietin, the aim of our investigation was to confirm the hypothesisthat the origin of this anemia is multifactorial. Material/Methods: Therefore we cultivated peripheralblood CFU GEMM, CFU GM, and BFU E in 65 patients treated by hemodialysis, subdivided in two groups accordingto creatinine concentration (Group 1: 900 micromol/l). Hematopoietic stemcells were cultivated on methylcellulose with growth factors added. Results: Growth inhibition of BFUE and CFU GM and a negative correlation between CFU GEMM, CFU GM, and BFU E growth and urea concentrationwere found in the entire group of patients. CFU GEMM growth in Group 2 was inhibited. Positive correlationbetween CFU GM and BFU E, CFU GEMM and BFU E, and CFU GM and CFU GEMM growth was established. In Group1 a negative correlation between BFU E and CFU GM growth and creatinine concentration was found, andin Group 2 a negative correlation between BFU E and CFU GM growth and urea concentration. Conclusions:Relatively decreased erythropoietin concentration is one of the major causes of renal anemia. As CFUGM and CFU GEMM growth was decreased, hematopoiesis must be disturbed at a higher level and is affectedby other factors connected with uremia, such as the lack of T[sub]4[/sub] lymphocytes and the dialysis procedure.

Keywords: Colony-Forming Units Assay, Enzyme-Linked Immunosorbent Assay, Erythroid Precursor Cells - drug effects, Erythropoietin - pharmacology, Hematopoiesis - drug effects, Hematopoietic Cell Growth Factors - pharmacology, Hematopoietic Stem Cells - drug effects, Kidney Failure, Chronic - pathology, Renal Dialysis