Inhibitors of erythroid colony forming cells in sera of azotemic patients with anemia of renal disease.

1. The plasma clot method of McLeod, et al8 was used to study the inhibitors of erythroid colony forming cells (CFU-E and BFU-E) in sera of patients with anemia of uremia. 2. Compared to sera from hematologically normal human subjects, sera from undialyzed patients with anemia of uremia produced a significant inhibition of CFU-E and BFU-E. 3. A marked reduction in the inhibitor(s) of CFU-E was seen in sera of 3 out of 4 patients following 16 wks of intermittent hemodialysis. 4. Creatinine, guanidine, guanidinosuccinic acid and guanidinobutyric acid had no effect on the erythroid colony forming cells. 5. Together with the relative erythropoietin deficiency, inhibitor(s) of the erythroid progenitor cell compartment may play a major role in the mechanism of the anemia of renal insufficiency.