維持血液透析患者におけるエリスロポエチン活性 ： 第1報 CFU-E由来コロニー形成能と血漿EPO濃度の比較

Abstract

We have simultaneously determined the plasma levels of erythropoietin (EPO) in 40 chronic hemodialytic patients by an in vitro bioassay and a radioimmunoassay (RIA) and have made a comparative study of the results. In the in vitro bioassay, the EPO plasma titers were determined by a method of Sakata et al, using fetal mouse liver cells obtained from 12-day-old mice. The mean EPO level of the hemodialytic patients was revealed to be 74.4±29.1 mU/ml in the bioassay and 17.1±10.1 mU/ml in the RIA. In contrast, the normal level of the control subjects were 158.0±33.4 mU/ml in the bioassay and 15.7±1.3 mU/ml in the RIA. In the bioassay, in 27 (67.5%) of the 40 hemodialytic cases, the EPO titer levels were found to be lower than the normal lower limit (90 mU/ml). Conversely, in the RIA, the EPO levels were found to be higher than the normal lower limit in all caces, except for only one. The plasma EPO value in the bioassay showed a positive correlation with the hemoglobin (Hb) concentration and the count of the reticulocytes, but no significant correlation in the RIA. On the other hand, there is no correlation between the in vitro bioassay and the RIA, but in the comparative study limited to 21 cases who were did not show very low EPO levels in the bioassay, there was a significant relationship between the two methods. Therefore, it is felt that plasma EPO level data obtained by the RIA do not necessarily reflect the true erythropoietic stimulatory activity in hemodialytic patients with chronic glomerulonephritis.