title: Quantitative reticulocyte analysis may be of benefit in monitoring erythropoietin treatment in dialysis patients.
abstract: Reticulocyte responses to low-dose erythropoietin (EPO) were monitored using automated flow cytometric analysis. Sixteen adult dialysis patients were treated with 1,000 U of recombinant human EPO (rHuEPO), subcutaneously, thrice weekly (mean dose 15.7, SD 3.7 U/kg). The reticulocyte count (baseline 31.1, SD 19.1 x 10(9)/L) increased in 14 patients in the first week, with a peak response occurring at Week 2 (mean 57.3, SD 26.5 x 10(9)/L, p < 0.01). There was a wide spectrum of response, the maximal absolute increment ranging from 6.8-69.7 x 10(9)/L (maximal percentage increase 19-863%). Overall there was no relationship between the early increment in reticulocyte count and hemoglobin (Hb) response over the ensuing 4 months. Nine patients became transfusion independent (mean Hb increasing from 6.9, SD 0.8-9.2, SD 1.2 g/dl). Two patients had poor reticulocyte increments and no significant change in Hb. The remaining 5 patients responded partially with a brisk reticulocyte response and a marked reduction in transfusion dependency, but without a sustained increase in Hb. On investigation, all had gastrointestinal bleeding (melena in 1, commencing after initiation of treatment, positive fecal occult bloods in 4), whereas none of the other patients showed evidence of blood loss. It is notable that the erythron was sensitive to this modest dose of rHuEPO in the majority of patients as evidenced by the reticulocyte response. The results provide useful information in the management of patients on rHuEPO. A small or inapparent reticulocyte response suggests a confounding factor; a poor Hb response in the presence of active reticulocyte synthesis points to occult blood loss or hemolysis.
authors.affiliation: Department of Renal Medicine, St. James's University Hospital, Leeds, United Kingdom.
authors.forename: R F
authors.initials: RF
authors.lastname: Jeffrey
authors.forename: A A
authors.initials: AA
authors.lastname: Khan
authors.forename: R G
authors.initials: RG
authors.lastname: Kendall
authors.forename: D R
authors.initials: DR
authors.lastname: Norfolk
authors.forename: E J
authors.initials: EJ
authors.lastname: Will
authors.forename: A M
authors.initials: AM
authors.lastname: Davison
mesh_terms: D000328:Adult; D000368:Aged; D002452:Cell Count / Q000187:drug effects; D003430:Cross-Sectional Studies; D004921:Erythropoietin / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D005434:Flow Cytometry; D006454:Hemoglobins / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007279:Injections, Subcutaneous; D007676:Kidney Failure, Chronic / Q000097:blood / Q000188:drug therapy / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000627:therapeutic use; D006435:Renal Dialysis; D012156:Reticulocytes / Q000166:cytology / Q000187:drug effects*
chemical_list: D006454:Hemoglobins; D011994:Recombinant Proteins; D004921:Erythropoietin