title: Changes of red blood cell surface markers in a blood doping model of neocytolysis.
abstract: BACKGROUND
  Neocytolysis, the selective hemolysis of young circulating red blood cells (RBCs), contributes to the physiologic control of red cell mass and to pathophysiologic phenomena such as anemia of renal disease, anemia after spaceflight, and blood doping by athletes. Progress in understanding the process is hampered by the lack of established markers to distinguish young from older RBC.
  
  
  METHODS
  Twelve potentially informative RBC surface markers were assayed by flow cytometry in normal blood samples, and 4 were preferentially expressed in young RBC. To create a model of neocytolysis, 3 normal volunteers had recombinant human erythropoietin (rhEpo) administered until mild erythrocytosis occurred, then were studied upon rhEpo withdrawal.
  
  
  RESULTS
  Neocytolysis ensued that most evident from a rapid rise in serum ferritin as the iron from young RBC was transferred back to stores. Five additional volunteers had surface markers monitored during and after rhEpo administration. Three subjects with marginal baseline iron stores had blunted response to rhEpo, no significant neocytolysis, and no change in RBC surface marker expression. Two subjects with adequate baseline iron stores developed erythrocytosis followed by neocytolysis. Decreased expression of CD44 (homing-associated cell adhesion molecule) and CD71 (transferrin receptor) seemed to correlate best with neocytolysis; CD35 (complement receptor) less so. Of note, further studies are needed to determine if these changes are causative of red cell destruction.
  
  
  CONCLUSIONS
  This study begins to establish a human model of neocytolysis, to establish markers differentiating young and old RBC, and to establish a basis for better definition of the process. Although our study is preliminary, the results support the possibility that flow could be useful to detect blood doping because neocytolysis should predictably occur in athletes who surreptitiously blood dope.
authors.affiliation: Department of Pathology, The Methodist Hospital and The Methodist Hospital Research Institute, Weill Medical College of Cornell University, NY, USA. jeffchang@tmhs.org
authors.forename: Chung-Che
authors.initials: CC
authors.lastname: Chang
authors.forename: Yayan
authors.initials: Y
authors.lastname: Chen
authors.forename: Kapil
authors.initials: K
authors.lastname: Modi
authors.forename: Omar
authors.initials: O
authors.lastname: Awar
authors.forename: Clarence
authors.initials: C
authors.lastname: Alfrey
authors.forename: Lawrence
authors.initials: L
authors.lastname: Rice
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000097:blood; D015415:Biomarkers / Q000097:blood; D004300:Doping in Sports; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004921:Erythropoietin / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D011994:Recombinant Proteins
chemical_list: D015703:Antigens, CD; D015415:Biomarkers; D011994:Recombinant Proteins; D004921:Erythropoietin