title: Serum osteoprotegerin is markedly increased and may contribute to decreased blood T cell count in hemodialysis patients.
abstract: OBJECTIVE
  Acquired immunity is impaired in hemodialysis (HD) patients, and decreased T cell number may contribute. Receptor activator of nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) are expressed in cells of the immune system and affect T cell development, homeostasis and proliferation. Serum levels of RANKL and OPG and their relation to blood T cell number were evaluated in HD patients.
  
  
  METHODS
  Thirty-four HD patients and 20 healthy controls participated in the study. Serum RANKL and OPG were measured by ELISA and T cell number was assessed by flow cytometry.
  
  
  RESULTS
  Median RANKL concentration did not differ between HD patients and healthy volunteers (300.00 pmol/L; range, 3,340.00 vs. 330.00 pmol/L; range, 440.00 pmol/L; p = 0.528). Median OPG was markedly higher in HD patients than in healthy volunteers (13.12 ± 4.71 vs. 4.71 ± 0.93 pmol/L, p < 0.001). The T cell count was significantly lower in HD patients than in healthy controls (1,177.00 ± 567.71 vs. 1,519.80 ± 594.96 cells/mm(3), p = 0.044). In HD patients, blood T cell number was correlated positively with serum RANKL (ρ = 0.462, p = 0.007) and negatively to serum OPG (r = -0.449, p = 0.008).
  
  
  CONCLUSIONS
  Serum OPG concentration is markedly increased in HD patients and may contribute to decreased blood T cell count and impaired acquired immunity that characterizes this population.
authors.affiliation: Department of Nephrology, Medical School, University of Thessaly, Neo Ktirio, Mezourlo Hill, 41110, Larissa, Greece, teleftheriadis@yahoo.com.
authors.forename: Theodoros
authors.initials: T
authors.lastname: Eleftheriadis
authors.forename: Efi
authors.initials: E
authors.lastname: Yiannaki
authors.forename: Vassilios
authors.initials: V
authors.lastname: Liakopoulos
authors.forename: Georgia
authors.initials: G
authors.lastname: Antoniadi
authors.forename: Georgios
authors.initials: G
authors.lastname: Pissas
authors.forename: Grammati
authors.initials: G
authors.lastname: Galaktidou
authors.forename: Ioannis
authors.initials: I
authors.lastname: Stefanidis
mesh_terms: D000368:Aged; D002097:C-Reactive Protein / Q000378:metabolism; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D053244:Osteoprotegerin / Q000097:blood*; D010281:Parathyroid Hormone / Q000097:blood; D053245:RANK Ligand / Q000097:blood*; D006435:Renal Dialysis; D013601:T-Lymphocytes
chemical_list: D053244:Osteoprotegerin; D010281:Parathyroid Hormone; D053245:RANK Ligand; D002097:C-Reactive Protein