title: Baseline levels and temporal stability of 27 multiplexed serum cytokine concentrations in healthy subjects.
abstract: BACKGROUND
  Cytokines are humoral molecules that elicit regulatory function in immunologic pathways. The level and type of cytokine production has become critical in distinguishing physiologic from pathologic immune conditions. Cytokine profiling has become an important biomarker discovery tool in monitoring of the immune system. However, the variations in cytokine levels in individual subjects over time in healthy individuals have not been extensively studied. In this study, we use multiplex bead arrays to evaluate 27 analytes in paired serum samples taken seven days apart from 144 healthy individuals in order to assess variations over a short time period.
  
  
  METHODS
  Fluorescent bead-based immunoassay (Luminex) was used to measure 27 analytes in serum samples. Measurements were performed on matched samples from 144 healthy donors. To assess inter-plate variability, one arbitrarily selected serum sample was analyzed on each of the first ten plates as bridge sample.
  
  
  RESULTS
  Using the bridge sample, we showed minimal inter-plate variations in the measurement of most analytes. In measurement of cytokines from the 144 patients at two time points, we found that three cytokines (IL-2, IL-15 and GM-CSF) were undetectable and five analytes (RANTES, MCP-1, VEGF, MIP-1β and PDGF-BB) showed significant difference in concentrations at Day 0 compared to Day 7.
  
  
  CONCLUSIONS
  The current study demonstrated higher variations in cytokine levels among individuals than were observed for samples obtained one week apart from identical donors. These data suggest that a serum sample from each subject for use as a baseline measurement is a better control for clinical trials rather than sera from a paired cohort.
authors.affiliation: Center for Human Immunology, Autoimmunity, and Inflammation, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Angelique
authors.initials: A
authors.lastname: Biancotto
authors.affiliation: Center for Human Immunology, Autoimmunity, and Inflammation, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Abigail
authors.initials: A
authors.lastname: Wank
authors.affiliation: Center for Human Immunology, Autoimmunity, and Inflammation, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Shira
authors.initials: S
authors.lastname: Perl
authors.affiliation: Center for Human Immunology, Autoimmunity, and Inflammation, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Wendell
authors.initials: W
authors.lastname: Cook
authors.affiliation: Center for Human Immunology, Autoimmunity, and Inflammation, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Olnes
authors.affiliation: Center for Human Immunology, Autoimmunity, and Inflammation, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Pradeep K
authors.initials: PK
authors.lastname: Dagur
authors.affiliation: Center for Human Immunology, Autoimmunity, and Inflammation, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: J Christopher
authors.initials: JC
authors.lastname: Fuchs
authors.affiliation: Center for Human Immunology, Autoimmunity, and Inflammation, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Marc
authors.initials: M
authors.lastname: Langweiler
authors.affiliation: Center for Human Immunology, Autoimmunity, and Inflammation, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Ena
authors.initials: E
authors.lastname: Wang
authors.affiliation: Center for Human Immunology, Autoimmunity, and Inflammation, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: J Philip
authors.initials: JP
authors.lastname: McCoy
mesh_terms: D000328:Adult; D000368:Aged; D000077214:Becaplermin; D018932:Chemokine CCL2 / Q000097:blood; D054407:Chemokine CCL4 / Q000097:blood; D018946:Chemokine CCL5 / Q000097:blood; D016207:Cytokines / Q000097:blood*; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000097:blood; D006801:Humans; D007118:Immunoassay; D019409:Interleukin-15 / Q000097:blood; D007376:Interleukin-2 / Q000097:blood; D008297:Male; D008875:Middle Aged; D020574:Proto-Oncogene Proteins c-sis / Q000097:blood; D042461:Vascular Endothelial Growth Factor A / Q000097:blood
chemical_list: D018932:Chemokine CCL2; D054407:Chemokine CCL4; D018946:Chemokine CCL5; D016207:Cytokines; D019409:Interleukin-15; D007376:Interleukin-2; D020574:Proto-Oncogene Proteins c-sis; D042461:Vascular Endothelial Growth Factor A; D000077214:Becaplermin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor