title: Stability of pro- and anti-inflammatory immune biomarkers for human cohort studies.
abstract: Although discovery research has identified the importance of dozens of pro- and anti-inflammatory immune mediators in the pathogenesis, maintenance, exacerbation and resolution of inflammatory diseases, most human cohort studies have incorporated few or no immunological intermediate phenotypes in their analyses. Significant hindrances have been (1) the limited panel of biomarkers known to be readily detected in healthy human populations and (2) the stability, hence utility, of such biomarkers to repeated analysis.
  
  
  
  The frequency and stability of 14 plasma biomarkers linked to in vivo immune regulation of allergic and autoimmune inflammatory disorders was determined in 140 healthy pediatric and adult participants. The impact of initial and multiple subsequent freeze/thaw cycles on pro-inflammatory (CCL2, CXCL10, IL-18, TNFα, IL-6), anti-inflammatory (IL-10, sTNF-RII, IL-1Ra), acute phase proteins (CRP, PTX3) and other biomarkers (sST2, IL-1RAcP) was subsequently quantified.
  
  
  
  Multiple biomarkers capable of providing an innate immune signature of inflammation were readily detected directly ex vivo in healthy individuals. These biomarker levels were unaffected when comparing paired data sets from freshly obtained, never frozen plasma or serum and matched aliquots despite extensive freeze/thaw cycles. Neither age nor sex affected stability. Similarly, no quantitative differences were found following repetitive analysis of inflammatory biomarkers in culture samples obtained following in vitro stimulation with TLR and RLR ligands.
  
  
  
  A broad panel of in vivo and ex vivo cytokine, chemokine and acute phase protein biomarkers that have been linked to human chronic inflammatory disorders are readily detected in vivo and remain stable for analysis despite multiple freeze thaw cycles. These data provide the foundation and confidence for large scale analyses of panels of inflammatory biomarkers to provide better understanding of immunological mechanisms underlying health versus disease.
authors.affiliation: Department of Immunology, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Graham
authors.affiliation: Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Chooniedass
authors.affiliation: Department of Immunology, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: W P
authors.initials: WP
authors.lastname: Stefura
authors.affiliation: Department of Immunology, University of Manitoba, Winnipeg, MB, Canada.|Community Health and Epidemiology-‎Saskatchewan Population Health and Evaluation Research Unit, University of Saskatchewan, Saskatoon, SK, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Lotoski
authors.affiliation: Department of Immunology, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Lopez
authors.affiliation: Division of Pulmonary Medicine, Department of Medicine, University of Alberta, Edmonton, AB, Canada.
authors.forename: A D
authors.initials: AD
authors.lastname: Befus
authors.affiliation: Department of Immunology, University of Manitoba, Winnipeg, MB, Canada.|Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB, Canada.|Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada.
authors.forename: A B
authors.initials: AB
authors.lastname: Becker
authors.affiliation: Department of Immunology, University of Manitoba, Winnipeg, MB, Canada. kent.hayglass@umanitoba.ca.|Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB, Canada. kent.hayglass@umanitoba.ca.|Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada. kent.hayglass@umanitoba.ca.
authors.forename: K T
authors.initials: KT
authors.lastname: HayGlass
mesh_terms: D000893:Anti-Inflammatory Agents / Q000097:blood*; D015415:Biomarkers / Q000097:blood*; D002478:Cells, Cultured; D015331:Cohort Studies; D005260:Female; D005615:Freezing; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood*; D008297:Male; D044967:Serum / Q000378:metabolism; D014019:Tissue Donors
chemical_list: D000893:Anti-Inflammatory Agents; D015415:Biomarkers; D018836:Inflammation Mediators
keywords: Allergy; Autoimmunity; Cohort; Human immunology; Immune regulation; Inflammation; Innate