title: The effect of assay type and sample matrix on detected cytokine concentrations in human blood serum and nasal lavage fluid.
abstract: Cytokine concentrations in biological fluids are widely used markers for activation of immunological processes. Confirming the reproducibility of measurements is important, especially in longitudinal or multicenter studies where time between analyses or different analyzing laboratories increases the intra-assay variability. In this study, the reproducibility of the cytokine analysis conducted with different assay platforms was studied by comparing the results of two cytokines [interleukin (IL)-6 in serum and nasal lavage fluid (NAL) and IL-8 in NAL] analyzed with Meso Scale Discovery (MSD) ultra-sensitive single and multiplex assay kits (n=76). In addition, the difference in cytokine levels between two biological sample matrices was studied by comparing the results of altogether 9 cytokines [IL-6, IL-2, IL-8, IL12p70, IL-1β, granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon (IFN)γ, IL-10 and tumor necrosis factor (TNF)α] measured from serum and NAL of the same study subjects (n=460). The results show that the cytokine concentrations analyzed with single and multiplex assays are concordant but not equal. Comparison of the different matrices revealed that cytokine concentrations in serum do not correspond with concentrations detected in nasal lavage fluid. It can be concluded that comparability of the results from single and multiplex analysis of cytokines is high, but the concentrations should not be compared directly with each other. The differences between concentrations analyzed from serum and nasal lavage fluid indicate that the levels are specific for each matrix and represent distinct immunological conditions.
authors.affiliation: Department of Environmental Science, University of Eastern Finland (UEF), P.O. Box 1627, FI-70211 Kuopio, Finland. Electronic address: kati.huttunen@uef.fi.
authors.forename: Kati
authors.initials: K
authors.lastname: Huttunen
authors.affiliation: Department of Environmental Science, University of Eastern Finland (UEF), P.O. Box 1627, FI-70211 Kuopio, Finland. Electronic address: kati.tiihonen@uef.fi.
authors.forename: Kati
authors.initials: K
authors.lastname: Tiihonen
authors.affiliation: Department of Environmental Science, University of Eastern Finland (UEF), P.O. Box 1627, FI-70211 Kuopio, Finland. Electronic address: marjut.roponen@uef.fi.
authors.forename: Marjut
authors.initials: M
authors.lastname: Roponen
authors.affiliation: Institute for Risk Assessment Sciences (IRAS), Utrecht University, P.O. Box 80178, 3508 TD Utrecht, The Netherlands. Electronic address: d.heederik@uu.nl.
authors.forename: Dick
authors.initials: D
authors.lastname: Heederik
authors.affiliation: Centre for Research in Environmental Epidemiology (CREAL), Doctor Aiguader 88, E-08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), Plaça de la Mercè 10-12, 08002 Barcelona, Spain; CIBER Epidemiología y Salud Pública (CIBERESP), Melchor Fernández Almagro 3-5, 28029 Madrid, Spain. Electronic address: jpzock@creal.cat.
authors.forename: Jan-Paul
authors.initials: JP
authors.lastname: Zock
authors.affiliation: CIBER Epidemiología y Salud Pública (CIBERESP), Melchor Fernández Almagro 3-5, 28029 Madrid, Spain. Electronic address: martin.taubel@thl.fi.
authors.forename: Martin
authors.initials: M
authors.lastname: Täubel
authors.affiliation: CIBER Epidemiología y Salud Pública (CIBERESP), Melchor Fernández Almagro 3-5, 28029 Madrid, Spain. Electronic address: anne.hyvarinen@thl.fi.
authors.forename: Anne
authors.initials: A
authors.lastname: Hyvärinen
authors.affiliation: Department of Environmental Science, University of Eastern Finland (UEF), P.O. Box 1627, FI-70211 Kuopio, Finland; Department of Environmental Health, National Institute for Health and Welfare (THL), P.O. Box 95, FI-70701 Kuopio, Finland. Electronic address: maija-riitta.hirvonen@uef.fi.
authors.forename: Maija-Riitta
authors.initials: MR
authors.lastname: Hirvonen
mesh_terms: D003430:Cross-Sectional Studies; D016207:Cytokines / Q000032:analysis* / Q000097:blood / Q000378:metabolism; D006801:Humans; D017817:Nasal Lavage Fluid / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D016207:Cytokines
keywords: Cytokine; Multiplex assay; Nasal lavage fluid; Reproducibility; Serum