How to: Measuring blood cytokines in biological psychiatry using commercially available multiplex immunoassays.
Cytokines produced by both immune and non-immune cells are likely to play roles in the development and/or progression of psychiatric disorders. Indeed, many investigators have compared the blood cytokine levels in psychiatric patients with those of healthy controls or monitored their levels in patients during disease progression to identify biomarkers. Nevertheless, very few studies have confirmed that such cytokines remain stable in healthy individuals through periods of weeks and months. This is an important issue to consider before using blood cytokine levels as biomarkers of disease traits, disease state, or treatment response. Although multiplex assay technology represents an advance in identifying biomarkers because it allows simultaneous examination of large panels of analytes from a small volume of sample, it is necessary to verify whether these assays yield enough sensitivity and reproducibility when applied to the blood from neuropsychiatric patients. Therefore, we compared two multiplex immunoassays, the bead-based Luminex®(Bio-Rad) and the electro-chemiluminescence-based V-plex®(MesoScaleDiscovery), for the detection and quantification of 31 cytokines, chemokines and growth factors in both the sera and plasma of patients with major depressive episodes (MDE) and age- and sex-matched healthy control subjects during a 30-week period. Although both platforms exhibited low coefficients of variability (CV) between the duplicates in the calibration curves, the linearity was better in general for the V-PLEX®platform. However, neither platform was able to detect the absolute values for all of the tested analytes. Among the 16 analytes that were detected by both assays, the intra-assay reproducibility was in general better with the V-PLEX®platform. Although it is not a general rule that the results from sera and plasma will be correlated, consistent results were more frequent with the V-PLEX®platform. Furthermore, the V-PLEX®results were more consistent with the gold standard ELISA simplex assay for IL-6 in both sera and plasma. The intra-individual variability of the measurements, among the sera and plasma for the 4 samples harvested from each healthy individual, was low for Eotaxin, G-CSF, IL-4, IL-7, IL-9, IL-12p40, IL-12p70, IL-15, MIP-1β, PDGF-BB, TNF, TNF-β and VEGF, but intermediate or high for IFN-γ, IL-6, IL-8, IL-10, and IP10. Together, these data suggest that extreme caution is needed in translating the results of multiplex cytokine profiling into biomarker discovery in psychiatry.
Aix-Marseille Univ., CNRS, CRN2M-UMR7286, Marseille, France; Pôle de Psychiatrie, Assistance Publique-Hôpitaux de Marseille, Marseille, France; Fondation FondaMental, Fondation de Recherche et de Soins en Santé Mentale, Créteil, France.
Raoul
R
Belzeaux
CIC-CPCET, AP-HM, Hôpital La Timone, Marseille, France.
Marie-Noëlle
MN
Lefebvre
Institut de Pharmacologie Moléculaire et Cellulaire CNRS, INSERM, Université de Nice-Sophia Antipolis Valbonne, France.
Anne
A
Lazzari
Inserm, U1141, Paris, France; Univ. Paris Diderot, Sorbonne Paris Cité, UMRS 1141, Paris, France.
Tifenn
T
Le Carpentier
Aix-Marseille Univ., CNRS, CRN2M-UMR7286, Marseille, France; Pôle de Psychiatrie, Assistance Publique-Hôpitaux de Marseille, Marseille, France; Fondation FondaMental, Fondation de Recherche et de Soins en Santé Mentale, Créteil, France.
Julia-Lou
JL
Consoloni
Pôle de Psychiatrie, Assistance Publique-Hôpitaux de Marseille, Marseille, France.
Xavier
X
Zendjidjian
Pôle de Psychiatrie, Centre Hospitalier Régional Universitaire Carémeau, Nîmes, France.
Mocrane
M
Abbar
Fondation FondaMental, Fondation de Recherche et de Soins en Santé Mentale, Créteil, France; Département des Urgences et Post-Urgences Psychiatriques, Centre Hospitalier Régional Universitaire, Hôpital Lapeyronie, Montpellier, France.
Philippe
P
Courtet
Pôle de Psychiatrie, Assistance Publique-Hôpitaux de Marseille, Marseille, France.
Jean
J
Naudin
Aix-Marseille Univ., CNRS, CRN2M-UMR7286, Marseille, France; Fondation FondaMental, Fondation de Recherche et de Soins en Santé Mentale, Créteil, France; Laboratoire d'Immunologie, AP-HM, Hôpital de la Conception, Marseille, France.
José
J
Boucraut
Inserm, U1141, Paris, France; Univ. Paris Diderot, Sorbonne Paris Cité, UMRS 1141, Paris, France.
Pierre
P
Gressens
Institut de Pharmacologie Moléculaire et Cellulaire CNRS, INSERM, Université de Nice-Sophia Antipolis Valbonne, France.
Nicolas
N
Glaichenhaus
Aix-Marseille Univ., CNRS, CRN2M-UMR7286, Marseille, France; Fondation FondaMental, Fondation de Recherche et de Soins en Santé Mentale, Créteil, France. Electronic address: el-cherif.ibrahim@univ-amu.fr.
El Chérif
EC
Ibrahim
D000328:Adult; D001689:Biological Psychiatry / Q000379:methods / Q000592:standards*; D016207:Cytokines / Q000097:blood*; D003865:Major Depressive Disorder / Q000097:blood*; D006801:Humans; D007118:Immunoassay / Q000379:methods / Q000592:standards*; D011933:Reagent Kits, Diagnostic / Q000592:standards*
D016207:Cytokines; D011933:Reagent Kits, Diagnostic
Cytokine; Inflammation; Multiplex immunoassay; Psychiatry