Best practice recommendations for the measurement and interpretation of salivary proinflammatory cytokines in biobehavioral research

• Published in: Brain, behavior, and immunity behavior, and immunity, 2021-01, Vol.91, p.105-116
• Main Authors: Riis, Jenna L., Ahmadi, Hedyeh, Hamilton, Katrina R., Hand, Tracey, Granger, Douglas A.
• Format: Article
• Language: English
• Subjects: Adult; Best practices; Cold chain; Cytokine; Cytokines; Humans; Inflammation; Interleukin-1beta; Saliva; Tumor Necrosis Factor-alpha
• ISSN: 0889-1591; 1090-2139
• DOI: 10.1016/j.bbi.2020.09.009

•Salivary IL-1β, IL-6, IL-8, and TNF-α were measured in healthy adults.•Cytokine changes were assessed across a series of saliva collection and handling procedures.•IL-1β, IL-6, and IL-8 were less sensitive to filtration and cold chain methods than TNF-α.•Cytokines were positively correlated with other indices related to oral health.•Best practices for salivary cytokine measurement and interpretation are provided. Despite the integration of salivary inflammatory cytokines into research across the biobehavioral, psychological, clinical, and health-related disciplines, there is little guidance regarding the biospecimen collection, handling, and storage practices that maximize the quality and validity of salivary cytokine data. Furthermore, associations between salivary cytokines and measures related to oral health are rarely assessed and accounted for in studies outside the oral health fields. To address these gaps, we examine the sensitivity of salivary interleukin-1β (IL-1β), IL-6, IL-8, and tumor necrosis factor-α (TNF-α) to changes in saliva sample collection technique and cold chain management procedures. Using subsets of saliva samples collected from 150 healthy adults, we measure salivary IL-1β, IL-6, IL-8, TNF-α, and other oral health-related indices (i.e., blood contamination [transferrin], and salivary matrixmallotprotienase-8). In addition to examining changes in cytokine levels associated with sample collection technique and cold chain management procedures, we assess relations between cytokine concentrations and levels of other oral health-related measures. We found that IL-1β, IL-6, and IL-8 were more robust to changes in sample collection and cold chain management procedures than TNF-α, and all cytokines were positively associated with other oral health-related measures. Based on our findings, we recommend analyte-specific guidance for measuring and interpreting salivary cytokine concentrations.