Severe symptoms predict salivary interleukin-6, interleukin-1β, and tumor necrosis factor-α levels in children and youth with obsessive-compulsive disorder

Abstract

ObjectiveChildhood-onset obsessive-compulsive disorder (OCD) has been associated with immune dysregulation, including aberrant plasma inflammatory markers and increased rates of infectious and immune-mediated disorders. Saliva may provide a minimally-invasive tool for assessing oral mucosal immunity and inflammatory biomarkers in this population. The primary aim of this study was to compare salivary defense proteins and inflammatory mediators in saliva from children and youth with OCD and healthy controls, and evaluate their associations with measures of oral health and OCD phenotype. MethodsIn this cross-sectional observational study, saliva was collected from 41 children and youth with childhood-onset OCD and 46 healthy controls. Levels of lysozyme, α-amylase, secretory immunoglobulin A (sIgA), C-reactive protein (CRP), interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α) were quantified by enzyme-linked immunosorbent assays or electrochemiluminescent-based immunoassays. ResultsAll analytes were detectable in saliva. When adjusting for salivary flow rate and total protein, multiple linear regression models including demographic variables, oral health measures, and OCD status explained a significant proportion of the variance in IL-6, IL-1β, and sIgA but not TNF-α, CRP, α-amylase, or lysozyme levels. Diagnosis of OCD was associated with significantly higher IL-6 (β = 0.403, p = 0.026), while severity of OCD was a significant predictor of increased cytokines (IL-6, β = 0.325, p = 0.009; IL-1β, β = 0.284, p = 0.020; TNF-α, β = 0.269, p = 0.036), but not other analytes. ConclusionThese data point to the feasibility of analyzing soluble immune mediators in the saliva in childhood-onset OCD, suggesting that pro-inflammatory cytokines are associated with OCD diagnosis and symptom severity. Further work is required to elucidate the factors contributing to this association and implications for clinical practice.