Altered levels of salivary cytokines in patients with major depressive disorder.

OBJECTIVE: Accumulating evidence indicate the involvement of inflammation in the pathogenesis of mental disorders. Numerous studies have shown that proinflammatory cytokines were elevated in peripheral blood of patients with major depressive disorder (MDD). A few recent research have explored the possibility of using saliva as a biomarker for depressive symptoms. The objective of this study is to examine the salivary cytokine levels in patients with MDD and healthy controls. METHODS: Participants were 19 patients with MDD and 50 healthy controls. The levels of 27 cytokines in saliva were measured by multiplex bead array assay. RESULTS: The Mann-Whitney U-test showed that the levels of IL-1ß, IL-6, IL-9, IL-12p70, IL-13, Chemokine CCL11 (Eotaxin), MIP-1α, RANTES, and VEGF were significantly higher in patients than controls. The quantile regression analysis showed that IL-1ß, IL-12p70, CCL11, and VEGF remained significant after controlling for possible confounding factors. CONCLUSION: The findings were in line with previous studies that showed elevated peripheral levels of cytokines in patients with MDD. Our present data provide preliminary support for altered salivary cytokine levels in patients with MDD and suggest that salivary cytokines may serve as a novel target for elucidating the pathophysiology underlying MDD.