Interleukin-6 and Interleukin-10 in mood disorders: A population-based study

Objective: The aim of this study was to assess if cytokines levels (IL-6 and IL-10) are related to major depressive disorder (MDD) and bipolar disorder (BD), in a population-based study. Methods: This was a cross-sectional study population-based, involving 1037 people aged 18-35. MDD, BD, anxiety and suicide risk were assessed using the Mini International Neuropsychiatric Interview. Serum IL-6 and IL-10 were measured by ELISA using a commercial kit. Results: The total sample comprised 1034 young adults, being 14.4% with MDD and 13.7% with BD. MDD and BD groups showed significantly higher serum IL-6 levels (p <= 0.001) and IL-10 levels (p <= 0.001) when compared to healthy control group. No correlation was found between serum IL-6 and IL-10 levels in health control group (p = 0.830; r = - 0.008), non-suicide risk (p = 0.337; r = 0.032) and non-anxiety disorder (p = 0.375; r = 0.031). Covariance analysis showed that mood disorders alone, increase both interleukin levels (IL-6, p = 0.019; and IL-10, p = 0.026), whilst the interaction of mood disorders and suicide risk or anxiety disorders did not. Conclusion: Our results suggest that inflammatory dysregulation may be involved in the physiopathology of mood disorders and serum IL-6 and IL-10 levels are putative biomarkers for these disorders.