Childhood Adversity and Current Stress are related to Pro- and Anti-inflammatory Cytokines in Major Depression

Stress during early childhood, for example as a result of maltreatment, can predict inflammation in adulthood. The association of depression with inflammation and current and long-term stress resulting from childhood maltreatment and threatening experiences in the past year has not yet been studied. Therefore, we assessed these variables in a group of patients with major depressive disorder (MDD) and measured levels of the pro-inflammatory cytokine IL-6 and the anti-inflammatory cytokine IL-10. High levels of IL-6 are associated with depression and of IL-10 with stress.

We included 44 patients who fulfilled DSM-IV diagnostic criteria for MDD and 44 age- and gender-matched healthy controls. We used Cohen's Perceived Stress Scale (PSS), the list of life-threatening experiences questionnaire (LTE-Q) and the childhood trauma questionnaire (CTQ) to assess the level of stress and analyzed IL-6 and IL-10 cytokines in venous blood plasma.

The patient group showed significantly higher scores on the maltreatment scale LTE-Q (2.7 vs. 1.1; P = 0.001, and the stress scales CTQ (emotional abuse; P = 0.048 and physical neglect; P = 0.002) and PSS (35.2 vs 15.5; P < 0.001) as well as significantly higher levels of IL-6 (1.5pg/ml vs. 0.9pg/ml; P = 0.012). They also had significantly higher levels of IL-10 (1.1pg/ml vs. 0.7pg/ml; P < 0.001). Higher actual stress levels were associated with childhood maltreatment and higher IL-6 (tau = 0.004) and IL-10 (tau = 0.027) levels.

The results need to be replicated in a larger sample, and the study did not evaluate causal relationships. Although the assessment of childhood trauma was retrospective, the CTQ is a well-established assessment instrument.

The patients with MDD in this study showed an immune activation in response to stress. This study highlights the association of childhood trauma and current and long-term stress with an increased immune activation in MDD.