Pro-inflammatory cytokines IL-1α, IL-6 and TNF-α in major depressive
disorder: Sex-specific associations with psychological symptoms
Abstract
The pro-inflammatory cytokines IL-1α, IL-6 and TNF-α are associated with
major depressive disorder, psychological distress, cardiovascular
health, and obesity. However, there is limited research that has
examined multiple associations between these variables, among
individuals with major depressive disorder in comparison to a control
cohort, including sex differences. In this study, data was analysed from
60 individuals with major depressive disorder and 60 controls, including
plasma IL-1α, IL-6 and TNF-α, adiposity measures (body mass index; waist
circumference), cardiovascular health indices (blood pressure; heart
rate) and psychological symptoms (depressive severity; anxiety;
hostility; stress). The cytokines were compared by group and sex, and
correlated with measures of adiposity, cardiovascular health indices and
psychological health. Plasma IL-1α and IL-6 were higher in major
depressive disorder group versus control, but with a sex interaction for
IL-6, with this group difference only among females. TNF-α did not
differ between groups. IL-1α and IL-6 correlated with depressive
severity, anxiety, hostility, and stress, while TNF-α correlated only
with anxiety and hostility. Psychopathology was associated with IL-1α in
males only, and with IL-6 and TNF-α in females only. None of the
cytokines correlated with body mass index, waist circumference, blood
pressure or heart rate. The result of group by sex interaction for IL-6,
and sex specific associations between pro-inflammatory cytokines and
psychometrics could be aetiologically important in depression
interventions and treatments for females versus males, warranting
further investigation.