Serum concentrations of CRP, IL-6, TNF-α and cortisol in major depressive disorder with melancholic or atypical features

The aim of the present study was to explore possible differences between serum C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and cortisol concentration in patients with major depressive disorder (MDD) with melancholic features, and MDD with atypical features. As secondary aim, we investigated possible associations with clinical features such as suicidal ideation, number of episodes, duration of depression and symptomatology severity. We included 55 MDD patients (32 with melancholic features and 23 with atypical features) and 18 healthy controls. When compared to healthy controls, MDD with melancholic or atypical features showed higher CRP and IL-6, but not TNF-α. Cortisol concentration was higher in MDD with melancholic type, in comparison to the atypical type of MDD or controls. A positive correlation was found between the severity of depressive symptoms, concentrations of IL-6 and cortisol in the MDD group with melancholic features, while a negative correlation was observed between IL-6 and CRP in the MDD group with atypical feature. Also, in the MDD group with atypical features, there was a correlation between the severity of anxiety symptoms based on the Hamilton Rating Scale for Anxiety (HARS), concentration of CRP, and the duration of symptoms. In conclusion, we observed several differences in serum CRP, IL-6, and cortisol concentrations in MDD patients considering clinical features as well.