Faster speed of onset of the depressive episode is associated with lower cytokine serum levels (IL-2, -4, -6, -10, TNF-α and IFN-γ) in patients with major depression

•Cytokines might play a key role in the pathophysiology of depression.•Serum level of cytokines were measured in 92 patients with MDD.•Faster onset of the depressive episode was associated with lower serum levels for IL-2, -4, -6, -10, TNF-α and IFN-γ.•Depressive episodes with a faster onset might represent a biological subtype of depression.