CCL4 and treatment resistant depression: These alterations were observed in TRD patients with pain, including GM-CSF, fractalkine, IFN-γ, IL-10, MIP-3α, IL-12P70, IL-17α, IL-1β, IL-2, IL-4, IL-23, IL-5, IL-6, IL-7, MIP-1β, and TNF-α, while only TNF-α levels decreased after ketamine infusions in patients without pain.