Interleukin-2 (IL-2), tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) in the cerebrospinal fluid (CSF) have been shown to correlate with mood disorders (Rossi et al., 2017), while serum interleukin-6 (IL-6) and increases in interferon-gamma (IFN-γ) and TNF-α (using whole-blood-cytokine-stimulation) correlate with fatigue (Patejdl et al., 2016). Here, IL6 is linked to mood disorder.