IL6 and Behcet disease: As for neuroinflammation, in general, and cytokine levels, in particular, in bipolar disorder (BD), a meta-analysis of 30 studies [70] found significantly elevated plasma concentrations of IL-4, IL-6, IL-10, soluble IL-2 receptor (sIL-2R), sIL-6R, TNF-α, sTNFR1, and IL-1 receptor antagonist; IL-1β and IL-6 tended to show higher values in patients.