IL10 and major depressive disorder: Interestingly, higher levels of circulating T-cell cytokines in serum were found to be predictive for the development of MDD in response to cytokine administration: higher levels of circulating sIL-2r, and of the anti-inflammatory cytokine IL-10 [50] before the start of IFN-α treatment were associated with increased risk for development of MDD in response to the treatment.