In many cases the levels of cytokines fell below the analytical sensitivity of the luminex assays, a finding that has also been reported in the literature when individuals with low levels of inflammation are included among the comparison groups (for example, see: [24–26]) The lack of difference between MDD and control groups was not due to poor sensitivity of the assays as high-sensitivity analysis of IL-1β levels in serum using a digital ELISA also did not reveal any difference between MDD patients and controls. This evidence concerns the gene IL1B and major depressive disorder.