IL6 and major depressive disorder: Accordingly, we investigated the association between biomarkers of maternal immune activity in serum drawn at the end of the second and beginning of the third trimesters and the risk of MDD in adult offspring using data from the New England Family Study (NEFS).17, 18 We measured concentrations of three pro-inflammatory cytokines—interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF-α)—and one anti-inflammatory cytokine, IL-10, in maternal serum.