Similar results were found in two studies of sertraline plus celecoxib or placebo in MD (n = 40 and n = 30) (18, 19), where Hamilton Depression Rating Scale scores decreased significantly more in the celecoxib group; in one of the studies (18), serum IL-6, a pleiotropic immune-activating cytokine that primarily promotes innate and B- and T-cellular immunity and plays an important role in inflammation, correlated with the decrease in the depression rating score. This evidence concerns the gene IL6 and major depressive disorder.