PROS1 and major depressive disorder: Interestingly, there is evidence of impaired T helper function in depression.109 IL-6, IL-1β, TNF-α and CRP are also among inflammatory markers shown consistently to be elevated in patients with depression.97,110,111 Nuclear factor (NF)-κB is another marker that has been implicated in both AS and depression,112,113 as are inflammasomes.114, –116 Production of these inflammatory proteins may be activated by psychological stress through the hypothalamic pituitary adrenal (HPA) axis.