TNF and major depressive disorder: To date, researchers in the few preliminary studies on pain physiology in axSpA have reported normal [43] (also in response to anti-TNF treatment [44]) to even elevated [45] pain pressure thresholds compared with control subjects and a moderate relationship with depression [46], non-superiority of algometry over manual palpation in the evaluation of entheseal pain [47] and pain-related brain morphology changes in response to anti-TNF treatment [11, 44], but all studies lacked proper gender comparisons.