TNF and Behcet disease: Several individual research studies and previous works reported that blood concentrations of TNF-α, soluble TNF receptor 1 (sTNF-R1), and IL-6 are increased in BD patients compared with controls [206–213], as well as CRP [214–216], interleukin-1β (IL-1β) [206], soluble IL-2 receptor (sIL-2R) (related to T-lymphocyte activation) [212], interleukin-8 (IL-8) [213,217] and interleukin-18 (IL-18) [211], among others.