IFNG and thromboangiitis obliterans: Moreover, cytokines of cellular immunity, including interferon-gamma (IFN-γ) and interleukin 12 (IL-12), cytokines of humoral immunity including interleukin 4 (IL-4), interleukin 5 (IL-5), and interleukin 13 (IL-13), have been reported in TAO patients compared to smoker controls [83].