TNF and psoriasis: Cellular receptorfor IL-2 is expressed on activated T cells and can be shed fromthe cells and measured as a soluble protein (sIL-2R) [16].Several cytokines have been increased in psoriasis, either atlocal or systemic level or both including TNF-α, IL-2,IL-6, IL-8, interferon gamma (IFN-γ), and transforminggrowth factor alpha (TGF-α) which are regarded as hallmarkcytokines in psoriatic cytokine network [4,7, 17–19].