Our meta-analysis showed systemic inflammation in psoriasis patients compared with healthy individuals, with 13 of 23 analysed pro-inflammatory soluble factors (TNF-α, IFN-γ, sE-selectin, IL-2, IL-6, IL-8, IL-18, IL-22, chemerin, lipocalin-2, resistin, fibrinogen and C3) being increased and one anti-inflammatory marker (adiponectin) being decreased in psoriasis patients. The gene discussed is IFNG; the disease is psoriasis.