[7] Leptin has structural similarities with the cytokines of the long-chain helical family, and displays proinflammatory properties that are most evident in inflammation and in autoimmunity. [7]–[8] The levels of this adipocytokine are increased in infection and in inflammation, or after exposure to inflammatory stimuli such as LPS, TNF-α, and IL-1. [7] Circulating leptin is also elevated in most SLE patients, and appears to contribute to proinflammatory events associated with the disease [9]–[10]. The gene discussed is LEP; the disease is infection.