During infection, there is an increase in the production and release of inflammatory mediators and proinflammatory cytokines, e.g., interleukin 2 (IL-2), interleukin 6 (IL-6), granulocyte colony-stimulating factor (G-CSF), and tumor necrosis factor α (TNF-α); the concentration of C-reactive protein increases; and the concentration of procalcitonin in infected patients increases 4-fold. The gene discussed is IL2; the disease is infection.