IL2/Interleukin-2 belongs to the IL-1 family. It is a cytokine structurally related to interleukin 1. IL2/Interleukin-2 can be detected in skin, trachea, and other tissues. It is produced by activated keratinocytes and monocytes and transmits an intracellular signal through two distinct cell-surface receptor complexes on keratinocytes and other epithelial cells.It has been shown that interleukin-2 transduce its signal through signal transducer and activator of transcription 3 (STAT3) in keratinocytes. It may be involved in epidermal function and psoriasis. It also regulates proliferation and differentiation of keratinocytes during inflammation, particularly inflammation associated with the skin. In addition, IL2/Interleukin-2 also causes cell expansion of multipotential hematopoietic progenitor cells. A specific receptor for this cytokine is found to be expressed in skin and upregulated dramatically in psoriatic skin, suggesting a role for this protein in epidermal function and psoriasis.