The protein encoded by this gene is a member of the interleukin 1 cytokine family. The activity of this cytokine is mediated by interleukin 1 receptor-like 2 (IL1RL2/IL1R-rp2), and is specifically inhibited by interleukin 1 family, member 5 (IL1F5/IL-1 delta). Interferon-gamma, tumor necrosis factor-alpha and interleukin 1, beta (IL1B) are reported to stimulate the expression of this cytokine in keratinocytes. The expression of this cytokine in keratinocytes can also be induced by a contact hypersensitivity reaction or herpes simplex virus infection. This gene and eight other interleukin 1 family genes form a cytokine gene cluster on chromosome 2. [provided by RefSeq]