IL18BP Gene

IL18BP (Interleukin 18 Binding Protein) is a protein coding gene located on chromosome 11q13.4. Alternatively spliced transcript variants encoding different isoforms have been described for this gene.

The protein encoded by this gene functions as an inhibitor of the proinflammatory cytokine IL18, binding IL18, preventing IL18 from binding to its receptor, and thus inhibiting IL18-induced IFN-gamma production, resulting in a reduced T helper type 1 immune response.

Recently, secreted IL-18-binding proteins (IL-18BPs) have been described in humans and mice that block IL-18 activity but do not share sequence similarity with IL-18 membrane receptors.

Several poxvirus genes encode proteins with sequence similarity to IL-18BPs. Smith VPet al. (2000) demonstrated that vaccinia, ectromelia, and cowpox viruses secrete a soluble IL-18BP (vIL-18BP) from infected cells that modulates the host antiviral response. Furthermore, Molluscum contagiosum virus, a molluscipoxvirus , has also been shown to encode a related, larger vIL-18BP (gene MC54L). This protein may contribute to the lack of inflammatory response characteristic of Molluscum contagiosum virus lesions. The expression of vIL-18BP by several poxvirus genera that cause local or general viral dissemination or persistent or acute infections in the host underscores the importance of IL-18 in response to viral infections.

Elevated levels of interleukin 18 binding protein protein are detected in the intestinal tissue of patients with Crohn's disease.

Diseases associated with IL18BP include.

Fulminant hepatitis A (Belkaya S et al. 2019).

1. Aringer M (2020) Inflammatory markers in systemic lupus erythematosus. J Autoimmun 110:102374.
2. Belkaya S et al (2019) Inherited IL-18BP deficiency in human fulminant viral hepatitis. J Exp Med 216: 1777-1790.
3. Smith VPet al (2000) Ectromelia, vaccinia and cowpox viruses encode secreted interleukin-18-binding proteins. J Gen Virol 81:1223-1230.