Interferon lambda 3 (IFNL3)

Interferon lambda 3 (IFNL3) is a secreted cytokine of the type III interferon family and is closely related to interleukins IL28A (now IFNL2) and IL29 (now IFNL1)[1][3]. IFNL3 plays a key role in antiviral defense, especially in epithelial tissues, by activating the JAK-STAT pathway following engagement with its heterodimeric receptor composed of IFNLR1 and IL10RB[1][3]. It has a restricted receptor distribution, mainly affecting epithelial cells, and is upregulated during viral infection. IFNL3 is particularly notable for its genetic polymorphisms that strongly predict clearance of hepatitis C virus, and these variants serve both as pharmacogenomic biomarkers for response to therapy and for spontaneous infection resolution[1][2]. IFNL3 is not only involved in antiviral responses but also has antitumor and immunomodulatory activities, and is associated with a few other disease states, including cryoglobulinemia[3]. Patient response to drugs such as pegylated interferon-α and ribavirin can be strongly modulated by IFNL3 genotype, and several SNPs (notably rs12979860 and rs4803217) are commonly used for genotype-based patient selection[1][2][3].

Other names

IL28BInterleukin-28BZCYTO22Cytokine Zcyto22IFN-lambda-3IL-28BIFNL3IL28CInterleukin-28CIL-28CIFN-lambda-4

As a cytokine: binds the heterodimeric class II cytokine receptor (IL10RB and IFNLR1), activates JAK/STAT pathway, induces expression of interferon-stimulated genes[1][3] Polymorphisms in IFNL3 and upstream regions (linked to IFNL4) may influence antiviral efficacy by altering ligand expression/structure[1][2]