IL-37/IL-1F7: ProductsHuman interleukin 37, also named IL-1F7, FIL1 zeta, IL-1H4, and IL-1rp1, belongs to the IL-1 cytokine family. With the exception of IL-18 that maps to human chromosome 11, all IL-1 family members map to the same cluster on human chromosome 2. Mouse IL-37 has not been reported, but human IL-37 is active on mouse cells. Five isoforms (IL-37a through e) are generated through alternative exon usage and have distinct expression profiles. Like IL-1 alpha, IL-1 beta and IL-18, all of the IL-37 variants lack a typical signal peptide.