The MaxDiscovery™ Human IL-11 ELISA Test Kit is designed for quantitative determination of the concentration of human IL-11 in serum, plasma, and cell culture supernatant. Human interleukin 11 (IL-11), also known as adipogenesis inhibitory factor (AGIF) and oprelvekin, is a highly conserved 19 kDa protein of 178 amino acids after cleavage of the first 21 amino acid signal peptide. IL-11 is thermally stable and contains neither cysteine residues nor N-glycosylation sites. IL-11 is a member of the gp130 family of cytokines. These cytokines drive the assembly of multi-subunit receptor complexes containing at least one gp130. IL-11 exerts biological activity through IL-11 receptor by utilizing the gp130 molecule as the signaling component of its receptor. Many cell and tissue types throughout the body, such as CNS, thymus, lung, bone, connective tissues, uterus, skin, and testis, can produce IL-11 depending on the local environment of the cell or tissue. IL-11 promotes primary and secondary immune responses in vitro and in vivo and modulates antigen-specific antibody reactions. IL-11 has activity in bone metabolism and activity in protection and restoration of the gastrointestinal mucosa. Human endometrial stromal cells produce biologically active IL-11, which promotes progesterone-induced decidualization. Therefore, the IL-11 has both paracrine and autocrine actions on human endometrial stromal cells and plays an important role in preparing the human endometrium for implantation. Reports indicate that abnormal IL-11 levels in serum or plasma is related to immune thrombocytopenia, rheumatoid arthritis, and urogenital infection. Immunoreactive IL-11 has also been linked to aseptic loosening of total hip replacement implants. The production of IL-11 is elevated in lesional skin organ cultures of patients with active plaque-type psoriasis as compared with non-lesional and normal skin.