Description
Interleukin 11 (IL-11), also known as AGIF, is a member of the IL-6-type cytokine family and key regulator of multiple events in hemtaopoiesis. It stimulates growth of myeloid, erythroid and megakaryocyte progenitor cells.1 IL-11 also regulates bone metabolism, inhibits production of proinflammatory cytokines and protects against gastromucosal injury.2 Compared to other interleukins, IL-11 is relatively under-characterized. It is secreted by bone marrow stromal cells (fibroblasts) and is produced also by a number of mesenchymal cells. IL-11 is expressed in a wide variety of tissues including thymus, lung, bone, connective tissue and central nervous system. Signal transduction is initiated upon binding of IL-11 to IL-11Rα and gp130, facilitating the homodimerization of gp130 molecules.2 This permits gp130-associated JAK kinases to become activated and phosphorylate intracellular tyrosine residues on gp130. IL-11 shares many functions of IL-6 and LIF, including potentiation of megakaryocyte activity, enhancement of human myeloma cell proliferation and enhancement of hepatic acute phase protein production.3 It has been found to stimulate the T cell dependent development of specific immunoglobulin-secreting B cells.4 Clinically, IL-11 is used to prevent severe thrombocytopenia and the reduction of the need for platelet transfusion following myelosuppressive chemotherapy. Another possible application may be as a therapeutic for osteoporosis