IL-11 is a multifunctional cytokine produced by stromal cells such as fibroblasts, epithelial cells and osteoclasts. It is expressed in a wide variety of tissues including thymus, lung, bone, connective tissue and central nervous system. IL-11 plays an important regulatory role in hematopoiesis by stimulating growth of myeloid, erythroid and megakaryocyte progenitor cells. It also regulates bone metabolism, inhibits production of proinflammatory cytokines and protects against gastromucosal injury. Recombinant Human IL-11 is a 19.3 kDa protein consisting of 179 amino acid residues.