IL-11isamultifunctionalcytokineproducedbystromalcellssuchasfibroblasts,epithelialcellsandosteoclasts.Itisexpressedinawidevarietyoftissuesincludingthymus,lung,bone,connectivetissueandcentralnervoussystem.IL-11playsanimportantregulatoryroleinhematopoiesisbystimulatinggrowthofmyeloid,erythroidandmegakaryocyteprogenitorcells.Italsoregulatesbonemetabolism,inhibitsproductionofproinflammatorycytokinesandprotectsagainstgastromucosalinjury.RecombinantHumanIL-11isa19.1kDaproteinconsistingof179aminoacidresidues.