CD116 (GM-CSF R alpha) is the low affinity receptor for granulocyte-macrophage colony-stimulating factor (GM-CSF) . CD116 heterodimerizes with CD131, the common beta chain subunit shared with IL-3 and IL5- receptors, to form the high affinity GM-CSF receptor. CD116 is expressed by myeloid cells including macrophages, neutrophils, eosinophils, dendritic cells, and their precursors, as well as on endothelial cells. It is being used as a specific marker of myeloid leukemias.