CD11c (integrin ?X, ITGAX) is a transmembrane glycoprotein that forms an ?/? heterodimer with CD18 (integrin ?2), which interacts with a variety of extracellular matrix molecules and cell surface proteins. CD11c is primarily used as a dendritic cell marker. Dendritic cells can be classified into two major types: CD11c+ conventional dendritic cells that specialize in antigen presentation, and CD11c- plasmacytoid dendritic cells that specialize in type I interferon production. CD11c expression has also been observed on activated NK cells, subsets of B cells, monocytes, granulocytes, and some B cell malignancies including hairy cell leukemia.