Description
CD23 (cluster of differentiation 23), also known as Fc epsilon RII or FcεRII, is a type 2 transmembrane C-type lectin and a member of the Ig family that is expressed on most mature B cells. CD23 is a surface marker of activated B cells as well as a low-affinity Fc receptor for IgE.1 CD23 has pleiotropic roles in the control of lymphocyte behaviour, suggesting that CD23 may interact with another ligand in addition to IgE.2 CD23 is important in the differentiation of chronic lymphocytic leukemia (CLL) from other lymphoid leukemias.3