CD23, also known as Fc epsilon RII, or FcεRII, is the "low-affinity" receptor for IgE. Unlike many of the antibody receptors, CD23 is a C-type lectin. It is found on mature B cells, activated macrophages, eosinophils, follicular dendritic cells, and platelets. CD23 is known to have a role of transportation in antibody feedback regulation. Antigens which enter the blood stream can be captured by antigen specific IgE antibodies. The IgE immune complexes that are formed bind to CD23 molecules on B cells, and are transported to the B cell follicles of the spleen. In flow cytometry, CD23 is helpful in the differentiation of chronic lymphocytic leukemia （CD23-positive） from mantle cell lymphoma （CD23-negative）. CD23 can also be demonstrated in germinal centre follicular dendritic cells using immunohistochemistry but is minimally expressed by benign germinal center B cells.