CD15 (3-fucosyl-N-acetyl-lactosamine) is a cluster of differentiation antigen - an immunologically significant molecule. CD15 is a carbohydrate adhesion molecule that can be expressed on glycoproteins, glycolipids and proteoglycans.
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Function
CD15 mediates phagocytosis and chemotaxis, found on neutrophils; expressed in patients with Hodgkin disease, some B-cell chronic lymphocytic leukemias, acute lymphoblastic leukemias, and most acute nonlymphocytic leukemias. It is also called Lewis x and SSEA-1 (stage-specific embryonic antigen 1) and represents a marker for murine pluripotent stem cells, in which it plays an important role in adhesion and migration of the cells in the preimplantation embryo. It is synthezised by FUT4 (fucosyltransferase 4) and FUT9.
Diagnostic relevance
CD15 is present on almost all Reed–Sternberg cells, including their rare mononuclear variants, and, as such, can be used in immunohistochemistry to identify the presence of such cells in biopsies. The presence of these cells is diagnostic of Hodgkin's lymphoma. Reed-Sternberg cells display a characteristic pattern of CD15 positivity, with membranous staining combined with staining of the Golgi apparatus. Immunohistochemical panels for the diagnosis of Hodgkins disease typically employ CD15 along with CD30 and CD45; the latter does not stain Reed-Sternberg cells, but does stain almost all other lymphoid cells. CD15 is also present in about 50% of adenocarcinoma cells and can be used to distinguish such conditions from mesothelioma, which is typically negative.