CD1

one of a family of a transmembrane proteins non-covalently linked with b2 microglobulin, expressed on cortical thymocytes but absent on mature T cells; thought to have a role in thymic T cell development; expressed on blast cells of some T-lineage ALL, a subset of normal B cells (CD1c only), the cells of some B cell neoplasms and Langerhans cells, the cells of Langerhans cell histiocytosis; the CD1 family includes CD1a, CD1b, CD1c, CD1d.

CD2

receptor for sheep red blood cells (previous designations LFA-2 and leucocyte function associated antigen 1); binds to CD58 on antigen presenting cells and is costimulatory for B cells; expressed on cortical and late thymocytes, mature T cells, most NK cells, blast cells of many cases of T-lineage ALL and cells of many leukaemias/lymphomas of mature T cells; may be expressed on the leukaemic cells in M3 and M4Eo AML.

CD3

part of the T-cell receptor complex; expressed on late thymocytes and mature T cells and essential for antigen recognition and binding by T cells; expressed on blast cells of many cases of T-lineage ALL and neoplastic cells of many leukaemias/lymphomas of mature T cells; occurs in three forms CD3g, CD3d, CD3e.

CD4

coreceptor for MHC class-II restricted antigen-induced T-cell activation; coexpressed with CD8 on cortical thymocytes, expressed on a major subset of late thymocytes and mature T cells without coexpression of CD8, expressed on blast cells of many cases of T-lineage ALL and on cells of many leukaemia/lymphomas of mature T cells, expressed on immature myeloid cells, eosinophils, monocytes and macrophages, sometimes expressed on blast cells in AML, particularly in M4 and M5 AML; receptor for HIV; the number of CD4-positive lymphocytes is greatly reduced in advanced HIV infection and overt AIDS.

CD5

signal transducing molecule that modulates signalling through the T-cell and B-cell receptor complexes: ligand of the B cell antigen CD72; expressed on cortical and late thymocytes and some early thymocytes, on blast cells of many T-lineage ALL, on mature T cells and cells of many T-lineage leukaemias/lymphomas, on a subset of normal B cells, on cells of chronic lymphocytic leukaemia and mantle cell lymphoma; CD5-positive lymphocytes are expanded in various autoimmune diseases, e.g. rheumatoid arthritis.

CD6

an adhesion molecule mediating binding of developing thymocytes to thymic epithelium; expressed on thymocytes, the majority of peripheral blood T cells, a subset of normal B cells (involved in the production of autoreactive antibodies) and the cells of chronic lymphocytic leukaemia; CD6-positive T cells are thought to be involved in graft-versus-host disease.

CD7

a member of the immunoglobulin superfamily of cell surface glycoproteins; expressed on thymocytes, the majority of mature T cells, NK cells, blast cells of T-lineage ALL, leukaemic cells of T-lineage prolymphocytic leukaemia and, less often, the cells of other T-lineage leukaemias/lymphomas, a subset of immature myeloid cells and blast cells of a significant minority (c. 15%) of cases of AML.

CD8

a T-cell glycoprotein which is the heterodimeric product of an a and a b chain encoded by closely linked genes on chromosome 2; the a gene also gives rise to an alternatively spliced transcript that encodes a small secreted polypeptide which is thought to have an immunoregulatory role; expressed on cortical thymocytes together with CD4; expressed on a subset of late thymocytes and mature T cells without coexpression of CD4, these being cytotoxic T cells that recognize antigen in context with class I major histocompatibility antigens; expressed on cells of most cases of large granular lymphocyte leukaemia and on cells of a smaller proportion of cases of other T-lineage leukaemias/lymphomas.

CD9

expressed on platelets, early B cells, activated B and T cells, eosinophils, basophils, mast cells, endothelial cells, cells of the brain and peripheral nerves, vascular and cardiac smooth muscle, epithelial cells and the leukaemic cells of hypergranular promyelocytic leukaemia.

CD10

neutral endopeptidase, a cell surface metalloproteinase, the common ALL antigen; expressed on a subset of normal B-cell progenitors, expressed on blast cells of the majority of cases of B-lineage ALL, more weakly on the blast cells of some cases of T-lineage ALL, on the cells of many cases of follicle centre cell lymphoma and cells of a lower proportion of cases of other B-lineage non-Hodgkin's lymphoma, on some myeloma cells, on neutrophils, on bone marrow stromal cells, on renal, bronchial and intestinal epithelium and on breast myoepithelium.

CD11a

LFA1a (a chain of leucocyte function associated antigen 1), expressed as a heterodimer with CD18; CD11a/CD18 is an adhesion molecule of the b2 integrin family that is expressed on all leucocytes and is important in many inflammatory and immune responses; CD11a/CD18 is necessary for lymphocyte recirculation through lymph nodes; CD11a/CD18 binds to ICAM-1 (CD54), ICAM-2 (CD102) and ICAM-3 (CD50); expression is absent in leucocyte adhesion deficiency, a congenital disorder characterized by neutrophilia and recurrent bacterial infections.

CD11b

expressed as a heterodimer with CD18; CD11b/CD18 is a b2 integrin which is a C3bi receptor (CR3 complement receptor), expressed on mature monocytes, macrophages and NK cells, expressed more weakly on mature granulocytes, expressed on a subset of B cells and a subset of T cells, expressed on cells of many cases of AML particularly those with monocytic differentiation, expressed on hairy cells; CD11b/CD18 promotes binding and phagocytosis of complement-coated particles and has a role in interactions of neutrophils and monocytes with stimulated endothelium; expression is absent in leucocyte adhesion deficiency, a congenital disorder characterized by neutrophilia and recurrent bacterial infections.

CD11c

expressed as a heterodimer with CD18; CD11c/CD18 is a b2 integrin expressed on monocytes, macrophages, natural killer cells and neutrophils; it is a ligand for iC3b; expressed on hairy cells and cells of some cases of hairy cell variant leukaemia and splenic lymphoma with villous lymphocytes but not usually on cells of other lymphoproliferative disorders; expression is absent in leucocyte adhesion deficiency, a congenital disorder characterized by neutrophilia and recurrent bacterial infections.

CDw12

the gene encoding this antigenic determinant has not yet been cloned; expressed on monocytes, neutrophils and natural killer cells.

CD13

expressed as a homodimer, a membrane-bound zinc-binding metalloprotease that degrades regulatory peptides; expressed on early committed progenitors of granulocytes and monocytes and on maturing cells of these lineages, expressed on the blast cells of the majority of cases of AML, expressed on endothelial cells, bone marrow stromal cells, osteoclasts, bile duct canalicular cells, proximal tubule cells of the kidney and the intestinal brush border (where it is thought to function as a coronavirus receptor).

CD14

receptor for endotoxin (lipopolysaccharide); expressed on monocytes and macrophages and more weakly on granulocytes; when endotoxin is bound to CD14 of neutrophils and monocytes there is release of tumour necrosis factor and upregulation of cellular adhesion molecules; soluble CD14 is required for endotoxin signalling to endothelial and epithelial cells; expressed on the blast cells of many cases of AML, particularly those showing monocytic differentiation.

CD15

a fucose-containing, cell surface glycoprotein that is the ligand of E and P selectins; expressed on maturing cells of monocyte lineage and more weakly on maturing cells of granulocyte lineage, expressed on the blast cells of many cases of AML particularly those with monocytic differentiation, expressed on Reed-Sternberg cells and mononuclear Hodgkin's cells (except in nodular lymphocyte predominant Hodgkin's disease); expressed on cells of a small proportion of NHL; CD15a is the sialylated form.

Rambam-Hasharon syndrome is an autosomal recessive inborn error of fucose metabolism associated with recurrent infections; the immune defect, designated leucocyte adhesion deficiency type II, results from CD15 deficiency; in addition, the patient's red blood cells lack H substance, a fucosylated glycoprotein, which is the precursor molecule of the A, B and O blood groups; consequently patients manifest the Bombay blood type.

CD16

part of the low affinity Fc receptor, FcRIII; expressed on NK cells, neutrophils and macrophages and on the cells of a significant minority of cases of AML, expressed on some cases of large granular lymphocyte leukaemia of NK lineage.

CDw17

an antigenic determinant defined by the lactosyl disaccharide group of the glycosphingolipid lactosyl ceramide; the protein carrying this antigenic determinant is not known; expressed on monocytes, neutrophils, basophils, platelets, a subset of B cells and tonsillar dendritic cells.

CD18

the b chain of the b2 integrins - CD11a/CD18, CD11b/CD18 and CD11c/CD18; a mutation in the CD18 gene is responsible for leucocyte adhesion deficiency, a congenital disorder characterized by neutrophilia and recurrent bacterial infection; CD18 binds unopsonized bacteria and fungi, thus promoting phagocytosis; expressed on all leucocytes.

CD19

a signal transduction molecule, regulating B-cell development, activation and proliferation; part of a large signal transduction complex that also involves CD21 and CD81, expressed on B lymphocytes and their precursors; it is one of the earliest of the B-lineage restricted antigens to be expressed; expressed on the cells of the majority of cases of B-lineage ALL and leukaemia/lymphoma of B-lineage; expressed on follicular dendritic cells.

CD20

expressed on B lymphocytes and their precursors, on blast cells of some cases of B-lineage ALL, on cells of the majority of cases of B-lineage leukaemia/lymphoma and on follicular dendritic cells; monoclonal antibodies to CD20 are used in treatment of B-cell neoplasms.

CD21

part of a large signal transduction complex that also involves CD19 and CD81; a complement receptor, CR2 or C3dR, that binds C3d, C3dg and iC3b; complement may activate B cells through CD21 binding with activated B cells no longer expressing CD21; a receptor for EBV; expressed on a subset of normal B cells including follicular mantle zone and marginal zone lymphocytes; expressed on follicular dendritic cells; expressed on cells of most cases of CLL and on cells of about 50% of cases of B-lineage NHL; CD21 monoclonal antibodies, used in conjunction with CD24 monoclonal antibodies, have been found useful in controlling post-transplant lymphoproliferative disorder.

CD22

an adhesion and signalling glycoprotein which is a negative regulator of antigen signalling in B cells; expressed on B lymphocytes and in the cytoplasm of their precursors; expressed in the cytoplasm of the blast cells of most cases of B-lineage ALL but less frequently on the surface membrane, expressed on the surface membrane of cells of most cases of B-lineage leukaemia/lymphoma with the exception of the cells of chronic lymphocytic leukaemia.

CD23

a low affinity Fce receptor; a negative feedback regulator of IgE synthesis; expressed on activated B cells, eosinophils, monocytes, follicular dendritic cells and platelets; mediates cytokine release by monocytes; expressed on cells of most cases of CLL but in only a minority of cases of PLL and NHL.

CD24

expressed on B lymphocytes and their precursors, on the blast cells of the majority of cases of B-lineage ALL, on the cells of the majority of cases of B-lineage leukaemia/lymphoma, on activated T lymphocytes, on neutrophils, on eosinophils, on blast cells of some cases of AML particularly M4 and M5 AML, expressed on some epithelial cells and carcinoma cells including cells of small cell carcinoma of the lung; CD24 has been reported to be a ligand for P-selectin (CD62), a lectin expressed on platelets and vascular endothelium (see below); CD24/CD62 binding could represent a mechanism for tumour dissemination; CD24 monoclonal antibodies, used in conjunction with CD21 monoclonal antibodies, have been found useful in controlling post-transplant lymphoproliferative disorder.

CD25

the a chain of interleukin 2 receptor (IL2R); high affinity IL2R is a complex of CD25 with CD122 and CD132; recently a first exon deletion mutation in CD25 has been described, leading to a severe immunodeficiency syndrome; expressed on activated B cells and T cells, on monocytes, on hairy cells and on the cells of the great majority of cases of adult T cell leukaemia/lymphoma.

CD26

a membrane bound serine exopeptidase; adenosine deaminase binding protein; a costimulatory molecule for T cell activation; an essential cofactor for the entry of HIV into CD4-positive T cells; expressed on mature thymocytes, activated T cells, B cells, NK cells, macrophages, renal proximal tubule cells, some epithelial cells including small intestinal epithelium and biliary canalicular cells, brain, heart, skeletal muscle and splenic sinus lining cells.

CD27

a membrane of the tumour necrosis factor receptor superfamily which exists as a homodimer; expressed on some T cells, memory B cells and NK cells; the ligand for CD27 is CD70 which belongs to the tumour necrosis family; the cytoplasmic tail of CD27 can bind to a fas-like molecule, Siva, which in turn induces apoptosis.

CD28

a member of the immunoglobulin superfamily of cell surface molecules which allows T cells to proliferate in the presence of phorbol esters; exists as a homodimer, the in vivo function of which is unknown; expressed on mature thymocytes, most T cells and plasma cells.

CD29

platelet GpIIa; the b chain of VLA (very late activation antigen), a b1 integrin, and of platelet glycoprotein IaIIa (CD49b/CD29).

CD30

a member of the nerve growth receptor superfamily expressed on activated B cells and T cells; binds to CD153 on neutrophils, activated T cells, monocytes and macrophages; strongly expressed on Hodgkin's cells and Reed Sternberg cells (except in lymphocyte-predominant Hodgkin's disease), strongly expressed on the lymphoma cells of anaplastic large cell lymphoma and may be weakly expressed on the cells of other types of large cell non-Hodgkin's lymphoma; weakly expressed on late erythroid cells and late cells of granulocyte lineage, expressed on plasma cells and some carcinoma cells (particularly embryonal carcinoma).

CD31

platelet/endothelial cell adhesion molecule (PECAM-1); an adhesion molecule of the immunoglobulin gene superfamily concerned in homophilic and heterophilic cell adhesion; activation of integrins occurs following CD31 cross-linking; expressed on endothelial cells, platelets, haemopoietic progenitors, monocytes, neutrophils, NK cells and a subset of T cells; has a role in the transendothelial migration of neutrophils and monocytes; thought to be a minor histocompatibility antigen, well defined polymorphism of which increases the risk of acute graft-versus-host disease following bone marrow transplantation.

CD32

FcgRII; allelic variants of the Fcg receptor confer differing phagocytic capacities, providing a mechanism for hereditable susceptibility to immune complex disease; certain polymorphisms in FcgRII are associated with an increased incidence of lupus nephritis.

CD33

a sialic acid-dependent adhesion molecule expressed on myeloblasts, promyelocytes, myelocytes and monocytes and on the blast cells of the majority of cases of AML.

CD34

a monomeric cell adhesion molecule expressed on lymphoid and haemopoietic stem cells, and used for selection of haemopoietic stem cells; expressed on the blast cells of most cases of AML and many cases of B-lineage ALL (pro-B and common but not pre-B or mature B); expressed on endothelial cells including high endothelial cells of lymph node veins where it permits binding to endothelium by lymphocytes expressing L-selectin, the lymphocyte homing receptor.

CD35

C3b/C4b complement receptor (CR1); expressed by erythroid cells, neutrophils, eosinophils, monocytes, B cells, 10-15% of T cells and follicular dendritic cells; has a role in splenic clearance of complement-coated erythrocytes; binds to C3b and C4b in immune complexes and promotes their clearance; mediates adhesion to and phagocytosis of complement-coated particles; makes C3b and C4b more susceptible to cleavage.

CD36

platelet glycoprotein IV, fatty acid translocase; expressed on megakaryocytes and platelets and on megakaryoblasts in M7 AML; expressed on erythroblasts, monocytes, macrophages and microvascular endothelium; has a role in cell adhesion and in recognition and removal of apoptotic cells; mediates scavenging of oxidized low density lipoprotein; CD36 deficiency is present in 2 - 3% of Japanese, Thai and African people but in less than 0.3% of Caucasians and can be involved in some cases of refractoriness to transfusion of HLA-matched platelets.

CD37

a molecule of the tetraspan family involved in signal transduction; forms complexes with CD53, CD81, CD82 and MHC class II molecules on the surface of B cells; strongly expressed on mature B cells and weakly on T cells, neutrophils and monocytes so that strong expression can be used a B cell marker.

CD38

NAD+ glycohydrolase, expressed on activated B and T lymphocytes, on haemopoietic precursors, on thymic cells, on pancreatic b cells where it is essential for insulin secretion, on myeloma cells, on cells of some cases of splenic lymphoma with villous lymphocytes and on cells of a minority of cases of B-CLL.

CD39

ATP diphosphohydrolase, expressed on the surface of vascular endothelium and essential for the hydrolysis of extracellular ATP to ADP and AMP in platelet recruitment and adhesion; expressed on activated B cells, some macrophages and some plasma cells.

CD40

a member of the tumour necrosis factor receptor superfamily; interacts with CD40 ligand on T cells (CD40L, CD154, see below) and this drives B cell proliferation; expressed on B cells and precursors and is involved in growth, differentiation and isotype switching of B cells, T cell-dependent B cell responses and rescue of germinal centre B cells from apoptosis; also expressed on CD34-positive haemopoietic progenitors, monocytes, macrophages, follicular dendritic cells, endothelial cells, fibroblasts and some epithelial cells; expressed on Reed-Sternberg cells and Hodgkin's cells in lymphocyte-predominant and classical Hodgkin's disease; has a role in cytokine production by macrophages and dendritic cells.

CD41a

platelet glycoprotein IIb/IIIa complex; expressed on megakaryocytes and platelets and on megakaryoblasts of M7 AML; receptor for von Willebrand's factor and fibrinogen; mutations in the genes for both platelet glycoprotein IIb and IIIa have been shown to be associated with different types of Glanzmann's thrombasthenia.

CD41b

platelet glycoprotein IIb; expressed on megakaryocytes and platelets and on megakaryoblasts of M7 AML.

CD42a

platelet glycoprotein IX; expressed on megakaryocytes and platelets; the CD42a-d complex is the platelet receptor for von Willebrand's factor and thrombin; it mediates adhesion to the subendothelium and amplifies the response to thrombin; mutations of the CD42a gene can cause Bernard-Soulier syndrome; expressed on megakaryoblasts of M7 AML.

CD42b

platelet glycoprotein Iba; expressed on megakaryocytes and platelets; CD42a-d complex is the platelet receptor for von Willebrand's factor and thrombin, the actual binding site being on the CD42b molecule; CD42b forms a heterodimer with CD42c with the heterodimer also being associated with CD42a and CD42d; mutations of the CD42b gene can cause Bernard-Soulier syndrome and platelet-type von Willebrand's disease in which the platelets have increased affinity for von Willebrand's factor; polymorphism of CD42b has been related to arterial thrombosis; expressed on megakaryoblasts of M7 AML.

CD42d

platelet glycoprotein Ibb; forms a heterodimer with CD42b and binds non-covalently with CD42a and CD42d to form the CD42a-d receptor complex; mutation of the CD42c gene can lead to Bernard-Soulier syndrome.

CD42e

platelet glycoprotein V; part of the CD42a-d complex.

CD43

a mucin-like glycoprotein, sialophorin, expressed on T lymphocytes, activated B cells and myeloid cells including haemopoietic progenitors; in some circumstances inhibits adhesion and in other circumstances may promote it; CD54 is a ligand for CD43.

CD44

the CD44 gene encodes a transmembrane protein expressed as a family of multiple isoforms generated by alternative RNA splicing; it is an adhesion molecule expressed on all blood cells except platelets; it has a role in neutrophil attachment to endothelial cells and in lymphocyte homing; it may have a role in the attachment of haemopoietic stem cells to stroma.

CD45

common leucocyte antigen: a tyrosine phosphatase expressed on all haemopoietic cells except mature red cells and their immediate precursors; different isoforms exist formed by differential splicing of exons 4, 5 and 6 to give CD45RA, CD45RB and CD45RC respectively as well as CD45RO (lacking any of exons 4,5 or 6); necessary for receptor-mediated activation of T and B cells; strongly expressed on T- and B-lineage lymphoblasts and lymphocytes and weakly expressed on blast cells of AML; also expressed by mast cells; Hodgkin's cells and Reed-Sternberg cells, however, are CD45 negative.

CD45RO

expressed on T-lineage lymphoblasts and lymphocytes and sometimes on granulocytes, monocytes and B-lineage lymphoid cells.

CD45RA

expressed on haemopoietic progenitors.

CD46

cofactor for proteolytic cleavage of C3b and C4b, expressed on lymphocytes, salivary gland ducts and kidney ducts; receptor for the measles virus.

CD47

thrombospondin receptor, an adhesion molecule also known as integrin associated protein, expressed on many cell types including haemopoietic cells; knockout studies in mice have shown CD47 to be important in neutrophil migration in response to bacterial infection.

CD47

thrombospondin receptor, an adhesion molecule, expressed on many cell types including haemopoietic cells.

CD48

a weak binder of CD2 and therefore acts as an adhesion molecule; expressed on lymphocytes; is bound to glycosyl phosphatidylinositol (GPI) and is therefore reduced in paroxysmal nocturnal haemoglobinuria.

CD49a

a1 integrin chain

CD49b

a2 integrin; integrin a2b1 is platelet glycoprotein Ia/IIa (CD49b/CD29) which mediates platelet adhesion to collagen.

CD49c

a3 integrin chain

CD49d

a4 integrin chain; a4b1 integrin permits adhesion of megakaryocytes to fibronectin.

CD49e

a5 integrin chain; a5b1 integrin strongly promotes adhesion of megakaryocytes to fibronectin and promotes adhesion of thrombin stimulated megakaryocytes to fibrinogen.

CD49f

a6 integrin chain

CD50

ICAM-3 (intercellular adhesion molecule-3), an adhesion molecule expressed on leucocytes; a ligand for the b2 integrin CD11a/CD18; gives costimulatory signals in immune responses.

CD51

av integrin chain, the a chain of the vitronectin receptor, avb3 integrin; the vitronectin receptor is expressed on osteoclasts, endothelial cells and macrophages; av can also pair with b5, b6 and b8.

CD52

expressed on thymocytes, lymphocytes, monocytes and macrophages, bound to glycosyl phosphatidylinositol (GPI) and is therefore reduced in paroxysmal nocturnal haemoglobinuria; antibodies to CD52, e.g. CAMPATH-1, can give long-term depletion of T lymphocytes when used in vivo and can be used for purging T lymphocytes in vitro.

CD53

expressed on leucocytes; has a role in signal transduction; structurally similar to and forms complexes with CD37.

CD54

ICAM-1 (intercellular adhesion molecule-1), an adhesion molecule that is a ligand for b2 integrins, CD11a/CD18 and CD11b/CD18; expressed on activated endothelial cells, activated B lymphocytes and activated T lymphocytes; functions as a rhinovirus receptor.

CD55

decay accelerating factor (DAF), binds C3b, C4b, C3bBb, C4b2a and protects against inappropriate complement activation; widely expressed including expression on erythroid cells; bound to a glycosyl phosphatidylinositol (GPI) anchor and is therefore reduced in paroxysmal nocturnal haemoglobinuria (PNH); CD55 antibodies can be used to identify cells of the PNH clone; receptor for echovirus, coxsackie virus and enterovirus.

The Cromer blood group system consists of antigens carried on the DAF molecule: in the rare Inab phenotype, all Cromer system antigens are lacking; this has been associated with mutations in the DAF gene resulting in a complete absence of DAF; such individuals are not known to have any associated abnormalities.

CD56

N-CAM, neural cell adhesion molecule, a member of the immunoglobulin superfamily; expressed on cells in the cerebellum and cerebral cortex; mediates homophilic adhesion of neural cells; expressed on NK cells, a subset of CD4-positive T cells and a subset of CD8-positive T cells; usually expressed in large granular lymphocyte leukaemia of NK lineage and sometimes in large granular lymphocyte leukaemia of T cell lineage; expressed on activated lymphocytes and the cells of many cases of AML; expressed on cells of many cases of plasma cell leukaemia but not on normal plasma cells; expressed on the cells of small cell carcinoma of the lung and neural-derived tumours.

CD57

expressed on NK cells, subsets of T cells, B cells and monocytes, usually expressed on large granular lymphocyte leukaemia of T cell lineage and sometimes in large granular lymphocyte leukaemia of NK lineage.

CD58

leucocyte function associated antigen 3 (LFA 3), the ligand of CD2, expressed on leucocytes, erythrocytes, endothelial cells, epithelial cells and fibroblasts; mediates adhesion between killer cells and their targets, between antigen presenting cells and T cells and between thymocytes and thymic epithelium; provides costimulatory signals in immune responses.

CD59

associates with the final component of the complement pathway, C9, inhibiting incorporation of C5b-8 to form a membrane attack complex; is bound to glycosyl phosphatidylinositol (GPI) anchor and is reduced in paroxysmal nocturnal haemoglobinuria, a disease which is characterized by abnormal complement sensitivity; CD59 antibodies can be used to identify cells of the PNH clone; a patient doubly heterozygous for different nonsense mutations in the CD59 gene leading to CD59 deficiency has been reported to have haemolytic anaemia and thrombosis causing cerebral infarction, but none of the other features of PNH; widely expressed including expression in erythrocytes, neutrophils, lymphocytes and monocytes; has a signalling role in T cell activation.

CDw60

a glycolipid which provides costimulatory signals for T cells; expressed on a subset of CD8-positive T cells, platelets, thymic epithelium, glomeruli, smooth muscle cells and astrocytes.

CD61

GpIIb, part of the GpIIb/IIIa complex, a b3 integrin, also known as aIIbb3 integrin; expressed on platelets and endothelial cells; GpIIb/IIIa is a receptor for fibrinogen, fibronectin, vitronectin and von Willebrand's factor; mutation in the CD61 gene results in a variant of Glanzmann's thrombasthenia.

CD62E

E selectin, expressed on activated endothelium and mediates rolling of neutrophils, monocytes and lymphocytes at sites of inflammation; polymorphisms in E selectin have been associated with premature atherosclerosis; a ligand for CD162 (cutaneous leucocyte antigen) which is expressed on lymphocytes.

CD62L

L selectin, expressed on B and T lymphocytes, some NK cells, thymocytes, haemopoietic progenitors, monocytes and neutrophils; mediates homing of lymphocytes to high endothelial venules of peripheral lymphoid tissues and rolling of leucocytes (neutrophils, monocytes and lymphocytes) on activated endothelium at sites of inflammation; a ligand of CD34 and CD162; CD62L is expressed on the majority of leukaemic cells and in AML high levels of soluble CD62L in the serum correlate with a worse prognosis.

CD62P

P selectin, expressed in the storage granules of platelets and on activated endothelial cells; mediates adhesion of platelets to endothelium and rolling of leucocytes on activated endothelium; binds to CD162 on lymphocytes and CD24 on neutrophils and B lymphocytes.

CD63

stored in cytoplasmic granules or lysosomes of platelets, endothelial cells, neutrophils, monocytes and macrophages and is exported to the cell surface on activation; deficient in the platelets of Hermansky-Pudlak syndrome; expressed on fibroblasts, osteoblasts, smooth muscle cells, neural tissue and melanoma cells.

CD64

FCgRI, expressed on monocytes, macrophages and activated granulocytes, a subset of circulating dendritic cells, germinal centre dendritic cells and early myeloid cells; has a role in antigen capture for presentation to T cells, antibody-dependent cellular cytotoxicity and endocytosis of immune complexes; a non-coding mutation in the CD64 transcript which reduces mRNA stability and hence phagocytic expression of CD64 has been reported; individuals with this CD64 deficiency have no known abnormalities.

CD65

a carbohydrate ceramide dodecasaccharide, expressed on cells of granulocyte lineage and, more weakly, on monocytes; expressed on blast cells of many cases of AML.

CD65s is the sialylated form; CD65s is expressed on granulocytes, monocytes and cells of myeloid leukaemias; its expression appears as CD34 expression disappears; aberrantly expressed on some pro-B ALL.

CD66a

also known as biliary glycoprotein I; expressed on neutrophils and epithelial cells; role in cell adhesion and signalling in neutrophils; a receptor for Neisseria spp.

CD66b

expressed in neutrophils; has a role in cell adhesion and signalling; GPI-linked.

CD66c

expressed in neutrophils and epithelial cells; has a role in cell adhesion and signalling; GPI-linked; closely related to carcinoembryonic antigen.

CD66d

expressed on neutrophils, function uncertain.

CD66e

expressed on epithelial cells; GPI-linked; has a role in cell adhesion and possibly in metastasis of tumour cells; found in the serum where is referred to as carcinoembryonic antigen (CEA) and is used as a tumour marker.

CD66f

expressed in the placenta and fetal liver; may protect the fetus from the maternal immune system.

CD68

a member of the family of haemopoietic mucin-like molecules that includes CD34 and CD43; expressed on monocytes and macrophages and more weakly on neutrophils; expressed on blast cells of many cases of AML and is useful for the immunohistochemical demonstration of myeloid differentiation; expressed on mast cells including those of systemic mastocytosis; expressed on some B lymphocytes and weakly on B-lineage ALL; occasionally expressed on hairy cells and CLL cells.

CD69

expressed on some thymocytes, mantle zone B cells, some germinal centre CD4-positive T cells, platelets, epidermal Langerhans cells, activated T cells, B cells, NK cells, neutrophils and eosinophils; probably has a role in cell signalling; its expression on activated T cells rapidly declines in the absence of exogenous stimuli.

CD70

a member of the tumour necrosis factor receptor family; ligand for CD27 (see above).

CD71

transferrin receptor; mediates iron uptake; expressed on erythroid precursors, immature erythroid cells in M6 AML, activated B and T lymphocytes and on proliferating cells in general.

CD72

expressed on B cells; ligand for CD5 (see above).

CD73

Ecto 5' nucleotidase, expressed on subsets of B and T cells, follicular dendritic cells, epithelial cells and endothelial cells; a costimulatory molecule for T cells; GPI-linked; catalyses dephosphorylation of purine and pyrimidine ribo- and deoxyribonucleoside monophosphates to nucleosides: the preferred substrate is AMP.

CD74

expressed on B cells, activated T cells, macrophages, and activated endothelial and epithelial cells; invariant (g) chain of the MHC class II complex.

CDw75

a carbohydrate; expressed on circulating B cells and germinal centre B cells of secondary follicles, a small subset of T cells and erythrocytes; a ligand for CD22.

CD76

a carbohydrate; expressed on circulating B cells, mantle zone B cells of secondary follicles, a subset of T cells, cells of mature B-lineage neoplasms, and subsets of endothelial and epithelial cells.

CD77

a carbohydrate; expressed on germinal centre B cells and the cells of Burkitt's lymphoma; weakly expressed on the cells of follicular centre cell lymphoma.

CD79a

part of the immunoglobulin-associated heterodimeric B-cell antigen receptor; expressed on B cells and their precursors, on blasts cells of B-lineage ALL and on plasma cells; a useful 'pan-B' marker applicable in immunocytochemistry and immunohistochemistry.

CD79b

part of the B-cell antigen receptor; crucial for the correct intracellular assembly and transport of the complex; expressed on most normal and abnormal mature B cells but not on the cells of chronic lymphocytic leukaemia and in only about a half of cases of lymphoplasmacytoid lymphoma and a quarter of cases of hairy cell leukaemia; expressed by late B-cell precursors (pre-B cell); expressed on the blast cells of some cases of ALL; the lack of expression in chronic lymphocytic leukaemia is useful in helping to differentiate this condition from non-Hodgkin's lymphoma.

CD80

expressed on activated B cells; ligand of CD28 and CD152; coregulator of T cell activation with CD86.

CD81

a tetraspanin; part of a large signal transduction complex, together with CD19 and CD21; broadly expressed on haemopoietic cells but not on erythrocytes, platelets or neutrophils; expressed on endothelial cells and hepatocytes, where it is thought to be the receptor for the hepatitis C virus.

CD82

a transmembrane protein which functions in signal transduction; expressed on activated/differentiated haemopoietic cells; a tumour metastasis suppressor gene whose transcription is down-regulated during the tumour progression of several human adenocarcinomas (prostate, pancreas and breast); the enhancer of the CD82 gene is positively regulated by p53 and loss of p53 function during tumour progression is associated with a loss of CD82 expression.

CD83

a transmembrane protein expressed on circulating dendritic cells, interdigitating dendritic cells and Langerhans cells.

CD84

a cell surface glycoprotein, expressed on mature B cells, thymocytes, a subset of T cells, monocytes, macrophages and platelets.

CD85

expressed on circulating B cells, a minority of circulating T cells and a subpopulation of circulating NK cells; strongly expressed on plasma cells, hairy cells, mantle zone B cells and germinal centre cells.

CD86

expressed on interdigitating reticulum cells, Langerhans cells, circulating dendritic cells, memory B cells and germinal centre B cells; a ligand of CD28, CD80 and CD152; coregulator, with CD80, of T cell activation; plays a critical role in induction and regulation of the immune response; expressed by Hodgkin's cells and Reed-Sternberg cells.

CD87

receptor for urokinase and pro-urokinase and also for vitronectin; expressed on T cells, NK cells, monocytes, neutrophils and many non-haemopoietic cells; has a possible role in the migration of leucocytes into tissues.

CD88

C5a receptor, expressed on neutrophils and monocytes and has a role in their activation.

CD89

Fca receptor, expressed on myeloid cells from the promyelocyte to the neutrophil stage, promonocytes, monocytes and activated eosinophils; induces phagocytosis, the respiratory burst, bacterial killing and degranulation; eosinophils of atopic individuals show up-regulation of CD89.

CD90

a glycoprotein coexpressed with CD34 on haemopoietic stem cells; also expressed on neurones and in secreted form by neuronal accessory cells.

CD91

a2 macroglobulin receptor, also known as low density lipoprotein receptor-related protein.

CDw92

expressed on monocytes and neutrophils.

CDw93

expressed on monocytes, neutrophils and endothelial cells.

CD94

expressed on NK cells, particularly if activated, and on a subset of T cells; an inhibitory receptor for HLA class I molecules.

CD95

Fas, a transmembrane protein that mediates programmed cell death (apoptosis) when trimerized by cross-linking to fas ligand; expressed on activated T and B lymphocytes; responsible for eliminating autoreactive T cells during ontogenesis and for maintaining lymphocyte homeostasis; inherited fas mutations are responsible for an autoimmune lymphoproliferative syndrome; fas is mutated in a significant proportion (about 10%) of cases of multiple myeloma and NHL, particularly MALT-type lymphoma and extra-nodal B-lineage diffuse large cell lymphoma.

CD96

a member of the immunoglobulin superfamily expressed on activated T cells and activated NK cells, peaking 6 to 9 days after the activating stimulus.

CD97

a glycoprotein expressed on activated leucocytes, related to the secretin and calcitonin receptors.

CD98

expressed on activated monocytes and T lymphocytes.

CD99

expressed on T cells; has a role in cell adhesion; also known as MIC2, the first identified Y chromosomal structural gene; located on the pseudo-autosomal region of the Y chromosome; the corresponding X chromosomal gene, MIC2X escapes X inactivation.

CD100

a semaphorin expressed on late haemopoietic cells, activated T cells and germinal centre B cells; has a role in cell adhesion; ligand of CD45; induces B cell aggregation and down-regulates B cell expression of CD23

CD101

expressed on monocytes, neutrophils, dendritic cells and activated T cells.

CD102

intercellular adhesion molecule 2 (ICAM-2); an adhesion molecule that is the ligand of b2 integrin CD11a/CD18; expressed on endothelial cells, monocytes and some lymphocytes; acts as a costimulatory molecule in the immune response and has a role in lymphocyte recirculation.

CD103

aE integrin which forms a heterodimer with b7 integrin; expressed on mucosa-associated T lymphocytes, a small subset of peripheral blood lymphocytes and on hairy cells; expressed in enteropathy-associated T cell non-Hodgkin's lymphoma.

CD104

b4 integrin chain, expressed as a6/b4 integrin in keratinocytes; mutations in the b4 integrin gene have been found in children with the non-lethal form of junctional epidermolysis bullosa and pyloric atresia; these cases have all been compound heterozygotes for a nonsense and a missense mutation; compound heterozygosity for two nonsense mutations or homozygosity for a single nonsense allele results in stillbirth.

CD105

endoglin, the target gene that is mutated in hereditary haemorrhagic telangiectasia; expressed on endothelial cells, activated monocytes, macrophages, stromal cells of the bone marrow and erythroid precursors.

CD106

VCAM-1, vascular cell adhesion molecule; expressed on activated endothelium; mediates the adhesion of monocytes and lymphocytes to activated endothelial cells.

CD107

a lysosomal membrane protein 1 (LAMP-1), expressed by degranulated platelets, activated T cells, neutrophils and activated endothelium.

CD107b

lysosomal membrane protein 2 (LAMP-2), expressed on activated platelets and weakly on activated endothelium and neutrophils.

CDw108

expressed on red cells and lymphoblasts and more weakly on lymphocytes; expressed on erythrocytes, the JMH blood group antigen.

CD114

G-CSFR; expressed at all stages of neutrophil differentiation and on monocytes, platelets and endothelial cells; has a major role in regulation of proliferation and differentiation of cells of neutrophil lineage; mutations of this gene are responsible for some cases of severe congenital neutropenia.

CD115

macrophage CSF-R or CSF1, a receptor tyrosine kinase which is encoded by the FMS oncogene; missense point mutations in codons 301 or 969 of the FMS gene have been found in CMML and M4 AML; in one series, 1/51 haematologically normal subjects were shown to have the mutation in codon 969; this may represent a marker of predisposition to myeloid malignancy.

CD116

the a chain of GM-CSFR, the b chain being CDw131; expressed on macrophages, neutrophils, eosinophils and dendritic cells; the gene for this protein is located in the pseudoautosomal region of the short arm of the X and Y chromosomes, distal to the CD99 locus.

CD117

c-KIT, the receptor for stem cell factor (SCF-R), a receptor tyrosine kinase; expressed on haemopoietic precursors, myeloblasts, primitive erythroid cells, some megakaryoblasts, mast cells including the neoplastic cells of systemic mastocytosis, blast cells of most cases of AML, some myeloma cells and various non-haemopoietic cells including melanocytes and the interstitial cells of Cajal in Auerbach's plexus; point mutations in c-KIT have been found in familial piebaldism and megacolon, gastrointestinal stromal tumours, systemic mastocytosis and AML with mast cell differentiation.

CDw119

IFNgR1; expressed on macrophages; a mutation in the gene encoding this protein causes susceptibility to atypical mycobacterial infections.

CD120a

TNFRI, a receptor for tumour necrosis factor a; expressed on epithelial cells.

CD120b

TNFRII, a receptor for tumour necrosis factor a; expressed on myeloid cells, activated T cells and activated B cells.

CD121a

IL1R, a receptor for IL1a and IL1b; expressed on T cells.

CD121b

type II IL1R; possibly inhibits IL1 activity by binding IL1 that would otherwise bind to IL1R.

CD122

interleukin 2 receptor b chain; together with CD25 and CD132, forms a high affinity IL2R which is expressed on T cells, B cells, NK cells, monocytes and macrophages; CD122 is also a subunit of IL15R which is expressed on activated monocytes and on various non-haemopoietic cells; targeted disruption of the murine gene leads to uncontrolled B cell proliferation with hypergammaglobulinaemia and an autoimmune haemolytic anaemia.

CD123

IL3R a subunit; the a subunit is ligand specific whereas the b subunit, CD133, is shared with GM-CSFR and IL5R; expressed on haemopoietic cells; the gene is located in the pseudoautosomal region at the end of the short arm of the X and Y chromosomes.

CD124

the a chain of IL4R, combining with the b chain, CD132, to form the receptor; expressed on T cells, B cells and haemopoietic cells; also contributes the a chain of IL13R, combining with IL13R b chain to form the receptor; susceptibility to atopy and increased levels of expression of CD23 have been associated with a missense mutation in codon 576 of the IL4R gene; several missense mutations at codon 50 have been associated with susceptibility to asthma, atopy and elevated IgE levels.

CDw125

IL5R a chain which combines with CDw131, the b chain, to form a high affinity IL5 receptor; expressed on eosinophils, activated B cells and basophils; soluble isoforms of the IL5R a chain occur normally because of alternative splicing.

CD126

IL6R, expressed on T cells, activated B cells and monocytes.

CD127

the a chain of IL7R, combining with the b chain, CD132, to form a high affinity receptor; expressed on most T cells, being down-regulated on T cell activation.

CDw128a

IL8RA, a high affinity receptor.

CDw128b

IL8RB, a low affinity receptor.

CD130

a widely expressed molecule that associates with CD126 after CD126 has bound to its ligand, IL6, and similarly with the IL11R after it has bound IL11; part of the signalling system after cells have bound IL6 or IL11.

CDw131

the b subunit of GM-CSFR (combining with CD116), of the IL3R (combining with CD123) and of the IL5R (combining with CDw125).

CD132

the common g chain of a number of cytokine receptors:

  • combining with CD122 and CD25 to form the high affinity IL2R;
  • combining with CD124 to form the high affinity IL4R;
  • combining with CD127 to form the high affinity IL7R;
  • combining with IL15Ra and CD122 to form the IL15R; and
  • also part of the receptor for IL9.
    Expressed on T cells, B cells, NK cells, monocytes, macrophages and neutrophils; mutation leads to severe sex-linked combined immunodeficiency.

CD134

a member of the TNF receptor superfamily; expressed on activated lymphocytes.

CD135

a receptor tyrosine kinase, a growth factor receptor that binds to FLT3 ligand; expressed on multipotent stem cells, myelomonocytic precursors and early B cell progenitors; has a role in the proliferation and differentiation of haemopoietic progenitors; expressed on blast cells in ALL, AML and the blast crisis of CGL.

CDw136

a receptor tyrosine kinase, receptor for macrophage stimulating protein; expressed on macrophages and ciliated epithelial cells; has a role in induction of macrophage migration.

CDw137

can be expressed by T and B cells and monocytes; expression is induced by activation; a costimulatory molecule in T cell proliferation.

CD138

an adhesion molecule, LFA-3 or Syndecam-1, a transmembrane heparan sulphate proteoglycan, that mediates the interaction between cells and the extracellular environment; expressed on post germinal centre B cell but not germinal centre B cells; expressed on multiple myeloma cells; expressed on neoplastic cells of some cases of classical Hodgkin's disease but not on the cells of nodular lymphocyte predominant Hodgkin's disease.

CD139

expressed on B cells, monocytes, neutrophils and follicular dendritic cells; expressed on cells of some but not all cases of B-CLL.

CD140a

PDGFRa, platelet-derived growth factor receptor alpha, a receptor tyrosine kinase.

CD140b

PDGFRb platelet-derived growth factor receptor beta, a receptor tyrosine kinase; the gene encoding CD140b, which is on chromosome 5, is often deleted in the 5q- syndrome and is rearranged in several uncommon chronic myeloid leukaemias.

CD141

thrombomodulin, expressed on endothelial cells; the cofactor for thrombin-mediated expression of activated protein C; heterozygosity for a missense mutation in the thrombomodulin gene has been associated with a familial thrombophilia.

CD142

tissue factor; CD142 plus VIIa initiates the coagulation cascade through factors X and IX; VIIa is the catalytic subunit while CD142 is the regulatory subunit; induced on monocytes and endothelial cells by inflammatory mediators.

CD143

ACE, angiotensin-converting enzyme; expressed on endothelial cells, and some epithelial and neuronal cells; metabolizes angiotensin II and bradykinin.

CD144

VE-cadherin, expressed on endothelium and mediates homotypic adhesion.

CD146

a member of the immunoglobulin superfamily; MUC18, S-endo; expressed on endothelium; possibly an adhesion molecule; a marker for melanoma, associated with tumour progression and metastasis.

CD147

a member of the immunoglobulin superfamily; neurothelin, basigin; expressed on leucocytes, erythrocytes, platelets and endothelial cells; possibly an adhesion molecule.

CD148

HPTP-eta, p260 phosphatase; expressed on neutrophils, monocytes, activated T cells, dendritic cells and platelets.

CDw149

MEM-133; expressed on lymphocytes and monocytes; the gene encoding this protein has not been cloned.

CDw150

SLAM, IPO-3; expressed on thymocytes, B cells, some T cells and dendritic cells; a costimulatory molecule on B cells and dendritic cells.

CD151

PETA (platelet-endothelial tetraspan antigen)-3; expressed on endothelial cells, platelets, monocytes and immature haemopoietic cells.

CD152

CTLA (cytotoxic T cell associated antigen)-4; expressed on activated T cells; partial homology with CD28; like CD28, binds CD80 and CD86 and is probably mainly a negative regulator of T cell activation; missense mutations in codon 17 have been reported to be associated with autoimmune endocrinopathies.

CD153

CD30L, CD30 ligand

; expressed on neutrophils, activated T cells, monocytes, macrophages; CD30 ligand is a cytokine which shows homology with TNF.

CD154

CD40L, CD40 ligand

; the ligand for CD40; expressed on activated CD4-positive lymphocytes, expression being essential for normal signalling to B cells, particularly for isotype switching; mutations in the CD154 gene are responsible for the X-linked immunodeficiency syndrome, the hyperIgM syndrome.

CD155

PVR, polio virus receptor; expressed on B cells and neural cells.

CD156

ADAM8, MS2 (mouse homologue); zinc metalloprotease expressed on neutrophils and monocytes; upregulated by retinoic acid.

CD157

BST (bone marrow stromal cell antigen)-1, a cyclic ADP-ribose hydrolase MO-5; expressed on neutrophils, monocytes, macrophages and B cell progenitors: over expressed in bone marrow stromal cells in rheumatoid arthritis.

CD158a

p58.1, MHC class I-specific NK receptors; expressed on a NK subset and rare T cells; there are two molecules within this cluster, p58.1 which is inhibitory and p50.1 which is stimulatory.

CD158b

p58.2, MHC class I-specific NK receptors; expressed on a NK subset and rare T cells; there are two molecules within this cluster, p58.2 and p50.2.

CD161

NKRP-1; a lectin; expressed on most NK cells, a subset of T cells and a subset of thymocytes.

CD162

PSGL-1, cutaneous leucocyte antigen, a mucin-like molecule expressed on lymphocytes, ligand for CD62E (E selectin) permitting lymphocytes to roll on activated endothelium; ligand for L selectin (CD62L) and E selectin (CD62E); expressed on haemopoietic progenitors and most myeloid cells, most T cells and some B cells.

CD163

M130; member of the scavenger receptor superfamily; expressed on macrophages.

CD164

a transmembrane homodimer, a mucin-like glycoprotein, MGC-24 (multiglycosylated core protein of 24 kilodaltons), expressed on haemopoietic progenitors, bone marrow stromal cells, endothelial cells and some epithelial cells; participates in the binding of CD34-positive cells to bone marrow stroma and inhibits the recruitment of such cells into the cell cycle.

CD165

GP/37/AD2; expressed on a subset of lymphocytes, immature thymocytes, monocytes and most platelets and expressed at a low level on most thymocytes and on thymic epithelium; may have a role in adhesion of thymocytes to thymic epithelium; strongly expressed in many T-lineage ALL; the gene encoding CD165 has not been cloned.

CD166

ALCAM, expressed on activated T cells and monocytes; an adhesion molecule; a ligand of CD6.