CD Markers

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CD Markers

CD2

Reviewers: Nat Pernick, M.D., (see Reviewers page)
Revised: 5 December 2010, last major update November 2010
Copyright: (c) 2002-2010, PathologyOutlines.com, Inc.

General
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● Early T cell marker
● Gene is at 1p13.1; protein is member of immunoglobulin superfamily

General
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● Also called E rosette receptor, because CD2 antibodies inhibit formation of rosettes with sheep erythrocytes
● Also called LFA2 (leukocyte function antigen), T11

Physiology
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(1) Binds CD58 (LFA3) on antigen-presenting cells, which enables T cells to respond to lower concentrations of antigen (J Exp Med 1999;190:1383)
(2) Mediates adhesion between T cells and antigen presenting cells
(3) Induces costimulatory signals in T cells
(4) Induces T cell cytokine production
(5) Regulates T cell anergy
(6) Regulates T and NK-mediated cytolysis
(7) Inhibits apoptosis of activated peripheral T cells
(8) CD2 distinguishes two subsets of human plasmacytoid dendritic cells with distinct phenotype and functions (J Immunol 2009;182:6815)

Diagrams
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T cells and antigen presenting cells

Uses by pathologists
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● T cell marker (membranous staining), although CD3 is more commonly used
● Marker of systemic mastocytosis

Clinical features
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● Abnormal levels of CD2 expression by flow cytometry are frequently observed in mature T-cell malignancies, but clinical significance is unclear because of variability of CD2 expression in normal T cells (Cytometry B Clin Cytom 2010;78:169)
● Siplizumab, an anti-CD2 monoclonal antibody, is being studied to treat plaque psoriasis (Int J Dermatol 2010;49:818)

Micro images
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CD2 on frozen section of skin

CD2 on paraffin section of T cell lymphoma (unspecified)

Angioimmunoblastic T cell lymphoma: Fig A - weak CD2 staining

Positive staining (normal)
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● Thymocytes (95%), mature peripheral T cells (almost all), NK cells (80-90%), mast cells
● Variable thymic B cells (50%), Langerhans cells

Positive staining (disease)
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● T-ALL, other T cell lymphoma/leukemia, acute promyelocytic leukemia-microgranular variant / FAB M3v (Leukemia 1995;9:1461), AML with pseudo-Chèdiak-Higashi anomaly (Am J Clin Pathol 2006;125:791), indolent systemic mastocytosis (Hum Path 2001;32:545), thymoma (lymphocyte predominant)
● Variable: acute myeloid lymphoma-M0
● Rare: pyothorax associated B cell lymphoma (Am J Surg Pathol 2002;26:724) or other non-Hodgkin B cell lymphomas, Reed-Sternberg/Hodgkin’s cells (Mod Path 2005;18:1542)), myeloma (Mod Path 1990;3:302), myeloid leukemia

Negative staining
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● B cells, basophils, nonhematopoietic neoplasms (Am J Clin Pathol 2003;120:64), mast cells in non-mastocytosis disorders

Additional references
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● MIM 186990

End of CD Markers > CD2

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