Home > A. Molecular pathology > CD5

CD5

MIM.153340 11q13 HGNC:1685

Tuesday 28 August 2007

CD5 belongs to ancient scavenger receptor superfamily. CD5 may serve as a dual receptor, giving either stimulatory or inhibitory signals depending both on the cell type and the development stage.

CD5 is a key regulator of immune tolerance and abnormalities may produce autoimmunity. CD5 binds to CD72.

CD5+ B cells

CD5+ B cells may arise from B-1 cells (subset of B cells) that produce “generalist antibodies” taht are polyreactive low affinity "natural" antibodies to exogenous antigens (tetanus toxoid, lipopolysaccharide) as well as autoreactive antibodies.

CD5+ B cells produce antibodies using germ line (non mutated) configuration of gene segments, usually IgM. They constitute the first line of defense against antigens and have a low activation threshold.

CD5+ B cells production is elevated in rheumatoid arthritis (27-52% of circulating B cells vs. 20% normal).

Pathology

A polymorphism in CD5 promoter associated with susceptibility to mantle cell lymphoma and CLL.

Immunochemistry

CD5 is a marker for :

- chronic lymphocytic leukemia (CLL)
- mantle cell lymphoma
- T cells (normal and malignant)
- thymic carcinoma

Normal expression

- thymocytes
- almost all T cells
- B cells of mantle zone of spleen and lymph nodes (12% of B cells in peripheral blood)
- B cells in peritoneal and pleural cavities
- In fetus, most B cells in spleen and cord blood are CD5 positive

Negative immunostaining

- enteropathy associated T cell lymphoma
- hepatosplenic alpha-beta T cell lymphoma
- hepatosplenic gamma-delta T cell lymphoma
- T cell large granular lymphocytic lymphoma
- most B cell lymphomas other than mantle cell or CLL (although there rarely are CD5+ variant forms)
- Reed-Sternberg cells in classic Hodgkin lymphomas

See also

- CDs