Home > A. Molecular pathology > CDs > CD23

CD23

Wednesday 28 October 2009

HUGO:FCER2

PO

See: FCER2

Roles

- CD23 is a key molecule for B-cell activation and growth. It is a low affinity IgE receptor (Fc fragment of IgE receptor, FCERs).
- CD23 is a type C lectin that can be secreted.
- After physiologic germinal cell development, the follicular dendritic cell meshwork expands and follicular dendritic cells in the light zone of the germinal center become CD23 positive.
- CD23 acts as a B cell growth and activation factor, promoting differentiation into plasma cells.
- CD23 regulates IgE synthesis through CD21 and IgE binding and mediates IgE related immune responses.
- CD21, CD23 and CD35 are dendritic cell markers.

Expression

- Follicular dendritic cells
- Activated mature B cells expressing IgM or IgD (particularly mantle cells)
- Activated monocytes / macrophages
- T cell subsets
- platelets
- eosinophils
- Langerhans cells,
- intestinal epithelium (encodes IgE receptor, Gastroenterology 2005;129:928)

Flow cytometry

- CD23 shows variability in flow cytometry expression between specimens from same patient.

Diagnosis

- CD21, CD23 and CD35 are dendritic cell markers.
- CD23 differentiate SLL/CLL (CD23+) vs. mantle cell lymphoma or MALT lymphoma (CD23-)
- CD23 is a B cell marker, particularly for SLL/CLL, mediastinal large B cell lymphoma and lymphoplasmacytic lymphoma.
- CD23 distinguishes nodal mantle cell lymphoma from follicular lymphoma by identifying a disrupted follicular dendritic cell pattern (Int J Surg Pathol 2005;13:73).

Positive staining - normal

- Activated mature B cells expressing IgM or IgD (particularly mantle cells),
- activated monocytes / macrophages,
- T cell subsets,
- platelets,
- eosinophils,
- Langerhans cells,
- follicular dendritic cells
- intestinal epithelium (encodes IgE receptor, Gastroenterology 2005;129:928)

Positive staining - disease

- B-cell CLL/SLL (almost all cases; high levels, Leuk Res 2002;26:809, Hum Pathol 1999;30:648)
- Atypical cases of CLL/SLL may have higher levels (Am J Clin Pathol 2001;116:655)
- Follicular dendritic cell tumors (including inflammatory pseudotumor type, Am J Surg Pathol 2001;25:721)
- Mediastinal large B cell lymphoma (70%, Histopathology 2004;45:619)
- Lymphoplasmacytic lymphoma (61%, usually dim intensity by flow cytometry, Am J Clin Pathol 2005;124:414, Clin Lymphoma 2005;5:246)
- Hairy cell leukemia (17%, Am J Clin Pathol 2006;125:251)
- Diffuse large B cell lymphoma (16%)

Negative staining

- Basophils, resting B cells
- Other B cell lymphomas including Burkitt lymphoma, Burkitt-like lymphoma (Am J Surg Pathol 2005;29:1652), follicular lymphoma, mantle cell lymphoma and marginal zone lymphoma (Am J Surg Pathol 1999;23:59, Mod Pathol 1998;11:967)
- Most T cell lymphomas,
- inflammatory fibroid polyps of the gastrointestinal tract (although of dendritic cell origin, Am J Surg Pathol 2004;28:107),
- follicular dendritic cell tumor and interdigitating dendritic cell tumor