CD23

Summary

CD23 is a broadly expressed molecule whose impotance lies in its value in distinguishing between CLL (consistent expression) and MCL (infrequent expression).

However, CD23 is not a CLL-specific marker, and is also expressed on other haematological and lymphoma cell types.

Normal expression and function

CD23 is a low-affinity receptor for IgE that is involved in antigen capture and presentation. It affects B-cell growth and differentiation and the activation of monocytes. It is expressed on activated B-cells, but also platelets eosinophils activated macrophages and follicular dendritic cells.

Diagnostic role

• CD23 is most frequently used to distinguish between CLL and MCL but this difference is not absolute: CD23 is expressed by the vast majority (90% of typical CLL patients), and is generally absent in MCL although it is detected in around 10% of cases where its expression may be bright.
• CD23 may also be expressed by other B-lymphoproliferative disorders although at lower frequency:including lymphoplasmacytic lymphoma, marginal zone lymphoma or follicular lymphoma.

Other relevant information:

When CD23 is expressed by MCL the cases may have a more indolent course and an improved outcome.

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SUMMARY TABLES

Note The colour and % refer to the proportion of cases expressing the marker. Additional comments on strength, or site of expression (if relevant) are given below the table. For full details of key click here. For further information about a particular disease state click <I> adjacent to the condition name

Expression in primitive cell types
AML	CMML	B ALL	BL	T ALL	ETP ALL	MPAL	Hgn
5-20%	<5%	<5%	<5%	<5%	<5%	<5%	<5%

Notes: CD23 expression may be seen in some cases of monocytic AML

Expression in mature B cell neoplasms
CLL	MCL	FL	MZL	HCL	DLBCL	LPL	PCL
80-100%	5-20%	20-40%	5-20%	<5%	20-40%	5-20%	<5%

Notes: xxxxx

Expression in mature T cell neoplasms*
ATLL	CTCL/Sezary	T-PLL	T-LGL	NK-LGL
<5%	<5%	<5%	<5%	<5%

Notes: xxxxx

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