CD14

Summary

CD14 aids recognition of bacteria by cells of monocytic lineage, it is regarded as a pan-monocyte antigen. Expression of CD14 is not restricted to malignant cells as it is also expressed by normal and reactive monocytes

when expressed in aml CD14 is a marker of monocytic lineage, but absence of CD14 expression does not preclude monocytic lineage in AML and CMML since some typical monoblasts may not express this marker

Normal expression and function

Together with co-receptors cell surface, CD14 binds the bacterial cell wall component lipopolysaccharide (LPS) helping initiate cytokine secretion and the inflammatory response when bacteria are detected. CD14 is expressed mainly by monocytes dendritic cells and macrophages and to a much lower extent by neutrophils. CD14 is weakly expressed or absent on early monocytes, but expression becomes progressively stronger as the cells mature.

Diagnostic role

• CD14 is a useful marker of monocytic lineage in aml

• CD14 may be absent on less mature monoblasts, while in myelomonocytic lineage cells will express CD14 on the monocytic population of blasts

• In cmml expression of CD14 is expected, so it does not distinguish cmml and monocytic aml

• Expression is very uncommon on lymphoid lineage

Other relevant information:

CD14 is glycophosphoinositol gpi linked and will therefore be absent in cells affected by paraxysmol nocturnal haemoglobinuria (PNH)

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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
20-40%	80-100%	<5%	<5%	<5%	<5%	<5%	<5%

Notes: In aml CD14 expression defines monocytic lineage restriction but may be absent especially in more primitive monoblastic cases

Expression in mature B cell neoplasms
CLL	MCL	FL	MZL	HCL	DLBCL	LPL	PCL
<5%	<5%	<5%	<5%	<5%	<5%	<5%	<5%

Notes: Low level expression has been reported on activated lymphocytes, but it has no definite diagnostic role

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

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