CD14

CD14 aids recognition of bacteria by cells of monocytic lineage. it may generally be regarded as a pan-monocyte antigen

when expressed in aml CD14 is a marker of monocytic lineage

absence of CD14 expression does not preclude monocytic lineage since some typical monoblasts do not express this marker

CD14 is not restricted to malignant cells and will be expressed by reactive monocytes and also by neoplastic cells of cmml

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 anchored to the membrane by a glycosylphosphatidylinositol gpi tail attachment may be cleaved to release a soluble form. 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.

• cases with myelomonocytic lineage will express CD14 on the monocytic population of blasts *cases with pure monocytic differentiation will generally express CD14 although it may be absent on less mature monoblasts.

• expression is usual on cmml monocytes so it does not distinguish cmml and monocytic aml.

• expression is very uncommon on lymphoid lineage with 5 expression by all cells.

other relevant information

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

summary tables

expression by acute leukaemias and by haematogones file rare. pro-b all rare. early pre-b all rare. pre-b all rare. b all rare. pro-t all rare. mature-t all freq. aml rare. haemato-gones link flow cytometry key notes **in aml CD14 expression defines monocytic lineage restriction but may be absent especially in more primitive monoblastic cases expression by b-lymphoproliferative disorders file rare. frame cll rare. pll rare. mcl rare. fl\' rare. hcl rare. hclv rare. mzl rare. lpl rare.