CD15

Summary

The main practical use for CD15 is for the recognition of cells that have granulocytic or monocytic features. For this reason CD15 has a role in lineage distinction in AML. CD15 is however also expressed in a range of haematological cell types and was originally described as the Lewis blood group antigen: Sialyl Lewis X.

Background

CD15 is a carbohydrate important in the initial phases of cell-to-cell adhesion known in this context as E-selectin. In normal cells CD15 is constitutively expressed by granulocytes and monocytes, but not by resting lymphocytes - although induced strongly following activation. Deficiency of CD15 causes the clinical disorder Leukocyte Adhesion Deficiency Type 2.

Diagnostic Use

• In histopathology CD15 is important in the recognition of the Redd Sterberg cells of Hodgkin Lymphoma
• CD15 is expressed by most cases of AML that have granulocytic or monocytic differentiation where expression may vary within the population.
• CD15 should not however be regarded as an exclusive myeloid marker since it is expressed by some cases of CLL and ALL

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