CD15
Summary
CD15 (Lewis X antigen, SSEA-1) is a carbohydrate cell surface marker classically used as an immunohistochemical marker for Reed-Sternberg cells in classic Hodgkin lymphoma. It is also expressed on granulocytes and monocytes, making it useful in identifying myeloid lineage cells.
Detail
CD15 is a fucosylated oligosaccharide (Lewis X antigen) expressed on the surface of neutrophils, monocytes, and certain Reed-Sternberg cells. In classic Hodgkin lymphoma, Reed-Sternberg cells (binucleate 'owl eye' cells) characteristically co-express CD15 and CD30, while typically lacking CD45 (LCA) and CD20—a key distinguishing immunophenotype from non-Hodgkin lymphomas. This CD15+/CD30+ pattern is a classic board-tested fact for diagnosing classic Hodgkin lymphoma on pathology slides. CD15 also functions physiologically as an adhesion molecule involved in phagocytosis and neutrophil-endothelial interactions, contributing to leukocyte rolling and extravasation during inflammation. It is also used as a marker in myeloid leukemias (e.g., AML with monocytic differentiation) via flow cytometry. Clinically, pathologists use immunohistochemical panels including CD15, CD30, CD45, CD20, and PAX5 to differentiate classic Hodgkin lymphoma from nodular lymphocyte-predominant Hodgkin lymphoma (which is CD15-, CD30-, CD45+, CD20+) and from non-Hodgkin lymphomas.
Sources
- Robbins Basic Pathology
- First Aid for the USMLE Step 1
- Goljan Rapid Review Pathology
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