CD Markers

Last author update: 1 January 2011
Last staff update: 14 May 2021

Copyright: 2002-2023,, Inc.

PubMed Search: CD33 [title]

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Cite this page: Singh C. CD33. website. Accessed November 29th, 2023.
Definition / general
  • Classic myeloid antigen (also CD13)
  • Glycosylated transmembrane protein of sialic acid binding immunoglobulin-like lactic (siglec) family
  • May mediate cell to cell adhesion; acts as receptor that inhibits the proliferation of normal and leukemic myeloid cells
Clinical features
Uses by pathologists
  • Distinguish myeloid (CD33+) and lymphoid leukemias (CD33-)
  • Identify monocytes by flow cytometry
Positive staining - normal
Positive staining - disease
Negative staining
  • Pluripotent stem cells, B cells
  • Most B and T cell lymphomas, blastic NK lymphoma (usually)
  • Not expressed outside hematopoietic system
Additional references
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