CD Markers

Last author update: 1 October 2013
Last staff update: 9 February 2022

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PubMed Search: CD45RA[title]

Related topics: CD45, CD45RO, CD45RB, CD45RC

Nat Pernick, M.D.
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Cite this page: Pernick N. CD45RA. website. Accessed May 19th, 2024.
Definition / general
  • CD45 isoforms [functionally similar proteins with similar but not identical amino acid sequence], including CD45A, are generated by alternative mRNA splicing of exons 4 (CD45RA), 5 (CD45RB) and 6 (CD45RC), leading to changes in the extracellular domain of the molecule (J Exp Med 1987;166:1548)
  • CD45RA+ T regulatory cells are converted to CD45RO+ T regulatory cells after activation (J Immunol 2010;184:4317)
  • High molecular weight transmembrane protein with intrinsic tyrosine phosphatase activity
  • Heavily glycosylated, and expressed at high levels on nucleated hematopoietic cells
Uses by pathologists
  • Differentiate naive T cells (CD45RA+) from memory T cells (CD45RO+), but not in adult allogeneic hematopoietic cell transplant recipients (Bone Marrow Transplant 2003;32:609)
Microscopic (histologic) images

Images hosted on other servers:
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Intraepidermal T cells in fixed drug eruption lesions (fig d)

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Papulonodular lesion show dermal, intraepithelial neoplastic lymphocytes

Positive staining - normal
  • B cells, NK cells, naive / resting T cells (those not exposed to antigens), medullary thymocytes and plasmacytoid dendritic cells (Am J Pathol 2001;159:237)
Positive staining - disease
Negative staining
  • Basophils, endothelial cells, Langerhans cells, memory T cells (usually), most T cell lymphomas and most plasma cell neoplasms
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