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Table of Contents
Definition / General | Diagrams / Tables | Pathophysiology | Uses by Pathologists | Positive Staining - Normal | Positive Staining - Disease | Negative StainingDefinition / General
- CD45 isoform generated by alternative mRNA splicing of exon 5, leading to change in the extracellular domain of the molecule (J Exp Med 1987;166:1548)
- Influx of CD4+, CD45RB high T cells is present in inflammatory bowel disease; may be important in pathogenesis as they produce more proinflammatory cytokines than CD4+ CD45RB low T cells (J Leukoc Biol 2004;75:1010)
Diagrams / Tables
CD45RB expression changes during germinal center reaction
Pathophysiology
- CD45 is a high molecular weight transmembrane protein with intrinsic tyrosine phosphatase activity
- CD45 is heavily glycosylated, and expressed at high levels on nucleated hematopoietic cells
- CD45 isoforms, including CD45RB, 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
- Down regulated in memory cells
Uses by Pathologists
- No significant clinical use by pathologists
Positive Staining - Normal
- Similar staining as CD45, except not expressed in Langerhans cells and some T cells
- B cells, most T cells, monocytes, macrophages and granulocytes (weak)
Positive Staining - Disease
- Most leukemias and lymphomas
Negative Staining
- Some T cells; Langerhans cells, platelets
- Plasma cell neoplasms, Reed-Sternberg cells, some lymphoblastic lymphomas and some anaplastic large cell lymphomas
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