CD Markers
CD8

Author: Nat Pernick, M.D. (see Authors page)

Revised: 5 January 2016, last major update August 2013

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: CD8[title]

Cite this page: CD8. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/cdmarkerscd8.html. Accessed December 8th, 2016.
Definition / General
  • Cytotoxic T cell marker (Wikipedia); CD8+ cells are called T cell suppressor cells, cytotoxic T cells
  • Also called OKT8
Pathophysiology
  • Cell surface glycoprotein, member of immunoglobulin superfamily; at 2p12
  • Heterodimer of an alpha (CD8A, OMIM #186910 ) and a beta chain (CD8B, OMIM #186730 ) linked by two disulfide bonds; each chain has significant homology to immunoglobulin variable light chains; is present as a heterodimer on thymocytes and as homodimer on peripheral blood T cells
  • Both the CD8 antigen (acting as a coreceptor) and the T cell receptor recognize antigens displayed by an antigen presenting cell (APC) in the context of class I MHC molecules; CD8 binds to non-polymorphic region of class I molecules; may increase avidity of interactions between cytotoxic T cell and target cell during antigen-specific activation
  • Can kill target cells by recognizing peptide-MHC complexes on them or by secreting cytokines capable of signaling through death receptors on target cell surface
  • CD8 alpha cells promote survival and differentiation of activated T cells into memory CD8+ T cells
  • CD8 T cell clonal expansions occurr in normal young (PLoS One 2011;6:e21240) and elderly adults (Immunol Rev 2005;205:170)
  • May contribute to initiation, progression and regulation of autoimmune responses (Curr Opin Immunol 2005;17:624)
Diagrams / Tables

Images hosted on other servers:

CD8+ T cell activation requires 2 signals

Clinical Features
Uses by Pathologists
  • Marker of T cells (normal and malignant)
  • Marker of cytotoxic / suppressor T cells
  • Classify lymphomas
  • Differentiate splenic hamartoma (CD8+) from hemangioma or littoral cell angioma (CD8-)
  • Note: use of CD3, CD8 does NOT improve detection of gluten-sensitive enteropathy in duodenal biopsies (Mod Pathol 2013 Apr 5 [Epub ahead of print])
Micro Images

Image hosted on PathOut server:

Splenic littoral cell angioma, sinus lining cells are CD8-


Images hosted on other servers:

Various-quality control

Bladder: follicular cystitis (fig D)

Blood: T cell granular lymphocytic leukemia

Cervix:
lymphoepithelioma-
like carcinoma (fig 3)

Skin: cutaneous CD8+ epidermotropic T cell lymphoma

Skin: lymphomatoid papulosis (fig B, C)

Splenic hamartoma (left) sinus lining cells are CD8+


Images hosted on Nature.com:

Duodenum: intraepithelial lymphocytes (left: fig 1c; right: fig 2e)

Lymph node: nodal CD8+ cytotoxic T cell lymphoma

Skin: mycosis fungoides (fig B, D)

Soft tissue: subcutaneous panniculitis-like T cell lymphoma

Positive Staining - Normal
  • Cortical thymocytes (70-80%), T cells (25-35% of mature peripheral T cells, mostly cytotoxic T cells), NK cells (30%) and dendritic cells
Positive Staining - Disease
Negative Staining
  • Adult T cell leukemia / lymphoma, littoral cell hemangioma of spleen
Flow Cytometry Images

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Anaplastic large cell lymphoma: partial CD4 & CD8 coexpression