CD Markers

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

Revised: 31 December 2015, last major update August 2013

Copyright: (c) 2002-2015,, Inc.

PubMed Search: CD4[title]

Cite this page: CD4. website. Accessed February 20th, 2018.
Definition / general
  • Marker of T helper cells, important in T cell activation and receptor for HIV (Wikipedia, OMIM #186940)
  • Also called OKT4
  • At #12p13.31
  • Nonpolymorphous glycoprotein belonging to immunoglobulin superfamily (Cell 1985;42:93)
  • Expressed on surface of T helper cells; serves as coreceptor in MHC class II-restricted antigen induced T cell activation
  • CD4+ CD25+ FOXP3+ regulatory T cells maintain peripheral tolerance and prevent autoimmunity (Curr Top Microbiol Immunol 2005;293:115), and may be prognostic factor in malignancies (Mod Pathol 2013;26:448, J Clin Invest 2013;123:2873)
  • Serves as HIV receptor on T cells, macrophages and brain
    • Downregulated by HIV proteins during AIDS progression (J Virol 2003;77:11536, J Biol Chem 2003;278:33912)
    • Normally CD4 > CD8; in HIV patients, CD4 / CD8 ratio is inverted (i.e. CD4 < CD8) and patients are at risk for opportunistic infections, particularly if CD4 < 200
  • Homologous to CD223
  • Interpretation: staining is usually cytoplasmic and has membrane accentuation
Diagrams / tables

Images hosted on other servers:

CD4+ T cell and antigen presenting cell

CD4 acting as HIV receptor

Uses by pathologists
Microscopic (histologic) images

Images hosted on other servers:

Various images-quality control

CNS: acute demyelinating
disease (fig 12)

Joint: rheumatoid arthritis (fig B)

Lymph node: atypical paracortical hyperplasia (fig B)

Salivary gland: Sjgren syndrome (fig B)

Skin: EBV+

Skin: Mucha- Habermann disease (fig 3A)

Small bowel: T cell lymphoma (left: fig D; middle: fig D); right-stomach (fig C)

Soft tissue: inflammatory myopathy

Vagina: normal

Images hosted on

Lymph node: peripheral T cell lymphoma (fig B)

Nasopharynx: HSV related mass (fig E)

Skin: primary cutaneous CD4+ T cell lymphoma (fig e-f)

Flow cytometry Images

Images hosted on PathOut server:

Soft tissue mass: anaplastic large cell lymphoma

Positive staining - normal
  • T helper cells, thymocytes (80-90%), granulocytes, macrophages, Langerhans cells and dendritic cells
  • Expressed in specific regions of brain
Positive staining - disease
  • Many post-thymic T cell leukemia / lymphomas and T cell lymphoproliferative disorders
  • Dendritic / histiocytic neoplasms
    • Blastic plasmacytoid dendritic cell neoplasm
    • Granulomatous histiocytic lymphoma / sarcoma
  • Other hematologic / inflammatory lesions
Negative staining