Table of Contents
Definition / general | Essential features | Pathophysiology | Clinical features | Interpretation | Uses by pathologists | Microscopic (histologic) images | Positive staining - normal | Positive staining - disease | Negative staining | Flow cytometry description | Flow cytometry images | Sample pathology report | Board review style question #1 | Board review style answer #1Cite this page: Fraunfeld L, Schürch CM. CD3. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cdmarkerscd3.html. Accessed December 22nd, 2024.
Definition / general
- Common antibody for identifying T cells
- Member of immunoglobulin superfamily on 11q23
- Also called OKT3
Essential features
- Common antibody for identifying T cells
Pathophysiology
- CD3 is a cell surface complex composed of 4 distinct subunits; these subunits are chains of integral membrane glycoproteins that associate with T cell antigen receptor (TCR) and are required for TCR cell surface expression and signal transduction (Immunity 2006;24:133, Nature 2019;573:546)
- Delta (CD3ƍ) (OMIM: 186790 - CD3 Antigen, Delta Subunit [Accessed 18 March 2022])
- Epsilon (CD3ε) (OMIM: 186830 - CD3 Antigen, Epsilon Subunit [Accessed 18 March 2022])
- Gamma (CD3γ) (OMIM: 186740 - CD3 Antigen, Gamma Subunit [Accessed 18 March 2022])
- Zeta (CD3ζ, also called CD247) (OMIM: 186780 - CD247 Antigen [Accessed 18 March 2022])
- CD3 is expressed as either TCR alpha / beta or TCR gamma / delta heterodimers, coexpressed at cell surface with the TCR complex (Immunity 2006;24:133)
- CD3 is first expressed in the cytoplasm of developing T cells, then as they mature it moves to the membrane (Immunity 2006;24:133)
- Activation of the TCR by antigen peptides, presented via major histocompatibility complexes, induces phosphorylation of intracellular immunoreceptor tyrosine based activation motifs (ITAMs) in the CD3ζ subunits (Nature 2019;573:546)
Clinical features
- CD3 gamma, delta and epsilon defects cause autosomal recessive severe combined immunodeficiency (no T cells, although B cells and NK cells are normal) (Pediatr Allergy Immunol 2013;24:257, OMIM: 608971 - Severe Combined Immunodeficiency [Accessed 21 March 2022], Curr Opin Allergy Clin Immunol 2004;4:479)
- Anti-CD3 monoclonal antibodies as treatment:
- FDA approved to treat acute renal, cardiac or hepatic allograft rejection (antithymocyte antibody, ATG) (MAbs 2010;2:148)
- ATG is a polyclonal antibody, directed against multiple T cell epitopes
- In contrast to ATG, muromonab CD3, otelixizumab, teplizumab and visilizumab are monoclonal antibodies; in use for rejection, type 1 diabetes mellitus and inflammatory bowel disease (Lancet 2007;369:1641, Indian J Endocrinol Metab 2015;19:S58)
- Reverse steroid resistant acute graft rejection (J Immunol 2011;187:2015)
- Although initially thought to improve clinical parameters in new onset type 1 diabetes, phase III trials have been disappointing (N Engl J Med 2002;346:1692, Diabetes 2005;54:1763, Clin Dev Immunol 2011;2011:432016)
Interpretation
- Cytoplasmic positivity in immature T cells (cCD3), while negative surface CD3 (sCD3)
- Complete and membranous positivity in mature T cells (CD3)
- Reference: Histopathology 2000;36:544
Uses by pathologists
- Most specific T cell antibody; usually used to identify T cells in benign and malignant disorders; most antibodies are directed against epsilon chain
- CD3 in IHC stains both membrane and cytoplasm and stains both T cells and NK cells, thus NK cell processes / lymphomas are CD3 by IHC
- Flow cytometry can distinguish surface from cytoplasmic CD3 and therefore T cells (surface CD3+ from NK cells (surface CD3-)
- Flow cytometry can also distinguish T cells with surface CD3 (mature T cells) from T cells with cytoplasmic CD3 but without surface CD3 (T lymphoblasts)
- CD3 / CD20 combined immunostains are often performed in initial cytological evaluation of lymphoid rich pleural effusions but their cost effectiveness has been questioned (Diagn Cytopathol 2012;40:565)
- Does not improve detection of gluten sensitive enteropathy when H&E sections are normal (Mod Pathol 2013;26:1241)
Microscopic (histologic) images
Positive staining - normal
- Thymocytes, peripheral T cells (cytoplasmic expression at early T cell differentiation, then membranous expression) (Adv Biol Regul 2019;74:100638, Nat Methods 2017;14:531)
- NK cells (CD3 epsilon, cytoplasmic in 56%, not membranous); also Purkinje cells of cerebellum
- Note: nonspecific cytoplasmic staining may be present in plasma cells and macrophages (faint reactivity)
Positive staining - disease
- 80% of T cell lymphomas, NK cell lymphoma (cytoplasmic, not membranous), reactive T cells in lymphomatoid granulomatosis, lymphomatoid papulosis and precursor T cell acute lymphoblastic leukemia (pre-T ALL) (cytoplasmic staining, cCD3) (Rev Med Interne 2013;34:349, Adv Biol Regul 2019;74:100638)
- Small T lymphocytes surrounding LP cells in nodular lymphocyte predominant Hodgkin lymphoma (T cell rosettes, usually CD57+)
- Variable in B cell neoplasms (particularly in those with expression of EBV); e.g., in B cell non-Hodgkin lymphoma (B NHL) with plasmablastic differentiation, primary effusion lymphoma and pyothorax associated lymphoma (Mod Pathol 2018;31:718, Am J Surg Pathol 2022;46:353, Am J Surg Pathol 2002;26:724)
- Polykaryocytes (Warthin-Finkeldey) in various benign and malignant disorders (e.g., Kimura lymphadenitis, measles infections, HIV lymphadenitis) (Am J Clin Pathol 1992;97:179)
Negative staining
- B cells, histiocytes and histiocytic lesions, osteoblasts
- Most B cell lymphomas, but aberrant staining occurs
- Aberrant loss / dim positivity of CD3 in some cases of:
- Mycosis fungoides (Am J Clin Pathol 2000;114:467, Cytometry B Clin Cytom 2021;100:132, Blood 2005;105:3768)
- Anaplastic large cell lymphoma (Blood 2005;105:3768)
- Angioimmunoblastic T cell lymphoma (Am J Clin Pathol 2006;126:29, Blood 2005;105:3768)
- NK large granular lymphocyte leukemia
- Reed-Sternberg cells are negative in classic Hodgkin lymphoma (Cytometry B Clin Cytom 2019;96:116)
- LP cells in nodular lymphocyte predominant Hodgkin lymphoma are CD3- but may be surrounded by CD3+ T cell rosettes (Semin Hematol 1999;36:242)
- Small cell carcinoma, melanoma, myeloid sarcoma, Ewing sarcoma and posttransplant lymphoproliferative disorders
Flow cytometry description
- Adult T cell leukemia / lymphoma often has abnormally low CD3 T cell population (Am J Clin Pathol 2005;124:199, Virol J 2007;4:85)
- Angioimmunoblastic T cell lymphoma has decreased or absent CD3 expression (~60% of cases) (Leuk Lymphoma 2016;57:2804)
Sample pathology report
- Lymph node, excision:
- Peripheral T cell lymphoma, TBX21 (see comment)
- Comment: Lymph node with polymorphous infiltrate with atypical lymphocytic cells. The tumor cells are positive for CD3 with coexpression of CD4, CD2, CD5 and loss of CD7. CD8 marks reactive cytotoxic T cells. TFH markers (PD-1, ICOS, BCL6, CD10, CXCR13) remain negative. The tumor cells coexpress TBX21 / T bet and CXCR3 but remain negative in GATA3 and CCR4 (Blood 2019;134:2159).
Board review style question #1
Board review style answer #1