Uses: commonly used marker for B cells
Positive staining (normal): Most B cells (after CD19 and CD10 expression, before CD21/22 expression and surface immunoglobulin expression), retained on mature B cells until plasma cell development; also follicular dendritic cells
Positive staining (disease): 90% of B cell lymphomas, 40% of pre B ALL/LBL; 80% of lymphocyte predominant Hodgkin’s lymphoma, dimly expressed in T cells (benign and neoplastic), spindle cell thymomas
Negative staining: non-hemaoietic cells, most T cells, plasma cells
Micro images: large B cell lymphoma, CNS diffuse large B cell lymphoma (figure A), lymphoplasmacytic lymphoma/ Waldenström macroglobulinemia in brain-figure D
Micro images (Mod Path subscribers): post-transplant lymphoproliferative disorder
References: Mod Path 2002;15:647
CD21
Aka CR2, C3d receptor, EBV receptor
Binds to Epstein Barr virus and breakdown products of complement component C3
Forms a signaling complex with CD19, CD81 and CD225
Both CD21 and CD23 are dendritic cell markers
Hodgkin’s lymphoma demonstrates disruption of follicular dendritic cell-germinal cell clusters (evaluated by CD21 and CD23)
Positive staining (normal): Mature B cells, follicular dendritic cells
Micro images (AJSP subscribers): inflammatory pseudotumor-like follicular dendritic cell tumor A, B, Hodgkin’s lymphoma A, B
Micro images (Mod Path subscribers): extranodal follicular dendritic cell sarcoma
References: AJSP 2001;25:721, AJSP 2001;25:388, Mod Path 2002;15:50
CD22
Aka B lymphocyte cell adhesion molecule (BL-CAM)May localize B cells in lymphoid tissues; binds CD45
Positive staining (normal): B cells, B-ALL
Negative staining: plasma cells
CD23
Aka low affinity IgE receptor
Regulates IgE synthesis by negative feedback
Triggers monokine release (TNF, IL-1, IL-6, GM-CSF) by monocytes
After physiologic germinal cell development, the follicular dendritic cell meshwork expands and follicular dendritic cells in the light zone of the germinal center become CD23 positive
CD23 also acts as B cell growth factor, promoting differentiation into plasma cells
Both CD21 and CD23 are dendritic cell markers
Positive staining (normal): Activated mature B cells expressing IgM or IgD, monocytes/macrophages, T cell subsets, platelets, eosinophils, Langerhans cells, follicular dendritic cells
Positive staining (disease): B-cell CLL/SLL
Negative staining: other B cells; mantle cell lymphoma
CD24
Promotes antigen dependent proliferation of B cells; prevents differentiation into plasma cells
Expressed at high levels in small cell lung carcinoma
Positive staining (normal): all B cells, granulocytes, kidney cells, epithelial cells
Positive staining (disease): carcinomas, most pre-B ALL/LBL, virtually all B cell lymphomas
Negative staining: plasma cells, multiple myeloma, T cells, monocytes, red blood cells, platelets
CD25
Aka IL-2 receptor alpha chain, exists in at least 3 forms
Limited expression may safeguard against catastrophic T-cell proliferation by immunogenic stimulus.
Positive staining: Activated B, T, macrophages
Positive staining (disease): hairy cell leukemia
CD26
Aka dipeptidylpeptidase IV, adenosine deaminase complexing protein 2
Costimulatory molecule in T cell activation
Cofactor with CD4 for HIV entry into cells
Positive staining (normal): Activated T, B cells, NK cells, macrophages, renal proximal tubular epithelial cells, small intestinal epithelium, biliary canaliculae, splenic sinus lining cells
Negative/dim staining: T cells in peripheral blood of mycosis fungoides patients, AJCP 2001;115:885
CD27
Marker of T cell activation
CD27/CD70 interactions also regulate B cell proliferation and T cell differentiation
Positive staining: T cells, memory B cells
CD28
Cell adhesion molecule; co-receptor for B cell-T cell cooperation
Promotes T cell activation
Receptor for CD80 (B7) & CD86 (BB1), found on activated B cells
Constitutive, high abundance, low affinity receptor; opposite signals are mediated by CTLA4 (CD152)
Result of T cell antigen stimulation depends on sum of effects of T cell receptor, CD28 and its ligand, CTLA4 and its ligand
CD8+, CD28+ T cells mediate antigen specific cytotoxic T cells (class I restricted) (90% of CD8+ T cells)
CD8+, CD28- T cells mediate suppressor T cells (10% of CD8+ T cells)
Positive staining (normal): CD4+ T cells (95%), CD8+ T cells (50%); activated B cells, plasma cells
Reference: 186760
CD29
Aka platelet GPIIa, beta-1 integrin, fibronectin receptor
Positive staining (normal): fibroblasts, platelets, T cells
CD30
Aka Ki-1, Ber-H2
Lymphocyte activation antigen, related to tumor necrosis factor
Doesn’t work well with B5 fixed tissue
May be involved in negative T cell selection in thymus
Interpretation: membranous staining
Positive staining (normal): granulocytes, plasma cells, activated B, T and NK cells
Positive staining (disease): infectious mononucleosis, lymphocytes infected with HIV, HTLV-1, EBV, HHV8 or hepatitis B; Reed-Sternberg cells, 90% of anaplastic large cell lymphomas, lymphomatoid papulosis, peripheral T-cell lymphomas, embryonal carcinoma of testis, primary effusion lymphoma
Micro images: Hodgkin’s lymphoma #1, #2, #3-figure 3B (primary pulmonary), #4-figure 3B, anaplastic lymphoma, embryonal carcinoma-figure 6, intratubular embryonal carcinoma-figure 4
Micro images (Hum Path subscribers): anaplastic large cell lymphoma (figure E), AIDS related primary effusion lymphoma (figure D)
CD31
Aka platelet endothelial cell adhesion molecule, PECAM-1
Encoded on #17
Most sensitive and specific endothelial marker in paraffin sections
Important role in diapedesis step of leukocyte emigration in inflammation; also angiogenesis
Note: don’t confuse CD31+ macrophages (granular, membranous expression) with a vascular tumor, AJSP 2001;25:1167
Sensitive for malignant vascular tumors; may be less sensitive for benign lesions
Interpretation: membranous stain (not cylasmic); endothelium is a positive internal control
Positive staining (normal): endothelium, platelets, macrophages and Kupffer cells, granulocytes, T / NK cells, lymphocytes, megakaryocytes, fibroblasts, osteoclasts, neutrophils
Positive staining (tumors): epithelioid hemangioendothelioma; epithelioid sarcoma-like hemangioendothelioma (AJSP 2003;27:48); other vascular tumors, histiocytic malignancies, plasmacytomas; rare carcinomas and sarcomas
Micro images: epithelioid angiosarcoma (figure 1A)
Micro images (AJSP subscribers): epithelioid sarcoma-like hemangioendothelioma, epithelioid hemangioendothelioma, epithelioid angiosarcoma, CD31+ macrophages, malignant histiocytosis
Micro images (Hum Path subscribers): hepatic cavernous hemangiomas (figure 2B)
Micro images (Mod Path subscribers): angiosarcoma (figure E)
References: AJSP 2001;25:684, Mod Path 2002:15;434
CD32
Aka Fc gamma RII
Low affinity receptor that binds to the Fc region of IgG immune complexes
If B cells are stimulated so that surface immunoglobulin receptors are coclustered with CD32 receptors, B cells do NOT proliferative and may undergo apoptosis instead of proliferation
Positive staining: macrophages, granulocytes, B cells, eosinophils, basophils, platelets
CD33
Myeloid cell antigen (also CD13); a sialoadhesin that may mediate cell-to-cell adhesion, acts as a receptor that inhibits the proliferation of normal and leukemic myeloid cells
Positive staining (normal): Precursor myeloid cells; most monocytic cells, epidermal Langerhans cells (variable)
Positive staining (disease): AML M1-M5 (75-85%), M7 (variable), CML (90%); blasts (all), some ALL
Negative staining: granulocytes, mature bone marrow cells, non-myeloid cells
CD34
Cell-cell adhesion molecule and cell surface glycoprotein
May mediate attachment of stem cells to bone marrow extracellular matrix or directly to stromal cells
Antibodies are used to quantify and purify lymphohemaoietic stem cell / progenitor cells for research and for clinical bone marrow transplantation; however, counting CD34+ mononuclear cells may overestimate myeloid blasts in bone marrow smears due to hematogones and CD34+ megakaryocytes, Archives 2002;126:823
Interpretation: membranous stain; endothelium acts as a positive internal control
Uses: possibly confirm chronic intestinal pseudo-obstruction, AJSP 2003;27:228
Positive staining (normal): hemaoietic progenitor cells, vascular endothelial cells (these cells are TdT+, HLA-DR+)
Positive staining (disease): alveolar soft part sarcoma, preB-ALL (75%), AML (40%), AML-M7 (most), chordo
