CD Markers
CD22
Copyright: 2003-2021, PathologyOutlines.com, Inc.
PubMed Search: CD22[title]
CD22
Author: Nat Pernick, M.D.
Topic Completed: 1 May 2014
Minor changes: 2 October 2020
Copyright: 2003-2021, PathologyOutlines.com, Inc.
PubMed Search: CD22[title]
Table of Contents
Definition / general | Terminology | Pathophysiology | Clinical features | Uses by pathologists | Microscopic (histologic) images | Positive staining - normal | Positive staining - disease | Negative stainingCite this page: Pernick N. CD22. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cdmarkerscd22.html. Accessed January 15th, 2021.
Definition / general
- Pan B cell marker helpful for diagnosis of hairy cell leukemia
- References: OMIM #107266
Terminology
- Also called B lymphocyte cell adhesion molecule (BL-CAM), Sialic acid binding immunoglobulin-like lectin / Siglec-2
Pathophysiology
- Inhibits B cell receptor signaling via alpha 2,6 sialic acid ligand binding activity (Front Immunol 2012;2:96); also binds CD45 and has adhesion properties of a lectin (J Exp Med 2002;195:1207)
- May localize B cells in lymphoid tissues
- Ligand is CD75
- CD22 internalizes within the cell and recycles (Traffic 2014;15:255)
Clinical features
- Shows variability in flow cytometry expression between specimens from same patient (Am J Clin Pathol 2002;117:615), may be due to delayed processing (Cytometry B Clin Cytom 2011;80:83)
- Leukemic cells from infants with newly diagnosed preB leukemia may express CD22 with exon 12 deletion (Proc Natl Acad Sci U S A 2010;107:16852)
- Epratuzumab and other anti-CD22 antibodies may have therapeutic value as part of radioimmunotherapy
- Non-Hodgkin lymphoma (J Clin Oncol 2010;28:3709, Blood 2011;118:4053), including relapsed / resistant hairy cell leukemia (J Clin Oncol 2012;30:1822)
- ALL (Cancer 2013;119:2728, Lancet Oncol 2012;13:403)
- SLE and other autoimmune diseases (Blood 2013;122:3020)
- CD22 may be a component of immunotoxins (Eur J Immunol 2012;42:2792)
Uses by pathologists
- Pan B cell marker; helpful for diagnosis of hairy cell leukemia
- Aberrant CD22 expression is useful to detect monoclonal B cells of CLL admixed with benign polyclonal B cells (Am J Clin Pathol 2005;123:826)
Microscopic (histologic) images
Images hosted on other servers:
High grade B cell lymphoma, fig F
B ALL, fig D
Burkitt lymphoma, fig D
Normal tonsil
Positive staining - normal
- B cells (considered a pan B cell antigen), dendritic cells and basophils
Positive staining - disease
- Hairy cell leukemia; also pre B ALL
- Blastic plasmacytoid dendritic cell neoplasm (Cytometry B Clin Cytom 2009;76:237)
- Staining of other B cell leukemias / lymphomas is variable (Am J Clin Pathol 2002;117:615)
Negative staining
- Myeloblasts, plasma cells
- Lung carcinoma (Cancer Res 2014;74:263 but see Cancer Res 2012;72:5556)
