CD23 is a transmembrane glycoprotein expressed by different hematopoietic cells and is a low-affinity receptor for IgE.  It is also involved in promoting survival of B-cells in the germinal center.  CD23 is useful as a follicular cell dendritic cell marker and is classically expressed in cases of CLL/SLL.  CD23 has been identified in many types of lymphomas, but is most commonly used to differentiate between CLL/SLL (CD23+) and mantle cell lymphoma (CD23-).  This testing is typically performed by flow cytometry, but immunohistochemisty for CD23 is available.  Expression of CD23 has been associated with better prognosis (at least in limited published data) in follicular lymphoma, CLL/SLL, mantle cell lymphoma, and diffuse large B-cell lymphoma dependent upon expression characteristics.  CD23 is not commonly performed/used as a prognostic marker for B-cell lymphomas.

 

Rarely CD23 may be expressed in cases of Hairy cell leukemia (17%) and DLBCL (16%).  Approximately 70% of Mediastinal large B-cell lymphoma cases express CD23.  Practically, this IHC marker is used as a follicular dendritic cell marker and to help differentiate CLL/SLL from mantle cell lymphoma.  Follicular dendritic cell tumors will also express CD23 like CD21.  CD21 is more sensitive compared to CD23 as a follicular dendritic marker.

 

Follicular Lymphoma (FL) – CD23 has been found to be expressed in some cases of FL, especially from inguinal lymph nodes, and prognosis appears comparatively better.   Olteanuet. al found that 87% of inguinal lymph nodes expressed CD23, compared to 61% from other sites, and that survival was prolonged more in CD23+ cases. 

 

Diffuse Large B-Cell Lymphoma – A subset of DLBCLs may express CD23, which may have a better prognosis (CD23 is not commonly performed for this purpose).

 

Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL) – CD23 expression is characteristic of CLL/SLL, particularly in comparison to another CD5+ lymphoma, mantle cell lymphoma.  Strong membrane expression has been associated with a better outcome.  DiRaimondo,et. al found ~6% of CLL cases to be CD23 negative (flow cytometry), and they had a worse prognosis.  Many of these cases may have been misdiagnosed mantle cell lymphomas.

 

Mantle Cell Lymphoma (MCL) – CD23 is characteristically negative in MCL, which helps to differentiate it from CLL/SLL.  However, ~21% of cases of MCL were found to be CD23+ by Gao,et. al, and other studies have shown CD23 expression in MCL ranging from 0% to 45% (most data appears to be based on flow cytometry).

Bone Marrow IHC.  Torlakovic, EE, et. al. American Society for Clinical Pathology Pathology Press © 2009.  pp. 69.

 

Linderoth J, Jerkeman M, Cavallin-Stahl E, et al. Immunohistochemical expression of CD23 and CD40 may identify prognostically favorable subgroups of diffuse largeB-cell lymphoma: a Nordic Lymphoma Group Study.ClinCancer Res.2003;9:722-728.

 

Olteanu H, Fenske TS, Harrington AM, Szabo A, He P, Kroft SH. CD23 Expression in Follicular Lymphoma: Clinicopathologic Correlations. Am J Clin Pathol. 2011;135: 46–53. doi:10.1309/AJCP27YWLIQRAJPW

 

Gao J, Peterson L, Nelson B, Goolsby C, Chen Y-H. Immunophenotypic variations in mantle cell lymphoma. Am J Clin Pathol. 2009;132: 699–706. doi:10.1309/AJCPV8LN5ENMZOVY

 

Troxell ML, Schwartz EJ, van de Rijn M, Ross DT, Warnke RA, Higgins JP, et al. Follicular dendritic cell immunohistochemical markers in angioimmunoblastic T-cell lymphoma. Appl Immunohistochem Mol Morphol. 2005;13: 297–303.

 

Dalton RR, Admirand JH, Medeiros LJ. Small Lymphocytic Lymphoma. Pathology Case Reviews. 2004;9: 7.

 

DiRaimondo F, Albitar M, Huh Y, O’Brien S, Montillo M, Tedeschi A, et al. The clinical and diagnostic relevance of CD23 expression in the chronic lymphoproliferative disease. Cancer. 2002;94: 1721–1730. doi:10.1002/cncr.10401