CD5 is a T-cell marker, although it is the least specific of the group (CD2, CD3, CD4, CD5, CD7, and CD8). CD5 co-expression on B-cells is characteristic of certain lymphomas, specifically CLL/SLL and Mantle Cell Lymphoma. A subset of DLBCLs may also express CD5, although there may be a question as to if that represents de novo lymphoma vs. “transformed” CLL/SLL or Mantle Cell Lymphoma.
The expression level of CD5 will often be less than the expression on background T-cells in cases of CLL/SLL and Mantle Cell Lymphoma, and this expression differentiation may be helpful by both IHC and flow cytometry.
CD5 Expression
- CLL/SLL (often dimmer than background T-cells) – Typically co-express CD5 & CD23. A small portion of cases may be CD5-. LEF1 is a newer marker that is expressed in CLL/SLL and may be helpful for confirming atypical cases of CLL/SLL.
- Mantle Cell Lymphoma – Approximately 12% may not express CD5. SOX11, Cyclin D1 (bcl-1) and FISH for t(11;14) are helpful in atypical cases.
- Nodal Marginal Zone Lymphoma – Up to 8-9% of cases may have co-expression of CD5
- Normal T-cells
- Diffuse Large B-cell Lymphoma (small subset, ~5%) – Associated with more aggressive course, bone marrow involvement, and CNS involvement.
- Lymphoplasmacytic Lymphoma (~5%)
- T-cell Lymphomas
Many different B and T-cell lymphomas have reported CD5, and while it is a useful marker, specificity should be determined with a broader set of markers in addition to the morphology of the lymphoma. Molecular studies may also be helpful.
Photomicrographs
References
Dong HY, Gorczyca W, Liu Z, Tsang P, Wu CD, Cohen P, et al. B-cell lymphomas with coexpression of CD5 and CD10. Am J Clin Pathol. 2003;119: 218–230. doi:10.1309/U98A-DVKU-C26R-2RJA
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
Dalton RR, Admirand JH, Medeiros LJ. Small Lymphocytic Lymphoma. Pathology Case Reviews. 2004;9: 7.
Jaso JM, Yin CC, Wang SA, Miranda RN, Jabcuga CE, Chen L, et al. Clinicopathologic Features of CD5-Positive Nodal Marginal Zone Lymphoma. Am J Clin Pathol. 2013;140: 693–700. doi:10.1309/AJCPEMVXES72DUIF
Went P, Zimpfer A, Tzankov A, Dirnhofer S. CD5 expression in de novo diffuse large B-cell lymphomas. Annals of Oncology. 2009;20: 789–790. doi:10.1093/annonc/mdn793
Cook JR. Nodal and leukemic small B-cell neoplasms. Mod Pathol. 2013;26 Suppl 1: S15–28. doi:10.1038/modpathol.2012.180
Bone Marrow IHC. Torlakovic, EE, et. al. American Society for Clinical Pathology Pathology Press © 2009. pp. 27.