CD5

CD5 is a 67 kDa glycoprotein.

Antibody clone NCL-CD5-4C7 is effective on paraffin-embedded tissue3. The Leu1 antibody will also stain paraffin-embedded tisue after antigen retrieval and tyramine-enhanced detection.

Immunohistochemical expression

Thymocytes
The majority of T-cells
A small subset of lymphocytes (B-1 lymphocytes) which may increase in number in auto-immune conditions.

Diagnostic utility

T-cell lymphomas, including most T-LBL and some ALCL. Aberrant loss of expression may occur in T-cell lymphomas and may help to distinguish them from reactive T-cell proliferations2. Loss of CD5 may occur in extranodal T/NK cell lymphoma, intestinal T-cell lymphoma, hepatosplenic T-cell lymphoma and some cutaneous T-cell lymphomas.
Expressed in 85% of T-ALL/T-LBL
3-10% of AML
Expressed by > 90% of B-CLL, including transformed CLL
mantle cell lymphoma
almost all other low grade B cell lymphomas are CD5 negative
some diffuse large B cell lymphomas are CD5-positive, possible associated with a worse prognosis.
Differentiation of T-cell lymphoma (CD5+) from NK cell lymphoma (CD5-), for example in nasal lymphomas5.
Pomplun found CD5 possibly useful in distinguishing thymic carcinomas from pulmonary carcinomas1. Several other studies have reported that CD5 is a promising marker for thymic carcinoma. Other epithelial neoplasms generally do not express this marker, although there may be focal expression of CD5 in B3 thymomas, 15% of pulmonary squamous cell carcinomas, malignant mesothelioma, urothelial carcinoma and some adenocarcinomas6. Of note, the sensitivity and specificity depends on the clone of the anti-CD5 antibody: clone 54/F6 is less sensitive but more specific4. An panel consisting of CD5, CK5/6, PLAP, TTF-1, and CD57 is reportedly useful for the separation of thymic neoplasms from other epithelial malignancies involving the mediastinum7.

References

1 S Pomplun. Immunohistochemical markers in the differentiation of thymic and pulmonary neoplasms. Abstract 158, Pathological Society of Great Britain and Ireland January 2001.

2 Bakels, V., van Oostveen, J.W., van der Putte, S.C., Meijer, C.J. and Willemze, R. Immunophenotyping and gene rearrangement analysis provide additional criteria to differentiate between cutaneous T-cell lymphomas and pseudo- T-cell lymphomas. Am J Pathol 1997;150:1941-9.

3 Leong A S-Y, Cooper K and Leong FJ W-M. Manual of diagnostic antibodies for immunohistology. 2nd edition, 2003

4 Pan, C. C., P. C. Chen, et al. (2003). "Expression of calretinin and other mesothelioma-related markers in thymic carcinoma and thymoma." Hum Pathol 34(11): 1155-62.

5 Kitamura A, Yamashita Y, Hasegawa Y, et al. Primary lymphoma arising in the nasal cavity among Japanese. Histopathology 2005; 47:523-32

6 Nonaka D, Henley JD, Chiriboga L, et al. Diagnostic utility of thymic epithelial markers CD205 (DEC205) and Foxn1 in thymic epithelial neoplasms. Am J Surg Pathol 2007; 31:1038-44

7 Saad RS, Landreneau RJ, Liu Y, et al. Utility of immunohistochemistry in separating thymic neoplasms from germ cell tumors and metastatic lung cancer involving the anterior mediastinum. Appl Immunohistochem Mol Morphol 2003; 11:107-12