CD43, leukosialin, sialophorin

CD43 is a transmembrane protein with functions in T-cell immunity. Leu22, DFT-1 and MT1 identify epitopes in formalin-fixed, paraffin embedded tissue2.

Immunohistochemical expression

• normal T lymphocytes

• myeloid cells and macrophages

• plasma cells

• variable by megakaryocytes

• not normal or reactive B cells

• brain cells1

• 90% of T-cell lymphomas including pre-T lymphoblastic lymphomas

• 30% of low-grade B cell lymphomas, particularly those that are CD5+, including:

  • small lymphocytic lymphomas

  • all mantle cell lymphomas,

  • B-cell lymphoblastic lymphomas

  • some MALTomas (20% of cases)

  • it does not stain hairy cell leukaemias or follicle centre cell lymphomas

• 69% of B cell ALL

• 97% of T cell ALL

• 44% of anaplastic large cell lymphomas

• all extramedullary myeloid tumours / granulocytic sarcomas Some myeloid sarcomas are positive for CD43 while being negative for other myeloid-associated markers (the so-called CD43-only phenotype).

• some myelomas / plasmacytomas

• some non-haematopoietic neoplasms3

Diagnostic utility

• Because non-neoplastic B cells are CD43 negative, positivity in B cells is evidence of neoplasia.

See: Comparison of sensitivities and specificities of T and B cell markers

• Diagnosis of Adenoid cystic carcinoma

References

1 M Steward et al. Production and characterization of a new monoclonal antibody effective in recognizing the CD3 T-cell associated antigen in formalin-fixed embedded tissue. Histopathology 1997;30:16-22.

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

3 Fernandez-Rodriguez J, Andersson CX, Laos S, et al. The leukocyte antigen CD43 is expressed in different cell lines of nonhematopoietic origin. Tumour Biol 2002; 23:193-201

4 Woo VL, Bhuiya T,Kelsch R Assessment of CD43 expression in adenoid cystic carcinomas, polymorphous low-grade adenocarcinomas, and monomorphic adenomas. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2006; 102:495-500

©SMUHT/PW Bishop