CD45RA (4KB5, MB1, KiB3, MT2)

This group of antibodies recognise specific isoforms of CD45.

Antibodies are effective on paraffin-embedded tissue2.

Immunohistochemical expression

• most B lymphocytes

  • follicle centre cells (MB1 and KiB3 but not MT2)

  • mantle cells (MB1 and KiB3 but not MT2)

• some medullary thymocytes

• post-thymic naive T lymphocytes

• 80% of B cell lymphomas using MB1 or KiB3, 57% using MT2.

  • lymphocytic lymphoma is most commonly positive

  • MT2 positivity is seen in 57% of follicle centre cell lymphomas but not in reactive follicles.

• 10% of T cell lymphomas

Diagnostic utility

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

References

1M 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.

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

©SMUHT/PW Bishop