CD21 by IHC-12376 - Technical only, 12379 - Technical & interpretation

Test info

CD21 by IHC
12376 - Technical only, 12379 - Technical & interpretation

All IHC stains will include a positive control tissue

  • CD21 is often used to identify the follicular dendritic cell network in follicular lymphomas, and in follicular dendritic sarcomas
  • In T-cell lymphomas, this antibody is used to identify the hyperplastic dendritic islands in angioimmunoblastic T-cell lymphomas, and in some cases of pleomorphic T-cell lymphomas
  • CD21 will also illustrate the follicular dendritic meshwork in reactive germinal centers seen in normal and hyperplastic lymph nodes, as well as reactive germinal centers in some lymphomas (i.e. mantel cell lymphoma, MALT lymphoma)
  • Precursor B and T cell lymphomas (lymphoblastic lymphomas), Burkitt’s lymphomas, plasmacytomas and hairy cell leukemias lack follicular dendritic cells and will thus be CD21 negative
  • CD21 can also identify the follicular dendritic cell meshwork in nodular lymphocyte-predominate Hodgkin’s disease



Submit a formalin-fixed, paraffin-embedded tissue


Formalin-fixed, paraffin-embedded (FFPE) tissue block


FFPE tissue section mounted on a charged, unstained slide


Ambient (preferred)

  • Unlabeled/mislabeled block
  • Insufficient tissue
  • Slides broken beyond repair


AHL - Immunohistochemistry
Mo - Fr
1 - 2 days

Immunohistochemical staining and microscopic examination

Clinical and Interpretive info


If requested, an interpretive report will be provided



  • CD21 is a trans-membrane 145 kDa glycoprotein in the family of complement regulatory proteins, expressed on some mature B cells and on follicular dendritic cells
  • CD21 is a receptor for complement C3d, which mediates the phagocytosis of complement-coated particles
  • CD21 is also a receptor for EBV

Staining pattern

  • Cell surface membrane staining


  1. Chan JKC: Proliferative lesions of follicular dendritic cells: An overview, including a detailed account of follicular dendritic cell sarcoma, a neoplasm with many faces and uncommon etiologic associations. Adv Anat Pathol, 4, 6; 387-411, 1997.
  2. Mason DY et al: Immunohistochemical analysis of monoclonal anti B-cell antibodies. Leukocyte Typing II, Vol. 2, Human B-lymphocytes. Springer-Verlag, 1986; 245-55.


88342 - 1st stain
88341 - each additional stain