Cytometry

Cytometry is the quantification and measurement of cells.

It is typically done in the context of lymphoma via one of two techniques:

1. Flow cytometry.
2. Laser scanning cytometry (LSC).

Common markers

• CD3, CD4, CD8, CD5, CD7.
• CD19, CD20, FMC7.
• Kappa, lambda.

Normal

• T-cells to B-cells usually 1:1.
• In reactive nodes T-cells predominate.
• Normal thymic tissue has cells that are positive for both CD4 and CD8.
• Kappa (k) and lambda (l) are not expressed by the same cell.
• Rule-of-thumb for normal k:l range is: <6:1 and 1:<3.
  • Lambda dominance is less common.

GS guidelines - non-malignant is:

• CD19 ~= CD20.
• CD5 = CD3.
• CD2 > CD3 and CD5.
• CD4 + CD8 ~= CD3.
• CD7 = the smallest number of T-cell.

Abnormal

• CD4>CD8 predominance classically seen in:
  • Sarcoidosis.
  • Hodgkin's lymphoma.
• T cell lymphoma - loss of one of the T-cell markers (CD2, CD3, CD5 or CD7).
  • CD7 is usually the first to be lost.

Sample report

B-Cell Associated Markers

• CD10.
  • Germinal centre marker.
  • +ve in: follicular lymphoma, Burkitt lymphoma, precursor lymphoblastic leukemia.
• CD19.
  • B cell marker.
  • Should be ~=CD20.
• CD20.
  • B cell marker.
  • Should be ~=CD20.
• CD23.
  • +ve in CLL/SLL.
• FMC7
  • B cell marker.
• Kappa+CD19/20+.
  • B cell clonality.
• Lambda+CD19/20+
  • B cell clonality.

T-Cell Associated Markers

• CD3.
  • CD3 ~= CD4 + CD8.
  • Usually: CD2 > CD3 > CD7.
• CD5.
  • Usually: CD2 > CD5 > CD7.
• CD4.
  • CD3 ~= CD4 + CD8.
• CD8.
  • CD3 ~= CD4 + CD8.
• CD7.
  • Usually least prevalent T cell marker; < CD2, < CD3, < CD5.
• CD2.
  • Usually most prevalent T cell marker; > CD3, > CD5, > CD7.

NK-Cell Associated Markers

• CD56.
• CD16.

Miscellaneous Markers

• CD11c -- usu. +ve in marginal zone lymphoma.
• CD14.

See also

• Haematopathology.
• Flow cytometry.
• Cytopathology.