Immunophenotypic diagnosis of CLL


CD45 CLL.jpg

Typical CD45/SSC plot of CLL

The cells generally lie close to the position of normal lymphocytes. However, CLL cells may have lower expression of CD45 than typical B or T cells and may form a less tight group since the expression level of CD45 can be more variable (compare with position of normal lymphocytes here: CD45 gating)

Markers useful in diagnosis of CLL (Click on marker name for more detailed information):

  • CD19: Should be detected, but intensity is generally low in CLL
  • CD5: Should be expressed at moderate intensity in CLL (note: also on expressed on MCL and occasionally on other LPD)
  • CD23 Has expected expression in CLL often at low intensity (generally absent in MCL but variably present on other LPD)
  • CD79b Similar to CD19, this marker is expected to be expressed, but intensity is generally low in CLL
  • sIg: Expect either light chain restriction with low intensity, or undetectable
  • FMC7 A marker of B-cell activation that should have low or absent expression (high expression is particularly seen in PLL and hairy cell-like disorders)
  • CD200 Expressed on most CLL cases as well as other B-LPD, but is most frequently absent in MCL

Optional markers (extended panel for atypical cases):

  • CD20 A pan B-cell marker with expected expression in CLL, but intensity is generally low
  • CD43 A pan B-cell marker with expected expression in CLL; frequently but not always absent in MCL

Note Where markers are atypical consider alternative diagnoses:click for summary