Flow cytometry: Chronic Lymphocytic leukaemia
From haematologyetc.co.uk
Background
Typical CLL can be diagnosed with some confidence using flow cytometry.
However, individual markers may not be expressed in all cases - this can cause diagnostic difficulty particularly in distinguishing CLL from atypical cases of MCL or MZL. If this is the case then the atypical features should be reported, and the possibility of alternative diagnoses acknowledged.
Note also that cases with a low lymphocytosis (<1x109) may represent monoclonal B-lymphocytosis with CLL phenotype (click here for more).
Immunophenotype of CLL | |||
---|---|---|---|
Major markers useful in CLL diagnosis | |||
Marker | Freq | Level | Comment |
κ/λ | Expect weak restricted κ or λ or absent expression | ||
FMC7 | May be expressed by atypical cases, generally absent | ||
CD5 | - | Characteristic of CLL, usually less strong than on T cells | |
CD10 | - | Infrequent in CLL, consider FL if detected | |
CD11C | wk | Expressed in some cases, but tends to be weak | |
CD19 | - | Expression is expected, but less strong than normal B cells | |
CD20 | wk | Expression is expected, but characteristically weak | |
CD23 | - | Characteristic of CLL, although can rarely be weak or absent | |
CD25 | wk | Expressed by many cases of CLL but characteristically weak | |
CD38 | wk | Expressed by some cases of CLL, typically weak | |
CD43 | - | Similar to CD200, may be helpful in some cases | |
CD79b | wk | Expression is expected, but characteristically weak | |
CD103 | - | Not expressed by CLL, consider HCL if found | |
CD138 | - | Predominantly expressed at plasma cell differentiation | |
CD200 | - | Characteristically positive in CLL and negative in MCL |
Key to table:
Markers most useful in initial diagnosis are underlined in blue text
Key to colour code for expression frequency Click for link
Key to expression strength code and use Click for link