Flow cytometry: Chronic Lymphocytic leukaemia
From haematologyetc.co.uk
Background to flow cytometric diagnosis
Typical CLL can be diagnosed with some confidence using flow cytometry. However, individual markers may not be expressed in all cases - particularly it may be difficult to distinguish atypical CLL from some cases of MCL or MZL.
- Atypical features should always be reported and the possibility of alternative diagnoses acknowledged.
- Cases with a low lymphocytosis (<1x109) may represent monoclonal B-lymphocytosis with CLL phenotype (click here for diagnostic criteria).
Immunophenotype of CLL | |||
---|---|---|---|
CD45 expression in CLL | |||
Typically expression is waeker than normal T or B cells with variable expression by cells causing the cells to have a wide spread of CD45 intensity. However, this is not always seen. | |||
Major markers useful in CLL diagnosis | |||
Marker | Freq | Level | Comment |
CD19 | - | Expression is expected, but less strong than normal B cells | |
κ/λ | Expect weak restricted κ or λ or absent expression | ||
CD5 | - | Characteristic of CLL, usually less strong than on T cells | |
CD23 | - | Characteristic of CLL, although can rarely be weak or absent | |
CD79b | wk | Expression is expected, but characteristically weak | |
CD200 | - | Characteristically positive in CLL and negative in MCL | |
FMC7 | May be expressed by atypical cases, generally absent | ||
Other relevant markers | |||
CD10 | - | Infrequent in CLL, consider FL if detected | |
CD11C | wk | Expressed in some cases, but tends to be weak | |
CD20 | wk | Expression is expected, but characteristically weak | |
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 | |
CD103 | - | Not expressed by CLL, consider HCL if found | |
CD138 | - | Predominantly expressed at plasma cell differentiation |
Key to table:
Key to colour code for expression frequency Click for link
Key to expression strength code and use Click for link