CD79a
From haematologyetc.co.uk
- Summary
- A pan B-cell marker with relatively high specificity for the identification of B-lineage. CD79a is expressed initially in cytoplasm of early B cells, before appearing on the membrane at the time heavy chains of immunoglobulin become expressed.
- Other relevant information
CD79a expression is recognised on some AML and T-ALL cases so caution should be exercised particularly where other features are atypical. Like CD19, expression of CD79a is more often associated with aml that has t 8;21 translocation though less common
Normal expression and function
CD79a associates with CD79b and the immunoglobulin chains form part of the B-cell receptor (BCR). CD79a and CD79b each mediate intracellular signalling. However the two chains are expressed slightly differently in B cells - CD79a is a more lineage-specific marker than CD79b and expression is acquired at a very early stage of B-lymphocyte formation. CD79a is expressed initially in cytoplasm before appearing on the membrane of mature cells, persisting until plasma cell differentiation when it is progressively lost.
Diagnostic role
- CD79a is a reliable marker of B-lymphocyte lineage with low levels of aberrant expression; it is more specific for B-cell lineage than CD19 or CD20, although it may rarely be expressed on other cell lineages.
- in ALL expression of CD79a is acquired in the cytoplam at an early stage of B-lineage commitment making it useful for identification of more primitive cases of ALL
- Expression is then retained on the cell surface through at later differentiation uuntil plasma cell differentiation where about half of cases of myeloma expressing CD79A strongly and a further proportion have weak expression.
SUMMARY TABLES
Note The colour and % refer to the proportion of cases expressing the marker. Additional comments on strength, or site of expression (if relevant) are given below the table. For full details of key click here. For further information about a particular disease state click <I> adjacent to the condition name
Expression in primitive cell types | |||||||
---|---|---|---|---|---|---|---|
AML | CMML | B ALL | Burkitt | T ALL | ETP ALL <I> | MPAL <I> | Hgns <I> |
5-20% | <5% | 80-100%* | 80-100% | 5-20%** | <5% | 20-40% | 80-100% |
Notes: xxxxx
Expression in mature B cell neoplasms | |||||||
---|---|---|---|---|---|---|---|
CLL | MCL | FL | MZL | HCL | DLBCL | LPL | PCL |
80-100% | 80-100% | 80-100% | 80-100% | 80-100% | 80-100% | 80-100% | 40-80% |
Notes: xxxxx
Expression in mature T cell neoplasms* | ||||||
---|---|---|---|---|---|---|
ATLL | CTCL/Sezary | T-PLL | T-LGL | NK-LGL | ||
? <5% 5-20% 20-40% 40-80% 80-100% | ? <5% 5-20% 20-40% 40-80% 80-100% | ? <5% 5-20% 20-40% 40-80% 80-100% | ? <5% 5-20% 20-40% 40-80% 80-100% | ? <5% 5-20% 20-40% 40-80% 80-100% |
Notes: xxxxx