CD200
From haematologyetc.co.uk
- Summary
- CD200 is not lineage specific being seen in a lymphoid and myeloid disorders but has an role in diagnosis: CD200 expression aids the distinction between CLL where expression is consistent and mantle cell lymphoma (MCL) where expression is rare. It is important to realise that CD200 is not a CLL-specific marker and is also expressed on a wide range of other neoplastic B cell types
Normal expression and function
CD200 is a membrane glycoprotein that braodly delivers an inhibitory signal for inflammation in diverse tissues. CD200 is commonly expressed on cells of hematopoietic lineage, specifically macrophages, dendritic cells, neutrophils, mast cells and eosinophils, as well as B cells and activated T cells.
Diagnostic role
- CD200 is consisently expressed in chronic lymphocytic leukemia CLL, including cases with atypical morphology or atypical expression of other surface markers
- CD200 not usually expressed by MCL, making CD200 a particularly useful marker for discrimination between CLL and MCL. Note however that expression of MCL has been reported in a small number of cases so the distinction is not absolute
- CD200 is overexpressed by many different cell types and is neither lineage nor stage-specific, being expressed by B-cell progenitors and nearly all precursor B lymphoblastic leukemias. It is expressed by over 70% of myelomas, and hairy cell leukemia also exhibits a high level of staining
- expression in AML is also recorded
Other useful information
CD200 is also expressed on endothelial neuronal cells and cells of the reproductive organs ovaries and placental trophoblasts.
SUMMARY TABLES
| Expression in primitive cell types | |||||||
|---|---|---|---|---|---|---|---|
| AML | CMML | B ALL | BL | T ALL | ETP ALL | MPAL | Hgn |
| 40-80% | 20-40% | 80-100% | 80-100% | <5% | 20-40% | 20-40% | 80-100% |
| Expression in mature B cell neoplasms | |||||||
|---|---|---|---|---|---|---|---|
| CLL | MCL | FL | MZL | HCL | DLBCL | LPL | PCL |
| 80-100% | <5% | <5% | 5-20% | 80-100% | 5-20% | 5-20% | 40-80% |
Notes: expression is common but selective in mature B-lymphoproliferative disorders, with expression being rare in MCL and FL
| Expression: mature T cell neoplasms | ||||||
|---|---|---|---|---|---|---|
| ATLL | CTCL Sezary | T-PLL | T-LGL | NK-LGL | ||
| limited | limited | limited | limited | limited | ||
Notes: limited reports are consistent with expression being uncommon in T-lymphoproliferative disorders, but expression has been described in angioimmunoblastic lymphoma