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TCRαβ: Difference between revisions

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:<span style="color:navy">'''Summary'''</span>
:<span style="color:navy">'''Summary'''</span>


:In the detection of haematological malignancy the purpose of detecting γδ T cells is to define particular T cell lymphomas (αβ T cells strongly predominate in normal blood). However care must be taken when small populations of γδ T cells are detected however, since these may arise in response to viral or other immune responses.
:The αβ TCR is the primary form in health accounting for around 95% of circulating T cells. Alteration of that normal expression pattern may suggest a neoplastic or inflammatory disorder




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:<span style="color:navy">'''Background'''</span>
:<span style="color:navy">'''Background'''</span>


:T cell receptor (TCR) analysis in blood is not generally helpful in indicating T-cell clonality since around 95% express of circulating T cells express αβ chains and only 5% have gamma γδ. In tissues this can be different since the γδ T cells are more abundant in skin and intraepithelial areas. The receptors also have different functions:  αβ T cells behave as elements of the adaptive immune system while γδ cells have an innate immune function similar to NK cells.  
:The αβ chains expressed are expressed as part of the T-cell receptor (TCR) complex - these are the antigen recognising parts of the complex. T cells expressing this receptor are referred to as αβ T cells.




:<span style="color:navy">'''Diagnostic Use'''</span>
:<span style="color:navy">'''Diagnostic Use'''</span>


*A predominant population of γδ T cells circulate may indicate a clonal proliferation most commonly will be hepatosplenic gamma-delta T-cell lymphoma  or primary cutaneous t cell lymphoma (PTCL)
*Significant populations expressing gd chains may indicate autoimmune or inflammaotory disease
*Disturbance of the ratio of αβ/γδ may be seen in reactive conditions
*γδ restriction or predominance may suggest a γδ lymphoma  
*Absence of αβ or γδ is found in NK lineage disorders
 




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Latest revision as of 21:27, 14 May 2023


Summary
The αβ TCR is the primary form in health accounting for around 95% of circulating T cells. Alteration of that normal expression pattern may suggest a neoplastic or inflammatory disorder



Background
The αβ chains expressed are expressed as part of the T-cell receptor (TCR) complex - these are the antigen recognising parts of the complex. T cells expressing this receptor are referred to as αβ T cells.


Diagnostic Use
  • Significant populations expressing gd chains may indicate autoimmune or inflammaotory disease
  • γδ restriction or predominance may suggest a γδ lymphoma
  • Absence of αβ or γδ is found in NK lineage disorders


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