T-cell clonality (TCR)
|Category||Specialist Integrated Haematological Malignancy Diagnostic Service (SIHMDS) >> Molecular Pathology|
Immunoglobulin gene rearrangements are formed from the earliest stages of B-cell and T-cell development onwards. Random coupling between one of many V, (D) and J genes results in the formation of a unique V(D)J exon that encodes the actual antigen-binding moiety of the Ig or TCR chain. Owing to the huge diversity in Ig/TCR rearrangements, the diversity of different Ig or TCR molecules is estimated to be in the order of 1012. Consequently each lymphocyte has a unique antigen receptor molecule on its membrane and the chance that two different lymphocytes coincidentally bear the same receptor is almost negligible. Hence, identical rearrangements are not derived from multiple independently generated cells, but rather reflect the clonal nature of the involved cell population.
The human T cell receptor gamma locus is located on chromosome 7p15-p14. T-cell clonality analysis targets T-cell receptor (TCR) gene TCR gamma (TCRG);Variable (V), diversity (D), and joining (J) genes of antigen receptor gene complexes form rearrangements during lymphocyte development to yield highly diverse, functional coding sequences. The process is also referred to as V(D)J recombination and is specific to a particular clone, thus yielding V(D)J exons of different size in different clones (see figure 1& 2). The resulting rearranged V(D)J exons can be amplified using PCR and a fragment analysis performed using capillary analysis of fluorescently labelled products.
For diagnostic testing in lymphoid malignancies such as lymphomas.
|Sample & container required||4ml Blood or bone marrow in EDTA (lavender/purple top) within 72 hours of collection|
|Sample volume||1 mL blood OR bone marrow|
Please ensure the sample is sent to the lab ASAP after collection as it must be received within 72 hours.
|Turnaround time||14 calendar days|