|T-Cell Receptor Gamma Gene Rearrangement
||The T-Cell Receptor Gamma Gene Rearrangement test is based on the detection of rearrangements of the T-cell receptor genes that occur during T lymphocyte development. T-Cell Receptor Gamma gene (TRG@) rearrangement generates DNA segments that are unique in length and sequence for a specific lymphocyte clone. Polymerase chain reaction (PCR) assays can be used to identify lymphocyte populations derived from a single cell (monoclonal populations) by detecting the unique V-J gene rearrangements present within this antigen receptor locus. Reactive lymphocytic proliferations show a polyclonal rearrangement profile.The identification of a monoclonal population in the right clinical and pathological scenario, suggests the presence of a lymphoid neoplasm (leukemia or lymphoma). Non-neoplastic lymphocytic proliferations can also present with monoclonal populations.
A comprehensive T-cell clonality test that combines both the T-cell Receptor Beta and Gamma gene assays is available. Please see test codes #9217 (PB, BM, T) and #9245 (FFPE).
If the cell lineage is not known, this test can be combined with the Comprehensive B-Cell Clonality Analysis for detection of clonal B-cell proliferations. Please see test codes #9202 (PB, BM, T) or #9240 (FFPE).
To order this test on FFPE samples, please see test code #9235.
||This assay employs multiple consensus DNA primers that target conserved genetic regions within the TRG@ gene locus. The methodology used (Invivoscribe ASR reagents, VDJ recombination) is based on data produced by independent testing centers throughout Europe in a collaborative study known as the BIOMED-2 Concerted Action. Unique rearrangements products are amplified by PCR followed by size determination using capillary electrophoresis. A clonal population of cells will produced one or two prominent amplicons within the expected size range. In contrast, DNA from normal polyclonal populations will produce amplicon products that reflect the heterogeneous population of V-J rearrangements in a Gaussian distribution.