T-Cell Clonality – TCRB and TCRG Rearrangement Testing
Detection of monoclonal, polyclonal or oligoclonal populations of T-cells by PCR and fragment analysis of the TCRB and TCRG genes
A multimodality approach is used in the diagnosis of lymphomas. Diagnosis may be particularly challenging in some cases solely based on morphology and immunophenotyping. The molecular testing exploits the rearrangement of the T-cell receptor (TCR) gamma and T-cell receptor beta genes. These genes rearrange over kilobases of genetic sequence and are unique for each normal mature T-cell. A reactive process, thus will demonstrate a polyclonal expansion of T-cells with different sixe rearrangements whereas an oligoclonal process will produce a few clones and a malignant process will often demonstrate expansion of a T-cell population that originates from a single cell and hence all will have the same rearrangement. The detection of a clonal TCR gene rearrangement by polymerase chain reaction (PCR) can be extremely helpful as an aid in the diagnosis of clonal T-cell process.
If the nature of the T-cell lymphoproliferative process cannot be accurately determined by morphology and immunophenotyping, PCR-based studies for T cell receptor gene rearrangements can help in establishing clonality. The presence of a clonal T cell receptor gene rearrangement is usually (but not always) indicative of a neoplasmic process. This test can also be used to follow-up the patients post treatment to see if the clone still persists and compare the lesions from two different sites to determine if this is the same or a different clonal process.
T-cell clonality is determined by PCR and fragment analysis of fluorescently labeled products. Master mixes are commercially provided by InVivoScribe in a BIOMED-2 Assay for the TCRB and TCRG genes. Patterns consistent with polyclonal, oligoclonal and monoclonal T-cell populations are interpreted from fragment-sizing electropherograms. The tube B reaction for T gamma has been modified to provide more reliable detection of V11 rearrangements.
- Peripheral Blood: 3-5 ml, collected in EDTA (purple top) tube, store at room temperature 24 hours
- Bone Marrow: 0.5-1 ml, collected in EDTA (purple top)tube, store at room temperature, 24 hours
- Tissue: Frozen or fresh tissue may be used. A minimum of 2 x 2 x 2 mm is required (5 x 5 x 5 mm is preferred). For local facilities, we prefer the sample to be sent fresh on wet ice to arrive in the lab the same day. For outside facilities, the preferred approach is to snap freeze tissue directly or as cell pellets at -20 or -70°C and mail with sufficient dry ice to prevent thawing before arrival at our laboratory.
- Paraffin Sections: 10 sections on glass slides. More sections may be required if the tissue is small. Please call the lab if you have questions. Include % tissue area involved by neoplasm and pathologist’s signature.
- Unacceptable Specimens: Decalcified specimen, Frozen blood or bone marrow specimens are unacceptable as are tissue samples that have undergone a freeze/thaw cycle(s).
Twice each week
Within 3-7 business days of receipt
TCRB Gene 81340; TCRG Gene 81342
Shipment Must Include
- Cossman,J. and M. Uppenkamp, (1988), T-cell gene rearrangements and the diagnosis of T-cell neoplasms, in Classification, Diagnosis and Molecular Biology of Lymphoproliferative Disorders, Clinics in Lab Med., 8(1): 31-44.
- Benhattar, J. et al, (1995), Improved polymerase chain reaction detection of clonal T-cell lymphoid neoplasms, Diagn.Mol.Path., 4(2): 108-112.
- Coad,J. et al, (1997), Molecular assessment of clonality in lymphoproliferative disorders: II. T-cell receptor gene rearrangements, Mol.Diagn., 2 (1): 69-81.
- Vargas, R.L., R.E.Felgar, et al. 2008. Detection of clonality in lymphoproliferations using PCR of the antigen receptor genes: Does size matter? Leukemia Res. 32:: 335-338.
- van Dongen, JJM et al. 2003. Design and standardization of PCR primers and protocols for detection of clonal immunoglobulin and T-cell receptor gene recombinations in suspect lymphoproliferations: Report of the BIOMED-2 Concerted Action BMH4-CT98-3936, Leukemia 17: 2257–2317.
- Sandberg, Y et al. 2005. BIOMED-2 Multiplex Immunoglobulin/T-Cell Receptor Polymerase Chain Reaction Protocols Can Reliably Replace Southern Blot Analysis in Routine Clonality Diagnostics, J. Mol. Diag., 7:, 495.
- Langerak, A.W. et al. 2012. Euroclonality/BIOMED-2 guidelines for interpretation and reporting if G/TCR clonality testing in suspected lymphoproliferations. Leukemia 26: 2159-2171.
- Rothberg, P.G. et al. 2012. Clonal antigen receptor gene PCR products outside the expected size range. J. Hematopathol. 5: 57-67.