IdentiClone™ TCRG Gene Rearrangement Assay 2.0

Intended Use

IdentiClone™ TCRG Gene Rearrangement Assay 2.0The IdentiClone™ T Cell Receptor Gamma Gene Rearrangement Assay 2.0 is an in vitro diagnostic product intended for PCR-based detection of clonal T-cell receptor gamma chain gene rearrangements in patients with suspected lymphoproliferations.

Specifically, the IdentiClone™ T Cell Receptor Gamma Gene Rearrangement Assay 2.0 can be used to:
  • Identify clonality in suspect lymphoproliferations.

Summary and Explanation of the Test

Rearrangements of the antigen receptor genes occur during ontogeny in B- and T-lymphocytes. These gene rearrangements generate products that are unique in length and sequence. Polymerase chain reaction (PCR) assays can be used to identify lymphocyte populations derived from a single cell by detecting the unique V-J gene rearrangements present within these antigen receptor loci1.

Invivoscribe’s newest IdentiClone™ assay represents an improved approach to PCR-based clonality testing of lymphoproliferative disorders, as it can detect the vast majority of T-cell receptor gamma gene rearrangements with a single multiplex master mix. Amplifying the region with fluorescently labeled primers is followed by fractionation by capillary electrophoresis and analysis by instrument software. Presence or absence of molecular clonality can support the differential diagnosis of reactive lesions and certain B- and T-cell malignancies if the results are interpreted in the context of all available clinical, histological and immunophenotypic data.

1. Miller JE, Wilson SS, Jaye DJ, and Kronenberg M. An automated semiquantitative B and T cell clonality assay. Mol. Diag. 1999, 4(2):101-117.

Performance Characteristics

To assess the performance of the TCRG 2.0 assay, testing was performed on cell lines with known clonal rearrangements, followed by testing on previously sequenced clinical samples.

When used in combination with the TCRG Algorithm worksheet, the assay was capable of detecting DNA from 6 control cell lines (200 ng/μL) diluted into polyclonal tonsil DNA (200 ng/μL) at 5% (v/v).

Furthermore, the performance of the TCRG 2.0 assay was evaluated on clinical samples for which the T-cell receptor gamma gene rearrangement status had been identified by Roche 454 sequencing. For the 7 samples that had been identified as clonal by sequencing, the TCRG 2.0 assay had 100% concordance. For the 12 samples that were either negative for a clonal event or were oligoclonal, concordance of the TCRG 2.0 assay was 75%. Sample types included peripheral blood, bone marrow, and formalin-fixed paraffin-embedded (FFPE) tissue.

The results of molecular clonality tests should always be interpreted in the context of clinical, histological and immunophenotypic data.

Cat. No.
DescriptionAmount
9-207-0101
IdentiClone T Cell Receptor gamma Gene Rearrangement Assay 2.0 - ABI Detection
1 kit
9-207-0111
IdentiClone T Cell Receptor gamma Gene Rearrangement Assay 2.0 MegaKit - ABI Detection
1 kit

Reagents

Cat. No.
DescriptionAmount
2-096-0021
Specimen Control Size Ladder - 6FAM
1 ea
2-207-0091
TCRG v2.0 - 6FAM
1 ea
4-088-3320
5% TCRG Positive Control DNA
1 ea
4-092-0020
TCRG Negative Control DNA
1 ea

Capillary Electrophoresis Detection

Capillary Electrophoresis Detection
Fluorescence detection is commonly used to resolve the different-sized amplicon products using a capillary electrophoresis instrument. Primers are conjugated with a 6FAM fluorescent dye (fluorophore) so that they can be detected upon excitation by laser. This detection system results in a high sensitivity, single nucleotide size resolution, and relative quantification. Inter- and intra-assay reproducibility in size determination using capillary electrophoresis is approximately 1 to 2 nucleotides. This reproducibility and sensitivity coupled with the automatic archiving of specimen data allows for the monitoring, tracking, and comparison of data from individual patients over time. The data shown above was generated using the TCRG - 6FAM Master Mix. Amplified products were run on an ABI 3130 instrument. 

Reference

Anaplastic Large Cell Lymphoma Mimicking a Necrotizing Granulomatous Lesion: A Case Report
Tralongo V, Becchina G, Nagar C, Ottoveggio G, Giacalone B, Canciglia R and Genovese F



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Brands: Invivoscribe
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Product groups: Assays