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Pitfalls in TCR gene clonality testing: teaching cases.

Groenen PJ, Langerak AW, van Dongen JJ, van Krieken JH - J Hematop (2008)

Bottom Line: Several immunobiological and technical pitfalls that should be taken into account to avoid misinterpretation of data are addressed in this report.Furthermore, we discuss the need to integrate the molecular data with those from immunohistology, and preferably also flow cytometric immunophenotyping, for appropriate interpretation.Such an interactive, multidisciplinary diagnostic model guarantees integration of available data to reach the most reliable diagnosis.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Radboud University Nijmegen Medical Centre, Geert Grooteplein 24, 6525 GA, Nijmegen, The Netherlands, P.Groenen@pathol.umcn.nl.

ABSTRACT
Clonality testing in T-lymphoproliferations has technically become relatively easy to perform in routine laboratories using standardized multiplex polymerase chain reaction protocols for T-cell receptor (TCR) gene analysis as developed by the BIOMED-2 Concerted Action BMH4-CT98-3936. Expertise with clonality diagnostics and knowledge about the biology of TCR gene recombination are essential for correct interpretation of TCR clonality data. Several immunobiological and technical pitfalls that should be taken into account to avoid misinterpretation of data are addressed in this report. Furthermore, we discuss the need to integrate the molecular data with those from immunohistology, and preferably also flow cytometric immunophenotyping, for appropriate interpretation. Such an interactive, multidisciplinary diagnostic model guarantees integration of available data to reach the most reliable diagnosis.

No MeSH data available.


Related in: MedlinePlus

Flow chart for clonality testing for suspected T-cell proliferations. Both TCRG and TCRB gene rearrangements are analyzed simultaneously because of complementarity of the targets and, as such, increase the clonality detection rate. For tissues showing fragmented DNA, testing the TCRG-gene target is most useful and reliable because of the lower-length amplicon sizes. Assessment of TCRB is not recommended in the case of severe fragmentation of DNA samples
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Fig4: Flow chart for clonality testing for suspected T-cell proliferations. Both TCRG and TCRB gene rearrangements are analyzed simultaneously because of complementarity of the targets and, as such, increase the clonality detection rate. For tissues showing fragmented DNA, testing the TCRG-gene target is most useful and reliable because of the lower-length amplicon sizes. Assessment of TCRB is not recommended in the case of severe fragmentation of DNA samples

Mentions: Following the guideline of the BIOMED-2 group as presented in a flowchart in Fig. 4, both TCRG and TCRB gene rearrangements are analyzed simultaneously in the routine diagnostic setting for T-cell clonality testing because both targets provide complementary information [15]. In addition, usage of both targets in parallel (instead of consecutively) is efficient and fast, since most laboratories run clonality assays not more than once a week. The majority of T-cell neoplasms have clonal TCRG and TCRB rearrangements with clear complementarity of clonality detection [17], which is one of the advantages of the BIOMED-2 clonality testing approach. In fact, the detection of clonal TCRG and clonal TCRB rearrangements in itself is a confirmation of clonality detection. Only rarely, isolated clonal TCRG or TCRB rearrangements are seen. A two-step triage is recommended for testing TCRD rearrangements. Because of its complexity, the single tube TCRD assay should not be routinely used in T-cell clonality diagnostics. TCRD clonality testing is recommended (1) when there is evidence for a TCR-γδ proliferation through, e.g., flow cytometry, (2) upon detection of an isolated clonal TCRG rearrangement, as this may be considered as indirect evidence for a TCR-γδ proliferation since TCRG is the second TCR locus after TCRD to undergo gene rearrangements, or (3) when there is a suspicion of an immature T-cell neoplasm, e.g., in case of TdT-positive lymphoblasts.Fig. 4


Pitfalls in TCR gene clonality testing: teaching cases.

Groenen PJ, Langerak AW, van Dongen JJ, van Krieken JH - J Hematop (2008)

Flow chart for clonality testing for suspected T-cell proliferations. Both TCRG and TCRB gene rearrangements are analyzed simultaneously because of complementarity of the targets and, as such, increase the clonality detection rate. For tissues showing fragmented DNA, testing the TCRG-gene target is most useful and reliable because of the lower-length amplicon sizes. Assessment of TCRB is not recommended in the case of severe fragmentation of DNA samples
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2713482&req=5

Fig4: Flow chart for clonality testing for suspected T-cell proliferations. Both TCRG and TCRB gene rearrangements are analyzed simultaneously because of complementarity of the targets and, as such, increase the clonality detection rate. For tissues showing fragmented DNA, testing the TCRG-gene target is most useful and reliable because of the lower-length amplicon sizes. Assessment of TCRB is not recommended in the case of severe fragmentation of DNA samples
Mentions: Following the guideline of the BIOMED-2 group as presented in a flowchart in Fig. 4, both TCRG and TCRB gene rearrangements are analyzed simultaneously in the routine diagnostic setting for T-cell clonality testing because both targets provide complementary information [15]. In addition, usage of both targets in parallel (instead of consecutively) is efficient and fast, since most laboratories run clonality assays not more than once a week. The majority of T-cell neoplasms have clonal TCRG and TCRB rearrangements with clear complementarity of clonality detection [17], which is one of the advantages of the BIOMED-2 clonality testing approach. In fact, the detection of clonal TCRG and clonal TCRB rearrangements in itself is a confirmation of clonality detection. Only rarely, isolated clonal TCRG or TCRB rearrangements are seen. A two-step triage is recommended for testing TCRD rearrangements. Because of its complexity, the single tube TCRD assay should not be routinely used in T-cell clonality diagnostics. TCRD clonality testing is recommended (1) when there is evidence for a TCR-γδ proliferation through, e.g., flow cytometry, (2) upon detection of an isolated clonal TCRG rearrangement, as this may be considered as indirect evidence for a TCR-γδ proliferation since TCRG is the second TCR locus after TCRD to undergo gene rearrangements, or (3) when there is a suspicion of an immature T-cell neoplasm, e.g., in case of TdT-positive lymphoblasts.Fig. 4

Bottom Line: Several immunobiological and technical pitfalls that should be taken into account to avoid misinterpretation of data are addressed in this report.Furthermore, we discuss the need to integrate the molecular data with those from immunohistology, and preferably also flow cytometric immunophenotyping, for appropriate interpretation.Such an interactive, multidisciplinary diagnostic model guarantees integration of available data to reach the most reliable diagnosis.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Radboud University Nijmegen Medical Centre, Geert Grooteplein 24, 6525 GA, Nijmegen, The Netherlands, P.Groenen@pathol.umcn.nl.

ABSTRACT
Clonality testing in T-lymphoproliferations has technically become relatively easy to perform in routine laboratories using standardized multiplex polymerase chain reaction protocols for T-cell receptor (TCR) gene analysis as developed by the BIOMED-2 Concerted Action BMH4-CT98-3936. Expertise with clonality diagnostics and knowledge about the biology of TCR gene recombination are essential for correct interpretation of TCR clonality data. Several immunobiological and technical pitfalls that should be taken into account to avoid misinterpretation of data are addressed in this report. Furthermore, we discuss the need to integrate the molecular data with those from immunohistology, and preferably also flow cytometric immunophenotyping, for appropriate interpretation. Such an interactive, multidisciplinary diagnostic model guarantees integration of available data to reach the most reliable diagnosis.

No MeSH data available.


Related in: MedlinePlus