The polymerase chain reaction in the demonstration of monoclonality in T cell lymphomas.
OBJECTIVE
To evaluate polymerase chain reaction (PCR) amplification of T cell receptor (TCR) beta and gamma chain genes as a means of demonstrating monoclonality in T cell lymphomas using histological samples; to compare the performance of PCR with Southern blot analysis.


METHODS
TCR-beta, TCR-gamma and immunoglobulin heavy chain (IGH) genes were analysed using PCR in 55 cases of T cell lymphoma (28 frozen tissue and 27 paraffin wax embedded samples), diagnosed using morphological and immunohistochemical criteria. The 28 frozen samples were subjected to Southern blot analysis using TCR-beta, TCR-gamma and IGH gene probes. Twenty five B cell lymphomas and 21 non-neoplastic lymphoid tissue samples were used as controls.


RESULTS
Using TCR-beta PCR, monoclonality was detected in 24 (44%) of 55 T cell lymphomas compared with 43 (78%) of 55 using TCR-gamma PCR and in 82% with both techniques. Five (9%) of 55 T cell lymphomas were IGH PCR positive. None of the non-neoplastic lymphoid control samples were PCR positive. All B cell lymphomas showed a polyclonal pattern with TCR-beta PCR while a single B cell lymphoma was positive using TCR-gamma primers. With TCR-beta PCR, a monoclonal result was seen in 12 (43%) of 28 frozen samples of T cell lymphoma, compared with 23 (82%) of 28 using Southern blot analysis. With TCR-gamma PCR, 19 (68%) of 28 frozen tissue samples were positive, compared with 26 (93%) of 28 using Southern blot analysis. A single case showed IGH rearrangement by Southern blot analysis.


CONCLUSIONS
TCR-gamma PCR should be the method of choice for analysis of clonality in paraffin wax embedded sections of lymphoproliferative lesions, as TCR-beta PCR has a high false negative rate. Southern blot analysis remains the most successful technique when sufficient fresh tissue samples and resources are available.
Department of Histopathology, University College London Medical School.
T C
TC
Diss
M
M
Watts
L X
LX
Pan
M
M
Burke
D
D
Linch
P G
PG
Isaacson
D001483:Base Sequence; D015139:Blotting, Southern; D004591:Electrophoresis, Polyacrylamide Gel; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor; D005803:Genes, Immunoglobulin; D006801:Humans; D016399:Lymphoma, T-Cell / Q000235:genetics*; D008969:Molecular Sequence Data; D014411:Neoplastic Stem Cells / Q000473:pathology; D016133:Polymerase Chain Reaction