T cell receptor Vbeta repertoire usage and clonal expansion of T cells in chronic myelogenous leukemia.
BACKGROUND
In general, it is very important to understand the state of T cell immune response against tumor cells in leukemia patients and it is especially critical to assess the T cell repertoire of untreated patients. As we know, few studies have dealt with the distribution of oligoclonal T cells in leukemia, so we investigated the distribution and clonality of TCR Vbeta repertoire of T cells in patients with chronic myelogenous leukemia (CML) in chronic phase.


METHODS
The complementarity determining region 3 (CDR3) of TCR Vbeta24 subfamily genes were amplified in peripheral blood mononuclear cells from 27 cases with CML using reverse transcription-polymerase chain reaction (RT-PCR). In order to observe the distribution of TCR Vbeta repertoire, the PCR products were further analyzed by genescan technique to evaluate clonality of the detectable TCR Vbeta T cells. The PCR products of the oligoclonal T cells from three cases were analyzed by direct sequencing to define the sequence of CDR3.


RESULTS
The expression pattern of TCR Vbeta repertoire in different individuals are different. Vbeta2-21 subfamilies could be detected in CML cases. The frequent usage Vbeta repertoire in CML was Vbeta1, Vbeta2 or Vbeta13. Most of the PCR products from 27 patients displayed polyclonality, while a part of the PCR products from 21 out of 27 samples displayed clonal expansion pattern. The clonal expanded T cells in CML could be found in Vbeta16 subfamilies. The frequent usage of Vbeta genes in clonal expansion was Vbeta3, Vbeta13 or Vbeta21. Multiple Vbeta clonal expansion was a general phenomenon in the same patient. The CDR3 sequence of Vbeta21 oligoclonal T cells from 3 cases showed some difference in splice regions and in the usage of J segments.


CONCLUSIONS
These results indicated that clonal expanded T cells could be found in patients with CML and were tendentious in Vbeta3, Vbeta13 and Vbeta21 subfamilies that may be related to the specific immune response for leukemia cell associated antigen.
Li
Yang-qiu
YQ
Institute of Hematology, Medical College, Jinan University, Guangzhou 510632, China.
Yang
Li-jian
LJ
Chen
Shao-hua
SH
Zhang
Yu-ping
YP
Zhang
Xue-li
XL
Luo
Geng-xin
GX
D002999:Clone Cells; D022801:Complementarity Determining Regions / Q000032:analysis; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000276:immunology*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000032:analysis*; D013601:T-Lymphocytes / Q000276:immunology* / Q000473:pathology
D022801:Complementarity Determining Regions; D016693:Receptors, Antigen, T-Cell, alpha-beta