[Prediction of T-cell immune reconstitution by investigating T cell receptor excision circle and T-cell receptor beta-chain variable region clonal repertoire in leukemia patients after allogeneic hematopoietic stem cell transplantation].

OBJECTIVE: To predict T-cell immune reconstitution by investigating T cell receptor excision circles (TREC) and T-cell receptor beta-chain variable region (TCRBV) clonal repertoire in leukemia patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT).

METHODS: Real-time quantitative PCR was used to detect the TREC in 43 leukemia patients undergoing matched sibling donor bone marrow transplantation (MSD BMT), matched unrelated donor (MUD) BMT, or haploidentical-stem cell transplantation (HID-SCT), and in 70 normal individuals. RT-PCR was used to amplify 24 subfamily genes of T-cell receptor beta-chain variable region (TCRBV) in 24 of the 43 patients and 5 normal donors as control. The PCR products were further analyzed by genescane to evaluate the clonality of BV subfamily, characteristics of complementarity determining region 3 (CDR3), and the usage rate in BV subfamily.

RESULTS: There were (335.1 +/- 782.5) copies/10(5) cells in the 43 patients before transplantation, far lower than the normal value. The TREC values of the patients of the 3 groups all decreased obviously 3 months after transplantation. The TREC value of the MSD-BMT group recovered faster than the other two groups and reached the value before transplantation in 24 months. The recovery of TREC value in the HID-BMT group was delayed. 3 - 19 months after transplantation, the usage of TCRBV subfamilies was still restricted. There were 6 - 16 BV subfamilies expressed and 33% - 48% of them were polyclonals, the others were monoclones and oligoclones and existed in 24 BV subfamilies, no common monoclone BV subfamilies was expressed.

CONCLUSION: Investigation of the TREC and TCRBV clonal repertoire showed that the number of naive T cell is lower and the usage of TCRBV subfamilies skewed 3 - 24 months after allo-HSCT. The immune deficiency of the patients undergoing HID-BMT is more prominent and consistent with the clinical process.