The Expression And Role Of CD4⁺CD25⁺CD127^low/- Regulatory T Cell In Acute Lymphoblastic Leukemia

Objective:(1)To evaluate the efficacy and security of risk-adjusted therapy of adult acute lymphoblastic leukemia(ALL),to explore the relationship between minimal residual disease and relapse, and to establish a individualized treatment system. (2)To explore the dynamic changes of CD4+CD25+CD127low/- regulatory T cells in adult acute lymphoblastic leukemia, to evaluate the relationship between CD4+CD25+CD127low/- regulatory T cells and minimal residual disease. Methods (1)55 adult ALL patients hospitalized in our institute between January 2006 and Feburary 2009 were divided into standard-risk group and high-risk group.The standard-risk group received standard chemotherapy,and the high-risk group patients who had matched donor received hematopoietic stem cell transplantation. Minimal residual disease were detected at different time points during the treatment process. Event free survival(EFS)and overall survial(OS) were estimated by Kaplan-Meier method. (2)Thirty-five patients aged from 15 to 50 years were enrolled in this study. Collect peripheral blood of adult acute lymphoblastic leukemia at different time during the process of chemotherapy (at diagnosis, at the first complete remission, 2 month, 4 month, 6 month after first complete remission ,respectively). The CD4+CD25+CD127low/- subpopulations ratios in CD4+T lymphocytes (CD4+CD25+CD127low/-/CD4+) were detected with flow cytometry, and the expression of FOXP3 gene were analyzed with the real-time PCR assays to study the changes of CD4+CD25+CD127low/- regulatory T cell in adult ALL during the chemotherapy and the the correlations of minimal residual disease with CD4+CD25+CD127low/- regulatory T cell. Results (1)The complete remission rate was 94.5%. The 1 year and 3 year OS rate were (79.0±6.3)% and (59.3±10.1)%, respectively. The 1 year and 3 year EFS rate were (60.5±7.7)% and(57.3±7.9)%, respectively (P=0.012). Patients with MRD>10-2 after induction therapy(after 1 month)and patients with MRD>10-3 after consolidation therapy(after 4 month)were prone to relapse(P=0.000 and 0.020,respectively)(.2)The CD4+CD25+CD127low/-/CD4+ ratio were higher in newly diagnosed acute lymphoblastic leukemia than that in normal control. The CD4+CD25+CD127low/-regulatory T cells in the newly diagnosed group and MRD10-2 group were higher than that in MRD10-3 and MRD10-4 group, and were associated with relapse. Conclusion (1)Risk-adjusted therapy regimen improve CR rate, and have good tolerance.(2)MRD results could predict the risk of relapse. (3)The expression of CD4+CD25+CD127low/- regulatory T cells in newly diagnosed adult ALL, which may contribute to the immunological tolerance of ALL. ( 4 ) The expression of CD4+CD25+CD127low/- regulatory T cells could be used to assess the prognosis.