The Effect of Donor CD4+CD25+ Regulatory T Cells on Hematopoietic and Immune Reconstitution, GVHD and Disease-Free Survival after Allogeneic Hematopoietic Stem Cell Transplantation.

Abstract

Objectives To explore the effect of donor CD4+CD25+ regulatory T cells (TReg) on hematopoietic reconstitution, immune reconstitutuion and GVHD in patients who received allogeneic hematopoietic stem cell transplantation (allo-HSCT).Methods 30 patients were divided into high TReg cell group (TReg≥10.0×106 cells/kg) and low TReg cell group (TReg<10.0×106 cells/kg) according to the number of TReg cells in the grafts. 13 patients were in high TReg cell group and 17 in low TReg cell group. The patients details of the two groups are in the following table. Flow cytometry (FCM) was used to continuously detect the percentage of TReg cells in the graft, T lymphocyte subsets and TReg cells in the recipients' peripheral blood at different time after allo-HSCT. The hematopoietic reconstitution, immune reconstitution, TReg cell reconstitution, the incidence of GVHD and the disease-free survival were observed in the two groups.Results The reconstitution of WBC and plantelet of high TReg cell group and low TReg cell group were 8.62±2.293 and 8.88±2.713, 12.69±5.736 and 15.18±16.708 days, respectively, and differed little between the two groups (P value was 0.778, 0.613, respectively). The incidence of acute GVHD (aGVHD) in high TReg cell group (15.38%) was obviously lower than that in low TReg cell group (58.82%) (P=0.016). There was significantly negative correlation (r=−0.382, P=0.037) between the number of infused donor TReg cells and severity of aGVHD. The reconstitution of CD4+CD3+T, CD45RO+CD4+T cells at 15 days and CD3+T, CD4+CD3+T cells at 30 days in high TReg cell group were notably faster than those in low TReg cell group after allo-HSCT (P value was 0.039, 0.024, 0.014, 0.020, respectively). The reconstitution of TReg cells at 15 and 180 days were significantly faster than those in low TReg cell group after allo-HSCT (P value was 0.013, 0.005, respectively). The 2-year disease-free survival of high TReg cell group and low TReg cell group were (69.90±15.50)% and (85.60±9.50)%, respectively, and there were no significantly difference between the two groups (P=0.514).Conclusion TReg cells could contribute to decreasing the incidence of aGVHD, promoting immune reconstitution and TReg cells reconstitution.