The Role of CD4⁺CD25⁺ T Cell and FOXP₃ in Allogeneic Hematopoietic Stem Celltransplantation.

Objective To explore the relationship among CD4⁺CD25⁺ regulatory T cell, the expression of FOXP3 mRNA levels of donor BM and GVHD in allogeneic hematopoietic stem cell transplantation(allo-HSCT). Methods (1)Thirty patients undergoing allo-HSCT were enrolled in this study. The levels of donor CD4⁺CD25⁺ regulatory T cell were compared in the patients with GVHD and those without GVHD by immnofluorescence and flowcytometry. (2)The donor BM expressions of FOXP3 mRNA levels were analyzed by using reverse transcriptase polymerase chain reaction (RT-PCR). Results (1)All patients achieved engraftment. ANC ≥ 0.5′10⁹•L⁻¹and Plt ≥ 20′10⁹•L⁻¹ were at day 14(range, 12~15)and day 18 (range, 15~25) respectively. Acute GVHD occurred in 15 of 30 patients(50.0%) with gradeII°-IV° aGVHD (40.0%). Chronic GVHD developed in 6 (extensive 2, limited 4) out of 30 patients (20.0%). 3 patients relapsed.(2)The levels of CD4⁺CD25⁺ regulatory T cell pre-and pro-mobilization were (2.67±0.38) % and (5.01± 1.33)% respectively, no difference were observed(P>0.05).(3)Patients with I°~II° aGVHD demonstrated higher donor-type CD4⁺CD25⁺ immune regulatory T cell level than those with III°~IV° aGVHD; Patients with III°~IV° aGVHD showed much lower donor-type CD4⁺CD25⁺ immune regulatory T cell level than those without GVHD; no difference were observed between patients withI°~II° aGVHD and those without aGVHD.(4)The transcripts of FOXP₃ donor BM were detected in seven donors of thirty recipients who received allo-HSCT. Three relapsed after transplantation;two developedI°aGVHD; and the other two had no GVHD. Donor BM FOXP₃ transcripts were never detected in patients with II°~IV° aGVHD. Conclusion(1)Donor-type CD4⁺CD25⁺ immune regulatory T cell level was relative to recipient II°~IV° aGVHD. Up-grade donor-type CD4⁺CD25⁺ immune regulatory T cell level could reduce the incidence of aGVHD.(2)Donor BM FOXP₃ transcripts were detected in patients without serious aGVHD after transplantation.