The Effect of Costimulatory Moleculars on Graft-Versus-Host Disease after Allogeneic Hematopoietic Stem Cell Transplantation.

Objective: To explore the effect of costimulatory molecular and CD25 expressed on peripheral CD4⁺ T lymphocytes on graft-versus-host disease(GVHD) after allogeneic hematopoietic stem cell transplantation(allo-HSCT).

Methods: 1. The 21 patients who suffered of hematology diseases or malignant solid tumors and were underwent allo-HSCT and 10 normal individuals were enrolled in the study.2. For the sake of difference conditioning regimens we divided the 21 patients into two groups: patients undergoing non-myeloablative stem cell transplantation(NST) belonged to group A, others undergoing traditional myeloablative stem cell transplantation belonged to group B; we divided them into five groups for with GVHD or without GVHD and types of GVHD: group 1(group A with acute GVHD), group 2(group A with chronic GVHD), group 3(group B with acute GVHD), group 4(group B without GVHD), group 5(group A without GVHD).3. The levels of CD28, CD80, CD152 and CD25 expressions on peripheral CD4⁺ T lymphocytes were detected by three colors flow cytometry (FCM)in different time(before allo-HSCT,7days,14days,21days,30days after allo-HSCT, the time of GVHD and the time after GVHD treated).4.STR-PCR for detecting micro-satellites chimeras forming.

Results: 1. All 21 patients achieved engraftment. By STR-PCR assay,12 cases formed complete chimeras(CC) and 9 cases formed mixed chimeras(MC). In group A,3 cases developed acute GVHD and 4 cases developed chronic GVHD; in group B,4 cases developed aGVHD. The incidence of GVHD and infection rates between group A and B has no difference(X²=3.711, P=0.144).2. Among these 21 cases,5 cases died:2 cases died of multiple organs function failure due to primary disease relapse,1 case died of bleeding in brain and 2 cases died of liver function failure for the sake of complicated with acute GVHD; others survive with disease free till present.3. The results of multivariate logistic regression models and Kaplan-Meier survival curves analyses showed: age, sex, infection, HLA-type, blood type, conditioning regiment and the times of absolute neutrophil counts and platelets recovering to normal, had no association with the incidence of GVHD;A multivariate COX survival function model analysis showed CD4CD152 and CD4CD25 are independent prognostic factors for GVHD(X²=13.128, P<0.0001).4. Patients with GVHD demonstrated higher CD4⁺CD28⁺ and CD4⁺CD80⁺ T cell levels than those without GVHD(P<0.01);patients with aGVHD demonstrated higher than those with cGVHD(P<0.05) and without GVHD(P<0.05); Patients with GVHD demonstrated lower CD4⁺CD152⁺ and CD4⁺CD25⁺ T cell levels than those without GVHD(P<0.01); the same result occurs between aGVHD and cGVHD and without GVHD. After effective treatment, unnormal CD4⁺CD28⁺, CD4⁺CD80⁺, CD4⁺CD152⁺ and CD4⁺CD25⁺ T cell levels recovered to the levels before transplantation.

Conclusions:

1. The incidences of GVHD between NST and traditional myeloablative stem cell transplantation had no difference.

2. B7-CD28/CD152 costimulatory pathway plays a critical role in developing of GVHD.

3. Peripheral CD4⁺CD28⁺, CD4⁺CD80⁺, CD4⁺CD152⁺ and CD4⁺CD25⁺ T cell levels were relative to recipient GVHD, especially CD4⁺CD152⁺ and CD4⁺CD25⁺ T cell levels.

Down-grade CD4⁺CD28⁺ and CD4⁺CD80⁺ T cell levels and up-grade CD4⁺CD152⁺ and CD4⁺CD25⁺T cell levels could reduce the incidence of GVHD.