[Kinetics of Infiltrating CD3 T Cells and Their Relationship with Target Organ Injury of Graft-Versus-Host Disease].

Objective: To explore the kinetics of infiltrated T cell in murine acute graft-versus-host disease (aGVHD) target organs after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and its relationship with tissue pathological damage and aGVHD progress.

Methods: Male C57BL/6 (H-2K) mice at age of 8-10 weeks were selected as donors, from which splenic cells and bone marrow cells were isolated. And 10-12 weeks of BALB/c (H-2K) male mice which received 7.5 Gy total body irradiation (TBI) were recipients to transplant. Recipients were randomly divided into allogeneic bone marrow transplantation (BMT) group and BMT+T group, which were transplanted bone marrow cells with or without splenic cells, respectively. All recipients were daily monitored and the dynamic changes of the body weights along with clinical scores of aGVHD were detected. HE staining was used to investigate the pathological damage and score of aGVHD target organs. The number of infiltrated CD3 T cells in target organs was numerated and statistically analyzed after immunohistochemistry staining on day 7, 14, 28, 40 and 47 after transplantation.

Results: Compared with BMT group, the number of infiltrated T cells in aGVHD target organs including liver, lung and gut increased since day 7 in BMT+T group (P<0.05). On day 14, 28, 40 and 47 after transplantation, more infiltrated CD3 T cells were detected in target tissues of mice in BMT+T group than those in BMT group (P<0.05). Higher clinical score and histopathological score of target organs in aGVHD mice were detected (P<0.05). Positive correlation was found in the number of liver infiltrated T cells and pathological damage, and the numbers of infiltrated CD3 T cells in gut were positively related to aGVHD clinical scores.

Conclusion: Pathological damage of aGVHD target organs is induced by CD3 T cell infiltration, and the number of infiltrated T cell may be an important evaluated index of aGVHD severity.