ABSTRACT
AIM:To investigate the expression and potential role of complement 5a receptor (C5aR) in chro-nic graft-versus-host disease (cGVHD).METHODS:The expression of C5aR on lymphocytes and the frequency of CD4+CD25+ Foxp3+ regulatory T cells (Tregs) in 20 cGVHD patients and 9 healthy donors was detected by flow cytometry.The correlation between the expression of C5aR and the percentage of Tregs in the cGVHD patients was analyzed.In addition, the splenocytes from the mice were cultured in vitro, and stimulated these splenocytes with recombinant mouse C5a protein (rmC5a).The peripheral blood mononuclear cells (PBMCs) from cGVHD patients were cultured in vitro, which was inhibited by C5aR antagonist (C5aRA).The frequency of Tregs in these splenocytes and the PBMCs were evaluated by flow cytometry.RESULTS:The expression of C5aR on the lymphocytes was significantly increased in the cGVHD patients compared with the healthy donors, while the percentage of Tregs was markedly lower in the cGVHD patients.The expression of C5aR was negatively correlated with the percentage of Tregs.Furthermore, the development of Tregs was suppressed by rmC5a stimulation, but was promoted by C5aRA in vitro.CONCLUSION:C5aR elevation is associated with Treg reduction in cGVHD, indicating that C5aR may play a potential role in suppressing Tregs, resulting in the incidence of cGVHD.