Abstract:ObjectiveTo explore the association of complement C4d, high-sensitivity C-reactive protein(hs-CRP) and helper T cell 1（Th1）、 Th2 levels with acute allograft rejection(AR) in the patients after renal transplantation. Methods A retrospective analysis was performed on the clinical data of 155 renal transplant patients in the First Affiliated Hospital of Xian Jiaotong University from January 2016 to January 2018. According to whether or not AR occurred after operation, there were 32 cases in AR group and 123 cases in non-AR group. The association of C4d expression in renal biopsy tissue, serum hs-CRP, Th1, Th2 levels with AR after renal transplantation were analyzed. Results There was no significant difference in the incidence of monoclonal antibody use, pre-transplantation blood transfusion, post-transplantation blood transfusion and preoperative group-reactive antibody≥10% between two groups(P＞0.05）. The cold ischemia time, warm ischemia time and human leukocyte antigen(HLA) mismatch number of donor kidney during operation in AR group were statistically lower than those in non-AR group(P＜0.01). The positive rate of complement C4d, serum hs-CRP and post-operative Th1, Th1/Th2 levels in AR group were significantly higher than those in non-AR group, and Th2 level was lower than that in non-AR group(P＜0.05). Spearman correlation analysis showed that complement C4d, serum hs-CRP, Th1, Th1/Th2 levels were positively correlated with AR after renal transplantation(P＜0.05), while Th2 level was negatively correlated it(P＜0.05). Logistic regression analysis showed that high levels of Th1 and hs-CRP and positive complement C4d were the independent risk factors of AR after renal transplantation(P<0.05), while high Th2 was a protective factor for AR(P＜0.01). Conclusion Complement C4d positive, higher hs-CRP and Th1 levels are associated with increased risk of AR, higher Th2 is associated with decreased risk of AR in the renal transplant patients.