To investigate the influence factors of allograft acute rejection (AR) at the metaphase and long-term after kidney transplantation and the postoperative survival of allograft.

The clinical data were retrospectively analysed in 43 recipients who accepted kidney transplantation were more than 1 years and were diagnosed with AR by allograft renal biopsy during January 2018 to December 2019. Seventeen of them with acute antibody-mediated rejection were as acute antibody rejection group, 26 of them with acute T cell-mediated rejection were as acute T cell rejection group, and 39 recipients who got kidney transplantation during the same period (in 2 weeks) were matched as control group. Paired sample t test or one-way ANOVA was used to compare the measurement data conforming to normal distribution among multiple groups. Chi-square test or Fisher exact probability was used for comparison between counting data groups. Kaplan-Meier was used for survival analysis and log-rank was used for comparison. A P<0.05 was considered statistically significant.

The proportion of 2 mismatches at HLA-A sites in HLA match before operation (4/17) was more higher in acute antibody rejection group than that in control group (1/39), and the difference was statistically significant (P=0.026). Serum creatinine and estimated glomerular filtration rate (eGFR) at the onset and last time of AR were higher in acute antibody rejection group and acute T cell rejection group than those before AR (all P<0.05). Serum creatinine and eGFR at the onset and last time of AR in acute antibody rejection and acute T cell rejection group were higher than those in control group (all P<0.05). The proportion of chronic kidney disease (CKD)-4 recipients in acute antibody rejection group was lower than that in acute T cell rejection group (χ²=5.73, P<0.05). The proportion of CKD-4 recipients in acute T cell rejection group and the proportion of renal allograft failure in acute antibody rejection group were higher than those in control group (χ²=17. 727 and 9.882, all P<0.05). When AR happened, the rate of PRA-Ⅰ positive recipients [41.2% (7/17)] and the rate of PRA-Ⅱ positive recipients [88.2% (15/17)] in acute antibody rejection group were both higher than those in acute T cell rejection group [11.5% (3/26) and 26.9% (7/26), respectively], the difference had statistical significance (P=0.042, P<0.001). The serum concentration of tacrolimus was significantly decreased in the acute antibody rejection group (3.72±0.76) ng/mL and in the acute T cell rejection group (3.37±0. 86) ng/mL when the AR occurred, which were all lower than that of the control group (5.73±1.25) ng/mL, the difference had statistical significance (all P<0.05), and also lower than the serum concentration of tacrolimus before AR occurred, the difference had statistical significance (t=7.120 and 6.216, all P<0.05). There were 4 recipients in the acute T cell rejection group used cyclosporine, and the serum concentration of cyclosporine of 3 recipients among them was not up to the mark at 33 (112.4 ng/mL), 36 (138.3 ng/mL) and 55 (7.0 ng/mL) months after transplantation. The serum concentration of cyclosporine of 2 recipients who used cyclosporine in the acute T cell rejection group was 43.2 (16 months after transplantation) and 24.6 ng/mL (177 months after transplantation), which were not up to the mark. All the recipients were followed up until June 30, 2021, the survival rate of transplant kidney of the acute antibody rejection group was lower than the control group (χ²=8.738, P<0.05).

Mismatch at the HLA-A sites and the lower serum concentration of tacrolimus were the important factors for inducing AR in the metaphase and long-term after kidney transplantation. Acute antibody-mediated rejection was the important factor that affected the survival of transplant kidney.