Impact of red blood cell transfusion timing and volume on biopsy-proven rejection: a single-center cohort study

Perioperative red blood cell transfusion (RBCT) and immunosuppressive therapy are critical factors influencing the risk of kidney transplantation (KT) rejection. In this study, we examined how RBCT volume, timing, and immunosuppressive therapy affect biopsy-proven rejection (BPR).

We analyzed 170 living donor KT recipients, assessing RBCT timing, volume, immunosuppressive therapy, and recipient characteristics. RBCT timing was classified as none, within 1 month, or over 1 month post-KT. Random forest and SHapley Additive explanation (SHAP) were used to identify risk factors for BPR. To mitigate overlearning, tenfold cross-validation was performed.

The calcineurin inhibitor type was the most significant risk factor for BPR, with tacrolimus use associated with a lower risk than cyclosporine use. An RBCT exceeding 6 units and an RBCT administered more than 1 month post-KT were identified as critical thresholds for BPR risk. SHAP analysis indicated a nonlinear relationship between pre-transplant hemoglobin levels and BPR risk. RBCT timing and volume significantly influenced BPR risk. Late RBCT and those exceeding 6 units were linked to increased BPR risk. Additionally, tacrolimus may offer superior immunosuppressive control compared with that of cyclosporine regarding BPR. Stratified analysis using SHAP value showed that the high-risk group had significantly lower death-censored graft survival than the low-risk group.

RBCT volume and timing impact the rejection risk, with an increased risk observed for more than 6 units and over 1 month post-KT. Proper immunosuppressive management is crucial and warrants further research.