ABSTRACT Background Complement system overactivation contributes to transplanted kidney injury in both ischemia‐reperfusion and antibody‐mediated rejection, ultimately affecting post‐transplant renal function. C1 esterase inhibitor (C1‐INH) may reduce complement‐mediated injury, yet its effects on renal function and safety outcomes remain uncertain in randomized trials. Methods Four RCTs were included, all focusing on the use of C1‐INH in kidney transplant recipients, comparing it with control groups receiving saline. The studies were evaluated for methodological quality using the Jadad scoring system and the Cochrane Risk of Bias tool. Meta‐analysis was performed using RevMan software, assessing outcomes such as renal function (eGFR), AMR incidence, and SAE occurrences. Results This study included four randomized controlled trials encompassing 148 kidney transplant recipients. The findings suggest that treatment with C1‐INH may be associated with an improvement in renal function, as reflected by eGFR. No statistically significant difference was observed in the incidence of delayed graft function or antibody‐mediated rejection between the treatment and control groups. The overall incidence of serious adverse events was comparable between groups, with no significant differences detected in infection‐related, renal, cardiovascular, or gastrointestinal events. Conclusion The use of C1‐INH may be associated with improved graft renal function following kidney transplantation. However, no significant benefit was observed with respect to delayed graft function or antibody‐mediated rejection. The available evidence suggests an acceptable safety profile for C1‐INH in this setting. Nevertheless, given the clinical heterogeneity of the included studies and the limited cumulative sample size, these findings should be interpreted as preliminary. Larger, well‐designed randomized controlled trials are required to further clarify the therapeutic role of C1‐INH in kidney transplantation.
Feng et al. (2026) studied this question.