Appropriate Risk Classification and Low-Dose Rituximab May Help Prevent Acute Rejection in ABO-Compatible Living Kidney Transplantation.

BACKGROUND

Rituximab desensitization improves outcomes in ABO-incompatible (ABOi) kidney transplantation, and a fixed dose of 200 mg has been shown to prevent antibody-mediated rejection with fewer infections. Although the risk of ABO-compatible (ABOc) transplants is generally low, acute rejection still occurs, suggesting undetected antibodies. Previous studies on ABOc have emphasized conventional dosing or universal administration in non-sensitized recipients, without individualized stratification. We assessed low-dose rituximab in ABOc recipients and propose a preoperative risk-classification framework.

METHODS

We retrospectively reviewed 264 living-donor kidney transplants between January 2015 and July 2024. After excluding ABOi transplants and cases involving double-filtration plasmapheresis/intravenous immunoglobulin, 158 ABOc recipients were included. Recipients were stratified into rituximab (n = 28; single 200 mg dose 14 days before transplant) and rituximab-free (n = 130) groups. The primary endpoints were 1-year acute rejection and infections.

RESULTS

The rituximab group had a higher immunologic risk, with fewer related donors (32.1% vs 66.2%; p = .002), and more sensitized (67.9% vs 39.2%; p = .011) or donor-specific antibody (DSA)-positive (17.9% vs 1.5%; p = .001) recipients. Despite this, 1-year acute rejection was lower (0% (0/28) vs 10.8% (14/130); p = .133), with a trend toward improved rejection-free survival (log-rank p = .075), and 1-year infection rates were similar (21.4% vs 23.1%; p = 1.0; log-rank p = .83). In the DSA-positive subgroup (rituximab n = 5; control n = 2), all treated patients remained rejection-free, whereas both untreated patients developed rejection.

CONCLUSIONS

In ABOc recipients, risk-stratified preoperative low-dose rituximab may help prevent rejection without increasing infections. Our proposed risk-stratification framework may guide patient selection, but these preliminary findings require validation in larger prospective studies.