COMPARING HISTOPATHOLOGY OF ACUTE REJECTION IN ABO-COMPATIBLE VS ABO INCOMPATIBLE KIDNEY TRANSPLANT RECIPIENTS: A PROPENSITY SCORE-MATCHED STUDY.

Introduction:

Acute rejection is one of the causes of poor long-term renal allograft outcomes. The available literature is scarce on the comparison of graft histology and BANFF scores in patients with acute rejection between ABO-incompatible (ABOi) and ABO-compatible (ABOc) kidney transplant recipients (KTR). 

Methods:

This is a single-centre, propensity score-matched case-control study of end-stage renal disease patients transplanted between 2014 and 2019. Among 100 ABOi KTR, 37 had biopsy-proven acute rejection (BPAR). A matched cohort of 37 ABOc KTR with BPAR was identified as controls from 680 ABOc KTx by propensity score matching using recipient and sex, donor and sex, donor glomerular filtration rate and HLA match as covariates. The graft histology of acute rejection, individual BANFF scores [acute (g, i, t, ptc, v) and chronic (ci, ct, cg, cv) scores] and mean BANFF scores between the two groups were analysed. 

Results:

A total of 100 ABOi KTRs and 680 ABOc KTRs were included in the study. Among them, 37 (37%) ABOi KTRs (cases) and 97 (7%) ABOc KTRs (control) had biopsy-proven acute rejection. Out of 97 BPAR patients in ABOc KTRs, 37 patients were matched for the cases using propensity score. Except for ABO incompatibility, other immunological factors (HLA matches, pre-transplant donor-specific antibodies) were not statistically different in both groups [Table 1]. All were complement-dependent cytotoxicity (CDC) and flow-cross match negative before transplant. None of those with pre-transplant donor-specific antibody (DSA) positivity (11 in ABO-incompatible and 7 in ABO-compatible) had significant mean fluorescence intensity (MFIs) (i.e. less than 1500) requiring desensitization for donor-specific anti-HLA antibodies. Time to first acute rejection was similar in both groups (6.0±9.86and 10.96±14.0 months; P= 0.088). Early acute rejection occurred in 29 (78%) vs. 17(46%) (P=0.008) and late acute rejection occurred in 8(22%) vs. 20 (54%); (P=0.008) in ABOi KTRs and ABOc KTRs respectively. No significant difference was noted between individual acute and chronic BANFF scores in both groups [Figure 2]. The mean BANFF scores were similar in both ABOi KTRs and ABOc KTRs except for interstitial inflammation, which is significantly higher in ABOc KTRs (1.43 ±0.728 vs. 1.11 ± 0.516; p=0.030) [Figure 3,4]. The post-rejection graft survival was significantly shorter in ABOi KTRs than in ABOc KTRs (80% vs. 92% at one year and 63% vs. 92% at three years; log-rank p=0.017). 

Conclusions:

This study shows no significant differences in BANFF scores in acute rejection patients between ABO-incompatible and propensity score-matched ABO-compatible renal transplant recipients except for interstitial inflammation.

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.