Impact of ABO incompatibility on the development of acute antibody-mediated rejection in kidney transplant recipients presensitized to HLA

Whether the coexistence of anti-A/B antibody and donor specific anti-HLA antibody (HLA-DSA) has a synergistic impact on the development of acute antibody-mediated rejection (AAMR) in kidney transplant recipients (KTRs) is unclear. This study includes 92 KTRs who received a kidney from an ABO-incompatible (ABOi) donor or were presensitized to donor HLA (HLAs) and 292 controls (CONT). HLAs was defined as a crossmatch positivity or the presence of HLA-DSA. We compared the incidence of AAMR among ABOi (n = 58), ABOi +HLAs (n = 12), HLAs (n = 22), and CONT (n = 292) groups and evaluated the risk factors and antibody type (anti-A/B vs. HLA-DSA) responsible for AAMR. AAMR developed less frequently in ABOi and CONT than in the ABOi+HLAs or HLAs (P < 0.05 for all); however, there was no difference between the ABOi+HLAs and HLAs groups. AAMR developed more frequently with strong HLA-DSA at baseline; however, high baseline anti-A/B titer did not affect AAMR development. Strong baseline HLA-DSA was an independent predictor for AAMR, however the baseline anti-A/B titer was not. All four AAMR episodes in ABOi+HLAs were positive to HLA-DSA but not to anti-A/B. In conclusion, ABO incompatibility does not increase the risk for AAMR in HLAs KTRs.