Clinical significance of de novo donor-specific antibody in kidney transplant recipients with chronic antibody-mediated rejection.

Background: Chronic antibody-mediated rejection (CABMR) is an important cause of late graft loss. De novo donor-specific antibody (dnDSA) is an important prognostic factor for long-term allograft outcomes. However, the prognosis of CABMR based on the presence of dnDSA is uncertain. Methods: We retrospectively analyzed 35 kidney transplant recipients with CABMR between 2010 and 2018. Fourteen recipients had no detectable DSA, and 21 recipients had detectable DSA. We investigated the pathologic findings at diagnosis of CABMR, allograft function 12 months later, related factors for allograft failure, and allograft survival rate based on the presence of dnDSA. Results: The pathologic findings showed that acute and chronic changes were more severe in the dnDSA (+) group than in the dnDSA (-) group. There was no significant difference in the allograft function 12 months after the diagnosis of CABMR and in the amount of proteinuria at diagnosis between the two groups. However, the death-censored graft survival rate was lower in the high-proteinuria group than in the low-proteinuria group in both groups. The treatment rate of recipients was higher in the dnDSA (+) group than in the dnDSA (-) group; however, there was no significant difference in the death-censored graft survival rate between the two groups. Conclusions: Although the effect of dnDSA on the prognosis of CABMR is not clear, it would be important not to neglect treatment for CABMR with risk factors for allograft failure even without dnDSA. Continuous and rigorous surveillance of DSA and allograft function is needed in patients with CABMR.