The clinicopathological relevance of pretransplant anti-angiotensin II type 1 receptor antibodies in renal transplantation

Background: Anti-angiotensin II type 1 receptor antibodies (AT1R-Abs) have been suggested as a risk factor for graft failure and acute rejection (AR). However, the prevalence and clinical significance of pretransplant AT1R-Abs have seldom been evaluated in Asia. Methods: In this multicenter, observational cohort study, we tested the AT1R-Abs in pretransplant serum samples obtained from 166 kidney transplant recipients. Statistical analysis was used to set a threshold AT1R-Abs level at 9.05 U/mL. Results: Pretransplant AT1R-Abs were detected in 98/166 (59.0%) of the analyzed recipients. No graft loss or patient death was reported during the study period. AT1R-Abs (I) patients had a significantly higher incidence of biopsy-proven AR than AT1R-Abs ( ) patients (27.6 versus 10.3%, P = 0.007). Recipients with pretransplant AT1R-Abs had a 3.2-fold higher risk of AR within a year of transplantation (P = 0.006). Five study subjects developed microcirculation inflammation (score >= 2). Four of them were presensitized to AT1R-Abs. In particular, three patients had a high titer of anti-AT1R-Abs (>22.7 U/mL). Conclusions: Pretransplant AT1R-Abs is an independent risk factor for AR, especially acute cellular rejection, and is possibly associated with the risk of antibody-mediated injury. Pretransplant assessment of AT1R-Abs may be useful for stratifying immunologic risks.