Background

The antibodies (Abs) against angiotensin II type 1 receptor (AT1R) have been suggested as a risk factor for graft failure and acute rejection. However, incidence and importance of anti-AT1R Abs had not been evaluated in Asia. The aim of our study was to evaluate the incidence of anti-AT1R Abs and their impact on post- transplant outcomes.

Methods

In this multicenter, observational cohort study, we tested anti-AT1R Abs by using AT1R assay kits (One Lambda, CA, USA) in pre-transplant sera from 166 consecutive kidney recipients. A threshold of anti-AT1R antibody levels was statistically determined at 9.05 U/mL based on the time to acute rejection. Serum creatinine and glomerular filtration rates (GFR) at 1 year and were evaluated to compare graft function.

Results

Anti-AT1R Abs were observed in 98/166 (59.0%) of the analyzed recipients. During the 12 month observation period, no graft failure was reported. AT1R (+) patients showed significantly higher incidence of biopsy-proven acute rejection than in AT1R (-) patients (27.6% vs. 10.3%, p=0.007). Multivariate analysis showed that anti-AT1R Abs was an independent risk factor for acute rejection (HR = 3.18, 95% CI = [1.37, 7.39], p=0.007). Mean serum creatinine after 1 year showed a significant difference (1.13 ± 0.34 mg/dL in AT1R (-) vs. 1.27 ± 0.51 mg/dL in AT1R (+), p=0.047). However, there was no significant difference in GFR between groups.

Kaplan-Meier analysis of acute rejection episodes according to pretransplant anti-AT1R Abs

Patients with anti-AT1R Abs > 9.05 U/mL have an increased risk of developing an acute rejection episode during 1 year.

Conclusion

Pretransplant anti-AT1R Abs are associated with acute rejection. Detection of anti-AT1R Abs could be helpful for assessment of immunologic risk for acute rejection.

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