The effect of pre-transplant and post-transplant anti-AT1R antibodies in heart transplant recipients

Background

The presence of autoantibodies to angiotensin 2 type 1 receptor (anti-AT1R) have been implicated in allograft pathobiology following organ transplantation. While the significance of these antibodies has been described in renal transplantation, relatively few studies have examined their frequency and clinical implications in heart transplant patients.

Methods

We analyzed serum collected from 291 heart transplant recipients at the time of transplantation for the presence of anti-AT1R and repeated testing on serum collected from 176 of these patients following transplantation. Patients were followed for outcomes including overall survival, rejection episodes (acute cellular and antibody mediated), coronary allograft vasculopathy, and measures of allograft structure and cardiac function.

Results

Anti-AT1R was detected in the serum of 165/291 patients pre-transplant and in 86/176 patients post-transplant. The detection of anti-AT1R (either at risk or positive) compared with no detection in serum of patients pre- or post-transplantation had no influence on 10-year survival (Log rank 0.061 and 0.228, detection pre- or post-transplant, respectively). Similarly, the detection of anti-AT1R had no influence on important clinical outcomes of heart transplantation including acute cellular rejection (ACR), antibody-mediated rejection (AMR) or cardiac allograft vasculopathy (CAV), left ventricular ejection fraction (LVEF) or left ventricular mass (LV-mass).

Conclusions

The presence of anti-AT1R detected in patient serum samples by commercially available testing pre- or post- heart transplantation was not associated with clinically important outcomes including LV-mass, LVEF, ACR, AMR, CAV and overall survival. Our data brings into question the relevance of anti-AT1R testing as a risk factor or target for therapy among heart transplant recipients.