Association between anti‐endothelial antigen antibodies and allograft rejection in kidney transplantation

BACKGROUND: Endothelial cells are vital in the transplant immune system as semiprofessional antigen‐presenting cells. Few studies have investigated the importance of anti‐endothelin subtype A receptor (ETAR) antibodies in kidney transplantation. Here, we aimed to analyze the association between anti‐angiotensin II type I receptor (AT1R) and anti‐ETAR antibodies and the association between the presence of anti‐endothelial antibodies and the risk of allograft rejection in kidney transplantation. METHODS: In total, 252 patients who underwent kidney transplantation were enrolled in this study. Antibodies for human leukocyte antigens (HLAs) and non‐HLAs were analyzed immediately before transplantation. Patients were categorized based on the occurrence of antibody‐mediated rejection (AMR) or T‐cell‐mediated rejection (TCMR) by 2017 Banff classification. All p‐values were two‐tailed, and statistical significance was set at p < 0.05. RESULTS: Patients with anti‐AT1R antibodies had a 3.49‐fold higher risk of TCMR than those without anti‐AT1R antibodies. Patients with anti‐ETAR antibodies had a 5.84‐fold higher risk of AMR than those without anti‐ETAR antibodies. The hazard ratio of AMR in patients with both HLA DSAs and anti‐ETAR antibodies, relative to patients without anti‐ETAR antibodies and HLA DSAs, was 32.85 (95% CI = 1.82–592.91). CONCLUSION: Our findings indicated that anti‐ETAR antibodies are associated with AMR, and patients with both anti‐ETAR antibodies and de novo HLA DSAs were at a high risk of AMR.