Presentation and Outcomes of Antibody-Mediated Rejection Associated With Angiotensin II Receptor 1 Antibodies Among Kidney Transplant Recipients

Background: It remains challenging to manage antibody-mediated rejection (ABMR) associated with angiotensin II type 1 receptor antibodies (AT1R-Abs) in kidney transplant recipients and the outcomes are not well defined. We describe the presentation, clinical course, and outcomes of this condition. Methods: This retrospective study included kidney transplant recipients with AT1R-Ab levels ≥10 units/mL and biopsy-proven ABMR in the absence of significant HLA-donor-specific antibodies at the time of rejection. Results: We identified 13 recipients. Median creatinine (Cr) at rejection was significantly higher (2.05 mg/dL) compared with baseline (1.2 mg/dL), P = .006. After ABMR management, the difference in median Cr was not significant (1.5 mg/dL), P = .152. Median AT1R-Ab level was higher in the pretransplant sample (34.5 units/mL) compared with the level at rejection (19 units/mL) and after rejection treatment (13 units/mL); however, these differences were not significant, P = .129. Eight of the 13 recipients received antibody reduction therapy with plasmapheresis and intravenous immunoglobulin, and 5 of the 13 recipients had other therapies. After rejection management, 6 of the 13 recipients had improvement in Cr to baseline and 7 of the 13 recipients had > 50% reduction in proteinuria. Conclusions: AT1R-Ab–associated ABMR management and outcomes depend on the clinical presentation and may include antibody-reducing therapies among other therapies. Further prospective cohorts will improve recognizing and managing this condition.