Angiotensin Type 1 Receptor Antibody Positivity in a Pediatric Liver Transplant Patient With Antibody-Mediated...

Antibody-mediated rejection (AMR) in pediatric liver transplantation (LT) is uncommon and poorly understood. While human leukocyte antigen (HLA) antibodies are usually implicated in AMR, non-HLA antibodies have also been reported.

We describe a 7-year-old female with non-HLA AMR in the setting of positive angiotensin type 1 receptor (AT1R) antibodies.

She was diagnosed with acute T-cell mediated rejection (TCMR) 6 months post-LT which was treated with intravenous methylprednisolone (IVMP) but had minimal response. A repeat biopsy revealed features of AMR including C4d staining and capillaritis, but donor-specific antibodies (DSAs) were negative. However, AT1R antibodies were elevated at 21 U/mL. She received antithymocyte globulin (ATG) and was started on losartan to block AT1R antibodies, with excellent response.

While the recognition and mechanisms of AMR in pediatric LT are in its infancy, this case highlights the importance of considering non-HLA antibodies as potential mediators of AMR. Children who fail to respond to TCMR treatment should be evaluated for AMR by obtaining DSAs, C4d staining on biopsy, and non-HLA antibodies.