Role of angiotensin II type 1 receptor-activating antibodies in solid organ transplantation.

Angiotensin type I receptor (AT1R) mediates physiologic and pathophysiologic actions of its ligand, angiotensin II. Overactivity of the AT1R and angiotensin II interaction results in hypertension and vascular remodeling. Antibodies to AT1R have been implicated in several vascular pathologies. In renal transplantation, elevated levels of anti-AT1R antibodies have been associated with antibody mediated rejection (AMR) in the absence of donor HLA specific antibodies. In heart transplantation, increased levels of anti-AT1R antibodies have been associated with cellular and AMR as well as an early onset of microvasculopathy. This review summarizes the current investigations regarding the impact of anti-AT1R antibodies in solid organ transplantation and provides insight into the humoral response in the presence of non-HLA and HLA specific antibodies.