Angiotensin II type 1 receptor (AT1R) autoantibodies (AT1Rab) have been associated with pre-eclampsia and malignant hypertension. Overactivity of the angiotensin-II/AT1R complex has also been implicated in cardiac, renal, and vascular remodeling, leading to mortality and morbidity from cardiovascular disease. Pre-donation prevalence and possible post-donation effects of AT1Rab in living kidney donors (LKD) are unknown. In this study, sera obtained the day before nephrectomy and kept frozen at -70 degrees C from 113 strictly normotensive and non-obese LKD were tested for AT1Rab by OneLambda detection assay. AT1Rab titers >or=17 international units were considered positive. Pre-donation renal function [estimated glomerular filtration rate (eGFR)] and blood pressure at 1 and 12 months post-donation were recorded in every patient. Ten of 113 (8.8%) LKD yielded a positive AT1Rab result. History of sensitization events was similar in both groups. There was no difference in renal function between LKD with positive and negative AT1Rab results, 1 (mean eGFR 73.8 versus 72.4 mL/min/1.73m2) and 12 months post-donation (mean eGFR 74.1 versus 74.5 mL/min/1.73m2). During follow-up, none of the LKD developed hypertension (defined as blood pressure >130/85), nor did they require antihypertensive drugs. AT1Rab are apparently indolent in healthy adults after short-term follow-up. Longer observation of all LKD will be necessary to draw final conclusions.