Autoantibodies against the angiotensin receptor (AT(1)) in patients with hypertension

Sera from patients with malignant essential hypertension (n = 14), malignan t secondary hypertension mainly attributable to renovascular diseases (n = 12) and renovascular diseases without malignant hypertension (n = 11) and f rom normotensive healthy blood donors (n = 35) were studied for the presenc e of autoantibodies against G-protein-coupled cardiovascular receptors, Aut oantibodies against the angiotensin II receptor (AT(1)) were detected in 14 , 33, 18 and 14% of patients with malignant essential hypertension, maligna nt secondary hypertension, renovascular diseases and control patients, resp ectively. Sensitivity of the enzyme immunoassay was assessed as 5 mu g/ml I gG, Patients did not show antibodies against bradykinin (B-2) Or angiotensi n II subtype 2 (AT(2)) receptors, Autoantibodies affinity-purified from pos itive patients localized AT receptors in Chinese hamster ovary transfected cells, and displayed a positive chronotropic effect on cultured neonatal ra t cardiomyocytes, These results demonstrate the existence of autoantibodies against a functional extracellular domain of human AT1 receptors in patien ts with malignant hypertension, and suggest that these autoantibodies might be involved in the pathogenesis of malignant hypertension. J Hypertens 200 0, 18:945-953 (C) Lippincott Williams & Wilkins.