title: A pilot study on the role of autoantibody targeting the beta1-adrenergic receptor in the response to beta-blocker therapy for congestive heart failure.
abstract: BACKGROUND
  Autoantibodies directed against the beta1-adrenergic receptor exert agonist-like actions by inducing receptor uncoupling and cause myocardial damage as well as fatal ventricular arrhythmias. Previous studies have shown that beta-blockers can modulate these actions of the autoantibodies. We investigated the influence of such autoantibodies in patients with congestive heart failure (CHF) receiving beta-blocker therapy.
  
  
  RESULTS
  Eighty-two CHF patients were randomly assigned to treatment with metoprolol or carvedilol for 16 weeks. Autoantibodies were detected in 20 patients (24%) by enzyme-linked immunosorbent assay. Left ventricular function in response to beta-blocker therapy did not differ significantly by the presence of the autoantibody in global analysis. However, changes of the left ventricular end-diastolic dimension (P = .04), end-systolic dimension (P < .01), and ejection fraction on radionuclide ventriculography (P = .02) were significantly larger in autoantibody-positive patients than antibody-negative patients. Changes in the plasma level of brain natriuretic peptide tended to be larger in autoantibody-positive patients (P = .09). The increase of heart rate normalized by the increase of plasma norepinephrine during exercise (an index of adrenergic responsiveness) showed a greater decrease in autoantibody-positive patients than autoantibody-negative patients (P = .035).
  
  
  CONCLUSIONS
  Our data suggest that beta-blocker therapy might be more effective in CHF patients with autoantibodies targeting the beta1-adrenergic receptor.
authors.affiliation: Cardiology Division, Department of Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nagatomo
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Kohno
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yoshizawa
authors.forename: Akiyasu
authors.initials: A
authors.lastname: Baba
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Anzai
authors.forename: Tomomi
authors.initials: T
authors.lastname: Meguro
authors.forename: Toru
authors.initials: T
authors.lastname: Satoh
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ogawa