Rinsho Shinkeigaku (Clinical Neurology)

Original Article

Anti-beta 1 adrenoreceptor antibody is frequently elevated in patients with muscular dystrophy

Tsuyoshi Matsumura, M.D.1), Taku Yoshio, M.D.2), Keiji Yamamoto, M.D.3), Toshio Saito, M.D.1), Harutoshi Fujimura, M.D.1) and Susumu Shinno, M.D.1)

1)Department of Neurology, National Hospital Organization Toneyama National Hospital
2)Division of Rheumatology and Clinical Immunology, School of Medicine, Jichi Medical University
3)Division of Cardiovascular medicine, School of Medicine, Jichi Medical University

Various autoantibodies had been detected in patients with dilated cardiomyopathy (DCM). Among them, anti-beta 1 adrenoreceptor antibody (ARAb) had been proven to act as agonist on beta 1 adrenoreceptor and cause DCM. Cardiomyopathy is also serious problem in progressive muscular dystrophy (PMD). Because cardiac dysfunction is quite variable even in siblings sharing identical mutations, it is highly possible that there are some modifier factors. Thus, we measured ARAb in 93 patients with PMD and 11 patients with DCM to clarify immune function for cardiac impairment of PMD. The titer was abnormally elevated in 30.1% of PMD, 72.7% of DCM and 75.0% (9/12) of PMD patients with symptomatic cardiac failure. ARAb was weakly correlated to fractional shortening, brain natriuretic peptide, noradrenalin and severity of premature ventricular contractions (Lown grade). During the study period, four patients developed cardiac failure and ARAb was increased in all these patients. In DMD, although the patients receiving both beta blocker and angiotensin converting enzyme inhibitor showed worst cardiac function, the titers were rather low compared to patients with angiotensin converting enzyme inhibitor alone. Four of five patients initiating beta blocker showed decrease of ARAb. Autoantibodies for myocardium actually exist in PMD in certain ratio as is the case with DCM. It is highly possible that immune system plays some role in cardiac impairment even in PMD. We should pay enough attention to immune system to elucidate the mechanism of cardiac dysfunction and refine strategy of cardiac treatments.

(CLINICA NEUROL, 46: 687－692, 2006)
key words: muscular dystrophy, cardiomyopathy, cardiac failure, autoantibody, anti-beta 1 adrenoreceptor antibody

(Received: 7-Feb-06)