Objective: To determine whether the autoantibodies against beta(1)-adrenergic and M(2)-muscarinic receptors are related to congestive heart failure (CHF) patients with different cardiac diseases.
Methods: Both synthetic peptides corresponding to amino acids sequence of the second extracellular loops of the beta(1) and M(2) receptors were used as the antigens to screen the serum from CHF patients with ischemic cardiomyopathy (ICD, n = 42), idiopathic dilated cardiomyopathy (IDCM, n = 52) and hypertensive heart disease (HHD, n = 44). Meanwhile healthy donors were tested as normal controls (NC, n = 40).
Results: The positive rates of serum for beta(1)-adrenergic-receptor were 45.7% (86/188) and 10.4% (8/77) in CHF patients and controls respectively (P < 0.01); the positive rates of serum for M(2)-muscarinic receptor were 52.7% (99/188) and 11.7% (9/77) in CHF patients and controls (P < 0.01). The frequencies of the both receptor autoantibodies in patients with cardiac function of class II approximately III were significantly higher than those with cardiac function of class VI.
Conclusions: Our finding indicates indicates that autoantibodies against beta(1)-adrenergic-receptor and M(2)-muscarinic receptor can be detected not only in the serum of CHF patients with IDCM, but also in CHF patients with ICM and HHD. It is suspected that autoantibodies against beta(1) and M(2) receptors may be related to the myocardial remodeling and/or CHF.