Elevated M2-muscarinic and β1-adrenergic receptor autoantibody levels are associated with paroxysmal atrial fibrillation

Pathophysiologic mechanisms underlying lone atrial fibrillation (AF) have not been clearly demonstrated yet. Emerging evidence has indicated that autoimmunity may play a role in the development of AF. Relationship between serum anti-M2-muscarinic receptor autoantibody (anti-M2-R) and anti-beta 1-adrenergic receptor autoantibody (anti-beta 1-R) levels and lone paroxysmal atrial fibrillation (PAF) has not been investigated. We aimed to compare anti-M2-R and anti-beta 1-R levels between lone PAF patients and healthy control subjects. 75 patients with lone PAF (age: 52.80 +/- A 6.80 years, 53 % male) and 75 healthy control subjects (age: 53.30 +/- A 6.80 years, 54 % male) were enrolled in the study. Serum anti-M2-R and anti-beta 1-R levels were measured by ELISA and compared between two groups. Anti-M2-R [142.30 (77.65-400.00) vs. 69.00 (39.48-299.04) ng/mL; p < 0.001) and anti-beta 1-R [102.56 (65.18-348.41) vs. 44.17 (30.89-158.54) ng/mL; p < 0.001] levels were significantly higher in patients with lone PAF compared to healthy controls. Multivariate regression analysis showed that left atrial diameter (OR: 1.471, p < 0.001), hs-CRP(OR: 1.940, p < 0.001), anti-M2-R (OR: 1.158, p < 0.001) and anti-beta 1-R (OR: 1.296, p < 0.001) levels were independent predictors for the presence of lone PAF. Using a cut-off level of 101.83 ng/mL, anti-M2-R levels predicted presence of lone PAF with a sensitivity of 94.68 % and specificity of 81.33 %. Anti-beta 1-R levels predicted presence of lone PAF with a sensitivity of 92.00 % and specificity of 73.30 %, using a cut-off level of 72.16 ng/mL. Our results demonstrated that higher serum anti-M2-R and anti-beta 1-R levels are associated with lone PAF. Autoantibodies related to autonomic system may play an important role in the development of lone AF.