β1-adrenoreceptor antibody measurement and antibody removal effects on left ventricular contractility in dilated cardiomyopathy patients

Abstract

Aim. To develop a test system measuring β1-adrenoreceptor antibody (anti- β1-AR) level. To study the effects of autoantibody removal on left ventricular (LV) contractility. Material and methods. Peptides, according to second human extracellular β1-AR loop fragments (197-222 amino acid fragments), were synthesized by modified hard-phase method and then lyophilized. Molecular mass control was performed by laser desorption mass spectrometry. In total, 47 patients were examined, with the aim of anti- β1-AR detection. Dilated cardiomyopathy (DCMP) was diagnosed in 22 patients, ischemic CMP – in 8, post-infarction cardiosclerosis – in 6, myocarditis – in 3, alcohol CMP – in 1, and post-transplantation CMP – in 7 participants. Anti- β1-AR were removed in 4 DCMP patients, by plasmapheresis (PF; n=3) or immunoadsorption (IA; n=1). Results. A new immune-enzyme test system for autoantibody detection has been developed, using the second extracellular β1-AR loop 26 amino acid peptide as the antigen. Anti- β1-AR removal by IA or PF methods resulted in improved LV contractility among DCMP patients. Conclusion. It is important to determine whether LV contractility improvement is explained by anti-β1-AR removal exclusively. More advanced methods for anti- β1-AR and other anti-myocardial antibody detection should be developed, and auto-antibodies’ role in impaired myocardial contractility should be studied.

Keywords

• β1-adrenoreceptpor auto-antibodies
• immuno-adsorption
• plasmapheresis
• left ventricular myocardial contractility