Organ-Specific Cardiac Autoantibodies in Dilated Cardiomyopathy: Pathogenetic Implications

In autoimmune conditions, disease- and organ-specific autoantibodies are found in patients and a proportion of their symptom-free relatives [1]. In patients with dilated cardiomyopathy (DCM) circulating autoantibodies to multiple cardiac autoantigens have been described, providing evidence for autoimmune involvement [2–6]. Using indirect immunofluorescence (IFL) and absorption studies, we reported organ- and disease-specific cardiac autoantibodies in one third of distinct patient series from England [7], Poland [8] and Italy [9]. Similar findings have been presented in DCM patients from the United States [10]. Relevant autoantigens recognised by the antibodies detected by IFL include a (atrial) and β (ventricular and slow skeletal) myosin heavy chain [5]. In the majority of other organ-specific autoimmune conditions autoantibodies are not directly involved in myocardial damage, which is T cell-mediated, but represent reliable pathogenetic markers and non-invasive predictors of symptom-free individuals at risk, particularly relatives of affected patients [1]. We will focus upon clinical significance and pathogenetic implications of the organ-specific cardiac antibodies detected by the IFL test in DCM patients and their relatives.