INCREASED FREQUENCY OF ORGAN-SPECIFIC CARDIAC ANTIBODIES IN HEALTHY RELATIVES OF PATIENTS WITH DILATED CARDIOMYOPATHY - EVIDENCE FOR AUTOIMMUNITY IN POLISH FAMILIES

Background and hypothesis: Autoantibodies represent markers of autoimm une involvement and are found with increased frequency in patients and their symptom-free relatives al risk compared with normal controls. C ardiac-specific autoantibodies, detected by immunofluorescence were fo und in 20% of symptom-free relatives of patients with dilated cardiomy opathy (DCM) from England and Italy. The role of autoimmunity may vary in DCM patients from Poland due to ethnic differences in genetic susc eptibility to autoimmune disease. Methods: We assessed the frequency o f the organ-specific cardiac autoantibodies in 162 symptom-free relati ves of DCM patients [85 male, mean (SD) age 27 (18 years] and 80 contr ol subjects from Poland. Familial DCM (> 1 affected member) was presen t in 1 families, nonfamilial DCM in the remaining 24 pedigrees. We per formed antibody screening and noninvasive cardiological assessment in the whole group. Results: The frequency of cardiac-specific autoantibo dies was higher among patients with documented DCM (probands and relat ives) (50%) and their symptom-free relatives (38%) than in unrelated n ormal subjects (10%; p=0.0001). In 24 (86%) of the pedigrees studied, autoantibodies were found in the proband and/or in at least one family member and tended to be more common in familial than in nonfamilial D CM (50 vs. 35%, p=NS). Echocardiographic indices of left ventricular s ize and function were similar in relatives with and without detectable antibodies. Conclusions: The presence of cardiac-specific autoantibod ies in symptom-free relatives of DCM patients provides evidence for au toimmunity in the majority (86%) of our pedigrees, including both fami lial and nonfamilial forms of DCM.