Abstract 10319: Are the Therapeutic Benefits of Extracorporeal Immunoglobulin Adsorption in Beta-1 Adrenoceptor Autoantibody Positive Patients with Dilated Cardiomyopathy Indeed Related to the Removal of these Antibodies?
Objective: After detection of immunological abnormalities in dilated cardiomyopathy (DCM), including autoimmune reactivity against myocytes, attention has been focused on autoimmune mechanisms as potential key elements in DCM pathogenesis. DCM often appeared related to elevated autoantibody (AAB) levels against cardiac proteins including β1-adrenoreceptors. IgG reduction by unselective immunoadsorption (IA) i.e. extracorporeal IgG adsorption to levels at which β1-AABs become nearly undetectable, can be an efficient treatment. Nevertheless, there is controversy on whether β1-AAB removal by IA is indeed the major cause for cardiac improvement. We compared the results of unspecific IA and selective β1-AAB removal.
Methods: In 8/2000–1/2005 DCM patients with LVEF ≤ 30%; and evidence of serum β1-AABs underwent random selection for either unspecific or specific IA which was performed on 5 consecutive days with daily β1-AAB measurements. For unspecific (unselective) IA we used columns containing polyclonal anti-human immunoglobulin antibodies produced in sheep. Selective β1-AAB removal (specific IA) was performed on peptide columns. A bioassay consisting of cell cultures of spontaneously beating neonatal rat cardiomyocytes was used for β1-AAB measurements. Cardiac function was closely monitored after IA and regular β1-AAB measurements were performed. Final outcome evaluation was performed in 1/2010 (follow-up 5–9.5 years).
Results: There was a LVEF improvement during the first 6 months after both unspecific and specific IA (p < 0.05) but there was no difference in improvement between the 2 groups and the prevalence of responders to IA (LVEF improvement) was similar (73.9%; vs 76.2%;). Htx/VAD free survival after unspecific and specific IA was reached at 5 years by 78.3 ± 8.6%; and 95.3%; ± 4.7%; of patients, respectively. For responders the probability of Htx/VAD free survival after unspecific and specific IA was 94.1 ± 5.7%; and 100%;, resp. (p = 0.171).
Conclusions: Removal of β1-AABs by both unselective and selective IA allows long-term stable cardiac improvement in DCM patients. IgG substitution after unspecific IA and the possible removal of other AABs during unspecific IA appears to have no relevant influence on the therapeutic results of β1-AAB removal.
- © 2010 by American Heart Association, Inc.