Potential role of autoantibodies belonging to the immunoglobulin G-3 subclass in cardiac dysfunction among patients with dilated cardiomyopathy


  • A. Staudt
  • M. Boehm
  • F. Knebel
  • Y. Grosse
  • C. Bischoff
  • A. Hummel
  • J.B. Dahm
  • A. Borges
  • N. Jochmann
  • K.D. Wernecke
  • G. Wallukat
  • G. Baumann
  • S.B. Felix


  • Circulation


  • Circulation 106 (19): 2448-2453


  • Background- Immunoadsorption capable of removing circulating autoantibodies represents an additional therapeutic approach in dilated cardiomyopathy (DCM). The role played by autoantibodies belonging to the immunoglobulin (Ig) subclass G-3 in cardiac dysfunction remains to be elucidated. Methods and Results- Patients with DCM (left ventricular ejection fraction <30%) participated in this case-control study. Nine patients underwent immunoadsorption with protein A (low affinity to IgG-3), and 9 patients were treated with anti-IgG, which removes all IgG subclasses. Immunoadsorption was performed in 4 courses at 1-month intervals until month 3. In the 2 groups, immunoadsorption induced comparable reduction of total IgG (>80%). IgG-3 was effectively eliminated only by anti-IgG adsorption (eg, during the first immunoadsorption course; protein A, −37±4%; anti-IgG, −89±3%; P<0.001 versus protein A). The {beta}1-receptor autoantibody was effectively reduced only by anti-IgG (P<0.01 versus protein A). Hemodynamics did not change in the protein A group. In the anti-IgG group during the first immunoadsorption course, cardiac index increased from 2.3±0.1 to 3.0±0.1 L · min−1 · m−2 (P<0.01 versus protein A). After 3 months, before the last immunoadsorption course, cardiac index was 2.2±0.1 L · min−1 · m−2 in the protein A group and 3.0±0.2 L · min−1 · m−2 in the anti-IgG group (P<0.01 versus protein A). Left ventricular ejection fraction increased only in the anti-IgG group (P<0.05 versus protein A). Conclusions- Autoantibodies belonging to IgG-3 may play an important role in cardiac dysfunction of DCM. The removal of antibodies of the IgG-3 subclass may represent an essential mechanism of immunoadsorption in DCM.