Abstract 2444: Prevalence and Role of Autoantibodies Against Beta 1- Adrenoceptor in Children with Dilated Cardiomyopathy
Background: Autoimmunity seems to have a role in the pathogenesis of dilated cardiomyopathy (DCM). Autoantibodies against beta 1 adrenoceptors have been identified in 30 to 90 % adult pts and their removal with immunoadsorption has been associated with haemodinamic and clinical improvement. No data exist in children with DCM.
Aim of the study: Evaluate the prevalence of autoantibodies against beta 1- adrenoceptors in children with DCM, their influence on cardiac function and the clinical outcome.
Material and Methods: From 60 living pts with DCM (biopsy proven) seen in our hospital from 1986 to 2005 we selected all children with EF < 40% (16 patients, mean age 5.4 ± 4.6 years, mean weight 23±20 Kg). The FU period was 3.9 ± 3.6 years (median 1.8 years, range 1 month to 12 years). We tested blood samples of these pts for IgG antibodies reacting with beta receptor peptides. All the patients were treated according to ACC/AHA guidelines . Values are presented as mean ± SD. Statistical analysis was performed with a two-sample t test.
Results: Among 16 children , 6 (37.5%) had autoantibodies against beta 1 adrenoceptors. During FU the EF of the overall population increased to 33.35% ± 9.5. The EF worsened (−6.1%) among the pts with autoantibodies but improved among those without (+7%) and this difference was statistically significant.
Conclusions: In our population the prevalence of autoantibodies against beta 1- adrenergic receptors is 37.5% similar to the data reported in adult pts. The children with DCM and presence of autoantibodies seem to have worsening ventricular function during the FU when compared with the children without autoantibodies . Longer FU in more pts is needed to confirm our findings and to better understand the real role of autoantibodies in DCM.