Author + information
- Kathleen Simpson,
- Caroline K. Lee,
- Madeleine Cunningham,
- Catherine Simon,
- Jeffrey Delaney,
- Kent Ward,
- Alan Tong,
- Saar Danon and
- Charles Canter
Recent adult and animal studies have linked autoimmunity to host proteins to the pathophysiology of myocarditis/recent onset dilated cardiomyopathy (MC/DCM) in rodents and adults. The prevalence of autoimmunity in pediatric myocarditis and its relationship to outcome and cardiac dysfunction is unknown.
Evidence of autoimmunity was evaluated by measuring serum titers of autoantibodies to human cardiac myosin (HCM), beta-1 and 2 adrenergic receptors (BAR1 and BAR2), and muscarinic-2 receptor (M2) as well as antibody-mediated protein kinase A activation (PKA) in children with acute MC/DCM (N=16) at presentation, previously diagnosed (<6 years, but > 6 months since diagnosis) MC/DCM (N=12), and healthy age-matched controls (N=16). LV systolic dysfunction was defined as an LV shortening fraction (LVSF) echocardiographic z-score < −2 with recovery defined as improvement of LVSF z-score to > −2.
Presenting clinical and echocardiographic findings were similar with a mean LVSF z-score of −8.6 (−17.5 to −3.4) in the presentation group and −10.9 (−19.4 to 0.85) in the previously diagnosed group (p= 0.336). Antibodies against HCM were significantly higher in both newly (400 vs. 200, p=0.006) and previously (400 vs. 200, p=0.004) diagnosed groups compared to controls. PKA activation was also signficiantly higher in newly (21 vs. −2.5, p=0.013) and previously (31.5 vs. −2.5, p=0.002) diagnosed groups compared to controls. HCM and PKA activation did not differ between the newly and previously diagnosed groups. Previously diagnosed patients had 75% recovery at a median follow-up of 24 months, but there was no difference in any titer levels or PKA activation based on recovery status.
Autoimmune activation is present in pediatric MC/DCM at diagnosis and persists with follow-up. No apparent relationship between autoantibody production or PKA activation with recovery of normal systolic function could be discerned in this pilot study, but will require confirmation with a larger study population.
Poster Sessions, Expo North
Sunday, March 10, 2013, 9:45 a.m.-10:30 a.m.
Session Title: Myocarditis: Mechanistic Insights
Abstract Category: 23. Pericardial/Myocardial Disease
Presentation Number: 1207-150
- 2013 American College of Cardiology Foundation