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J Clin Immunol (2009) 29:730737 DOI 10.1007/s10875-009-9339-z
Myocarditis: Infection Versus Autoimmunity
Noel R. Rose
Received: 14 September 2009 /Accepted: 23 September 2009 /Published online: 14 October 2009 # Springer Science + Business Media, LLC 2009
AbstractIntroduction Myocarditis, which is the inflammation of the heart muscle, remains a vexing therapeutic problem. Many cases are associated with viral infection, and appropriate treatment may depend upon whether the disease is primarily infectious, immune-mediated, or both. Discussion The combination of endomyocardial biopsies with newer molecular and immunologic tools holds a promise of distinguishing the different etiologies of myocarditis, thus, guiding future treatments. Nucleic acid hybridization and polymerase chain reaction have been applied to detect viral genome persisting in the heart. Early trials with type 1 interferons have shown a promise in patients with biopsy-proven enteroviral infection. Antibodies to cardiac antigens and increased HLA expression in cardiac biopsies have been used to identify patients, most likely, to benefit from immunosuppression or immunoadsorption. Future advances in the therapy of inflammatory disease of the heart may be based on detailed studies of myocarditis in animal models. Using coxsackievirus B3 infection or cardiac myosin immunization, we have identified some critical steps leading from a self-limited viral myocarditis to chronic autoimmune myocarditis and sometimes, to dilated cardiomyopathy.
Conclusion Myocarditis offers an opportunity to dissect the complex interaction between a viral infection and an autoimmune disease. The lessons learned from investiga-
tions in humans and in animal models hold a promise that may lead the way to improved treatments.
Keywords Myocarditis . autoimmunity. cardiomyopathy
Background
Myocarditisisbestdefinedsimplyasinflammationoftheheart muscle. Despite this simplistic definition, the diagnosis and treatmentofmyocarditiscontinuetopresentclinicalproblems. The more regular use of the endomyocardial biopsy has promotedgreaterunderstandingofthenaturalhistoryofhuman myocarditisandpromptedneweffortsatclassification.In1991, Lieberman et al. proposed a classification based on analysis of the histologic findings of biopsies and clinical course of the patient [1]. They distinguished patients with fulminating myocarditis who become acutely ill after a distinct viral prodrome and have severe cardiovascular compromise, histologic evidence of active myocarditis, and left ventricular dysfunction. The disease in these patients either results in death or resolves spontaneously. Patients with acute myocarditis present with established ventricular dysfunction and show histologic evidence of active or borderline myocarditis. This form of disease may lead to complete resolution but sometimes progresses to dilated cardiomyopathy. Like active myocarditis,...