Targeting T Cells to Treat Trypanosoma cruzi-Induced Myocarditis

In 1995, the last World Health Organization (WHO)/International Society and Federation of Cardiology (ISFC) Task Force on the definition and classification of cardiomyopathies defined myocarditis (also named “inflammatory cardiomyopathy”) as an “inflammatory disease of the myocardium associated with cardiac dysfunction” [1]. In myocarditis, the inflammatory infiltrate of the myocardium is associated with necrosis and/or degeneration of adjacent myocytes, which is not typical of – nor consistent with – myocardial ischemic damage seen with coronary artery disease [1, 2]. The clinical presentation of myocarditis is dependent upon the magnitude of myocardial inflammation, thus it may be quite variable. Clinical signs and symptoms may range from subclinical disease (which may initially be unrecognized) to newonset acute heart failure or sudden death due to ventricular arrhythmias [3]. Moreover, the clinical course of myocarditis may be as variable as its clinical presentations: some individuals may develop acute myocarditis that resolves spontaneously within a few weeks, while others may develop symptoms of chronic heart failure due to dilated cardiomyopathy (DCM) [3]. Although many patients with hemodynamically stable heart failure may respond well to optimal medical therapy, a significant percentage of patients with DCM become medically refractory and progress to irreversible end-stage heart failure for which heart transplantation becomes the only hope of survival. Indeed, it is estimated that acute myocarditis resolves completely in approximately 50% of cases, with an additional 25% of patients having incom‐ plete recovery (i.e.; partial normalization of cardiac function), while the remainder 25% will inexorably progress to end-stage heart failure and death [1, 4-6].