Giant cell
myocarditis (GCM) is an aggressive inflammatory
myocardial disease. Immunosuppression is an effective treatment for some cases. However, the duration of action of agents such as
muromonab CD3 is short and others such as the
calcineurin inhibitors may lead to
renal failure. Here we describe the outcome of a novel approach to treatment using rabbit
anti-thymocyte globulin (RATG). A retrospective analysis of 6 patients treated with RATG for GCM was performed. Diagnosis was confirmed by endomyocardial biopsy, and RATG was administered with a high dose of
corticosteroids. None of the patients had
cytokine release syndrome or
leukopenia, and 5 had
thrombocytopenia (2 of them severe). Only 1 had a serious
bleeding event that occurred after implantation of mechanical circulatory support. None developed impaired renal function after the treatment. Five were successfully discharged home with an increase in global left ventricular ejection fraction of 29%. Four are currently alive without recurrent disease, 1 of them after
heart transplantation, with a mean follow-up of 970 days (423 to 1,875 days), left ventricular ejection fraction of 53%, and all in current New York Heart Association Classification class ≤II. Only 1 case had GCM recurrence. There were 2 deaths: one because of intracranial
bleeding after mechanical circulatory support implantation and the other caused by
primary graft dysfunction. In conclusion, patients with GCM can be successfully immunosuppressed with RATG and
corticosteroids, thereby avoiding renal impairment. Early
thrombocytopenia is the main adverse event. Larger cohorts of patients are necessary to compare the different
immunosuppressant strategies available for GCM in a randomized fashion.