The multiple faces of autoimmune/immune-mediated myocarditis in children: a biopsy-proven case series treated with immunosuppressive therapy.

The role of immunosuppressive therapy (IT) in paediatric autoimmune/immune-mediated myocarditis remains poorly defined. To explore its role, we present a series of three consecutive paediatric patients with biopsy-proven, virus negative, autoimmune/immune-mediated myocarditis, with distinct clinical and pathological features, who have been successfully treated with IT, a 14-year-old boy with Loeffler's fibroblastic parietal endomyocarditis, a 6-year-old child with celiac disease with chronic active lymphocytic myocarditis, and a 13-year-old boy with long-standing heart failure and active lymphocytic myocarditis. Patients started IT and entered follow-up between July 2017 and September 2019; the first patient completed IT. IT was associated with a substantial and sustained recovery of cardiac function in our patients, regardless of their heterogeneous clinical and pathological features. Combination IT was well tolerated and enabled tapering and weaning off steroids.