Myocardial immune vulnerability unmasked after treatment with immune checkpoint inhibitors: a case report.

BACKGROUND: Although uncommon (incidence <1%), cardiac immune-related adverse events (irAEs) associated with immune checkpoint inhibitor (ICI) therapy can be fatal. Their underlying mechanisms remain incompletely understood, although autoimmune predisposition and cross-antigen responses have been implicated. CASE SUMMARY: We report the case of a young, immunologically predisposed patient with renal cell carcinoma who developed recurrent episodes of myocardial injury following an initial mild ICI-related myocarditis. Subsequent viral infections acted as triggers for repeated myocardial damage despite discontinuation of ICI therapy. DISCUSSION: Novel immune biomarkers were identified, and distinctive findings on endomyocardial biopsy, together with tumour protein expression patterns, provided insight into the patient's heightened myocardial immune vulnerability to viral infections. This case highlights the complex interplay between ICI therapy, host immune predisposition, and viral triggers in the pathogenesis of cardiac irAEs.