Enhanced Myocardial Deposition of DSG2-Reactive IgG in a Patient with Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited myocardial disease characterized by desmosomal disruption, fibrofatty replacement, and ventricular arrhythmias. Although autoantibodies against desmoglein-2 (DSG2) are implicated in ARVC, their myocardial localization remains unproven. We investigated DSG2-reactive IgG in myocardial tissue from a patient with ARVC and compared the findings with non-failing donor myocardium. Immunofluorescence and confocal microscopy revealed reduced, discontinuous DSG2 expression and altered desmoplakin and plakoglobin distribution. IgG colocalized more extensively with DSG2 in ARVC than in control myocardium, consistent with elevated serum anti-DSG2 autoantibodies. These findings provide tissue-level evidence of the spatial co-occurrence of tissue-bound IgG and DSG2 in ARVC and support further investigation of autoimmune mechanisms in disease progression.