Giant cell myocarditis in a 12-year-old girl with common variable immunodeficiency.

Giant cell myocarditis (GCM) is a rare and often fatal disease that infrequently affects children. Common variable immunodeficiency (CVID) describes a heterogeneous group of disorders characterized by hypogammaglobulinemia and poor specific antibody responses. To our knowledge, CVID and GCM have not been reported together in 1 patient. We describe a 12-year-old girl with CVID who developed acute severe GCM that necessitated cardiac transplantation. Histopathological and immunohistochemical studies of the endomyocardial biopsy specimen and the explanted heart revealed numerous histiocytes, eosinophils, T cells, and multinucleated giant cells. Both CVID and GCM are thought to involve dysregulation of T-cell function and have been associated with a similar spectrum of autoimmune conditions. The coincidence of CVID and GCM in a single patient may reflect a pathophysiologic connection.