Active Fulminant Myocarditis Characterized by T-Lymphocytes Expressing the Gamma-Delta T-Cell Receptor: A New Disease Entity?

Lymphocytic myocarditis is thought to be a virus-induced disease. T cells expressing the alpha-beta T-cell receptor seem to play a central role in the pathogenesis and to mediate tissue injury in this disease. A case of active fulminant myocarditis is described, which was analyzed by immunohistochemical, molecular biologic, and serologic methods. Infiltration of the heart tissue predominantly by gamma-delta T cells was detected by immunohistochemistry. No evidence of viral disease could be obtained by in situ hybridization with different enterovirus-specific DNA probes; by reverse-transcriptase polymerase chain reaction using specific primers for enteroviruses, adenoviruses, herpes simplex viruses, influenza A and B viruses, and cytomegaloviruses; or by enzyme-linked immunosorbent assay and electron microscopy. Because gamma-delta T cells may have an autoimmune capacity, we propose that these cells may trigger autoimmune myocarditis. These findings may be important in order to identify subgroups of patients who may benefit from immunosuppressive therapy.