Th1/Th2 balance alteration in the clinical course of a patient with acute viral myocarditis.

Cytokines have an important role in the pathogenesis and pathophysiology of myocarditis. In this study, subsets of peripheral helper T lymphocytes (Th) in a patient with acute viral myocarditis were analyzed by 3-color flow cytometry. During the clinical course of myocarditis, the Th1/Th2 ratio of peripheral lymphocytes changed. Th1 was dominant in the acute inflammatory phase during which levels of creatine kinase (CK) increased (day 6), then Th2 levels overtook those of Th1 in the recovery phase during which levels of CK decreased (day 13 and 20). At the time of discharge (day 35), Th1 and Th2 had normalized. Thus, it was speculated that the induction of lymphocytic myocarditis was associated with Th1 dominant status, and recovery was related to Th2 polarity. Th subset imbalances may play an important role in the pathogenesis of acute viral myocarditis and these analyses may be useful for understanding the disease activity of myocarditis.