Effects of lobenzarit on murine acute viral myocarditis.

Lobenzarit (CCA) is a newly developed immunomodulating drug that has been demonstrated to enhance suppressor T-cell number and function. In this study we investigated the effect of CCA on murine myocarditis induced by the encephalomyocarditis (EMC) virus. Mice were first inoculated with the EMC virus. CCA (100 mg/kg) was administered daily for 14 days, starting on the day the mice were inoculated. The concentrations of Lyt2+ (suppressor/cytotoxic T) cells in the peripheral blood and heart were examined by laser flow cytometry and in situ staining. The concentration of Lyt2+ cells increased significantly in the peripheral blood and heart of CCA-treated mice when compared with untreated mice (blood: 23.0 +/- 2.6% vs. 18.8 +/- 2.8%, p less than 0.05; heart: 30.1 +/- 4.6% vs. 15.8 +/- 4.3%, p less than 0.05, respectively). Surprisingly, however, the severity of myocardial inflammation in CCA-treated mice was significantly greater than in untreated mice (area of inflammation: 33.1 +/- 10.5% vs. 18.8 +/- 19.5%, respectively, p less than 0.05). Thus, these findings suggest that CCA may aggravate EMC-induced acute myocarditis by enhancing the number of Lyt2+ cells.