Myopericarditis and enhanced dystrophic cardiac calcification in murine cytomegalovirus infection

In mice inoculated with murine cytomegalovirus (MCMV) an acute myopericarditis developed which varied from a focal lymphohistiocytic inflammation to intense inflammation with necrosis and cytomegalic inclusion-bearing cells. Sublethal doses caused focal transient nonspecific chronic inflammation, followed months later by an increased frequency and extent of dystrophic cardiac calcification. When such latently infected hearts were heterotopically transplanted into uninfected animals which were then immunosuppressed (IS), a fatal generalized CMV infection followed. Cytomegalic inclusion-bearing endothelial, fibroblastic, and myocardial cells were seen in the intense inflammation found in hearts taken from mice 4 days after lethal inoculation and transplanted into uninfected mice, which were then IS. These findings may be relevant to human cardiac transplantation because they show that MCMV regularly causes cardiac infection with both acute and chronic consequences; chronic injury may follow a morphologically nonspecific myopericarditis which might not be attributed to CMV infection.