LE MIOCARDITI INFETTIVE NELL'OSPITE COMPROMESSO

The pathogenetic role and the clinical importance of infectious myocarditis in the compromised host are considerable, although little known. Among HIV-infected patients the prevalence of myocarditis is high. Toxoplasma gondii, fungi and human Cytomegalovirus are the most frequently reported aetiologies. In about 80% of cases, however, the cause is not identified. These cases could be attributed either to a direct or indirect toxic effect exerted bv HIV itself, or to a non-permissive Cytomegalovirus infection of myocytes. As regards other populations of compromised hosts, infectious myocarditis constitutes a problem especially for heart transplant recipients. T. gondii and Cytomegalovirus are the most common causes. The inflammatory infiltrate of infectious myocarditis must be differentiated from that of acute rejection activity. Cytomegalovirus myocarditis, according to several studies, could be associated with cardiac allograft rejection and development of accelerated graft arteriosclerosis in the transplanted heart. Research on epidemiology and evolution of infectious myocarditis in the compromised host could contribute to elucidate the relationship linking viral myocarditis to dilated cardiomyopathy in immunocompetent individuals.