Virological study of idiopathic cardiomyopathy. Serological study of virus antibodies and immunofluorescent study of myocardial biopsies.

Abstract

In 113 patients with idiopathic cardiomyopathy paired sera obtained 2-4 wk apart were examined for neutralizing antibody to coxsackievirus B [CB] 1-6, and echovirus 4, 6, 7, 9 and 11. Only 8 cases (6.9%) showed a significant change in titer, indicating a virus infection during or shortly before the study. Complement-fixing antibody titers were measured in 126 patients and neutralizing antibodies in 116 patients with idiopathic cardiomyopathy. More patients had complement-fixing antibody titers .gtoreq. 1:4 to CB and herpes simplex virus than did controls (P < 0.05). Neutralizing antibody titers to CB 1 and CB 3 virus were also higher in patients (P < 0.01 for titers .gtoreq. 1:4 and P < 0.05 for titers .gtoreq. 1:16). Complement-fixing antibody titers .gtoreq. 1:4 to herpes simplex virus were more frequent (P < 0.05) in hypertrophic cardiomyopathy and those to CB, herpes simplex and influenza A virus were more frequent in congestive cardiomyopathy. Neutralizing antibody titers were more common to CB 3 (P < 0.05 for titers of .gtoreq. 1:4) in hypertrophic cardiomyopathy; in congestive cardiomyopathy they were more common to CB 1 (P < 0.01 for titers .gtoreq. 1:4 and P < 0.05 for titers .gtoreq. 1:16), to CB 3 virus (P < 0.001 for titers .gtoreq. 1:4 and P < 0.05 for titers .gtoreq. 1:16) and to CB 5 (P < 0.05 for titers .gtoreq. 1:4 or more) and to echovirus 6 (P < 0.05 for titers .gtoreq. 1:4 and .gtoreq. 1:128). Immunofluorescent study of 61 cases showed no virus antigens in the biopsied myocardium even in patients who had significant changes in neutralizing antibody titers in paired sera. A relationship between virus infection and idiopathic cardiomyopathy, not only of the congestive type but also of the hypertrophic type was suggested. Definite proof of the virus infection theory of the disease was not provided.