Immunologic studies in familial cardiomyopathy

Immunoglobulins and complement in chronic myocardial disease. A myocardial biopsy study

Autoimmune mechanisms have been suggested to be of significance in chronic myocardial diseases. However, the frequency and importance of these factors are unknown. In the present study, endomyocardial biopsy specimens from 21 patients with chronic myocardial disease have been examined by direct immunofluorescence for the presence of immunoglobulins and complement factor C3. Positive staining for immunoglobulin and/or complement was observed in 7 cases. None of the specimens stained for albumin or amyloid. The immunoglobulin deposits were located on the surface of the myofibre and in all but one case, complement was found in the same location. The presence of the complement together with immunoglobulin, and also the lack of albumin, may suggest an immune reaction and not just a passive deposition secondary to heart muscle damage. The localization along the fibres further suggests that the deposits represent an autoimmune reaction to antigens on the fibres and not a trapping of circulating antigen-antibody complexes. It is not known whether the deposits are primary or secondary events, but they may be of importance in initiating or maintaining derangement in heart function.

Immunopathologic studies in myocardial biopsies of patients with Chagas' disease and idiopathic cardiomyopathy

Right ventricular endomyocardial biopsies were studied in 30 patients, 15 with myocardiopathy from chronic Chagas'disease and 15 with idiopathic congestive myocardiopathy; five other myocardial samples were taken at necropsies of patients with chronic Chagas' disease. The authors tried to establish by means of direct immunofluorescence techniques whether there were immunoglobulins G, A and M, fibrinogen and C3 complement deposition in the myocardium; only one of these 30 patients exhibited a positive reaction to IgG, it was a patient with idiopathic congestive myocardiopathy. All fragments from patients with Chagas' disease showed no response to any of the fluorescent conjugates. These findings do not support the idea that anti-myoeardial antibodies have pathogenic importance in the evolution of dilated or chagasic myocardiopathies.

Humoral immunity in cardiomyopathy

Sera from patients with heart disease were examined by single sandwich indirect immunofluorescence for the presence of antibodies to human heart muscle. Endocardial biopsy specimens were also examined by direct immunofluorescence for deposition of antibodies in vivo. No consistent or specific abnormality was found in the biopsy specimens or sera of patients with congestive cardiomyopathy. The presence of anti-heart antibodies in cardiac disease appears to reflect damage to cardiac muscle whatever the cause. Immunofluorescence is an insensitive test for anti-heart antibodies.

Heart antibodies in cardiomyopathies

The reported frequency of circulating heart reactive antibodies in cardiomyopathies has varied and their significance is unknown. In this study such antibodies were sought in patients with primary congestive and hypertrophic cardiomyopathies and other heart diseases. Standard "single sandwich" and the more sensitive "double sandwich" indirect immunofluorescence techniques failed to disclose a significant difference between any cardiomyopathic group and controls in repeated experiments. With both techniques results were subject to considerable method-specific artefacts and observer variation. No published work associating heart antibodies detected by immunofluorescence methods with cariomyopathies adequately takes these into account.

The clinical course of primary myocardial disease in infants and children

A total of 161 infants and children, ranging in age from 1 day to 17 years at initial encounter (mean, 3.7 years), was seen over a 30 year period with primary myocardial disease (idiopathic myocarditis, nonobstructive cardiomyopathy, endocardial fibroelastosis, and an anatomically unknown category). These patients were observed from 1 hour to 23 years after initial encounter and cardiac disease has resolved in 27 per cent, resulted in death in 35 per cent, and continues in 38 per cent. The majority were first referred to us with congestive heart failure; all exhibited ST-T changes and cardiomegaly, 67 of 150 had left ventricular hypertrophy, 23 of 151 arrhythmias, and 55 of 153 pulmonary vascular congestion. Initial ventricular depolarization abnormalities were very frequent. Significant clinical predictors of fatal outcome included pulmonary vascular congestion, "northwest" axis deviation, and a cardiac index less than three L./min./M.2. Death occurred during the first year after initial encounter in 44 of 57 who died, and in all 13 with proved myocarditis. Primary myocardial disease is a serious disease of infancy and childhood, resulting in death or residual cardiac disease in three fourths of those affected.

[Autoantibodies against heartmuscle sarcolemma in sera of patients with an idiopathic cardiomyopathy (author's transl)]

68 patients with clinical and hemodynamical diagnosis of idiopathic cardiomyopathy (CM) were analysed for antibody in their sera using an immunofluorescence sandwich technique after titration of the sera in tissue sections. 60 of these patients had antibodies against heart muscle sarcolemma with titers up to 1:64. Out of these, the antibodies in 9 sera could be absorbed with group A streptococci. The antibodies reacted in no case with striated or smooth muscle sarcolemma. The 25 patients with an obstructive type of CM showed the highest titers and 12 of them, in addition, had antinuclear factors in their sera. These findings suggested an auto-allergic etiology for most cases of idiopathic CM.