Autoantibodies reacting with heart muscle tissue in coronary heart disease

Incidence and significance of heartmuscle antibodies in patients with acute myocardial infarction and unstable angina

The incidence of heartmuscle antibodies was studied prospectively in 136 patients consecutively admitted for acute myocardial infarction (AMI) and in 95 patients with unstable angina. Heartmuscle antibodies were determined with the indirect immunofluorescence technique on days 1, 10, 20 and 30 in patients with AMI and on days 1 and 10 in patients with unstable angina. Heartmuscle antibodies were found in 16/136 AMI patients (12%) and in 3/95 (3%) with unstable angina. None of the AMI patients developed post-myocardial-infarction syndrome in the 2--4 weeks after infarction or during the one-year follow-up. The AMI patients with and without heartmuscle antibodies were comparable with respect to age, sex, site and size of infarction, incidence of early pericarditis and previous infarction.

Autoantibody production after cardiopulmonary bypass with special reference to postpericardiotomy syndrome

A prospective study of children undergoing open heart surgery with cardiopulmonary bypass showed that many of them produced autoantibodies. No association was found between these antibodies, including anticardiolipin antibodies, and the occurrence of postpericardiotomy syndrome.

Rheumatic symptoms after cardiac surgery: a prospective study

The incidence of different types of shoulder pain after open heart surgery was studied prospectively. Of 101 patients studied, 45 developed rheumatic symptoms during the first six weeks after the operation. Thirty eight patients reported pain in the region of the shoulder girdle with no loss of shoulder function (postpericardiotomy rheumatism). Three of these patients also had features compatible with the postpericardiotomy syndrome (fever, malaise, or pleuritic chest pain), and seven developed the syndrome without pain in the shoulder girdle. Of these 10 patients, one had generalised myalgia. Postpericardiotomy rheumatism alone was not associated with increased inflammation (measured by the erythrocyte sedimentation rate and concentration of C reactive protein); immunological tests including measurement of antibodies to cardiac muscle yielded inconclusive results. Replies to a postal questionnaire showed that symptoms of postpericardiotomy rheumatism were present for over three months in 18 patients and for six months or longer in 14. In view of the large number of patients now having open heart surgery postpericardiotomy rheumatism should be considered when patients report pain around the shoulders so that it is not misdiagnosed as angina.

Longitudinal study of immune response in human Chagas' disease

Immune response, clinical status, and reactivity to heart tissue were studied longitudinally for 1 year in 42 patients with Chagas' disease (South American trypanosomiasis). The patients were divided into two groups. Group 1 was composed of patients with chagasic infection with no evidence of heart disease. Group 2 patients had chagasic infection and cardiomyopathy. Humoral immune response to Trypanosoma cruzi was measured serologically, and cell-mediated immune responses to T. cruzi and rat heart antigens were evaluated by lymphoblastogenesis. Parasitemia was detected by xenodiagnosis. Serological tests for anti-T. cruzi antibodies were positive in all patients of both groups, and the titers were significantly higher in group 2. A change of titer during the study period was more frequently associated with a positive xenodiagnosis in both groups. Lymphoblastogenesis in response to T. cruzi antigen was positive at least once in all patients of both groups. When rat heart antigen was used, 44.4% of the patients in group 1 and 40.0% of those in group 2 were positive on at least one occasion. Xenodiagnosis revealed that 20% of the patients in group 1 and 50% of those in group 2 (P = 0.01) had detectable circulating parasites during the course of the study. Positive xenodiagnosis was associated with lower lymphoblastogenic responses to T. cruzi in group 1 patients, suggesting the presence of a regulatory or modulatory mechanism which is lost in patients with chagasic cardiomyopathy. No relationship between positive xenodiagnosis and positive lymphoblastogenesis in response to heart antigen could be established. In addition, no correlation was found between clinical heart disease and reactivity to rat heart tissue.

Cardiac specific antigen and antibody in immunopathogenesis of cardiac disease

Antibody to human cardiac extracts was detected in the sera of many patients undergoing open heart surgery. A passive hemagglutination assay using cardiac extracts as antigen coated onto erythrocytes showed the development of cardiac antibody in the patients, with peak titers usually one to three weeks after the surgery. Radioimmunoassay revealed the presence of cardiac specific myoglobin antigen antigen in the sera of many patients, with peak levels 1-3 days after the procedure. A correlation was observed between development of circulating serum antibody and appearance of cardiac myoglobin antigen. These results support the view that immunologic disease related to release of cardiac antigen in patients undergoing heart surgery may be a factor in post-cardiotomy disease.

Leucocyte migration inhibition test in cases of ischaemic heart disease

Cases of ischaemic heart disease have been studied for the cell-mediated immune response against human heart antigen by using the leucocyte migration inhibition test. In 30 cases of acute myocardial infarction, the leucocyte migration inhibition values started increasing from the first week reaching a peak in 3 to 4 weeks and then declining but still above control values 12 months after infarction. The leucocyte migration inhibition values were significantly higher than control values in another 10 patients with late complications of previous infarction and in those patients with acute myocardial infarction who were less than 40 years of age, who had extensive anterior infarction, or who had a past history of angina pectoris. The leucocyte migration inhibition values were negligible in all the 12 patients with stable angina pectoris, but were high in 2 of the 8 with unstable angina and in 3 of the 4 with the intermediate coronary syndrome. The leucocyte migration inhibition values were much higher in patients with complications, which may be the result of cardiac damage by a cell-mediated immune response.

Characterization of anti-heart mitochondria autoantibodies produced in dogs following myocardial infarction

A complement-fixing, heart-reactive serum component that develops in dogs following experimental myocardial infarction was characterized with respect to its immunoglobulin nature and its subcellular membrane and organ specificities. The immunoglobulin nature of the heart-reactive serum factor was established by the following evidence: (1) the factor was not removed from the serum following absorption of up to 90% of the first component of dog complement with bovine serum albumin (BSA)-anti-BSA immune precipitates, (2) the serum factor sedimented in the 19S region of sucrose density gradients, and (3) affinity chromatography using a Sepharose column coupled with rabbit anti-dog µ-chain-specific antibody resulted in the removal of nearly all of the heart-reactive substance. The major subcellular autoantigenic locus of the dog heart was determined to be the outer mitochondrial membrane. Serum containing the autoantibody demonstrated a six-fold greater autoantibody titer when outer mitochondrial membrane was used as the test antigen than it did when inner mitochondrial membrane was used. Absorption experiments suggested that the autoantigenic determinants residing on inner and outer mitochondrial membranes were unique to the individual membranes. Significant cross-reaction of the anti-heart autoantibody between heart and skeletal muscle mitochondria was observed, but no cross-reaction was seen with dog liver mitochondrial membranes.

Development of complement-fixing 19S, anti-heart mitochondria autoantibody, following myocardial infarction in dogs

The development of anti-heart autoantibody following experimental myocardial infarction in dogs was studied with respect to (1) the subcellular localization of the heart autoantigen(s), (2) the incidence of autoantibody following myocardial infarction, and (3) the temporal development of the autoantibody and its relation to serum enzyme elevations and electrocardiographic changes. Complement-fixing anti-heart autoantibody developed following myocardial infarction induced by either two-stage coronary artery ligation or by the injection of microspheres directly into the coronary circulation. The autoantibody was directed toward an autoantigen residing in the mitochondrial fraction of myocardial tissue and was found to be associated with the 19S class of immunoglobulin. Eighteen of 20 dogs with infarction produced anti-heart mitochondria autoantibody 10 days following induction of myocardial damage; the autoantibody persisted 4 to 6 weeks thereafter. In these dogs the presence of anti-heart mitochondria autoantibody was diagnostic of myocardial infarction at times when the serum enzymes and electrocardiograms were within normal limits. Our studies indicate that a serologic test, based on the detection of complement-fixing anti-heart mitochondria autoantibody, may be a valuable adjunct to tests currently available for diagnosing recent myocardial infarction.