Immunoglobulin response to intravenous streptokinase in acute myocardial infarction

Lung Immunobiochemical Research Laboratory, Department of Cardiology, General Hospital, Birmingham; and Department of Cardiology, Queen Elizabeth Medical Centre, Birmingham M Lynch W A Littler B L Pentecost R A Stockley Correspondence to Dr Mary Lynch, Department of Cardiology, The General Hospital, Steelhouse Lane, Birmingham B4 6NH. Accepted for publication 29 April 1991 Abstract Objective-To devise assays to assess and follow the specific antibody response in patients treated with streptokinase for acute myocardial infarction. Design-Venous blood samples were collected before treatment with streptokinase started and subsequently at regular intervals over one year. Specific IgG and subclass IgGi were assessed by an enzyme linked immunosorbent assay. Setting-Coronary care unit in a general hospital. Patients-48 patients with acute myocardial infarction: 22 patients had venous blood samples taken at presentation only; serial blood samples were taken from 20 patients who then received thrombolytic therapy with streptokinase and six patients who were unsuitable for thrombolytic therapy. Results-Titres of antibodies to streptokinase were low at presentation in 36 (75%) of the 48 patients. Serial measurements made in 20 patients showed the virtual disappearance of antibody within the first 24 hours. This was followed by a steady increase in the specific IgGl titre, which peaked at day 14 before gradually declining. Values at one year remained significantly higher than baseline values. There was no evidence of