Do high levels of antistreptokinase limit the efficacy of streptokinase in patients with myocardial infarction?

BACKGROUND: Antistreptokinase antibody in serum of people who had been exposed to streptococcal infections may interfere with thrombolytic effects of streptokinase. Streptokinase is the only thrombolytic medication in Iran, and is the first line treatment in myocardial infection. Considering the high prevalence of streptococcal infections in Iran as compared to developed countries, the high levels of serum antibody might neutralize streptokinase. METHODS: Serum levels of antistreptokinase antibody of 126 people with myocardial infarction who went to Noor Hospital (Isfahan, Iran) were measured before administrating streptokinase. The effects of the drug were then evaluated and compared by considering the consequent echocardiographic (ECG) changes during hospitalization. RESULTS: In 17 out of 126 patients (13.5%), the antibody levels were high and the drug did not have any effects. This number is 2.5 times more than the values in references. In 25 patients, among whom 3 had high levels of antistreptokinase antibody, the drug was effective. CONCLUSION: Considering the lack of relationship between high levels of antistreptokinase antibody and the efficacy of streptokinase in patients with myocardial infarction in this study, studies with larger sample size and more objective criteria, such as serum fibrinogen as the indicator of streptokinase efficacy, are recommended.