S. Patel et al., STREPTOKINASE NEUTRALIZATION TITERS UP TO 866 DAYS AFTER INTRAVENOUS STREPTOKINASE FOR ACUTE MYOCARDIAL-INFARCTION, British Heart Journal, 70(2), 1993, pp. 119-121
Objective-To follow the change in streptokinase neutralisation titres
in a group of patients after treatment with streptokinase for acute my
ocardial infarction. Design-Venous blood samples suitable for analysis
were obtained up to 866 days after treatment with 1.5 million units o
streptokinase in 189 patients. The ability of the patient's plasma to
inhibit lysis o a thrombin clot by streptokinase was assessed. Settin
g-A coronary care unit in a district general hospital. Patients-A retr
ospective review of coronary care records and the district health auth
ority computer showed that 329 patients who had received streptokinase
were alive. All were invited for venepuncture and 220 (67%) attended.
Satisfactory samples were obtained from 189 patients. Results-Raised
titres of antibody sufficient to neutralise a standard dose of 1.5 mil
lion units of streptokinase were found in 90% of patients. There was a
fall in streptokinase neutralisation titre with increasing time after
administration of streptokinase (r = -0.35, P < 0.0001) and though th
ere was considerable variation among the group the neutralisation titr
e was higher than in the general population in all patients, even thos
e who had received streptokinase at least two years previously. Conclu
sion-The ability of streptokinase to lyse a thrombin clot was apprecia
bly inhibited in vitro by the plasma from patients who had received 1.
5 million units of streptokinase. High streptokinase neutralisation ti
tres persisted for a long time after the use of streptokinase as throm
bolytic treatment for acute myocardial infarction. Readministration of
streptokinase may not be efficacious for considerably longer than the
one year currently advocated. Until the in vivo effects of streptokin
ase readministration are known a non-antigenic thrombolytic agent shou
ld be used instead.