RAISED LEVELS OF ANTISTREPTOKINASE ANTIBODY AND NEUTRALIZATION TITERS FROM 4 DAYS TO 54 MONTHS AFTER ADMINISTRATION OF STREPTOKINASE OR ANISTREPLASE

Streptokinase and anistreplase are antigenic and their administration often leads to antibody formation. These can cause allergic reactions and/or neutralization of streptokinase with resulting suboptimal treatment. Currently, streptokinase re-administration is considered appropriate for up to 5 days and from 1 year after a previous dose. Antistreptokinase antibody and neutralization titres (NT) were measured in three groups of patients to determine if this practice is appropriate: 1. (early)-36 patients whose titres were measured for at least 5 days after thrombolysis; 2. (late)-57 patients who received thrombolysis 12-54 months previously; 3. (controls)-182 consecutive suspected myocardial infarction patients (without previous exposure to thrombolysis). Results were as follows (mean ± SEM): 1. (early) - the antibody and/or NT were raised by day 4 in 19.4% of the patients. One patient could have neutralized 1.97 million units (MU) of streptokinase by day 4. (Day 4-antibody 1:39 ± 11, NT 0.19 ± 0.05 MU; day 5-1:136 ± 41 and NT 0.7 ± 0.43 MU respectively.) 2. (late)-23 patients (40%) had either antibody titres ≥ 1:160 and/or NT > 1.5 MU. (12-23 months - antibody 1:243 ± 43, NT 0.63 ± 0.15 MU; 24-35 months - 1:98 ± 31 and 0.69 ± 0.22 MU; 36-54 months-1:87 ± 14 and 0.54 ± 0.12 MU.) All titres were significantly higher than the controls (antibody 1:25 ± 3, NT 0.14 ± 0-01 MU, P < 0.01). After streptokinase or antistreplase, antibodies are raised from 4 days to at least 54 months. It would seem prudent to avoid their re-administration during this time interval. © 1993 The European Society of Cardiology.