Monitoring of streptokinase resistance titre in acute myocardial infarction patients up to 30 months after giving streptokinase or anistreplase and related studies to measure specific antistreptokinase IgG.
OBJECTIVE
To examine the induction of antistreptokinase antibodies after giving streptokinase or anistreplase to patients with acute myocardial infarction.


METHODS
Patients were randomly allocated to receive either 1.5 x 10(6) IU, streptokinase or 30U anistreplase in a double blind study. Blood samples were collected immediately before treatment and subsequently at intervals up to 30 months; plasma samples were assayed for streptokinase resistance titre (functional assay) and streptokinase binding by IgG (microradioimmunoassay).


METHODS
Cardiology department in a general hospital.


METHODS
128 consecutive eligible patients. Samples were collected for up to one year according to a prospective design: a subsection of 47 patients was selected for intensive study over the first 14 days. After one year, all available patients (67) were sampled on one further occasion.


RESULTS
Antibody responses to streptokinase and anistreplase were similar. Streptokinase resistance titres exceeded pretreatment concentrations five days after dosing, and values peaked at 14 days. By 12 months after dosing, 92% of resistance titres (n = 84) had returned to within the pretreatment range. Antistreptokinase IgG concentrations also exceeded baseline concentrations within five days and peaked at 14 days. Half of the individual values had returned to within the pretreatment range by 12 months (n = 84) and 89% by 30 months (n = 18).


CONCLUSIONS
Although we cannot be sure of the clinical significance, because of the increased likelihood of resistance due to antistreptokinase antibody, streptokinase and anistreplase may not be effective if administered more than five days after an earlier dose of streptokinase or anistreplase, particularly between five days and 12 months, and increased antistreptokinase antibody may increase the risk of allergic-type reactions.
Fears
R
R
SmithKline Beecham Pharmaceuticals, Great Burgh, Epsom, Surrey.
Ferres
H
H
Glasgow
E
E
Standring
R
R
Hogg
K J
KJ
Gemmill
J D
JD
Burns
J M
JM
Rae
A P
AP
Dunn
F G
FG
Hillis
W S
WS
D000328:Adult; D000368:Aged; D016255:Anistreplase / Q000276:immunology* / Q000627:therapeutic use; D000906:Antibodies / Q000032:analysis*; D000917:Antibody Formation / Q000276:immunology; D004311:Double-Blind Method; D004351:Drug Resistance / Q000276:immunology; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy / Q000276:immunology*; D011446:Prospective Studies; D013300:Streptokinase / Q000276:immunology* / Q000627:therapeutic use; D015912:Thrombolytic Therapy; D013997:Time Factors
D000906:Antibodies; D007074:Immunoglobulin G; D016255:Anistreplase; D013300:Streptokinase