RESUMO
BACKGROUND: Anisoylated plasminogen-streptokinase complex (APSAC, anistreplase) is a thrombolytic agent (131 kd) used for treatment of myocardial infarction. Like its principal antigenic determinant, streptokinase, APSAC has been reported to cause a variety of allergic reactions. OBJECTIVE: This study was intended to determine any association between isotypic antibody responses to streptokinase and observed allergic reactions to APSAC. METHODS: We measured sequential IgM, IgG, IgA, and IgE antistreptokinase serum levels in 21 patients who received APSAC or tissue-type plasminogen activator in a prospective, double-blind study. RESULTS: Of 11 patients who received APSAC, four had maculopapular rashes and one had urticaria; those with maculopapular rashes had significantly higher rises in serum IgM, IgG, IgA, and IgE antistreptokinase levels. We could not, however, define a temporal relationship between rises in antistreptokinase levels of a particular isotype and the onset of maculopapular rashes. The patient who had urticaria had no antistreptokinase responses but had also received several other potentially causal drugs. None of 10 patients who received tissue-type plasminogen activator had allergic reactions or significant rises in serum antistreptokinase levels. CONCLUSION: The more vigorous panisotypic antistreptokinase responses observed in patients who received APSAC and had maculopapular rashes may reflect generalized immune system activation that included other immune responses (such as cell-mediated hypersensitivity) that were responsible for these reactions.
