A BLEEDING DISORDER DUE TO DEFICIENCY OF ALPHA-2-ANTIPLASMIN

  • 1 January 1982
    • journal article
    • research article
    • Vol. 59  (6) , 1246-1251
Abstract
A deficiency of .alpha.2-antiplasmin was identified in a female patient with severe and frequent bleeding episodes. Routine coagulation and platelet assays of the patient''s plasma were within normal limits. Abnormally rapid whole blood or dilute plasma clot lysis times and an abnormal FXIII test in which clots were lysed in the presence of urea or saline suggested an abnormal fibrinolytic system. Analysis of .alpha.2-antiplasmin levels by radioimmunoassay revealed < 1.0 .mu.g/ml .alpha.2-antiplasmin. Functional assays indicated an .alpha.2-antiplasmin level .ltoreq. 10% of normal. Addition of purified .alpha.2-antiplasmin to the patient''s plasma restored its ability to inhibit plasmin in in vitro asays, and mixtures of patient plasma with normal plasma did not interfere with the antiplasmin activity of the normal plasma. Whereas normal platelets contain 68 ng .alpha.2-antiplasmin/109 platelets, platelets from the patient contained 30% of the normal level of antigen. Analysis of .alpha.2-antiplasmin functional and antigenic levels in the plasma of both parents and 4 siblings of the propositus provided evidence consistent with an autosomal mechanism of inheritance of .alpha.2-antiplasmin deficiency. One sibling appeared to be homozygous and 3 siblings and the parents were heterozygous for the deficiency. Two heterozygotes had positive bleeding histories. The association of a bleeding disorder with a deficiency of .alpha.2-antiplasmin emphasizes that lack of regulation of the fibrinolytic system can result in a hemostatic dysfunction.