Congenital Deficiency of α<sub>2</sub>-Plasmin Inhibitor Associated with Severe Hemorrhagic Tendency

Nobuo Aoki; Hidehiko Saito; Tadashi Kamiya; Katsuo Koie; Yoichi Sakata; Masateru Kobakura

doi:10.1172/JCI109387

Congenital Deficiency of α₂-Plasmin Inhibitor Associated with Severe Hemorrhagic Tendency

Nobuo Aoki, Hidehiko Saito, Tadashi Kamiya, Katsuo Koie, Yoichi Sakata, and Masateru Kobakura

Published May 1, 1979 - More info

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Abstract

α₂-Plasmin inhibitor (α₂PI) is a recently characterized, fast-reacting plasmin inhibitor in human plasma that appears to play an important role in regulation of in vivo fibrinolysis. We report here a case of complete deficiency of α₂PI in man. The patient, a 25-yr-old Japanese man, had a life-long severe bleeding tendency (hemarthrosis and excessive bleeding after trauma). The following tests were within normal limits: platelet count, bleeding time, thrombin time, prothrombin time, partial thromboplastin time, titers of known clotting factors, platelet glass bead retention, Factor VIII-related antigen, platelet aggregation by ADP, collagen and ristocetin, and clot retraction. Routine liver function tests were also normal. The only abnormal finding was that whole blood clot lysis was extemely rapid and was complete in 4-8 h. The concentration of plasma protease inhibitors, including α₂-macro-globulin, antithrombin III, α₁-antitrypsin, and C1̄INH, were all normal. The concentration of α₂-PI in the patient's plasma, assayed by immunological methods, was <0.1 mg/100 ml (normal concentration, 6.1±0.88 mg/100 ml [mean±SE]) and functional assays showed a complete deficiency of α₂PI. Addition of purified α₂PI to the patient's whole blood completely corrected the accelerated fibrinolysis. The patient's parents, four siblings, and four other members of this family were asymptomatic, but the titers of α₂PI in their plasmas were ≅50% of normal pooled plasma. There were three consanguineous marriages in this family, and the α₂PI deficiency appears to have been inherited as an autosomal recessive trait. We speculate that α₂PI deficiency in this patient has led to uninhibited in vivo fibrinolysis that probably causes the severe hemorrhagic tendency. Thus, this study indicates the important role of α₂PI in hemostasis.

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Congenital Deficiency of α₂-Plasmin Inhibitor Associated with Severe Hemorrhagic Tendency

Nobuo Aoki, Hidehiko Saito, Tadashi Kamiya, Katsuo Koie, Yoichi Sakata, and Masateru Kobakura

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Congenital Deficiency of α2-Plasmin Inhibitor Associated with Severe Hemorrhagic Tendency

Nobuo Aoki, Hidehiko Saito, Tadashi Kamiya, Katsuo Koie, Yoichi Sakata, and Masateru Kobakura

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Congenital Deficiency of α₂-Plasmin Inhibitor Associated with Severe Hemorrhagic Tendency