重症型ｖｏｎ Ｗｉｌｌｅｂｒａｎｄ病に生じたＶＩＩＩ Ｒ：Ａｇに対するｉｎｈｉｂｉｔｏｒに関する検討

Abstract

Nonprecipitating antibodies directed toward human-F VIII R: Ag were found in the plasma of a multitransfused patient with severe von Willebrand's disease (VIII: C 2%, VIII R: Ag 30min.) during replacement therapy with VIII concentrate for intracranial hemorrhage.Such antibodies were detected with newly developed semiquantitative assays of anti-VIII R: Ag antibodies by using ELISA. Partially purified AHF made from commercially available F VIII concentrate by Gel filtration was coated as solid phase antigen on the well of plastic microplate. The reacted patient's antibodies with VIII: Ag on the surface of the wells were detected and titrated by using enzyme conjugated anti-human IgG heavy chain, k or λ Light chain. These studies showed that the types of the anti-VIII R: Ag antibodies were IgG heavy chain, mainly k light chain and partially λ light chain. The anti-VIII R: Ag IgG antibody in the patient's plasma diluted (1:10, 000) with PBS was detected 3 weeks after initation of the repalacement therapy by this method. These antibodies were absorbed with normal plasma but not with severe von Willebrand's plasma.The anti-VIII R: Ag antibodies in patient's plasma blocked platelet retention by glass beads column measured by Bowie's method. But they did not block ristocetin-induced platelet aggulutination at all, and they weakly inhibited procoagulant activity of AHF in non-specific manner.These data suggest that the site or sites on the AHF complex molecule that are associated with ristocetin-induced platelet agglutination differ qualitatively from those associated with enhancement of platelet retention by glass beads.