Abnormal antigenic reactivity of factor VIII/von Willebrand factor subunit in variants of von Willebrand's disease
Girma, J.P.; Pietu, G.; Lavergne, J.M.; Meyer, D.; Larrieu, M.J.
Journal of Laboratory and Clinical Medicine 99(4): 481-494
1982
ISSN/ISBN: 0022-2143 PMID: 6174657 Document Number: 192301
Antibodies specific for either the subunit (MW 2.4 .times. 105) or conformational antigenic determinants of F. with the F.VIII/vWF subunits and with all subunit-containing multimers (MW 4.8 .times. 105 to > 15 .times. 106). The anticonformation antibody failed to react with F.VIII/vWF subunits but reacted with native (MW 1 to > 15 .times. 106) or partially reduced (MW 4.8 .times. 105) F.VIII/vWF. It was thus specific for antigenic sites resulting from the association of subunits in dimers or multimers of F.VIII/vWF. In 8 patients with a variant of vWD (type IIA), an abnormal antigenic reactivity in plasma, characterized by a dose-response curve not parallel to that of control, was consistently observed by IRMA using the antisubunit antibody. Six showed a normal dose-response curve with the anticonformation antibody, and 2 unique patients also demonstrated an abnormal (nonparallel) response. Subunit and conformational antigenic sites on F.VIII/vWF were distinguished. The decreased antigenicity in type IIA vWD is associated in all cases with an abnormality of F.VIII/vWF subunits and in some patients with an additional defect of polymerization. The heterogeneity of variants of vWD was emphasized.