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Factor V inhibitor associated with Sjögren's syndrome
Author(s) -
Koyama Takatoshi,
Saito Takako,
Kusano Takayoshi,
Hirosawa SHINSAKU
Publication year - 1995
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1995.tb08430.x
Subject(s) - partial thromboplastin time , medicine , coagulation , autoantibody , thrombin , thromboplastin , immunology , prothrombin time , factor v , thrombin time , protein c , coagulopathy , endocrinology , antibody , platelet , thrombosis
We report an unusual case of a 74‐year‐old male who developed a serum autoantibody reactive with human coagulation factor V (FV) in an activated form, as demonstrated by coagulation studies and immunoblotting analysis. Despite marked prolongation of a prothrombin time and an activated partial thromboplastin time in this patient, the inhibitor was not associated with clinical bleeding but with multiple cerebral infarctions. The patient had suffered from Sjögren's syndrome with polyclonal hypergamma‐globulinaemia. The patient's purified IgG, an immediately acting inhibitor to FV, reacted with a light chain of thrombin‐activated FV (FVa) and inhibited the procoagulant activity of FVa without affecting the cleavage of FVa by activated protein C. The FV inhibitor may arise from activation of FV with consequent exposure of neoantigen during the activation of coagulation cascade in the patient with an autoimmune disorder for the background.