open access
False-negative coagulation factor activity results due to the presence of antiphospholipid antibodies in a case of autoimmune hemolytic anemia
Affiliations- Department of Hematology and Oncology, Kita-Harima Medical Center, Hyogo, Japan
- Division of Laboratory Medicine, Kita-Harima Medical Center, Hyogo, Japan
- West Japan Sales Office II, Diagnostics Division, Sekisui Medical Co., Ltd., Osaka, Japan
- Department of Internal Medicine, Kita-Harima Medical Center, Hyogo, Japan
open access
Abstract
An 88-year-old female was admitted with autoimmune hemolytic anemia (AIHA). Coagulation test revealed severe prolongation of activated partial thromboplastin time (APTT). APTT cross-mixing test with patient plasma and normal plasma demonstrated an inhibitory pattern. Several intrinsic coagulation factor activities, particularly factor IX, showed remarkable decreases, and the inhibitor titers for coagulation factors VIII and IX were elevated. Although AIHA with existing antiphospholipid (aPL) antibodies was diagnosed initially, purpura developed on extremities intermittently during the clinical course. Considering the possibility of coexisting acquired hemophilia, APTT cross-mixing test with patient’s plasma and equal amount of the recombinant factor VIII product instead of normal plasma was performed. The APTT value on equal mixing samples with patient plasma and recombinant factor VIII product was decreased to within the normal range, and coagulation factor IX activity was restored. These results indicate that the recombinant factor VIII product had a neutralizing effect on aPL antibodies. We concluded that recombinant factor VIII product may lead to the repair of incorrect results from the APTT-dependent diagnostic system in the presence of aPL antibodies.
Abstract
An 88-year-old female was admitted with autoimmune hemolytic anemia (AIHA). Coagulation test revealed severe prolongation of activated partial thromboplastin time (APTT). APTT cross-mixing test with patient plasma and normal plasma demonstrated an inhibitory pattern. Several intrinsic coagulation factor activities, particularly factor IX, showed remarkable decreases, and the inhibitor titers for coagulation factors VIII and IX were elevated. Although AIHA with existing antiphospholipid (aPL) antibodies was diagnosed initially, purpura developed on extremities intermittently during the clinical course. Considering the possibility of coexisting acquired hemophilia, APTT cross-mixing test with patient’s plasma and equal amount of the recombinant factor VIII product instead of normal plasma was performed. The APTT value on equal mixing samples with patient plasma and recombinant factor VIII product was decreased to within the normal range, and coagulation factor IX activity was restored. These results indicate that the recombinant factor VIII product had a neutralizing effect on aPL antibodies. We concluded that recombinant factor VIII product may lead to the repair of incorrect results from the APTT-dependent diagnostic system in the presence of aPL antibodies.
Keywords
antiphospholipid antibody; anticoagulant inhibitor; APTT cross-mixing test; acquired hemophilia
About this articleTitle
False-negative coagulation factor activity results due to the presence of antiphospholipid antibodies in a case of autoimmune hemolytic anemia
Journal
Issue
Pages
37-41
Published online
2018-03-30
Page views
159
Article views/downloads
281
DOI
10.2478/ahp-2018-0007
Bibliographic record
Acta Haematol Pol 2018;49(1):37-41.
Keywords
antiphospholipid antibody
anticoagulant inhibitor
APTT cross-mixing test
acquired hemophilia
Authors
Takeshi Sugimoto
Kazuhide Morimoto
Hiromi Hashimoto
Yukie Kaneda
Shinya Ohata
Yoshiro Yasutomo