Antiphospholipid Antibodies in Patients With Lupus Anticoagulant Prozone Effect.
OBJECTIVES
Lupus anticoagulant (LAC) is typically associated with thrombosis but also rarely with hemorrhage. Some patients exhibit a prozone effect on LAC testing. Antiphosphatidylserine/prothrombin (aPS/PT) antibodies may provide a mechanism for both hemorrhage and prozone effect. Our goal was to evaluate whether antibody specificities, isotypes, and titers were associated with LAC prozone effect, factor II levels, hemorrhage, and thrombosis.


METHODS
Patients with prozone effect noted on LAC testing were entered into a database over 3 years. Factor II activity and aPS/PT antibody testing were performed when a sufficient residual sample was available.


RESULTS
All patients with LAC prozone effect and antibody testing were positive for at least 1 class of aPS/PT antibodies. In addition, aPS/PT IgG titers were significantly associated with thrombosis and significantly inversely associated with factor II levels.


CONCLUSIONS
In prozone effect patients, aPS/PT antibodies are associated with LAC prozone effect as well as thrombosis and decreased factor II levels.
['Murphy|Colin H|CH|', 'Jin|Jing|J|', 'Zehnder|James L|JL|']
D000293:Adolescent D000328:Adult D000368:Aged D000369:Aged, 80 and over D017152:Antibodies, Antiphospholipid D002648:Child D002675:Child, Preschool D005260:Female D006801:Humans D007223:Infant D016682:Lupus Coagulation Inhibitor D008297:Male D008875:Middle Aged D011516:Prothrombin D013927:Thrombosis D055815:Young Adult
Clinical pathology Coagulation Hematology