Assessment of thrombophilia in patients with lupus anticoagulant
Elena Pontara a, Maria Grazia Cattini a, Elisa Bison a, Marta Tonello b, Margherita Zen b, Cristina Vicenzetto a, Andrea Giordani a, Anna Baritussio a, Alida L.P. Caforio a, Vittorio Pengo c d
a) Cardiology, Cardioimmunology and Thrombosis Laboratory, Department of Cardiac-Thoracic-Vascular Sciences and Public Health, University of Padova, Padova, Italy
b) Department of Medicine, Rheumatology Section, University of Padua, Padova, Italy
c) Senior Scientist, University of Padova, Italy
d) Arianna Foundation on Anticoagulation, Bologna, Italy
Abstract
Background
A close link between anti phosphatidyl-serine/prothrombin antibodies (aPS/PT), Lupus Anticoagulant (LA) potency and thrombophilia detected by activated protein C Resistance (aPC-R) in triple-positive antiphospholipid syndrome (APS) patients (LA+/anticardiolipin-aCL+/aβ2-Glycoprotein I-aβ2GPI+) has been observed. Whether this interdependence is present in patients with isolated LA is not known.
Objectives
This cross-sectional study evaluates aPS/PT and aPC-R in isolated LA patients in relation on how the diagnosis of the coagulation inhibitor was made.
Methods
LA was determined using the diluted Russell Viper Venom Time (dRVVT) and the Silica Clotting Time (SCT). IgG and IgM aCL, aβ2GPI and aPS/PT were measured by ELISA. APC-R was determined by thrombin generation assay.
Results
We studied 32 patients with isolated LA (LA+/aCL-/aβ2GPI-), 53 triple positive patients (LA+/aCL+/aβ2GPI+) and 24 controls. Total (IgG + IgM) aPS/PT antibody titer was lower and aPC-R weaker in isolated LA compared to triple-positive patients. When isolated LA was diagnosed by both coagulation positive tests (dRVVT and SCT), total aPS/PT titers were higher and aPC-R stronger than when isolated LA was diagnosed by a single positive test (either dRVVT or SCT). Total aPS/PT and aPC-R in patients positive for SCT only (dRVVT-, SCT+), were like those of control subjects.
Conclusions
The relation between LA, aPS/PT and aPC-R is linked to the way the coagulation inhibitor is diagnosed. These data may be useful to clinicians when interpreting the clinical value of isolated LA.