Assessment of thrombophilia in patients with lupus anticoagulant

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.

Trial registration: ClinicalTrials.gov NCT02157272.

Keywords: Activated protein C resistance; Antibodies; Lupus coagulation inhibitor; Prothrombin.