Determination of Thrombogenicity Levels of Various Antiphospholipid Antibodies by a Modified Thrombin Generation Assay in Patients with Suspected Antiphospholipid Syndrome

Abstract

Antiphospholipid syndrome (APS) is a hypercoagulable state accompanied by the presence of heterogeneous antiphospholipid antibodies (aPL), which nonspecifically affect hemostasis by the presence of lupus anticoagulans (LA), anticardiolipin antibodies (aCL), antibodies against β2-glycoprotein-I (anti-β2GPI), but also non-criteria antibodies such as antibodies against β2-glycoprotein-I domain I (anti-DI), anti-phosphatidylserine/prothrombin (anti-PS/PT), anti-annexin V, and many others. The main target of the antibodies is the activated protein C (APC) system, the elimination of which can manifest itself as a thrombotic complication. The aim of this study was to determine the thrombogenicity of antibodies using a modified protein C-activated thrombin generation assay (TGA) on a group of 175 samples suspected of APS. TGA was measured with/without APC and the ratio of both measurements was evaluated (as for APC resistance), where a cut-off was calculated ≤4.5 (90th percentile) using 21 patients with heterozygous factor V Leiden mutation (FV Leiden heterozygous). Our study demonstrates the well-known fact that multiple positivity of different aPLs is a more severe risk for thrombosis than single positivity. Of the single antibody positivity, LA antibodies are the most serious (p value < 0.01), followed by aCL and their subgroup anti-DI (p value < 0.05). Non-criteria antibodies anti-annexin V and anti-PT/PS has a similar frequency occurrence of thrombogenicity as LA antibodies but without statistical significance or anti-β2GPI1 positivity. The modified TGA test can help us identify patients in all groups who are also at risk for recurrent thrombotic and pregnancy complications; thus, long-term prophylactic treatment is appropriate. For this reason, it is proving increasingly beneficial to include the determination antibodies in combination with modified TGA test.

Determining Thrombogenicity: Using a Modified Thrombin Generation Assay to Detect the Level of Thrombotic Event Risk in Lupus Anticoagulant-Positive Patients

“…Our current study follows up on our previous work in which we investigated the determination of thrombogenicity in patients with APS single, double, and triple positivity of various aPL including patients with SN-APS [51].…”

“…In all 85 patients, we performed a modified TGA test with the addition of an APC reagent [54]. To assess thrombogenicity, we used the AUC R parameter, which appears to be the most beneficial [50], using our previously established cut-off of ≤4.5 [51].…”

“…In the diagnosis of LA since its introduction in 2000, the dRVVT test has had the highest predictive value and has improved the correlation with the incidence of thrombosis the most [55]. The fact that the demonstration of multiple positivity of different lupoid anticoagulants in a patient is the strongest predictor of non-obstetric thrombosis complications means that they can be used to assess the severity of thrombotic risk in patients [51]. Similar findings were reported in a study by de Groot et al [56]; DVT occurred significantly more frequently in patients with LA positivity and anti-beta2GPI or anti-anti-prothrombin.…”

“…In patients with FV Leiden heterozygous, AUC R values ranged from 1.20 to 25.32. Based on these, a cut-off of ≤4.5 (90th percentile) was set for the AUC R parameter [51].…”

H3K4me3‐Mediated FOXJ2/SLAMF8 Axis Aggravates Thrombosis and Inflammation in β2GPI/Anti‐β2GPI‐Treated Monocytes

“…[ 2 ] These autoantibodies activate endothelial cells (ECs), monocytes, and platelets, contributing to the activation of hypercoagulable and hyperinflammatory states in APS. [ 3 ] Current therapeutic options for APS are limited, and long‐term anticoagulation therapy is commonly used to prevent recurrent thrombosis. However, this is unfavorable for patients who have not yet suffered from thrombosis but have aPLs.…”