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Comparison between anti‐β2 Glycoprotein I antibody and anti‐phosphatidylserine/prothrombin antibody pro‐thrombotic effects on peripheral blood monocytes and endothelial cells
Author(s) -
Cifu' Adriana,
Fabris Martina,
Pistis Cinzia,
Domenis Rossana,
Quaglia Sara,
Curcio Francesco
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.978.10
Subject(s) - antiphospholipid syndrome , peripheral blood mononuclear cell , medicine , antibody , immunology , lupus anticoagulant , tissue factor , umbilical vein , phosphatidylserine , coagulation , chemistry , in vitro , phospholipid , biochemistry , membrane
BACKGROUND Antiphospholipid Syndrome (APS) is a systemic autoimmune disease characterized by vascular thrombosis (venous or arterial) and/or adverse obstetric outcomes, accompanied by persistent and elevated levels of antiphospholipid (aPL) antibodies, namely lupus anticoagulant (LA), anticardiolipin (aCL) and anti‐β2 glycoprotein I (aβ2GpI) antibodies. However, there are several other aPL that are still not included in the diagnostic criteria, but that can be useful to better define the so‐called seronegative APS patients (negative for LA, aCL and aβ2GpI), such as anti‐phosphatidylserine/prothrombin (aPS/PT) antibodies. The aim of this study was to compare the pro‐thrombotic effects of aβ2GpI IgG and aPS/PT IgG antibodies on peripheral blood mononuclear cells (PBMC) and human umbilical vein endothelial cells (HUVEC) to support the independent role of aPS/PT in APS pathogenesis and diagnosis. METHODS PBMC isolated from blood donors (BD) and HUVEC (Life Technologies) were incubated four hours with lipopolysaccharides (LPS) alone or in combination with the IgG fraction obtained from a pool sera of BD (as control), and from a pool sera of 3 APS patients who were positive only for IgG aβ2GpI and from 3 APS patients who were positive only for IgG aPS/PT. TF mRNA up‐regulation, expressed as fold increase in respect to unstimulated cells, was measured by real‐time PCR. The experiments were done in triplicate. RESULTS Compared to treatment with LPS alone (6.4±1) or LPS plus the IgG fraction isolated from BD (6.5±1.7), PBMC stimulated either with LPS plus aβ2GpI IgG or with LPS plus aPS/PT IgG demonstrated an increased expression of TF (respectively 8.2±0.9 and 9.4±1.3; vs LPS + BD IgG p<0.05), but no difference was found between aβ2GpI and aPS/PT. Similarly, the HUVEC stimulated with LPS plus aβ2GpI or aPS/PT displayed a significant increase of TF expression (respectively 90±7 and 87±2) compared to stimulation with LPS alone (18.4±5; p=0.04) or plus the IgG fraction from BD (9.45±2.9; p=0.01). CONCLUSIONS This is the first direct comparison between the aβ2GpI and aPS/PT pro‐thrombotic effects in vitro on monocytes and endothelial cells. Our data show that both aβ2GpI and aPS/PT antibodies were able to upregulate TF expression in monocytes and HUVEC pre‐activated with LPS. As expected, the effect was stronger in endothelial cells than in monocytes, but no difference was appreciated between aβ2GpI and aPS/PT. These results suggest that aPS/PT antibodies exert an independent role on APS‐related manifestations.