Critically ill patients with coronavirus disease 2019 (COVID-19) have a profound hypercoagulable state and often develop coagulopathy which leads to organ failure and death. Because of a prolonged ...activated partial-thromboplastin time (aPTT), a relationship with anti-phospholipid antibodies (aPLs) has been proposed, but results are controversial. Functional assays for aPL (i.e., lupus anticoagulant) can be influenced by concomitant anticoagulation and/or high levels of C reactive protein. The presence of anti-cardiolipin (aCL), anti-beta2-glycoprotein I (anti-β
GPI), and anti-phosphatidylserine/prothrombin (aPS/PT) antibodies was not investigated systematically. Epitope specificity of anti-β
GPI antibodies was not reported.
To evaluate the prevalence and the clinical association of aPL in a large cohort of COVID-19 patients, and to characterize the epitope specificity of anti-β
GPI antibodies.
ELISA and chemiluminescence assays were used to test 122 sera of patients suffering from severe COVID-19. Of them, 16 displayed major thrombotic events.
Anti-β
GPI IgG/IgA/IgM was the most frequent in 15.6/6.6/9.0% of patients, while aCL IgG/IgM was detected in 5.7/6.6% by ELISA. Comparable values were found by chemiluminescence. aPS/PT IgG/IgM were detectable in 2.5 and 9.8% by ELISA. No association between thrombosis and aPL was found. Reactivity against domain 1 and 4-5 of β
GPI was limited to 3/58 (5.2%) tested sera for each domain and did not correlate with aCL/anti-β
GPI nor with thrombosis.
aPL show a low prevalence in COVID-19 patients and are not associated with major thrombotic events. aPL in COVID-19 patients are mainly directed against β
GPI but display an epitope specificity different from antibodies in antiphospholipid syndrome.
A single-chain fragment variable (scFv) recognizing β2-glycoprotein 1 (β2GPI) from humans and other species was isolated from a human phage display library and engineered to contain an IgG1 ...hinge-CH2-CH3 domain. The scFv-Fc directed against β2GPI domain I-induced thrombosis and fetal loss, thus mimicking the effect of antibodies from patients with antiphospholipid syndrome (APS). Complement is involved in the biological effect of anti-β2GPI scFv-Fc, as demonstrated by its ability to promote in vitro and in vivo complement deposition and the failure to induce vascular thrombosis in C6-deficient rats and fetal loss in C5-depleted mice. A critical role for complement was also supported by the inability of the CH2-deleted scFv-Fc to cause vessel occlusion and pregnancy failure. This antibody prevented the pathological effects of anti-β2GPI antibodies from APS patients and displaced β2GPI-bound patient antibodies. The CH2-deleted antibody represents an innovative approach potentially useful to treat APS patients refractory to standard therapy.
•A recombinant antibody recognizing the D1 domain of β2 glycoprotein I induces fetal loss and clot formation in animal models.•The CH2-deleted antibody fails to activate complement and prevents the procoagulant and proabortive effects of patient antibodies.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract The aim of this multicenter study was to assess the present risk of fetal complications and the inherent risk factors in pregnant women with lupus nephritis. Seventy-one pregnancies in ...61women (59 Caucasians and 2 Asians) with lupus nephritis were prospectively followed between October 2006 and December 2013. All patients received a counselling visit within 3 months before the beginning of pregnancy and were followed by a multidisciplinary team. At baseline mild active nephritis was present in 15 cases (21.1%). Six pregnancies (8.4%) resulted in fetal loss. Arterial hypertension at baseline (P = 0.003), positivity for lupus anticoagulant (P = 0.001), anticardiolipin IgG antibodies (P = 0.007), antibeta2 IgG (P = 0.018) and the triple positivity for antiphospholipid antibodies (P = 0.004) predicted fetal loss. Twenty pregnancies (28.2%) ended pre-term and 12 newborns (16.4%) were small for gestational age. Among the characteristics at baseline, high SLE disease activity index (SLEDAI) score (P = 0.027), proteinuria (P = 0.045), history of renal flares (P = 0.004), arterial hypertension (P = 0.009) and active lupus nephritis (P = 0.000) increased the probability of preterm delivery. Odds for preterm delivery increased by 60% for each quarterly unit increase in SLEDAI and by 15% for each quarterly increase in proteinuria by 1 g per day. The probability of having a small for gestational age baby was reduced by 85% in women who received hydroxychloroquine therapy (P = 0.023). In this study, the rate of fetal loss was low and mainly associated with the presence of antiphospholipid antibodies. Preterm delivery remains a frequent complication of pregnancies in lupus. SLE and lupus nephritis activity are the main risk factors for premature birth. Arterial hypertension predicted both fetal loss and preterm delivery. Based on our results the key for a successful pregnancy in lupus nephritis is a multidisciplinary approach with close medical, obstetric and neonatal monitoring. This entails: a) a preconception evaluation to establish and inform women about pregnancy risks; b) planning pregnancy during inactive lupus nephritis, maintained inactive with the lowest possible dosage of allowed drugs; c) adequate treatment of known risk factors (arterial hypertension, antiphospholipid and antibodies); d) close monitoring during and after pregnancy to rapidly identify and treat SLE flares and obstetric complications.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Objective
It has been suggested that only antibodies against domain 1 (D1) of β2‐glycoprotein I (β2GPI) are pathogenic and diagnostic. The role of antibodies against other β2GPI domains is still ...debated. This study was undertaken to evaluate the clinical relevance of domain specificity profiling of anti‐β2GPI IgG antibodies in antiphospholipid syndrome (APS) patients and in control groups of patients with systemic autoimmune rheumatic diseases and in asymptomatic antiphospholipid antibody (aPL) carriers.
Methods
We evaluated 159 subjects with persistently positive, medium or high‐titer anti‐β2GPI IgG, including 56 patients with thrombotic (obstetric or nonobstetric) primary APS, 31 women with obstetric primary APS, 42 aPL‐positive patients with systemic autoimmune rheumatic diseases, and 30 asymptomatic aPL carriers. One hundred healthy donors were included. Anti‐β2GPI D1 and D4/5 IgG were tested on research enzyme‐linked immunosorbent assays containing recombinant β2GPI domains.
Results
As compared to other groups, aPL carriers displayed higher frequency/titer of anti‐D4/5 IgG. Unlike anti‐D4/5, anti‐D1 IgG antibodies were more frequent and at higher titer in triple than in single or double aPL‐positive subjects. An anti‐D1 to anti‐D4/5 ratio of ≥1.5 was predictive of systemic autoimmunity (odds ratio 3.25 95% confidence interval 1.45–7.49, P = 0.005). Neither anti‐D1 nor anti‐D4/5 antibodies were associated with APS clinical criteria.
Conclusion
Anti‐D1 IgG is the preferential specificity not only in vascular and obstetric primary APS, but also in patients with systemic autoimmune rheumatic disease with no clinical features of APS. Conversely, aPL carriers do not have a polarized profile toward D1. Combined testing for anti‐β2GPI IgG with different domain specificity allows a more accurate aPL profiling, with polarization toward anti‐D1 IgG as a possible fingerprint of systemic autoimmunity.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Clinical studies have reported different diagnostic/predictive values of antibodies to domain 1 or 4/5 of β
glycoproteinI in terms of risk of thrombosis and pregnancy complications in patients with ...antiphospholipid syndrome. To obtain direct evidence for the pathogenic role of anti-domain 1 or anti-domain 4/5 antibodies, we analyzed the
pro-coagulant effect of two groups of 5 sera IgG each reacting selectively with domain 1 or domain 5 in lipopolysaccharide (LPS)-treated rats. Antibody-induced thrombus formation in mesenteric vessels was followed by intravital microscopy, and vascular deposition of β
glycoproteinI, human IgG and C3 was analyzed by immunofluorescence. Five serum IgG with undetectable anti-β
glycoproteinI antibodies served as controls. All the anti-domain 1-positive IgG exhibited potent pro-coagulant activity while the anti-domain 5-positive and the negative control IgG failed to promote blood clot and vessel occlusion. A stronger granular deposit of IgG/C3 was found on the mesenteric endothelium of rats treated with anti-domain 1 antibodies, as opposed to a mild linear IgG staining and absence of C3 observed in rats receiving anti-domain 5 antibodies. Purified anti-domain 5 IgG, unlike anti-domain 1 IgG, did not recognize cardiolipin-bound β
glycoproteinI while being able to interact with fluid-phase β
glycoproteinI. These findings may explain the failure of anti-domain 5 antibodies to exhibit a thrombogenic effect
, and the interaction of these antibodies with circulating β
glycoproteinI suggests their potential competitive role with the pro-coagulant activity of anti-domain 1 antibodies. These data aim at better defining "really at risk" patients for more appropriate treatments to avoid recurrences and disability.
In vitro studies have documented β2 glycoprotein I (β2GPI) binding to endothelial cells (ECs) and trophoblast using antiphospholipid antibodies. The in vivo binding of β2GPI to these cells and the ...conditions that favor their interaction have not been investigated. We analyzed the in vivo distribution of cyanine 5.5-labeled β2GPI in mice and evaluated the effect of pregnancy and circulating antibodies on its tissue localization. The signal was detected in the liver by whole body scan and ex vivo analysis. The β2GPI failed to bind to the vascular endothelium and reacted only with the ECs of uterine vessels. In pregnant mice the protein was localized on ECs and trophoblast at the embryo implantation sites. Immunized mice showed a similar β2GPI biodistribution to naive mice but the immunized pregnant animals exhibited a significant increase in fetal loss associated with C3 and C9 deposition at the implantation sites. Treatment of mice with LPS after β2GPI-Cy5.5 injection promoted protein localization on gut and brain ECs associated with IgG, C1q, and C9 deposition in immunized mice. These findings indicate that β2GPI binding to EC requires priming with pro-inflammatory factors which is not needed for uterine and placental localization probably dependent on hormonal changes.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by recurrent vascular thrombosis and miscarriages in the absence of known causes. Antibodies against ...phospholipid-binding proteins (aPL) are pathogenic players in both clotting and pregnancy APS manifestations. There is sound evidence that antibodies specific for beta2 glycoprotein I (β2GPI) trigger thrombotic and pregnancy complications by interacting with the molecule on the membranes of different cell types of the coagulation cascade, and in placenta tissues. In addition to the humoral response against β2GPI, both peripheral and tissue CD4
β2GPI-specific T cells have been reported in primary APS as well as in systemic lupus erythematosus (SLE)-associated APS. While adaptive immunity plays a clear role in APS, it is still debated whether innate immunity is involved as well. Acute systemic inflammation does not seem to be present in the syndrome, however, there is sound evidence that complement activation is crucial in animal models and can be found also in patients. Furthermore, neutrophil extracellular traps (NETs) have been documented in arterial and venous thrombi with different etiology, including clots in APS models. Keeping in mind that β2GPI is a pleiotropic glycoprotein, acting as scavenger molecule for infectious agents and apoptotic/damaged body constituents and that self-molecules externalized through NETs formation may become immunogenic autoantigens, we demonstrated β2GPI on NETs, and its ability to stimulate CD4
β2GPI-specific T cells. The aim of this review is to elucidate the role of β2GPI in the cross-talk between the innate and adaptive immunity in APS.
Antiphospholipid syndrome (APS) is defined by recurrent pregnancy morbidity and/or vascular thrombosis associated with the persistent presence of antibodies against anionic phospholipid-binding ...proteins. Beta 2 glycoprotein I (β2GPI) and prothrombin (PT) are the major antigens for antiphospholipid antibodies (aPL) detectable by functional coagulation lupus anticoagulant (LA) or solid-phase assays anti-β2GPI-dependent cardiolipin (aCL) and anti-β2GPI. β2GPI-dependent aPL are responsible for the positivity of the three classification laboratory criteria. While medium/high titers of antibodies against β2GPI are risk factors for both the vascular and the obstetric manifestations of APS, persistent low titers are also associated with pregnancy complications. There is evidence from animal models of aPL-dependent fetal loss and from in vitro systems that β2GPI-dependent aPL can be pathogenic. β2GPI is physiologically found in large quantities at the placental level being available for the specific antibodies circulating in the maternal blood. Once bound to the protein, the antibodies trigger a local inflammation via the activation of the complement cascade and affect trophoblast and decidual function. The final result is represented by defective placentation, while thrombotic events are apparently less important. β2GPI is a pleiotropic molecule with scavenging properties towards several molecules including apoptotic material and displays anti-oxidant activity. These functions may explain the β2GPI placental localization in an area of intensive tissue remodeling and low oxygen tension. Since β2GPI interacts also with the complement and the coagulation cascade, its binding with specific antibodies may affect the physiology of placentation in several ways.
The protection of first responders from radioactive contamination with alpha emitters that may result from a radiological accident is of great complexity due to the short range of alpha particles in ...the air of a few centimeters. To overcome this issue, for the first time, a system mounted on a UAS for the near-real-time remote measurement of alpha particles has been developed, tested, and calibrated. The new system, based on an optical system adapted to be installed on a UAS in order to measure the UV-C fluorescence emitted by alpha particles in the air, has been tested and calibrated, carried out in the laboratory and in field experiments using UV-C LEDs and 241Am sources. In experimental flights, the probability of detecting a point source was determined to be approximately 60%. In the case of a surface extended source, a detection efficiency per unit surface activity of 10 counts per second per MBq cm−2 was calculated. A background count rate of UV-C of around 26 ± 28 s−1 for an integration time of 0.1 s was measured during flights, which led to a decision threshold surface activity of 5 MBq cm−2.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Antiphospholipid antibodies (Abs) are associated with thrombosis and are a risk factor for recurrent pregnancy loss and obstetric complications in patients with the antiphospholipid syndrome. It is ...generally accepted that the major autoantigen for aPL Abs is beta (2) glycoprotein I, which mediates the binding of aPL Abs to target cells (i.e., endothelial cells, monocytes, platelets, trophoblasts, etc.) leading to thrombosis and fetal loss. This article addresses molecular events triggered by aPL Abs on endothelial cells, platelets, and monocytes and complement activation, as well as a review of the current knowledge with regard to the putative receptor(s) recognized by aPL Abs on target cells as well as novel mechanisms that involve fibrinolytic processes. A section is devoted to the description of thrombotic and inflammatory processes that lead to obstetric complications mediated by aPL Abs. Based on experimental evidence using in vitro and in vivo models, new targeted therapies for treatment and/or prevention of thrombosis and pregnancy loss in antiphospholipid syndrome are proposed.
PDF
