Antiphospholipid syndrome, antiphospholipid antibodies, and stroke.

Antiphospholipid syndrome (APS) is a prothrombotic autoimmune disease with heterogeneous clinicopathological manifestations and is a well-established cause of acute ischemic stroke (AIS) and transient ischemic attack (TIA), particularly in younger patients. There is growing recognition of a wider spectrum of APS-associated cerebrovascular lesions, including white matter hyperintensities, cortical atrophy, and infarcts, which may have clinically important neurocognitive sequalae. Diagnosis of APS-associated AIS/TIA requires expert review of clinical and laboratory information. Management poses challenges, given the potential for substantial morbidity and recurrent thrombosis, additional risk conferred by conventional cardiovascular risk factors, and limited evidence base regarding optimal antithrombotic therapy for secondary prevention. In this review, we summarize key features of APS-associated cerebrovascular disorders, with focus on clinical and laboratory aspects of diagnostic evaluation. The current status of prognostic markers is considered. We review the evidence base for antithrombotic treatment in APS-associated stroke and discuss uncertainties, including the optimal intensity of anticoagulation and efficacy of direct oral anticoagulants. Clinical practice recommendations are provided, covering antithrombotic treatment, supportive management, and options for anticoagulant-refractory cases, and we highlight the benefits of adopting a considered, multidisciplinary team approach.

Frequency of positive antiphospholipid antibodies in pregnant women with SARS-CoV-2 infection and impact on pregnancy outcome: A single-center prospective study on 151 pregnancies.

Background: At the beginning of the SARS-CoV-2 pandemic, there was a lack of information about the infection's impact on pregnancy and capability to induce de novo autoantibodies. It soon became clear that thrombosis was a manifestation of COVID-19, therefore the possible contribution of de novo antiphospholipid antibodies (aPL) raised research interest. We aimed at screening SARS-CoV-2 positive pregnant patients for aPL. Methods: The study included consecutive pregnant women who were hospitalized in our Obstetric Department between March 2020 and July 2021 for either a symptomatic SARS-CoV-2 infection or for other reasons (obstetric complications, labour, delivery) and found positive at the admission nasopharyngeal swab. All these women underwent the search for aPL by means of Lupus Anticoagulant (LA), IgG/IgM anti-cardiolipin (aCL), IgG/IgM anti-beta2glycoprotein I (aB2GPI). Data about comorbidities, obstetric and neonatal complications were collected. Results: 151 women were included. Sixteen (11%) were positive for aPL, mostly at low titre. Pneumonia was diagnosed in 20 women (5 with positive aPL) and 5 required ICU admission (2 with positive aPL). Obstetric complications occurred in 10/16 (63%) aPL positive and in 36/135 (27%) negative patients. The occurrence of HELLP syndrome and preeclampsia was significantly associated with positive aPL (p=0,004). One case of maternal thrombosis occurred in an aPL negative woman. aPL positivity was checked after at least 12 weeks in 7/16 women (44%): 3 had become negative; 2 were still positive (1 IgG aB2GPI + IgG aCL; 1 IgM aB2GPI); 1 remained positive for IgG aCL but became negative for aB2GPI; 1 became negative for LA but displayed a new positivity for IgG aCL at high titre. Conclusions: The frequency of positive aPL in pregnant women with SARS-CoV-2 infection was low in our cohort and similar to the one described in the general obstetric population. aPL mostly presented as single positive, low titre, transient antibodies. The rate of obstetric complications was higher in aPL positive women as compared to negative ones, particularly hypertensive disorders. Causality cannot be excluded; however, other risk factors, including a full-blown picture of COVID-19, may have elicited the pathogenic potential of aPL and contributed themselves to the development of complications.

Catastrophic Antiphospholipid Syndrome as a Complication of COVID-19 Infection.

COVID-19 infection has been found to precipitate hypercoagulability and transiently increase antiphospholipid antibodies. However, it is yet to be determined how likely these transient changes contribute to thrombotic events and antiphospholipid syndrome. We present a case in which antiphospholipid antibodies were detected in the presence of significant thromboses. The patient was subsequently treated for suspected catastrophic antiphospholipid syndrome following COVID-19 infection.

The APSANTICO Study: A Prospective Observational Study to Evaluate Antiphospholipid Antibody Profiles in Patients with Thromboembolic Antiphospholipid Syndrome (APS) after COVID-19 Infection and/or Vaccination.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new virus discovered in December 2019 that causes coronavirus disease 19 (COVID-19) and various vaccinations have been developed. The extent to which COVID-19 infections and/or COVID-19 vaccinations alter antiphospholipid antibodies (aPL) in patients with thromboembolic antiphospholipid syndrome (APS) remains unclear. Eighty-two patients with confirmed thromboembolic APS were included in this prospective non-interventional trial. Blood parameters including lupus anticoagulants, anticardiolipin IgG- and IgM-antibodies, and anti-ß2-glycoprotein I IgG- and IgM-antibodies were assessed prior to and after COVID-19 vaccination and/or COVID-19 infection. No increases in aPL in the total study population were detected. In fact, low but significant decreases were observed for anticardiolipin IgG- and anti-ß2-glycoprotein I IgG-antibodies, while anticardiolipin IgM- and anti-b2-glycoprotein I IgM-antibodies slightly increased only in patients with COVID-19 infection and vaccination. Although the investigated patient group is known to have a high risk of recurrent thrombosis, only one arterial thrombotic event was diagnosed (1.2%, 1/82). This low recurrence rate was probably due to the high vaccination rates prior to infections and a high rate of effective anticoagulation. Our data show that COVID-19 infections and/or vaccinations do not deteriorate the clinical course of anticoagulated thromboembolic APS patients.

COVID-19 and antiphospholipid antibodies.

Antiphospholipid syndrome and the coagulopathy of COVID-19 share many pathophysiologic features, including endotheliopathy, hypercoagulability, and activation of platelets, complement pathways, and neutrophil extracellular traps, all acting in concert via a model of immunothrombosis. Antiphospholipid antibody production in COVID-19 is common, with 50% of COVID-19 patients being positive for lupus anticoagulant in some studies, and with non-Sapporo criteria antiphospholipid antibodies being prevalent as well. The biological significance of antiphospholipid antibodies in COVID-19 is uncertain, as such antibodies are usually transient, and studies examining clinical outcomes in COVID-19 patients with and without antiphospholipid antibodies have yielded conflicting results. In this review, we explore the biology of antiphospholipid antibodies in COVID-19 and other infections and discuss mechanisms of thrombogenesis in antiphospholipid syndrome and parallels with COVID-19 coagulopathy. In addition, we review the existing literature on safety of COVID-19 vaccination in patients with antiphospholipid antibodies and antiphospholipid syndrome.

Antiphospholipid antibodies in patients with stroke during COVID-19: A role in the signaling pathway leading to platelet activation.

Background: Several viral and bacterial infections, including COVID-19, may lead to both thrombotic and hemorrhagic complications. Previously, it has been demonstrated an "in vitro" pathogenic effect of "antiphospholipid" antibodies (aPLs), which are able to activate a proinflammatory and procoagulant phenotype in monocytes, endothelial cells and platelets. This study analyzed the occurrence of aPL IgG in patients with acute ischemic stroke (AIS) during COVID-19, evaluating the effect of Ig fractions from these patients on signaling and functional activation of platelets. Materials and methods: Sera from 10 patients with AIS during COVID-19, 10 non-COVID-19 stroke patients, 20 COVID-19 and 30 healthy donors (HD) were analyzed for anti-cardiolipin, anti-ß2-GPI, anti-phosphatidylserine/prothrombin and anti-vimentin/CL antibodies by ELISA. Platelets from healthy donors were incubated with Ig fractions from these patients or with polyclonal anti-ß2-GPI IgG and analyzed for phospho-ERK and phospho-p38 by western blot. Platelet secretion by ATP release dosage was also evaluated. Results: We demonstrated the presence of aPLs IgG in sera of patients with AIS during COVID-19. Treatment with the Ig fractions from these patients or with polyclonal anti-ß2-GPI IgG induced a significant increase of phospho-ERK and phospho-p38 expression. In the same vein, platelet activation was supported by the increase of adenyl nucleotides release induced by Ig fractions. Conclusions: This study demonstrates the presence of aPLs in a subgroup of COVID-19 patients who presented AIS, suggesting a role in the mechanisms contributing to hypercoagulable state in these patients. Detecting these antibodies as a serological marker to check and monitor COVID-19 may contribute to improve the risk stratification of thromboembolic manifestations in these patients.

Longitudinal Analysis of Antiphospholipid Antibody Dynamics after Infection with SARS-CoV-2 or Vaccination with BNT162b2.

Antiphospholipid antibodies (aPL) comprise a group of autoantibodies that reflect prothrombotic risk in antiphospholipid syndrome (APS) but may also be present in a small proportion of healthy individuals. They are often transiently elevated in infections, including SARS-CoV-2, and may also be associated with vaccine-induced autoimmunity. Therefore, we aimed to investigate the dynamics of aPL in COVID-19 patients and in individuals (healthcare professionals-HCPs) after receiving BNT162b2 vaccine and to compare aPL levels and positivity with those found in APS patients. We measured solid-phase identifiable aPL, including anticardiolipin (aCL), anti-ß2 glycoprotein I (anti-ß2GPI), and anti-prothrombin/phosphatidylserine (aPS/PT) antibodies in 58 HCPs before and after vaccination (at 3 weeks, 3, 6, and 9 months after the second dose, and 3 weeks after the third booster dose), in 45 COVID-19 patients hospitalized in the ICU, in 89 COVID-19 patients hospitalized in the non-ICU (at admission, at hospital discharge, and at follow-up), and in 52 patients with APS. The most frequently induced aPL in COVID-19 patients (hospitalized in non-ICU) were aCL (50.6% of patients had positive levels at at least one time point), followed by anti-ß2GPI (21.3% of patients had positive levels at at least one time point). In 9/89 COVID-19 patients, positive aPL levels persisted for three months. One HCP developed aCL IgG after vaccination but the persistence could not be confirmed, and two HCPs developed persistent anti-ß2GPI IgG after vaccination with no increase during a 1-year follow-up period. Solid-phase aPL were detected in 84.6% of APS patients, in 49.4% of COVID-19 patients hospitalized in the non-ICU, in 33.3% of COVID-19 patients hospitalized in the ICU, and in only 17.2% of vaccinated HCPs. aPL levels and multiple positivity were significantly lower in both infected groups and in vaccinated individuals compared with APS patients. In conclusion, BNT162b2 mRNA vaccine may have induced aPL in a few individuals, whereas SARS-CoV-2 infection itself results in a higher percentage of aPL induction, but the levels, persistence, and multiple positivity of aPL do not follow the pattern observed in APS.

TIMELESS is a key gene mediating thrombogenesis in COVID-19 and antiphospholipid syndrome.

Abnormal coagulation and increased risk of thrombosis are some of the symptoms associated with COVID-19 severity. Anti-phospholipid antibodies (aPLs) present in critically ill COVID-19 patients contribute to systemic thrombosis. The aim of this study was to identify key common genes to characterize genetic crosstalk between COVID-19 and antiphospholipid syndrome (APS) using bioinformatics analysis and explore novel mechanisms of immune-mediated thrombosis in critically ill COVID-19 patients. The transcriptome data of mononuclear cells from severe COVID-19 patients and APS patients were evaluated to obtain the common genes. The protein-protein interaction network and cytoHubba module analysis in Cytoscape software were used to find the associated hinge genes and hub genes. Among the common differentially expressed genes, TIMELESS depletion was identified only in patients with severe COVID-19 and not in patients with mild COVID-19, and it was validated with the GSE159678 dataset. Functional analyses using gene ontology terms and the Kyoto Encyclopedia of Genes and Genomes pathway suggested that TIMELESS might contribute to the production of antiphospholipid antibody and thrombosis in both COVID-19 and APS patients. The potential role of TIMELESS and autophagy genes in momonuclear cells were further investigated, and GSK3B was found to be associated with TIMELESS. Autophagy targeting agents have a therapeutic potential against COVID-19 and thrombogenesis in APS, which may be related to the role of autophagy genes in the modification of circadian clock proteins. Interference with TIMELESS and other genes associated with it to regulate autoantibody expression may be a potential strategy for immunotherapy against thrombogenesis in severe COVID-19 patients.

Antiphospholipid antibodies: what is new in 2022 / Détection des anticorps antiphospholipides : actualités en 2022

Antiphospholipid syndrome (APS) is a clinicobiological entity defined by the association of thrombotic events and/or obstetric complications and the presence of persistent antiphospholipid antibodies (aPLs) detected by coagulation tests (lupus anticoagulant, LAC) and/or immunological assays (anticardiolipin and anti-glycoprotein-beta-I antibodies). The increased use of direct oral anticoagulants (DOAC) for the treatment of venous thromboembolism (VTE) is now a challenge for hematology laboratories for the diagnosis of APS. DOAC interfere with LAC screening and confirmation tests resulting in a risk of false positive results. To avoid these interferences, several solutions are suggested. Some of them rely on the use of DOAC-reversal systems (activated charcoal tablet, filter system) others on the use of reagents insensitive to DOAC presence in the sample. Detection of anti-phosphatidylserine/prothrombin antibodies may be helpful because they are strongly associated to the presence of LAC and are increasingly recognized as a useful tool in the diagnosis and prognosis of APS. Finally, positivity of LA in the setting of a viral infection is frequent and not specific to APS. During the Covid-19 pandemic, many patients developed arterial and VTE that could suggest testing for aPLs. The association between LAC and a risk of VTE or in-hospital mortality in hospitalized Covid-19 patients was not demonstrated. Moreover, aPLs do not persist after Covid-19. Currently, testing for aPLs in Covid-19 patients is not recommended.

Le syndrome des antiphospholipides (SAPL) est une entité clinico-biologique définie par l'association de manifestations thrombotiques et/ou de complications obstétricales et la présence persistante d'anticorps antiphospholipides (aPLs) détectés par des tests de coagulation (lupus anticoagulant, LA) et/ou par des tests immunologiques (anticorps anti-cardiolipine et anticorps anti-ß2-glycoprotéine-I). L'essor des anticoagulants oraux directs (AOD) dans la prise en charge des évènements thrombotiques veineux (ETV) constitue aujourd'hui un défi pour les laboratoires d'hémostase dans le cadre du diagnostic du SAPL. Les AOD interfèrent avec les tests de dépistage et de confirmation du LA occasionnant des faux positifs. Afin de se soustraire à ces interférences plusieurs solutions sont proposées. Certaines reposent sur l'utilisation de système neutralisant l'AOD (pastille de charbon activé, système de filtre) d'autres sur l'utilisation de réactifs insensibles à la présence d'AOD. On peut également faire appel aux anticorps anti-phosphatidylsérine/prothrombine très corrélés à la présence de LA et constituant un outil de plus en plus reconnu dans le diagnostic biologique du SAPL et son pronostic. Enfin, la positivité des aPLs dans un contexte infectieux est fréquente et non spécifique du SAPL. Au cours de la pandémie Covid-19, de nombreux patients ont présentés des ETV et artériels qui ont pu motiver la recherche d'aPLs. L'association entre LA et le risque d'ETV ou la mortalité hospitalière chez les patients Covid-19 hospitalisés n'a pas été démontrée. De plus, il ne semble pas qu'il y ait de persistance de ces aPLs après la Covid-19. A ce jour, la recherche d'aPLs chez les patients atteint de Covid-19 n'est pas recommandée.

The effect of the BNT162b2 vaccine on antinuclear antibody and antiphospholipid antibody levels.

The Food and Drug Administration (FDA) approved the first SARS-CoV-2 mRNA vaccine (Pfizer-BioNTech) in December 2020. New adverse events have emerged since these vaccines have reached market. Although no clear association between messenger ribonucleic acid (mRNA) vaccines and autoimmunity has emerged, the significance of such an association warrants further exploration. After obtaining consent, a standardized survey on baseline characteristics and other relevant variables was conducted on unvaccinated individuals who were scheduled for vaccination and had not previously contracted COVID-19. Blood samples were collected from participants prior to the first dose, prior to the second dose, and 1 month after the second dose. All collected samples were tested for antinuclear antibody (ANA) titers using indirect immunofluorescence microscopy kits, and antiphospholipid (APS) immunoglobulin M (IgM) and immunoglobulin G (IgG) levels using an enzyme-linked immunoassay (ELISA) technique. ANA titers were positive for 9 participants out of 101 (8.9%) in the first pre-vaccination draw. For the second draw, the number of participants testing positive for ANA decreased to 5 (5%). For the last draw, 6 (5.9%) participants tested positive for ANA titers. One participant tested positive for APS IgM at the first pre-vaccination draw, 2 tested positive at the second draw, and 2 at the third draw. As for APS IgG titers, all participants tested negative in the three draws. McNemar's test for two dependent categorical outcomes was conducted on all variables and did not show a statistical significance. The McNemar test of these two composite variables (i.e., ANA/APS, first draw vs. ANA/APS, second and third draws) did not show statistical significance. The 2-sided exact significance of the McNemar test was 1.0. The Friedman test also showed no significance (p = 0.459). No association was found between BNT162b2 vaccine administration and changes in APS and ANA titers. The benefits of the BNT162b2 vaccine significantly outweigh any possible risk of autoimmune dysregulation considering the current evidence.

Anti-Phospholipid Antibodies and Coronavirus Disease 2019: Vaccination Does Not Trigger Early Autoantibody Production in Healthcare Workers.

A molecular mimicry between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and human proteins supports the possibility that autoimmunity takes place during coronavirus disease 2019 (COVID-19) contributing to tissue damage. For example, anti-phospholipid antibodies (aPL) have been reported in COVID-19 as a result of such mimicry and thought to contribute to the immunothrombosis characteristic of the disease. Consistently, active immunization with the virus spike protein may elicit the production of cross-reactive autoantibodies, including aPL. We prospectively looked at the aPL production in healthcare workers vaccinated with RNA- (BNT162b2, n. 100) or adenovirus-based vaccines (ChAdOx1, n. 50). Anti-cardiolipin, anti-beta2 glycoprotein I, anti-phosphatidylserine/prothrombin immunoglobulin G (IgG), IgA, and IgM before and after vaccination were investigated. Anti-platelet factor 4 immunoglobulins were also investigated as autoantibodies associated with COVID-19 vaccination. Additional organ (anti-thyroid) and non-organ (anti-nuclear) autoantibodies and IgG against human proteome were tested as further post-vaccination autoimmunity markers. The antibodies were tested one or three months after the first injection of ChAdOx1 and BNT162b2, respectively; a 12-month clinical follow-up was also performed. Vaccination occasionally induced low titers of aPL and other autoantibodies but did not affect the titer of pre-existing autoantibodies. No significant reactivities against a microarray of approximately 20,000 human proteins were found in a subgroup of ChAdOx1-vaccinees. Consistently, we did not record any clinical manifestation theoretically associated with an underlying autoimmune disorder. The data obtained after the vaccination (two doses for the RNA-based and one dose for the adenovirus-based vaccines), and the clinical follow-up are not supporting the occurrence of an early autoimmune response in this cohort of healthcare workers.

Assessment of antiphospholipid antibodies profiles based on severity of COVID-19 pneumonia.

Introduction: thrombotic events are the most severe complications of the coronavirus disease 2019 (COVID-19). It is known that anti-phospholipid antibodies (APL) could be involved in thrombosis mechanism. Thus, APL profiles were studied particularly in patients with severe and critical COVID-19, and their clinical impact. Methods: a retrospective study of 54 COVID-19 hospitalized patients (34 in intensive care unit (ICU) and 20 in non-ICU) was conducted. These COVID-19 patients were tested for the presence of LAC (lupus anticoagulant) using the ACLTOP750®, anti-cardiolipine (ACL) and anti-ß2glycoprotéine I (anti-ß2GPI) IgG/IgM/IgA by enzyme-linked immunosorbent assay (ELISA). IgA isotype was tested in only 25 patients. Results: anti-phospholipid antibodies were present in 74.1% of tested patients. LAC positivity was the highest (60.8%) among all patients, followed by IgM aCL (18.5%) and IgM anti-ß2GPI (14.8%). Besides, LAC and anti-ß2GPI IgA were the most predominant APL regarding the 25 patients tested for IgA isotype (52% and 24% respectively). Nine patients had thrombotic events, among them 6 were positive in APL and 5 were positive in LAC. However, there was any significant association between APL positivity or titers and thrombosis. There was also no significant difference between the two COVID-19 groups regarding APL profiles. Conclusion: given the relatively high frequency of APL and especially LAC, and given the multitude of thrombotic risk factors in these severely and critically ill COVID-19 patients, a prophylactic anticoagulation remains essential.

Anti-cardiolipin IgG autoantibodies associate with circulating extracellular DNA in severe COVID-19.

Whereas the detection of antiphospholipid autoantibodies (aPL) in COVID-19 is of increasing interest, their role is still unclear. We analyzed a large aPL panel in 157 patients with COVID-19 according to the disease severity. We also investigated a potential association between aPL and extracellular DNA (exDNA, n = 85) or circulating markers of neutrophil extracellular traps (NET) such as citrullinated histones H3 (CitH3, n = 49). A total of 157 sera of patients infected by SARS-CoV-2 were collected. A large aPL panel including lupus anticoagulant, anti-cardiolipin and anti-beta-2 glycoprotein I (IgG, IgM and IgA), anti-phosphatidylethanolamine IgA, anti-prothrombin (IgG and IgM) was retrospectively analyzed according to the disease severity. We found a total aPL prevalence of 54.8% with almost half of the cases having aCL IgG. Within an extended panel of aPL, only aCL IgG were associated with COVID-19 severity. Additionally, severe patients displayed higher CitH3 levels than mild patients. Interestingly, we highlighted a significant association between the levels of aCL IgG and exDNA only in aCL positive patients with severe disease. In conclusion, we showed a significant link between aPL, namely aCL IgG, and circulating exDNA in patients with severe form of COVID-19, that could exacerbate the thrombo-inflammatory state related to disease severity.

Persistent Antiphospholipid Antibodies Are Not Associated With Worse Clinical Outcomes in a Prospective Cohort of Hospitalised Patients With SARS-CoV-2 Infection.

Objective: Patients with COVID-19 presented with an elevated prevalence of antiphospholipid antibodies (aPL) but the relationship with thrombosis is controversial. We analysed the persistence of aPL and their association with the clinical outcomes during hospitalisation in a cohort of COVID-19 patients. Patients and Methods: We conducted a prospective study including consecutive hospitalised patients with COVID-19 from Hospital Clínic of Barcelona between March 28th and April 22nd, 2020. Clinical outcomes during hospitalisation were thrombosis, intensive care unit (ICU) admission, and severe ventilatory failure. We determined both criteria and non-criteria aPL. Of note, in those patients with a positive result in the first determination, a second sample separated by at least 12 weeks was drawn to test the persistence of aPL. Results: One hundred and fifty-eight patients (59.5% men) with a mean age of 61.4 ± 14.9 years old were included. Thrombosis was present in 28 (17.7%) patients, severe respiratory failure in 47 (30.5%), and 30 (18.9%) patients were admitted to ICU. Sixteen (28.6%) patients were positive for the criteria aPL at both determinations and only two (3.6%) of them suffered from thrombosis during hospitalisations (both had aCL IgG). However, they presented with low titers of aCL. Of note, aPL were not related to thrombosis, ICU admission or severe respiratory failure. Conclusion: Although aPL were prevalent in our cohort of hospitalised COVID-19 patients and they were persistent in half of tested patients, most determinations were at low titers and they were not related to worse clinical outcomes.

Antiphospholipid antibodies and vitamin D deficiency in COVID-19 infection with and without venous or arterial thrombosis: A pilot case-control study.

BACKGROUND: Coronavirus disease-2019 (COVID-19) is associated with thromboembolism. Antiphospholipid antibody (APLa) formation is one of the mechanisms. Vitamin D deficiency has been associated with thrombosis in antiphospholipid antibody syndrome. OBJECTIVE: Measure APLa and vitamin D in hospitalized COVID-19 patients with and without thrombosis to evaluate if thromboembolism is associated with concomitant APLa and vitamin D deficiency. METHODS: Case-control study. Hospitalized COVID-19 patients with a thromboembolic event (ischemic stroke, myocardial infarction, deep venous thrombosis/pulmonary embolism, Cases n = 20). Controls (n = 20): Age, sex-matched without thromboembolic events. Patients with autoimmune disorders, antiphospholipid antibody syndrome, thrombophilia, anticoagulation therapy, prior thromboembolism, chronic kidney disease 3b, 4, end-stage renal disease, and malignancy were excluded. Given the limited current literature on the role of concomitant antiphospholipid antibodies and vitamin D deficiency in causing venous and/or arterial thrombosis in hospitalized COVID-19 patients, we enrolled 20 patients in each arm. Anti-cardiolipin IgG/IgM, beta-2 glycoprotein-1 IgG/IgM, lupus anticoagulant and vitamin D levels were measured in both groups. RESULTS: Cases were 5.7 times more likely to be vitamin D deficient (OR:5.7, 95% CI:1.3-25.6) and 7.4 times more likely to have any one APLa (OR:7.4, 95% CI: 1.6-49.5) while accounting for the effects of sex. Patients with both APLa and vitamin D deficiency had significantly more thrombosis compared to patients who were antibody positive without vitamin D deficiency (100% vs 47.4%; p = 0.01). CONCLUSIONS: Thrombosis in COVID-19 was associated with concomitant APLa and vitamin D deficiency. Future studies in COVID-19 should assess the role of vitamin D in reducing thrombosis.

Immunogenicity, safety, and antiphospholipid antibodies after SARS-CoV-2 vaccine in patients with primary antiphospholipid syndrome.

OBJECTIVE: Coronavirus disease 19 (COVID-19) has an increased risk of coagulopathy with high frequency of antiphospholipid antibodies (aPL). Recent reports of thrombosis associated with adenovirus-based vaccines raised concern that SARS-CoV-2 immunization in primary antiphospholipid syndrome (PAPS) patients may trigger clotting complications. Our objectives were to assess immunogenicity, safety, and aPL production in PAPS patients, after vaccinating with Sinovac-CoronaVac, an inactivated virus vaccine against COVID-19. METHODS: This prospective controlled phase-4 study of PAPS patients and a control group (CG) consisted of a two-dose Sinovac-CoronaVac (D0/D28) and blood collection before vaccination (D0), at D28 and 6 weeks after second dose (D69) for immunogenicity/aPL levels. Outcomes were seroconversion (SC) rates of anti-SARS-CoV-2 S1/S2 IgG and/or neutralizing antibodies (NAb) at D28/D69 in naïve participants. Safety and aPL production were also assessed. RESULTS: We included 44 PAPS patients (31 naïve) and 132 CG (108 naïve) with comparable age (p=0.982) and sex (p>0.999). At D69, both groups had high and comparable SC (83.9% vs. 93.5%, p=0.092), as well as NAb positivity (77.4% vs. 78.7%, p=0.440), and NAb-activity (64.3% vs. 60.9%, p=0.689). Thrombotic events up to 6 months or other moderate/severe side effects were not observed. PAPS patients remained with stable aPL levels throughout the study at D0 vs. D28 vs. D69: anticardiolipin (aCL) IgG (p=0.058) and IgM (p=0.091); anti-beta-2 glycoprotein I (aß2GPI) IgG (p=0.513) and IgM (p=0.468). CONCLUSION: We provided novel evidence that Sinovac-CoronaVac has high immunogenicity and safety profile in PAPS. Furthermore, Sinovac-CoronaVac did not trigger thrombosis nor induced changes in aPL production.

Antigens and Antibodies of the Antiphospholipid Syndrome as New Allies in the Pathogenesis of COVID-19 Coagulopathy.

High prevalence of both criteria and extra-criteria antiphospholipid antibodies (aPL) has been reported in COVID-19 patients. However, the differences in aPL prevalence decreased when an age-matched control group was included. The association of aPL with thrombotic events in COVID-19 is very heterogeneous. This could be influenced by the fact that most of the studies carried out were conducted on small populations enriched with elderly patients in which aPL was measured only at a single point and they were performed with non-standardized assays. The few studies that confirmed aPL in a second measurement showed that aPL levels hardly changed, with the exception of the lupus anticoagulant that commonly reduced. COVID-19 coagulopathy is an aPL-independent phenomenon closely associated with the onset of the disease. Thrombosis occurs later in patients with aPL presence, which is likely an additional prothrombotic factor. B2-glycoprotein deficiency (mainly aPL antigen caused both by low production and consumption) is very common during the SARS-CoV2 infection and has been associated with a greater predisposition to COVID-19 complications. This could be a new prothrombotic mechanism that may be caused by the blockage of its physiological functions, the anticoagulant state being the most important.

Impact of COVID-19 and COVID-19 vaccination on high-risk patients with antiphospholipid syndrome: a nationwide survey.

OBJECTIVES: Patients with APS and triple-positive for aPL are at high risk of recurrent events. As COVID-19 and COVID-19 vaccination may induce thrombotic complications, the objective of the study was to assess the course of COVID-19 and adverse events after vaccination in these patients. METHODS: This is a nationwide multicentre survey conducted in nine APS referral centres by means of a questionnaire. Included patients are thrombotic APS with triple-positive aPL confirmed 12 weeks apart. Reference specialist physicians used a four-graded scale of severity for COVID-19 [from 0 (asymptomatic) to 3 (hospitalization in intensive care unit)] and a six-graded scale for adverse reactions to vaccination [from 0 (transient local injection site sign/symptoms) to 5 (potentially life-threatening reactions)]. Outcomes were considered within a 30-day period. RESULTS: Out of 161 patients interviewed, 18 (11%) had COVID-19. All of them fully recovered without any progression to severe disease nor thromboembolic event. A total of 146 patients received the first (92%) and 129 (80%) the second dose of vaccine; side effects were minimal and, in most cases (83% after the first and 68% after the second vaccination) limited to a sore arm. Fifteen patients (9%) were unvaccinated. Most of them raised doubts on the need for vaccination, complained of poor safety and in general were reluctant about COVID-19 vaccination. CONCLUSION: Patients with triple-positive thrombotic APS did not suffer from severe COVID-19 outcomes. Importantly, COVID-19 vaccination was well tolerated. These data may reassure patients and physicians and contribute to reducing hesitancy in unvaccinated patients.

The clinical significance of antiphospholipid antibodies in COVID-19 infection.

INTRODUCTION: One of the factors that may aggravate the clinical presentation in COVID-19 is the increased level of antiphospholipid antibodies (aPLs) and thrombotic events that can be seen with the disease. In our retrospective study, we aimed to evaluate the effect of aPLs on the clinical findings in patients with a diagnosis of COVID-19. METHODOLOGY: Seventy-three patients diagnosed with COVID-19 and examined for aPLs were included in the study. Patients were divided into two groups according to the test results of aPLs. Clinical and laboratory parameters were compared in both groups to reveal whether there was any difference between the groups. RESULTS: There were 15 patients with a positive aPLs test. Dyspnea, nausea, vomiting, myalgia, and abdominal pain were significantly higher in the aPLs positive group than those with negative aPLs. The duration of hospital stays and the need for oxygen therapy of the patients in the aPLs positive group were significantly higher than the aPLs negative group. However, no difference was found between the two groups in terms of mechanical ventilation need, intensive care admission rate, thrombosis and mortality. In terms of laboratory findings, those with positive aPLs have higher median C-reactive protein (CRP) and ferritin values than those with negative aPLs. CONCLUSIONS: In our study group, we could not find a relationship between aPLs positivity and critical complications. According to our hypothesis, it may not be necessary to routinely examine aPLs in patients with a diagnosis of COVID-19 to determine the risk of thromboembolic complications.