Persistent Antiphospholipid Antibodies Research Articles

Rethinking antiphospholipid syndrome to guide future management and research.

Antiphospholipid syndrome (APS) consists of thrombotic, non-thrombotic and obstetric clinical manifestations developing in individuals with persistent antiphospholipid antibodies (aPL). Although researchers have made progress in characterizing different clinical phenotypes of aPL-positive people, the current approach to clinical management is still mostly based on a 'one size fits all' strategy, which is derived from the results of a limited number of prospective, controlled studies. With the 2023 publication of the ACR-EULAR APS classification criteria, it is now possible to rethink APS, to lay the groundwork for subphenotyping through novel pathophysiology-informed approaches, and to set a future APS research agenda guided by unmet needs in clinical management.

Changes in serum immunoglobulin G glycosylation patterns for antiphospholipid syndrome patients with lectin microarray.

Antiphospholipid syndrome is a rare autoimmune disease characterized by persistent antiphospholipid antibodies. Immunoglobulin G plays a vital role in disease progression, with its structure and function affected by glycosylation. We aimed to investigate the changes in the serum immunoglobulin G glycosylation pattern in antiphospholipid syndrome patients. We applied lectin microarray on samples from 178 antiphospholipid syndrome patients, 135 disease controls (including Takayasu arteritis, rheumatoid arthritis and cardiovascular disease) and 100 healthy controls. Lectin blots were performed for validation of significant differences. Here, we show an increased immunoglobulin G-binding level of soybean agglutinin (p = 0.047, preferring N-acetylgalactosamine) in antiphospholipid syndrome patients compared with healthy and disease controls. Additionally, the immunoglobulin G from antiphospholipid syndrome patients diagnosed with pregnancy events had lower levels of fucosylation (p = 0.001, recognized by Lotus tetragonolobus) and sialylation (p = 0.030, recognized by Sambucus nigra I) than those with simple thrombotic events. These results suggest the unique serum immunoglobulin G glycosylation profile of antiphospholipid syndrome patients, which may inform future studies to design biomarkers for more accurate diagnosis of antiphospholipid syndrome and even for the prediction of clinical symptoms in patients.

Clinical Characteristics, Treatment, and Outcomes of Provoked Acute Cerebral Sinovenous Thrombosis in Patients

Background Cerebral sinus venous thrombosis (CSVT) is a rare pediatric condition with an estimated incidence of 0.7 per 100,000 children. However, amongst pediatric venous thromboembolism (VTE), the proportion of CSVT is high, at about 10% of all pediatric VTE. Key risk factors include perinatal stressors in cases of neonatal CSVT and acute infections, especially head and neck infections, in older children. To date, few multinational trials of pediatric VTE treatment have reported findings specifically among CSVT patients. Aims We sought to describe the clinical characteristics, treatment strategies, and outcomes of the patients with provoked acute CSVT enrolled in the Kids-DOTT trial and to compare these features to those of Kids-DOTT participants with non-CSVT VTE. Methods Kids-DOTT was an NIH-sponsored multinational randomized clinical trial (RCT) comparing 6 weeks vs. 3 months of anticoagulation for provoked acute VTE treatment in patients <21 years, with two non-randomized cohort arms run in parallel to the RCT for patients with persistent antiphospholipid antibodies or complete veno-occlusion at 6 weeks post-diagnosis of the index VTE. The primary RCT findings were recently published. In the present analysis, descriptive statistics were used to summarize patient and thrombus characteristics, treatments, and outcomes, and variables were compared between CSVT and non-CSVT VTE groups using Mann-Whitney U test for continuous variables and Chi-squared or Fisher's exact test, as appropriate, for categorical variables. All statistical analyses were performed using R Core Team, 2021. A P-value of <0.05 was considered statistically significant. Results Among 532 patients enrolled in the Kids-DOTT trial, the index VTE was a CSVT in 75 (14%). Age distribution differed significantly ( P=0.002) between CSVT and non-CSVT VTE patients, with the CSVT more likely to occur in neonates and children, compared to non-CSVT VTE more likely to occur in adolescents. CSVT was less likely to be CVC-related compared to non-CSVT VTE. The frequency of any infection (56.9% vs 26%, p<0.001) and specifically infection of the head/neck (35.4% vs 2%; P<0.001) as a provoking factor was significantly higher for CSVT vs. non-CSVT VTE. Non-head and neck infections were less likely to be associated with CSVT compared to non-CSVT VTE. One-third of CSVT patients received 6 weeks, while two-thirds received > 3 months, of anticoagulation (Table 2). No patients developed ISTH-defined symptomatic recurrent VTE or clinically relevant bleeding. Conclusions These multinational trial findings substantiate those of retrospective studies implicating head/neck infection as an important provoking factor for CSVT in young patients. The absence of recurrent VTE or clinically relevant bleeding among CSVT patients managed with anticoagulation in Kids-DOTT serve to augment recent RCT findings of CSVT treatment in children involving direct oral anticoagulants, demonstrating the safety and efficacy of therapeutic anticoagulation for pediatric CSVT.

Non-criteria autoantibodies in antiphospholipid syndrome may be associated with underlying disease activity.

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by persistent antiphospholipid antibodies (aPLs) with arterial and venous thrombosis and/or pregnancy morbidity. In recent years, several studies have highlighted the potential role of non-criteria aPL in diagnosing APS patients. This study aimed to determine the association of the presence of non-criteria aPL antibodies to the clinical and laboratory features of patients with a diagnosis of APS. Eighty patients diagnosed with APS and under observation in the rheumatology clinic of Ankara City Hospital were assessed. Patient demographic and clinical features were meticulously recorded. Non-criteria antibodies tested in our center included antiphosphatidylserine IgA, antiphosphatidylserine IgM, beta 2 glycoprotein IgA, anti-cardiolipin IgA, antiphospholipid antibody IgG, and antiphospholipid antibody IgM. Antibodies from patients who were tested for at least one non-criteria antibody were documented. Out of 80 patients, 55 (68.8%) were tested for at least one non-criteria antibody, and 29 of those patients (52.7%) tested positive for at least one non-criteria antibody. The antiphospholipid antibody IgM and the beta 2 glycoprotein IgA were the most commonly tested non-criteria antibodies. Patients with non-criteria antibody positivity had a higher frequency of Ds DNA positivity and low complement (62.0% vs. 35.0%, p = 0.042; 69.0% vs. 38.0%, p = 0.023), respectively. In addition, positivity for anti-cardiolipin IgG and b2 glycoprotein IgG was significantly higher in the group positive for non-criteria antibodies (79% vs. 31%, p ≤ 0.001; 72.0% vs. 19%, p ≤ 0.001). There was no significant difference between the clinical features of patients with at least one positivity for non-criteria antibodies and those without. Systemic lupus erythematosus (SLE) is the most commonly associated disease with APS, being present in approximately 35% of cases[1]. Since the majority of the patient group in our study had APS that was secondary to SLE, non-criteria antibody positivity may be linked to the immunological activity of SLE. Large multicenter studies are necessary to investigate the clinical significance of isolated/combined positivity for criterion/non-criteria aPLs.

A review on management of antiphospholipid syndrome in clinical practice

Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by thrombotic or obstetric events occurring in patients with persistent antiphospholipid antibodies. Thrombotic APS is characterized by venous, arterial, or microvascular thrombosis. The diagnosis is accepted when both one clinical and one laboratory criteria according to the updated Sapporo classification are established. APS may occur in combination with other autoimmune diseases, mainly systemic lupus erythematosus, or in its primary form. Long-term anticoagulation with a vitamin K antagonist is the standard of care for patients who develop thrombosis, considering the high rate of recurrent thrombosis. The current international guidelines are not in favor of recommending direct oral anticoagulants for secondary prevention of thrombotic antiphospholipid syndrome, especially in the context of arterial thrombosis and triple-positive antiphospholipid patients. The most common approach, endorsed by the American College of Chest Physicians guidelines is the combination of heparin and low-dose aspirin (75-100 mg) daily for women who fulfill the clinical and serologic criteria for obstetric APS. New potential therapeutic approaches are under evaluation but actually the anticoagulation remains the cornerstone of treatment.

Antiphospholipid Syndrome: Thrombotic and Vascular Complications.

Antiphospholipid syndrome is a rare, autoimmune thrombophilia defined by vascular thrombosis and pregnancy morbidity, in the setting of documented persistent antiphospholipid antibodies including the lupus anticoagulant, anticardiolipin antibodies, or anti-β2 glycoprotein I antibodies. The presence of antiphospholipid antibodies can be completely asymptomatic, or they can lead to clinical manifestations as severe as catastrophic antiphospholipid syndrome, which involves widespread coagulopathy over a very short period of time. The degree of risk associated with antiphospholipid syndrome depends on the characteristics of the antiphospholipid antibody profile and on the presence of additional thrombotic risk factors. The current standard treatment for unprovoked thrombosis is long-term warfarin. Treatment to prevent recurrent obstetric complications is low-dose aspirin and prophylactic heparin in pregnant patients. The use of direct oral anticoagulants in patients with antiphospholipid syndrome is still being debated. Their use is generally contraindicated, especially in high-risk patients, such as those with all 3 antiphospholipid antibodies present, but they may potentially be of some use in some low-risk patients.

Small-Extracellular-Vesicle-Derived miRNA Profile Identifies miR-483-3p and miR-326 as Regulators in the Pathogenesis of Antiphospholipid Syndrome (APS).

Primary antiphospholipid syndrome (PAPS) is a systemic autoimmune disease associated with recurrent thrombosis and/or obstetric morbidity with persistent antiphospholipid antibodies (aPL). Although these antibodies drive endothelial injury and thrombophilia, the underlying molecular mechanism is still unclear. Small extracellular vesicles (sEVs) contain miRNAs, key players in intercellular communication. To date, the effects of miRNA-derived sEVs in PAPS are not well understood. We characterised the quantity, cellular origin and miRNA profile of sEVs isolated from thrombotic APS patients (PAPS, n = 50), aPL-carrier patients (aPL, n = 30) and healthy donors (HD, n = 30). We found higher circulating sEVs mainly of activated platelet origin in PAPS and aPL patients compared to HD, that were highly engulfed by HUVECs and monocyte. Through miRNA-sequencing analysis, we identified miR-483-3p to be differentially upregulated in sEVs from patients with PAPS and aPL, and miR-326 to be downregulated only in PAPS sEVs. In vitro studies showed that miR-483-3p overexpression in endothelial cells induced an upregulation of the PI3K-AKT pathway that led to endothelial proliferation/dysfunction. MiR-326 downregulation induced NOTCH pathway activation in monocytes with the upregulation of NFKB1, tissue factor and cytokine production. These results provide evidence that miRNA-derived sEVs contribute to APS pathogenesis by producing endothelial cell proliferation, monocyte activation and adhesion/procoagulant factors.

The ABCs of antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is a thromboinflammatory syndrome characterized by thrombotic, microvascular, obstetric, or non-thrombotic events in the setting of persistent antiphospholipid antibodies (aPL), namely anticardiolipin antibody (aCL), anti-β2 glycoprotein-I antibody (aβ2GPI), and lupus anticoagulant (LA). The diagnosis of APS requires careful assessment of the aPL profile, the clinical phenotype, and additional risk factors. The standard management of aPL-related thrombosis is anticoagulation, which is not effective for microvascular and non-thrombotic events. In parallel to our improved understanding of aPL-related mechanisms, the role of immunosuppression has been increasingly investigated. In this review, we summarize the basic concepts and future perspectives in APS.

High-throughput sequencing technology facilitates the discovery of novel biomarkers for antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is characterized by arterial and venous thrombosis and/or morbid pregnancy, accompanied by persistent antiphospholipid antibody (aPL) positivity. However, due to the complex pathogenesis of APS and the large individual differences in the expression of aPL profiles of patients, the problem of APS diagnosis, prognosis judgment, and risk assessment may not be solved only from the antibody level. It is necessary to use new technologies and multiple dimensions to explore novel APS biomarkers. The application of next-generation sequencing (NGS) technology in diseases with a high incidence of somatic mutations, such as genetic diseases and tumors, has been very mature. Thus, we try to know the research and application progress of APS by NGS technology from genome, transcriptome, epigenome and other aspects. This review will describe the related research of NGS technology in APS and provide more reference for the deep understanding of APS-related screening markers and disease pathogenesis.

Identifying high-risk profile in primary antiphospholipid syndrome through cluster analysis: French multicentric cohort study

IntroductionAntiphospholipid syndrome (APS) is an autoimmune disease characterised by thrombosis (arterial, venous or small vessel) or obstetrical events and persistent antiphospholipid antibodies (aPL), according to the Sydney classification criteria. Many...

Immune Thrombocytopenia Could be an Independent Clinical Phenotype of Antiphospholipid Syndrome: A Prospective Cohort Study.

Patients with persistent positive antiphospholipid antibodies (aPLs) and immune thrombocytopenia (ITP) hardly develop thrombosis but share many similar characteristics with antiphospholipid syndrome (APS). This is a prospective cohort study consecutively enrolling thrombocytopenic patients with continuous positive aPLs. Patients developing thrombotic events are classified as the APS group. Then we compare the clinical characteristics and prognosis between aPLs carriers and patients with APS. This cohort included 47 thrombocytopenic patients with continuous positive aPLs and 55 with diagnosed primary APS. The proportion of smoking and hypertension are higher in the APS group (p = 0.03, 0.04, 0.03, respectively). The platelet count of aPLs carriers at admission was lower than APS patients [26 × 109/l (9 × 109/l, 46 × 109/l) vs. 64 × 109/l (24 × 109/l, 89 × 109/l), p = 0.0002]. Triple aPLs positivity is more common in primary APS patients with thrombocytopenia [24 (51.1%) vs. 40 (72.7%), p = 0.04]. Regarding the treatment response, the complete response (CR) rate is similar between aPLs carriers and primary APS patients with thrombocytopenia (p = 0.2). Nonetheless, the proportion of response, no response, and relapse differed significantly between the two groups [13 (27.7%) vs. 4 (7.3%), p < 0.0001; 5 (10.6%) vs. 8 (14.5%), p < 0.0001; 5 (10.6%) vs. 8 (14.5%), p < 0.0001, respectively]. In Kaplan-Meier analysis, primary APS patients had significantly more thrombotic events than aPLs carriers (p = 0.0006). In the absence of other high-risk factors for thrombosis, thrombocytopenia could be an independent and long-lasting clinical phenotype of APS.

The interaction of persistent antiphospholipid antibodies positivity and cigarette smoking is associated with an increased risk of cardiovascular events: Cross-sectional and longitudinal analysis

BackgroundThe antiphospholipid antibody (aPL)-positivity was suggested as a nontraditional risk of coronary artery disease (CAD) and it was associated with cigarette smoking. The co-occurrence of them was usually reported in individuals with cardiovascular diseases. This study was to demonstrate their interaction on the increasing risk of cardiovascular events. Methods and resultsA total of 826 consecutive male individuals who underwent coronary angiography (CAG) /percutaneous coronary intervention (PCI) were prospectively followed and classified into three groups based on different smoking statuses. The current smoking subjects had the highest occurrence of aPL-positivity, including aCL IgM (20.1%) and aβ2GP1 IgM (15.5%). IgM isotype positivity was an independent risk factor of CAD in the multivariate model, OR: 2.70 (1.52–4.80) for aCL IgM and OR:2.50 (1.35–4.63) for aβ2GP1 IgM.The interaction of current smoking and IgM isotype positivity was significantly associated with increased risk of CAD, OR: 8.75(4.59–16.66) for aCL IgM and OR: 8.78(4.28–17.98) for aβ2GP1 IgM. During about 3 years of follow-up, the smoking patients carrying persistent aPL positivity had the highest cumulative incidence of recurrent myocardial infarction and in-stent restenosis after CAD. ConclusionThe interaction of current smoking and IgM isotype positivity was significantly associated with the increased risk of CAD, including positive aCL IgM and aβ2GP1 IgM. Cigarette smoking elevated the risk of subsequent cardiovascular events in the presence of IgM isotype positivity, including recurrent myocardial infarction and in-stent restenosis.

Maternal thrombotic and haemorrhagic complications in pregnant women with antiphospholipid syndrome.

Clinicians treating patients with antiphospholipid syndrome or antiphospholipid antibodies must often make treatment decisions based on relatively weak evidence. Antiphospholipid syndrome is diagnosed in patients who have persistent antiphospholipid antibodies with clinical manifestations, such as pregnancy complications, thrombotic manifestations, or both.1 In light of the various clinical manifestations, the design and conduct of randomised controlled trials to inform the optimal management of patients with antiphospholipid syndrome remains difficult.

PSUN43 Anti-phospholipid syndrome presenting with bilateral adrenal hemorrhage in a young female

Abstract Patient is a 29-year-old female with PCOS and morbid obesity and recent admission for abdominal pain is found to have bilateral adrenal hemorrhage and prolonged PTT. Patient was found to be anemic with hemoglobin of 6.1 a week prior to presentation, attributed to dysfunctional uterine bleeding and was treated with subsequent transfusion. She presents a week after her initial presentation with recurrent constant sharp pulsating abdominal pain, and reported pain was worse in mid-epigastric area radiating into her back, with a temperature of 38.2 and heart rate of 135, troponin level 2.64, with a negative CT for PE, but incidental bilateral adrenal hemorrhage absent on CTA from last week, with a CBC showing WBC 21.7 RBC 3.5 Hgb 8.6 MCV 76.9 MCH 24.7 RDW 17.6, with normal folate and B12. Patient was monitored closely and was started on IV hydrocortisone 50 mg every six hours, her PTT was found to be 88 and PT of 17.5, so antiphospholipid syndrome was suspected and confirmed with positive lupus anti-coagulant (LAC) and anticardiolipin IgG ab, and B2 glycoprotein. Patient had no evidence of adrenal infract that could have converted to hemorrhage. Objectives Antiphospholipid syndrome (APS) is an autoimmune systemic disorder characterized by persistent antiphospholipid antibodies including lupus anticoagulant, anticardiolipin or anti B2- glycoprotein I antibodies, presenting with arterial venous or small vessel thrombosis or recurrent early pregnancy loss. Other manifestation including livedo reticularis, cutaneous ulceration, thrombocytopenia, and hemolytic anemia, valvular heart disease and nephropathy. In our case, the patient APS was confirmed by the presence of the markers, but no evidence of adrenal infracts what could have converted to hemorrhage was found. Conclusions Although APS leads to a hypercoagulable state which can lead to adrenal vein thrombosis, leading to adrenal hemorrhage which can be fatal. Screening for antiphospholipid antibodies should be considered in all patients with unknown etiology of adrenal hemorrhage to promote diagnosis and timely management. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Trombosis portal en Síndrome antifosfolipídico: Reporte de caso

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by arterial, venous, or small vessel thrombosis and recurrent early pregnancy loss, fetal loss, or pregnancy morbidity in the context of persistent antiphospholipid antibodies. Characterized by the development of multiple thrombotic manifestations, simultaneously or within a short period of time; being portal vein thrombosis (DVT) a rare and serious clinical manifestation and a predictor of poor prognosis.The case of an elderly patient with abdominal pain and portal vein thrombosis associated with APS with antithrombotic treatment and analgesics of favorable evolution is presented.

Splenectomy outcomes in patients with autoimmune cytopenias and persistent antiphospholipid antibodies.

Splenectomy is a therapy for patients with treatment-refractory autoimmune cytopenias. Antiphospholipid antibodies (aPL) can be identified in 25%-85% of these patients. In this study, we sought to identify whether the presence of aPL was associated with worse outcomes in autoimmune cytopenia's patients who had undergone splenectomy. We conducted a retrospective cohort study of patients who underwent splenectomy from 2000 to 2018. We describe clinical characteristics and outcomes in patients with autoimmune cytopenia's diagnosis with positive determinations of aPL. Additionally, we performed a case-control sub-analysis 1:1 of the cases with autoimmune cytopenia's matched control patients with negative aPL determination. A splenectomy was performed in 707 patients, of which we included 34 for the analysis. The median age at the time of splenectomy was 37 years (range 19-61), 53% corresponded to immune thrombocytopenia (ITP) and 47% to autoimmune hemolytic anemia (AIHA). Compared with controls (n= 34), patients had more treatment lines in addition to steroids (p= .02). There were no differences in complete response rate, 65% in cases and 80% in controls (p= .17). However, there was numerically a higher incidence of early infections (21% of cases vs. 3% controls, p= .05). During the entire follow-up, 15% of aPL patients compared with 9% of control patients had a thrombotic event (p= .70). Splenectomy for treatment-refractory autoimmune cytopenia's patients with persistent aPL is an effective treatment despite some safety concerns related to early infections. These results suggest that the presence of aPL should not impact the decision to undergo splenectomy.

OA04 Paediatric APS - children are not just small adults

OA04 Paediatric APS - children are not just small adults

Prevalence, characteristics and outcome of cardiac manifestations in critically-ill antiphospholipid syndrome patients

AimsAntiphospholipid syndrome (APS) is a rare autoimmune disease defined by thrombotic events occurring in patients with persistent antiphospholipid antibodies. Cardiac manifestations in critically-ill APS patients are poorly investigated. We conducted a study to assess the prevalence, the characteristics and the prognosis of cardiac manifestations in thrombotic APS patients admitted to intensive care unit (ICU). Methods and resultsA French, national, multicentre, retrospective study, conducted, from January 2000 to September 2018, including all APS patients admitted to 24 participating centres’ ICUs with any new thrombotic (arterial, venous or microvascular) manifestation. Cardiac manifestations were defined as any new cardiac abnormalities relying on clinical examination, cardiac biomarkers, echocardiography, cardiac magnetic resonance (CMR) and coronarography. One hundred and thirty-six patients (female 72%) were included. Mean age at ICU admission was 46 ± 15years. Cardiac manifestations were present in 71 patients (53%). In patients with cardiac involvement, median left ventricular ejection fraction (LVEF) was 40% [28–55], troponin was elevated in 93% patients, coronary angiogram (n = 19, 27%) disclosing a coronary obstruction in 21%. CMR (n = 21) was abnormal in all cases, with late gadolinium enhancement in 62% of cases. Cardiac manifestations were associated with a non-significant increase of mortality (32% vs. 19%, p = 0.08). After 1-year follow-up, median LVEF was 57% [44–60] in patients with cardiac involvement. ConclusionCardiac involvement is frequent in critically-ill thrombotic APS patients and may be associated to more severe outcome. Increased awareness on this rare cause of myocardial infarction with or without obstructive coronary artery is urgently needed.

Antiphospholipid antibodies: what is new in 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.

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

ObjectivePatients 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 MethodsWe 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.ResultsOne 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.ConclusionAlthough 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.