Type I interferon pathway activation across the antiphospholipid syndrome spectrum: associations with disease subsets and systemic antiphospholipid syndrome presentation.

Introduction: While the type I interferon (IFN-I) pathway is crucial in autoimmunity, its role in antiphospholipid antibody (aPL)-positive subjects, including aPL carriers and antiphospholipid syndrome (APS) patients, is poorly understood. This study aims at characterizing IFN-I pathway activation within the spectrum of aPL-positive subsets. Methods: A total of 112 patients [29 aPL carriers, 31 primary APS (PAPS), 25 secondary APS (SAPS), 27 systemic lupus erythematosus (SLE) patients without aPL, and 44 healthy controls (HCs)] were recruited. IFI6, IFI44, IFI44L, MX1, IFI27, OAS1, and RSAD2 gene expression was evaluated in whole blood, and a composite index (IFN score) was calculated. Results: An overall activation of the IFN-I pathway was observed across the entire APS spectrum, with differences among genes based on the specific disease subset. The composite score revealed quantitative differences across subsets, being elevated in aPL carriers and PAPS patients compared to HCs (both p < 0.050) and increasing in SAPS (p < 0.010) and SLE patients (p < 0.001). An unsupervised cluster analysis identified three clusters, and correspondence analyses revealed differences in clusters usage across APS subsets (p < 0.001). A network analysis revealed different patterns characterizing different subsets. The associations between IFN-I pathway activation and clinical outcomes differed across APS subsets. Although no differences in gene expression were observed in systemic APS, the network analyses revealed specific gene-gene patterns, and a distinct distribution of the clusters previously identified was noted (p = 0.002). Conclusion: IFN-I pathway activation is a common hallmark among aPL-positive individuals. Qualitative and quantitative differences across the APS spectrum can be identified, leading to the identification of distinct IFN-I signatures with different clinical values beyond traditional categorization.

Assessing the steroid-sparing effect of biological agents in randomized controlled trials for lupus: a scoping review.

Prompt disease control of flares in patients with systemic lupus erythematosus (SLE) is a priority in treatment strategy planning. However, the long-term dosage-related collateral effects of glucocorticoids (GCs) have pushed researchers towards the identification and utilization of novel biological agents that could both induce and maintain low disease activity and remission, especially in the context of lupus nephritis (LN). This scoping review aims at assessing the current evidence of the potential steroid-sparing effect of biologic therapies by reviewing phase II and phase III randomized, placebo-controlled trials involving SLE/LN patients. A scoping review of the literature was carried out in accordance with PRISMA-ScR recommendations. Risk of bias was assessed through the utilization of the Cochrane Collaboration's tool for randomized controlled trials (RCTs). Eight RCTs met the inclusion criteria and were included in this analysis (treatment drug, 7 belimumab; 1 anifrolumab). Four studies showed a definite steroid-sparing effect (treatment drug, 3 belimumab; 1 anifrolumab), while in the remaining four RCTs, the steroid-sparing effect was not observed. When focusing on phase III trials, the overall quality of the studies resulted fair or good considering the risk of bias. However, a degree of heterogeneity of steroid regimen protocol (considering initial dosage, tapering and rescue treatment allowance) was observed. While a growing body of evidence is supporting the safety and efficacy of biological treatment in SLE, the evidence on their steroid-sparing effect remains scattered. Future research needs to pursue the identification of precise SLE clusters of patients who would benefit most from a specific treatment protocol with a definite steroid-sparing effect.

2023 ACR/EULAR classification criteria in existing research cohorts: an international study.

OBJECTIVE: Assessing the impact of the updated ACR/EULAR APS classification criteria to our research cohort. METHODS: Consecutive patients who tested persistently positive for at least one aPL in the last three years were enrolled. The first APS Sydney index event was considered and computed for the comparison between Sydney and 2023 APS criteria. When computing the 2023 APS criteria, additional manifestations were also considered. RESULTS: The cohort comprised 249 patients (185 with APS and 64 aPL carriers according to Sydney criteria). The 185 patients had as first index event VT in 55 cases (29.8%) AT in 63 (34%) and PM in 67 (36.2%). When applying the updated criteria, 90 subjects (48.7%) failed to reach the composite score of the new criteria. The percentage of thrombotic APS per Sydney criteria decreased from 47.3% to 34.9% because of high cardiovascular risk in 23 cases, IgM aPL profile in 6 cases and in 2 patients for both reasons. Patients with PM decreased from 26.9-3.2% (39 cases of recurrent early pregnancy loss and 20 of fetal losses). Consequently, the percentage of aPL carriers increased from 26% to 61%. When looking at the disease evolution at follow-up, 32 additional patients out of 90 (35.6%) fulfilled the new APS criteria, after developing additional clinical manifestation following index event. CONCLUSION: When applying the new APS criteria to our research cohort, not negligible differences exist in patients' classification. A multidisciplinary approach will be mandatory to assess the impact into research and, ultimately, patient's care of new criteria.

Pediatric Presentation of Antiphospholipid Syndrome: A Review of Recent Literature With Estimation of Local Prevalence.

We aimed to investigate the epidemiology, the clinical and laboratory characteristics of the pediatric involvement of antiphospholipid syndrome (APS), by performing a review of the current evidence and reviewing local experience in the Northwest Italy. To achieve this, we performed a detailed literature search to identify articles describing clinical and laboratory characteristics of pediatric APS. In concomitance, we conducted a registry-based study collecting data from the Piedmont and Aosta Valley Rare Disease Registry including pediatric patients diagnosed with APS in the last 11 years. The literature review led to inclusion of six articles with a total of 386 pediatric patients (65% females, 50% with systemic lupus erythematosus (SLE) as concomitant diagnosis). Rates of venous and arterial thrombosis were 57 and 35%, respectively. "Extra-criteria manifestations" included mostly hematologic and neurologic involvement. Almost one-quarter of patients (19%) reported recurrent events and 13% manifested as catastrophic APS. A total of 17 pediatric patients (mean age 15.1 ± 2.8, 76% female) developed APS in the Northwest of Italy. In 29% of cases, SLE was a concomitant diagnosis. Deep vein thrombosis was the most frequent manifestation (28%) followed by catastrophic APS (6%). The estimated prevalence of pediatric APS in Piedmont and Aosta Valley Region is 2.5/100,000 people, whereas the estimated annual incidence is 0.2/100,000 inhabitants. In conclusion, clinical manifestations of pediatric APS seem to be more severe and with a high prevalence of noncriteria manifestations. International efforts are needed to better characterize this condition and to develop new specific diagnostic criteria to avoid missed/delayed diagnosis in children with APS.

Thrombosis and APS: Lessons Learned from Another Black Swan Tale.

Antiphospholipid syndrome (APS) is a chronic systemic autoimmune disease characterized by venous, arterial, and microvascular thromboses and/or recurrent pregnancy morbidity, that occur in the persistent presence of antiphospholipid antibodies (aPL). APS can present with a wide range of clinical manifestations often reffered as "extra-criteria". These features, although apparently less common, can severely impact patients' outcome. Here, we report the case of a patient with a newly diagnosed APS. He previously experienced a recurrence of venous thrombosis after discontinuation of anticoagulant therapy in association with cutaneous ulcerations as presenting symptoms. Interestingly, skin lesions did not improve with full anticoagulant treatment. Due to concomitant presence of thrombotic and microvascular involvement, immunomodulatory therapy with steroid pulses followed by intravenous injections of belimumab was started, with progressive and significant amelioration, leading to complete recovery. Following the presentation of the current case report, we highlight the importance of suspecting APS in young patients experiencing unprovoked thrombosis. We also emphasized the critical issue of testing aPL during anticoagulant treatment and focused on the need of aPL retesting in patients with positivity at high titers. We also highlight the double nature of aPL-mediated clinical manifestations. While most patients presented with pure thrombotic complications, one should always remember that APS is an autoimmune-mediated disease, which can benefit from alternative therapeutic approaches beyond anticoagulation.

Safety and efficacy of pre-exposure prophylaxis with tixagevimab/cilgavimab (Evusheld) in patients with glomerular diseases who received rituximab.

Background: Patients on B-cell-depleting agents may have a suboptimal response to vaccination, placing them at a higher risk of contracting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or suffering from a more severe prognosis. Indeed, available data on pre-exposure prophylaxis with tixagevimab/cilgavimab (Evusheld) in subjects with glomerular diseases (GDs) who received rituximab are limited. Methods: We conducted a prospective study analysing the safety and efficacy of tixagevimab/cilgavimab for pre-exposure prophylaxis in patients with GDs who received rituximab in the previous 12 months. The rates of symptomatic infections and hospitalizations were compared with those for patients with GD treated with rituximab who refused to receive tixagevimab/cilgavimab. Results: Tixagevimab/cilgavimab was administered to 22 patients (12 females, mean age 58.4 ± 19.6 years) with GD diagnoses including membranous nephropathy, lupus nephritis, anti-neutrophil cytoplasmic antibody-associated vasculitis and focal segmental glomerulosclerosis. No patient treated with tixagevimab/cilgavimab experienced symptomatic infection with SARS-CoV-2 during the follow-up (mean observation time of follow-up was 112 ± 23 days), while 11 of 28 controls (39.3%) reported a symptomatic infection (P = .0001), requiring hospitalization in 2 cases. Reported adverse events were mild, namely self-limiting headache [4], discomfort at the injection site [3], flu-like symptoms/myalgia [3] and fever [1]. No serious adverse events (e.g. cardiac events, anaphylaxis) were reported. Conclusion: Pre-exposure prophylaxis with tixagevimab/cilgavimab seems safe and lowered the risk of symptomatic SARS-CoV-2 infection by ≈40% in vaccinated subjects with GD who received anti-CD20 therapy. Possible applications in the subset of patients who need immunosuppressive therapy, especially with rituximab, in a pandemic setting might be envisaged.

New Frontiers in Autoimmune Diagnostics: A Systematic Review on Saliva Testing.

(1) Background: Immunological laboratory testing is known to be complex, and it is usually performed in tertiary referral centers. Many criticalities affect diagnostic immunological testing, such as limited availability, the need for specifically trained laboratory staff, and potential difficulties in collecting blood samples, especially in the most vulnerable patients, i.e., the elderly and children. For this reason, the identification of a new feasible and reliable methodology for autoantibody detection is urgently needed. (2) Methods: We designed a systematic review to investigate the available literature on the utilization of saliva samples for immunological testing. (3) Results: A total of 170 articles were identified. Eighteen studies met the inclusion criteria, accounting for 1059 patients and 671 controls. The saliva collection method was mostly represented by passive drooling (11/18, 61%), and the most frequently described methodology for antibody detection was ELISA (12/18, 67%). The analysis included 392 patients with rheumatoid arthritis, 161 with systemic lupus erythematosus, 131 with type 1 diabetes mellitus, 116 with primary biliary cholangitis, 100 with pemphigus vulgaris, 50 with bullous pemphigoids, 49 with Sjogren syndrome, 39 with celiac disease, 10 with primary antiphospholipid syndromes, 8 with undifferentiated connective tissue disease, 2 with systemic sclerosis, and 1 with autoimmune thyroiditis. The majority of the reviewed studies involved adequate controls, and saliva testing allowed for a clear distinction of patients (10/12 studies, 83%). More than half of the papers showed a correlation between saliva and serum results (10/18, 55%) for autoantibody detection, with varying rates of correlation, sensitivity, and specificity. Interestingly, many papers showed a correlation between saliva antibody results and clinical manifestations. (4) Conclusions: Saliva testing might represent an appealing alternative to serum-based testing for autoantibody detection, considering the correspondence with serum testing results and the correlation with clinical manifestations. Nonetheless, standardization of sample collection processing, maintenance, and detection methodology has yet to be fully addressed.

Finding the Needle in the Haystack: Serological and Urinary Biomarkers in Behçet's Disease: A Systematic Review.

Urinary and serological markers play an essential role in the diagnostic process of autoimmune diseases. However, to date, specific and reliable biomarkers for diagnosing Behçet's disease (BD) are still lacking, negatively affecting the management of these patients. To analyze the currently available literature on serological and urinary BD biomarkers investigated in the last 25 years, we performed a systematic literature review using the Population, Intervention, Comparison, and Outcomes (PICO) strategy. One hundred eleven studies met the eligibility criteria (6301 BD patients, 5163 controls). Most of them were retrospective, while five (5%) were prospective. One hundred ten studies (99%) investigated serological biomarkers and only two (2%) focused on urinary biomarkers. One hundred three studies (93%) explored the diagnostic potential of the biomolecules, whereas sixty-two (56%) tested their effect on disease activity monitoring. Most articles reported an increase in inflammatory markers and pro-oxidant molecules, with a decrease in antioxidants. Promising results have been shown by the omics sciences, offering a more holistic approach. Despite the vast number of investigated markers, existing evidence indicates a persistent gap in BD diagnostic/prognostic indices. While new steps have been taken in the direction of pathogenesis and disease monitoring, international efforts for the search of a diagnostic marker for BD are still needed.

Thrombin generation assay and lupus anticoagulant synergically distinguish populations of patients with antiphospholipid antibodies.

AIM: To apply thrombin generation assay (TGA) in a large cohort of antiphospholipid antibodies (aPL)-positive patients. MATERIAL AND METHODS: 108 patients were tested with TGA and lupus anticoagulant (LA) testing and divided according to their aPL profile. Briefly, 21 patients were positive for anti-phosphatidylserine (aPS)/prothrombin (PT) IgG/IgM (group1), 29 for anti-ß2-glycoprotein-I (aß2GPI) and anti-cardiolipin (aCL) IgG/IgM (group2), 31 for aPS/PT, aß2GPI and aCL IgG/IgM (group3), 27 for aPS/PT and/or aß2GPI+aCL IgM at low-titres (group4). 31 healthy donors (HDs) and 24 controls treated with vitamin K antagonists (VKA) were included. RESULTS: The most deranged TGA and LA profiles were observed in tetra-positive patients (group3) that differed significantly to the other groups, thus those with isolated, double or triple aPL-positivity. Moreover, when comparing the TGA profile of all antiphospholipid syndrome (APS) patients, aPL-carriers, HDs and VKA controls, we observed that the aPL+ patients (especially APS) showed a distinctive profile that allowed to distinguish them from the other groups with significantly higher tLag and tPeak, and lower Peak and area under the curve.When focusing on APS clinical manifestations, patients with a high-risk profile (group3) showed significant differences from those presenting low-titres aPL (group 4) regarding the number of venous events (p=0.04), recurrence of any thrombotic event (p=0.01), of arterial events (5 vs 0, p=0.02), the occurrence of TIA (p=0.04), DVT (p=0.02) and, when analysing extracriteria manifestations, of peripheral artery disease (p=0.04). CONCLUSIONS: TGA seems a valuable approach to stratify aPL+ patients according to their risk profile. The differences among different populations of autoantibodies specificities could be considered a translational validation of the increased thrombotic risk of patients with triple or tetra aPL-positivity.

"How we treat" clinical dilemmas in antiphospholipid syndrome: A case-based approach.

Antiphospholipid syndrome (APS) is an autoimmune condition characterized by thrombosis (arterial, venous, and microvascular) and/or pregnancy morbidity occurring in subjects persistently positive for antiphospholipid antibodies (aPL). While the APS classification criteria are being currently updated to improve homogeneity in clinical research, patients who seek medical treatment often have a variety of laboratory and clinical characteristics that may not completely fulfill the classification criteria for overt APS. Those cases might represent a challenge in terms of treatment and overall management. We aim to present a collection of challenging scenarios of patients who tested positive for aPL and to discuss available literature to guide the therapeutic strategies.

Serum Biomarkers of Renal Fibrosis: A Systematic Review.

Chronic kidney disease (CKD) is a widely diffuse pathological condition which deeply impacts upon an affected patient's quality of life and its worldwide rate is predicted to further rise. The main biological mechanism underlying CKD is renal fibrosis, a non-reversible process representing, for the affected system, a point of no return of tissue damage and dysfunction, deeply reducing the possible therapeutic strategies at the disposal of physicians. The best tool clinicians can use to address the extent of renal fibrosis at any level (glomeruli, tubule-interstitium, vasculature) is kidney biopsy that, despite its overall safety, remains an invasive procedure showing some shortcomings. Thus, the identification of novel non-invasive renal fibrosis biomarkers would be of fundamental importance. Here, when systematically reviewing the available evidence on serological biomarkers associated with renal fibrosis evaluated in patients suffering from CKD in the last five years, we found that despite the presence of several promising biomarkers, the level of observed evidence is still very scattered. Probably, the use of multiple measures capable of addressing different aspects involved in this condition would be the most suitable way to capture the high complexity characterizing the renal fibrotic process, having consequently a great impact on clinical practice by maximizing prevention, diagnosis, and management.

Disease activity at conception predicts lupus flare up to two years after birth: A multicentre long term follow-up study.

OBJECTIVE: To assess predicting factors that might influence systemic lupus erythematosus (SLE) disease activity in women in an extended follow-up period of two years after giving birth with clinical assessments every three months. METHODS: The study was design as an international retrospective study, enrolling 119 women with a first birth and with a two years follow-up. RESULTS: Joint involvement was present in 80% of patients, acute cutaneous in 64%, haematological in 54%, renal in 41% and 75% of patients were positive for anti-dsDNA. The mean SLE disease activity index 2000 (SLEDAI-2K) at diagnosis was 13.5±6.8 and at first birth was 2.8±4.4. At follow-up, 51.3% of patients had at least one flare after a mean time after birth of 9±6.3 months (mean flare per patient 0.94±1.1). The most frequent flare manifestations were joint involvement (48%), renal (33%), cutaneous (28%) and haematologic (20%). Patients with remission of disease (SLEDAI-2K=0; no clinical or laboratory manifestations of SLE) at conception had significantly lower rates of flares (18/49-37% vs. 43/70-61%; p=0.008). Patients who experienced a flare during pregnancy (17 patients) had higher rates of flares during follow-up (76% vs. 47%; p=0.019), lower time for first flare (4.4±2.3 months vs. 10.3±6.5; p<0.001), lower rate of remission of disease at conception (12% vs. 46%; p<0.001), lower rates of SLEDAI-2K at conception (5.9±5.6 vs. 2.3±4; p<0.001) and lower rates of exclusive breastfeeding (24% vs. 57%: p=0.009). Results were confirmed after performing multivariate analysis. CONCLUSION: Remission at conception can influence SLE disease positively, even at long-term. Planned pregnancy counseling is fundamental when managing SLE patients.

Detection of Autoantibodies in Saliva as New Avenue for the Diagnosis and Management of Autoimmune Patients.

(1) Background: Autoimmune diseases are characterized by autoantibodies directed to a large number of antigenic targets and are measured using serum as sample matrix. Although serum is a very common specimen type, it comes with certain drawbacks. Most importantly, it depends on venous puncture and requires medical personnel for sampling. This is of particular importance in light of the limited healthcare access of patients with autoimmune diseases during the COVID-19 pandemic. Consequently, alternative sample matrices are being explored for the measurement of autoantibodies. Our study aimed to establish the feasibility of measuring autoantibodies in saliva samples using a novel and highly sensitive method for the detection of autoantibodies. (2) Methods: A total of 48 serum/saliva pairs were collected and tested using a novel particle-based multi-analyte technology (PMAT) system for the presence of a wide range of autoantibodies. (3) Results: A high level of correlation was observed between the results obtained with serum and saliva (Spearman's rho = 0.725). Study participants clearly preferred saliva over serum sampling as part of the usability assessment. (4) Conclusions: Saliva represents a promising alternative sample matrix for the detection of autoantibodies. The usability study showed a clear preference of saliva over serum as a sample matrix.

Assessing the cardiovascular risk in patients with systemic lupus erythematosus: QRISK and GAPSS scores head-to-head.

OBJECTIVES: We aimed to apply and compare the QRISK3 and the adjusted Global AntiPhospholipid Syndrome (APS) Score (aGAPSS) in a cohort of systemic lupus erythematosus (SLE) patients, with and without a concomitant diagnosis of APS, in order to assess their augmented risk of developing cardiovascular diseases (CVDs). METHODS: Patients (25-85 yo) with a diagnosis of SLE and/or of Secondary APS (SAPS) were included. QRISK3 was calculated using the official online calculator; aGAPSS using the validated point-values based on aPL-profile and independent risk factors. RESULTS: The cohort included 142 SLE patients: 34 SAPS (23.9%) and 108 SLE patients without APS (76.1%).When considering all the cohort, patients with cerebrovascular/coronary events showed higher values of aGAPSS (10.1 ± 6.2 vs. 5.8 ± 6.1; p = 0.007), but not of the QRISK3. Furthermore, a significant association was observed between the occurrence of these events and high-risk aGAPSS: p = 0.03 for aGAPSS≥8, p = 0.01 for aGAPSS ≥9, p = 0.008 for aGAPSS ≥10. aGAPSS strongly correlated with the occurrence of any thrombotic event, both at the uni- and multivariate analysis (p = 0.012 and p = 0.009). Male gender also resulted to positively correlate with the occurrence of any thrombotic event at both uni- and multivariate analysis (p = 0.017 and p = 0.03). Focusing on aPL-profile, regardless the diagnosis, we found a statistical significance only for aGAPSS (aPL+ =9.6 ± 6.3 vs. aPL- = 4.1 ± 5.1; p < 0.001). CONCLUSIONS: Despite QRISK3 being more accurate than traditional risk score in predicting CVD risk in SLE patients, aGAPSS appears to be the most valuable tool for this purpose.

Clinical Delphi on aPL Negativization: Report from the APS Study Group of the Italian Society for Rheumatology (SIR-APS).

BACKGROUND: The rate of antiphospholipid antibody (aPL) negativization in antiphospholipid syndrome (APS) patients is uncertain, but it is estimated to be as high as 8%. Currently, a consensus definition of aPL negativization is lacking, as well as international recommendations on how to approach treatment in patients with a persistent aPL-negative seroconversion. AIM: The aim of the Delphi survey was to evaluate the clinical approach and level of consensus among experts from the APS Study Group of the Italian Society for Rheumatology (SIR-APS) in different clinical scenarios. METHODS: Experts of SIR-APS were contacted using a survey methodology. RESULTS: A structured survey was circulated among 30 experts. Up to 90% of the interviewed experts agreed on defining aPL negativization as the presence of two negative determinations, 1 year apart (90%). Almost full consensus exists among experts in some clinical settings, including: (1) the role of aPL negativization in the management of a thrombotic event determined by concomitant presence of cardiovascular risk factors, both modifiable and not modifiable (90%); (2) approach to young patients with triple aPL positivity who experienced pulmonary arterial thrombotic events and tested negative for aPL detection after 5 years of vitamin K antagonist (VKA) treatment (90%); (3) the use of "extra criteria" aPL antibody testing before pondering VKA suspension (93%). CONCLUSION: A substantial agreement exists among experts on how to define aPL negativization. VKA suspension should be embraced with extreme caution, particularly in case of previous thrombotic events and/or triple aPL positivity. Nevertheless, VKA cessation might be considered when risk factors are carefully monitored/treated and the presence of "extra criteria" aPL is ruled out.

Disease evolution in a long-term follow-up of 104 undifferentiated connective tissue disease patients.

OBJECTIVES: To investigate the rate of disease evolution in a cohort of patients with undifferentiated connective tissue disease (UCTD) and to determine clinical and immunological features more frequently associated with disease progression. METHODS: This retrospective single-centre long-term follow-up cohort study included patients with UCTD diagnosis, ANA positive, with a follow-up of at least 2 years. RESULTS: A total of 100 UCTD patients were recruited. During the follow-up (6.2±2.1 years), 44 patients (44%) developed novel clinical and/or laboratory features (rate of development patient/year of 7%), and 21 patients (21%) evolved into a definite connective tissue disease (CTD) after a mean time of 7±5.5 years with a rate of disease evolution (patient/year) of 3%. New clinical manifestations (39 patients) included: joints (36%), haematological (30%), cutaneous (13%), pulmonary (10%) and renal (10%) involvement. New laboratory findings (17 patients (17%)) included: 2 anti-ENA positivity, 3 anti-dsDNA antibodies positivity and 6 low complement levels. At follow-up, 13 patients (61.9%) met the classification criteria for systemic lupus erythematosus, 1 patient (4.8%) for mixed CTD, 5 patients (23.8%) for systemic sclerosis and 2 patients (9.5%) for Sjögren's syndrome. Patients evolving towards a new diagnosis had longer disease duration (15.2±9.7 years vs. 10±5.8 years; respectively, p<0.005), had a higher prevalence of anti-Ro/SSA antibodies (63.2% vs. 28.4%; respectively, p<0.05) and anti-RNP antibodies (21.1% vs. 7.4%; respectively, p<0.05). The statistical difference was also confirmed after the multivariate analysis. CONCLUSIONS: Up to 45% of UCTD patients might develop novel clinical and/or laboratory features during the follow-up, leading to evolution into a definite CTD in 1 out 5 cases.

Cerebrovascular events in patients with isolated anti-phosphatidyl-serine/prothrombin antibodies.

The interest of extra-criteria antiphospholipid antibodies is growing, especially in patients negative for conventional antibodies. In this study we aimed to assess the clinical utility of anti-phosphatidyl-serine/prothrombin antibodies (aPS/PT) testing in patients negative for Beta2-Glycoprotein 1(ß2GPI)-dependent tests, for identifying antiphospholipid syndrome (APS) patients that developed cerebrovascular events (CVE). When screening APS patients attending our center, out of 119 aPS/PT IgG/IgM-positive patients, thus patients negative for aß2GPI and aCL, 42 patients (35%) tested negative for ß2GPI-dependent tests and were tested with thrombin generation assay (TGA). Ten patients (24%), with isolated aPS/PT IgG/IgM, had a history of CVE. Lupus anticoagulant (LA)-positive test was more frequently observed in patients with CVE (8/22 vs. 2/20; p = 0.045). Out of the 10 patients who experienced CVE, 3 patients were aPS/PT IgG positive (all LA positive), and 8 patients were aPS/PT IgM positive (6/8 LA positive). One patient was positive for both aPS/PT IgG and IgM. LA-positive patients had only high titers of aPS/PT IgG/IgM, all of them being ≥ 80 U/ml, while the 2 LA-negative patients were aPS/PT IgM positive with medium titers [40-60 U/ml]. LA-positive patients had significantly altered TGA profile when compared to those who were LA negative, considering all TGA parameters. LA-positive patients had significantly higher tLag (8.4 ± 3.3 min vs. 6.6 ± 1.8 min; p = 0.046), higher tPeak (14 ± 4.3 min vs. 11 ± 2.7 min; p = 0.015) and lower Peak (207 ± 152 nM vs. 356.3 ± 104.7 nM; p < 0.001) and lower AUC (2109.7 ± 1006.9 nM vs. 2772.5 ± 776.8 nM; p = 0.033). The use of aPS/PT might be of help in identifying patients with CVE and APS, as also confirmed by TGA testing.