Anti-vimentin/cardiolipin IgA in the anti-phospholipid syndrome: A new tool for 'seronegative' diagnosis

Non-criteria and criteria antiphospholipid antibodies and their association with pregnancy outcomes in women with a history of miscarriage: A retrospective study

INTRODUCTION

The objective of this study was to investigate both antiphospholipid antibodies (aPLs) and non-criteria aPLs (NC-aPLs) in relation with pregnancy outcomes.

METHODS

We retrospectively analyzed 1574 pregnant women with experienced at least one miscarriage who were tested for aPLs and NC-aPLs, and compared their clinical characteristics, immune biomarkers, and pregnancy outcomes. The χ2 test or Fisher's exact test compared pregnancy outcomes among patients negative for all aPLs, positive for NC‑aPLs subtypes, and positive for criteria aPLs subtypes.

RESULTS

Multivariate logistic regression analysis indicated that positive aPLs (OR = 2.216, 95 % CI 1.381-3.558), and positive NC-aPLs (OR = 1.619, 95 % CI 1.245-2.106) are linked to adverse outcomes. For fetal loss, positive aPLs (OR = 2.354, 95 % CI 1.448-3.829), NC-aPLs (OR = 1.443, 95 % CI 1.076-1.936) were significant. Premature delivery was associated with positive NC-aPLs (OR = 2.102, 95 % CI 1.452-3.043). In the NC-aPLs positive group, the rate of adverse outcomes was higher in the multiple-positive subgroup (77.8 %) compared to the double-positive (52.3 %) and single-positive (37.0 %) subgroups. The rates of fetal loss and premature delivery were also higher in the multiple-positive NC-aPLs subgroup compared to the single-positive subgroup (48.1 % vs. 22.6 % for fetal loss and 57.1 % vs. 16.5 % for premature delivery).

DISCUSSION

Our findings suggest that both aPLs and NC-aPLs are associated with an increased incidence of adverse pregnancy outcomes, and patients presenting with multiple NC-aPLs positivity were found to have a higher incidence of adverse outcomes compared to their single-positive counterparts.

Antiphospholipid Syndrome: Insights into Molecular Mechanisms and Clinical Manifestations

Antiphospholipid syndrome (APS) is a complex systemic autoimmune disorder characterized by a hypercoagulable state, leading to severe vascular thrombosis and obstetric complications. The 2023 ACR/EULAR guidelines have revolutionized the classification and understanding of APS, introducing broader diagnostic criteria that encompass previously overlooked cardiac, renal, and hematologic manifestations. Despite these advancements, diagnosing APS remains particularly challenging in seronegative patients, where traditional tests fail, yet clinical symptoms persist. Emerging non-criteria antiphospholipid antibodies offer promising new diagnostic and management avenues for these patients. Managing APS involves a strategic balance of cardiovascular risk mitigation and long-term anticoagulation therapy, though the use of direct oral anticoagulants remains contentious due to varying efficacy and safety profiles. This article delves into the intricate pathogenesis of APS, explores the latest classification criteria, and evaluates cutting-edge diagnostic tools and therapeutic strategies.

Viewpoint: The value of non-criteria antiphospholipid antibodies

In 2006, at a meeting in Sydney, Australia, consensus was reached by an international group of specialists to establish a number of serological criteria that identify patients with a history of thrombosis or pregnancy complications as having antiphospholipid syndrome (APS). These criteria were originally formulated for research purposes and to compare clinical trials in different centres. However, these same criteria are now generally used and accepted for the diagnosis and treatment of patients. The practice of using these criteria for direct patient care requires that these criteria are based on sound scientific evidence. Indeed, for all the autoantibodies that are officially included in the serological criteria, it has been shown that they induce thrombosis and fetal loss when infused into mice. There are also a number of additional autoantibodies that have been identified in these patients but for these antibodies there was not enough evidence to meet the official APS criteria in 2006. Seventeen years have now passed since the consensus meeting, therefore, this review examines whether additional studies performed with these 'non-criteria' autoantibodies have provided sufficient results to suggest the inclusion of these autoantibodies in the official serological criteria of APS.

Seronegative autoimmune diseases: A challenging diagnosis

Autoimmune diseases (AID) are increasingly prevalent conditions which comprise more than 100 distinct clinical entities that are responsible for a great disease burden worldwide. The early recognition of these diseases is key for preventing their complications and for tailoring proper management. In most cases, autoantibodies, regardless of their potential pathogenetic role, can be detected in the serum of patients with AID, helping clinicians in making a definitive diagnosis and allowing screening strategies for early -and sometimes pre-clinical- diagnosis. Despite their undoubted crucial role, in a minority of cases, patients with AID may not show any autoantibody, a condition that is referred to as seronegative AID. Suboptimal accuracy of the available laboratory tests, antibody absorption, immunosuppressive therapy, immunodeficiencies, antigen exhaustion, and immunosenescence are the main possible determinants of seronegative AID. Indeed, in seronegative AID, the diagnosis is more challenging and must rely on clinical features and on other available tests, often including histopathological evaluation and radiological diagnostic tests. In this review, we critically dissect, in a narrative fashion, the possible causes of seronegativity, as well as the diagnostic and management implications, in several AID including autoimmune gastritis, celiac disease, autoimmune liver disease, rheumatoid arthritis, autoimmune encephalitis, myasthenia gravis, Sjögren's syndrome, antiphospholipid syndrome, and autoimmune thyroid diseases.

Anti-vimentin/cardiolipin IgA in the anti-phospholipid syndrome: A new tool for 'seronegative' diagnosis

Anti-phospholipid syndrome (APS) is a systemic autoimmune disorder defined by the simultaneous presence of vascular clinical events, pregnancy morbidity and anti-phospholipid antibodies (aPL). In clinical practice, it is possible to find patients with APS who are persistently negative for the routine aPL tests (seronegative APS; SN-APS). Recently, the identification of aPL immunoglobulin (Ig)A and/or anti-β2-glycoprotein-I (β2-GPI) IgA was shown to represent a further test in SN-APS patients. In this study we analyzed the presence of anti-vimentin/cardiolipin (aVim/CL) IgA in a large cohort of patients with SN-APS, evaluating their possible association with clinical manifestations of the syndrome. This study includes 60 consecutive SN-APS patients, 30 patients with APS and 40 healthy donors. aVim/CL IgA were detected by enzyme-linked immunosorbent assay (ELISA). Results show that 12 of 30 APS patients (40%) and 16 of 60 SN-APS patients (26.7%) resulted positive for aVim/CL IgA. Interestingly, SN-APS patients who tested positive for aVim/CL IgA showed a higher prevalence of arterial thrombosis (p = 0.017, likelihood positive ratio = 5.7). This study demonstrates for the first time, to our knowledge, the presence of aVim/CL IgA in sera of patients with APS. In particular, they revealed a potential usefulness in identification of a significant proportion of SN-APS patients. Moreover, as patients tested positive for aVim/CL IgA reported a high likelihood ratio to have the clinical features of APS, this test may be considered a suitable approach in the clinical evaluation of SN-APS.