Activation of Platelet mTORC2/Akt Pathway by Anti-β2GP1 Antibody Promotes Thrombosis in Antiphospholipid Syndrome

Diagnostic efficacy of ACA, aβ2-GP1, hs-CRP, and Hcy for cerebral infarction and their relationship with the disease severity

OBJECTIVE

To evaluate the diagnostic efficacy of anti-cardiolipin antibodies (ACA), anti-β2-glycoprotein I antibodies (aβ2-GP1), high-sensitivity C-reactive protein (hs-CRP), and homocysteine (Hcy) in cerebral infarction and to explore their relationship with disease severity.

METHODS

Medical records of 67 cerebral infarction patients admitted from May 2020 to January 2023 and 50 healthy individuals undergoing health checkups were retrospectively analyzed. The levels of ACA, aβ2-GP1, hs-CRP, and Hcy were compared, their correlation with National Institutes of Health Stroke Scale (NIHSS) scores was assessed, and their diagnostic efficacy across different disease severities were evaluated. A joint predictive score formula, defined as -6.054712173 + aβ2-GP1*1.906727231 + Hcy*0.576221974, which combines aβ2-GP1 and Hcy levels, was developed to assess the likelihood of cerebral infarction in our study population.

RESULTS

The levels of ACA, aβ2-GP1, hs-CRP and Hcy, and joint predictive score were significantly higher in the patient group (all P < 0.001). ROC analysis yielded AUCs of 0.887 for ACA, 0.894 for aβ2-GP1, 0.899 for hs-CRP, 0.880 for Hcy, and 0.954 for the joint predictive score. Delong's test showed no statistical difference in most indicators compared to the joint predictive score (P > 0.05), except aβ2-GP1 (P < 0.05). Pearson's correlation analysis indicated that aβ2-GP1, Hcy, and the joint predictive score were positively correlated of with NIHSS score (all P < 0.05), while ACA and hs-CRP were not (P > 0.05). Notable differences in aβ2-GP1 and the joint predictive score were observed among varying severity levels (P < 0.01), with the joint predictive score showing superior diagnostic efficacy in distinguishing between mild and moderate/severe cases (P < 0.01).

CONCLUSION

ACA, aβ2-GP1, hs-CRP, and Hcy are effective biomarkers for diagnosing cerebral infarction, and are positively correlated with disease severity. The joint predictive score demonstrates enhanced accuracy in discerning degree of severity.

Assessment of the 2023 ACR/EULAR antiphospholipid syndrome classification criteria in a Chinese cohort: Impact on clinical practice

OBJECTIVES

To evaluate the effectiveness of the 2023 ACR/EULAR criteria for antiphospholipid syndrome (APS) in a Chinese cohort, and compare them with the Sapporo and revised Sapporo criteria.

METHODS

A cohort comprising 436 patients diagnosed with APS and 514 control subjects was enrolled, including 83 with seronegative APS and 86 classified as antiphospholipid antibody (aPL) carriers. We assessed IgG and IgM anticardiolipin antibodies (aCL) and anti-β2-glycoprotein I (aβ2GPI) antibodies using ELISA, along with a systematic collection of lupus anticoagulant data. Subsequently, we compared the sensitivity and specificity across the three classification criteria.

RESULTS

The 2023 ACR/EULAR criteria exhibited improved specificity at 98 %, surpassing the revised Sapporo (90 %) and original Sapporo (91 %) criteria. However, this came with decreased sensitivity at 82 %, in contrast to higher sensitivities in the revised Sapporo (98 %) and Sapporo (91 %) criteria. Examining individual components sheds light on the scoring system's rationale within the new criteria. The inclusion of microvascular thrombosis, cardiac valve disease, and thrombocytopenia improved the identification of nine patients previously classified as "probable APS". Insufficient scoring in 78 previously diagnosed APS individuals was linked to traditional risk factor evaluations for thrombotic events, the emphasis on determining whether obstetric events are linked to severe preeclampsia (PEC) or placental insufficiency (PI), and the lower scores assigned to IgM aCL and/or aβ2GPI antibody. Seronegative APS remained a challenge, as non-criteria aPL and other methods were not included.

CONCLUSIONS

The new criteria presented notable advancements in specificity. This study provides detailed insights into the strengths and possible challenges of the 2023 ACR/EULAR criteria, enhancing our understanding of their impact on clinical practice.

Antiphospholipid antibodies as potential predictors of disease severity and poor prognosis in systemic lupus erythematosus-associated thrombocytopenia: results from a real-world CSTAR cohort study

BACKGROUND

To investigate the role of antiphospholipid antibodies (aPLs) in the disease severity and prognosis of SLE-related thrombocytopenia (SLE-TP).

METHODS

This multicenter prospective study was conducted based on data from the CSTAR registry. TP was defined as a platelet count<100 × 109/L. Demographic characteristics, platelet count, clinical manifestations, disease activity, and autoantibody profiles were collected at baseline. Relapse was defined as the loss of remission. Bone marrow aspirate reports were also collected.

RESULTS

A total of 350 SLE-TP patients with complete follow-up data, 194 (55.4%) were aPLs positive. At baseline, SLE-TP patients with aPLs had lower baseline platelet counts (61.0 × 109/L vs. 76.5 × 109/L, P<0.001), and a higher proportion of moderate to severe cases (24.2% vs. 14.1% ; 18.0% vs. 8.3%, P<0.001). SLE-TP patients with aPLs also had lower platelet counts at their lowest point (37.0 × 109/L vs. 51.0 × 109/L, P = 0.002). In addition, thean increasing number of aPLs types was associated with a decrease in the baseline and minimum values of platelets ( P<0.001, P = 0.001). During follow-up, SLE-TP carrying aPLs had a higher relapse rate (58.2% vs. 44.2%, P = 0.009) and a lower complete response (CR) rate. As the types of aPLs increased, the relapse rate increased, and the CR rate decreased. Furthermore, there was no significant difference in the ratio of granulocytes to red blood cells (G/E), the total number of megakaryocyte and categories.

CONCLUSION

SLE-TP patients with positive aPLs had more severe disease a lower remission rate but a higher relapse rate.

Platelets and Thrombotic Antiphospholipid Syndrome

Antiphospholipid antibody syndrome (APS) is an autoimmune disorder characterised by thrombosis and the presence of antiphospholipid antibodies (aPL): lupus anticoagulant and/or IgG/IgM anti-β2-glycoprotein I and anticardiolipin antibodies. APS carries significant morbidity for a relatively young patient population from recurrent thrombosis in any vascular bed (arterial, venous, or microvascular), often despite current standard of care, which is anticoagulation with vitamin K antagonists (VKA). Platelets have established roles in thrombosis at any site, and platelet hyperreactivity is clearly demonstrated in the pathophysiology of APS. Together with excess thrombin generation, platelet activation and aggregation are the common end result of all the pathophysiological pathways leading to thrombosis in APS. However, antiplatelet therapies play little role in APS, reserved as a possible option of low dose aspirin in addition to VKA in arterial or refractory thrombosis. This review outlines the current evidence and mechanisms for excessive platelet activation in APS, how it plays a central role in APS-related thrombosis, what evidence for antiplatelets is available in clinical outcomes studies, and potential future avenues to define how to target platelet hyperreactivity better with minimal impact on haemostasis.

The mTOR pathway in the antiphospholipid syndrome

This perspective discussed the available evidence on the involvement of mTOR pathway in antiphospholipid syndrome (APS), from the aspects of endothelial cells, platelets, monocytes and anti-phospholipid antibodies (PLs), which may lead to future therapeutic applications of mTOR inhibition in APS.

Anti-phospholipid autoantibodies in human diseases

Anti-phospholipid autoantibodies are a group of antibodies that can specifically bind to anionic phospholipids and phospholipid protein complexes. Recent studies have reported elevated serum anti-phospholipid autoantibody levels in patients with antiphospholipid syndrome, systemic lupus erythematosus, rheumatoid arthritis, metabolic disorders, malaria, SARS-CoV-2 infection, obstetric diseases and cardiovascular diseases. However, the underlying mechanisms of anti-phospholipid autoantibodies in disease pathogenesis remain largely unclear. Emerging evidence indicate that anti-phospholipid autoantibodies modulate NETs formation, monocyte activation, blockade of apoptotic cell phagocytosis in macrophages, complement activation, dendritic cell activation and vascular endothelial cell activation. Herein, we provide an update on recent advances in elucidating the effector mechanisms of anti-phospholipid autoantibodies in the pathogenesis of various diseases, which may facilitate the development of potential therapeutic targets for the treatment of anti-phospholipid autoantibody-related disorders.

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.