Sex Differences in Clinical Characteristics and Prognosis in Primary Thrombotic Antiphospholipid Syndrome

Objectives

This study aimed to investigate whether there are sex differences in clinical characteristics and prognosis in patients with primary thrombotic antiphospholipid syndrome (ptAPS).

Methods

From January 2013 to July 2021, 154 consecutive patients diagnosed with ptAPS were prospectively recruited. Multivariable Cox regression was used to evaluate the association between gender and the composite endpoint including thromboembolic recurrence or all-cause death during follow-up.

Results

Totally, 80 (52%) male and 74 (48%) female patients with ptAPS were included, and men had a higher percentage of smokers/ex-smokers [50 (62%) vs. 6 (8%), p < 0.001] and hyperhomocysteinemia [26 (32%) vs. 9 (12%), p = 0.003]. The baseline thromboembolic events were similar in two genders, except for limb ischemia [15 (19%) in men vs. 1 (1%) in women, p < 0.001]. During a median follow-up of 42 months, the composite endpoint occurred in 30 (38%) male and 15 (20%) female patients (p = 0.019). Male gender [HR 2.499, 95% CI (1.316, 4.743), p = 0.005] and warfarin administration [HR 0.482, 95% CI (0.257, 0.905), p = 0.023] remained independent risk factors for the composite endpoint. Male gender [HR 3.699, 95% CI (1.699, 8.246), p = 0.001] and isolated lupus anticoagulant positivity [HR 2.236, 95% CI (1.039, 4.811), p = 0.040] were independent risk factors for thromboembolic recurrence.

Conclusion

There are sex disparities in the clinical characteristics in patients with ptAPS and the male gender is an independent risk factor for the poor prognosis. Male patients with isolated lupus anticoagulant (LA) positivity have the highest risk of thromboembolic recurrence.

Interleukin-17/Interleukin-21 and Interferon-γ producing T cells specific for β2 Glycoprotein I in atherosclerosis inflammation of systemic lupus erythematosus patients with antiphospholipid syndrome

Systemic lupus erythematosus is frequently associated with antiphospholipid syndrome. Patients with lupus-antiphospholipid syndrome are characterized by recurrent arterial/venous thrombosis, miscarriages, and persistent presence of autoantibodies against phospholipid-binding proteins, such as β2-Glycoprotein I. We investigated the cytokine production induced by β2-Glycoprotein I in activated T cells that infiltrate in vivo atherosclerotic lesions of lupus-antiphospholipid syndrome patients. We examined the helper function of β2-Glycoprotein I-specific T cells for tissue factor production, as well as their cytolytic potential and their helper function for antibody production. Lupus-antiphospholipid syndrome patients harbor in vivo activated CD4⁺ T cells that recognize β2-Glycoprotein I in atherosclerotic lesions. β2-Glycoprotein I induces T-cell proliferation and expression of both Interleukin-17/Interleukin-21 and Interferon-γ in plaque-derived T-cell clones. β2-Glycoprotein I-specific T cells display strong help for monocyte tissue factor production, and promote antibody production in autologous B cells. Moreover, plaque-derived β2-Glycoprotein I-specific CD4⁺ T lymphocytes express both perforin-mediated and Fas/FasLigand-mediated-cytotoxicity. Altogether, our results indicate that β2-Glycoprotein I is able to elicit a local Interleukin-17/Interleukin-21 and Interferon-γ inflammation in lupus-antiphospholipid syndrome patients that might lead, if unabated, to plaque instability and subsequent arterial thrombosis, suggesting that the T helper 17/T helper 1 pathway may represent a novel target for the prevention and treatment of the disease.

Arterial stenosis in antiphospholipid syndrome: Update on the unrevealed mechanisms of an endothelial disease

First described in 1983, antiphospholipid syndrome (APS) is an autoimmune condition characterized by the occurrence of recurrent arterial and/or venous thrombosis, and/or pregnancy morbidity, in the setting of persistent presence of antiphospholipid antibodies (aPL). While thrombosis is the most well-known pathogenic mechanism in this disorder, the relevance of some other mechanisms such as arterial stenosis is being increasingly recognized. Arterial stenosis has been first described in the renal arteries in patients with APS, however intracranial and coeliac arteries can also be involved with various and treatable clinical manifestations. The underlying pathophysiology of this stenotic arterial vasculopathy is not fully understood but some recent studies revealed new insights into the molecular mechanism behind this endothelial cell activation in APS. In this review, we discuss these newly discovered mechanisms and highlight the diagnostic and therapeutic modalities of the APS related arterial stenosis.

β2 Glycoprotein I Recognition Drives Th1 Inflammation in Atherosclerotic Plaques of Patients with Primary Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is characterized by recurrent arterial/venous thrombosis and miscarriages in the persistent presence of autoantibodies against phospholipid-binding proteins (aPLs), such as β2 glycoprotein I (β2GPI). In addition to the aPL thrombophilic effect, arterial thrombosis was related to accelerated atherosclerosis in animal models; however, contrasting findings were reported in primary APS patients with regard to the increased number of plaques or abnormal arterial wall thickness. We investigated the cytokine production induced by β2GPI in activated T cells that infiltrate in vivo atherosclerotic lesions of primary APS patients with atherothrombosis. We also examined the helper function of β2GPI-specific T cells for monocyte matrix metalloproteinase-9 and tissue factor production, as well as their cytolytic potential and their helper function for Ab production. APS patients with atherothrombosis harbor in vivo-activated CD4⁺ T cells that recognize β2GPI in atherothrombotic lesions. β2GPI induces T cell proliferation and IFN-γ expression in plaque-derived T cell clones. β2GPI-specific T cells display helper function for monocyte matrix metalloproteinase-9 and tissue factor production and promote Ig production in autologous B cells. Moreover, plaque-derived β2GPI-specific CD4⁺ T lymphocytes express perforin-mediated and Fas/Fas ligand-mediated cytotoxicity. β2GPI, and especially the DI domain, drive a local Th1 inflammatory response, with subsequent plaque instability that eventually favors atherothrombosis. This finding may explain the association between aPLs and arterial thrombosis, despite the lack of evidence of surrogate markers for atherosclerosis in primary APS.