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

Antiphospholipid antibody-related hepatic vasculitis in a juvenile after non-severe COVID-19: a case report and literature review

Antiphospholipid antibodies (aPL) are both laboratory evidence and causative factors for a broad spectrum of clinical manifestations of antiphospholipid syndrome (APS), with thrombotic and obstetric events being the most prevalent. Despite the aPL-triggered vasculopathy nature of APS, vasculitic-like manifestations rarely exist in APS and mainly appear associated with other concurrent connective tissue diseases like systemic lupus erythematous. Several studies have characterized pulmonary capillaritis related to pathogenic aPL, suggesting vasculitis as a potential associated non-thrombotic manifestation. Here, we describe a 15-year-old girl who develops hepatic infarction in the presence of highly positive aPL, temporally related to prior non-severe COVID-19 infection. aPL-related hepatic vasculitis, which has not been reported before, contributes to liver ischemic necrosis. Immunosuppression therapy brings about favorable outcomes. Our case together with retrieved literature provides supportive evidence for aPL-related vasculitis, extending the spectrum of vascular changes raised by pathogenic aPL. Differentiation between thrombotic and vasculitic forms of vascular lesions is essential for appropriate therapeutic decision to include additional immunosuppression therapy. We also perform a systematic review to characterize the prevalence and clinical features of new-onset APS and APS relapses after COVID-19 for the first time, indicating the pathogenicity of aPL in a subset of COVID-19 patients.

Thrombosis and Hyperinflammation in COVID-19 Acute Phase Are Related to Anti-Phosphatidylserine and Anti-Phosphatidylinositol Antibody Positivity

Antiphospholipid antibodies (APLA) are strongly associated with thrombosis seen in patients with antiphospholipid syndrome. In COVID-19, thrombosis has been observed as one of the main comorbidities. In patients hospitalised for COVID-19, we want to check whether APLA positivity is associated with COVID-19-related thrombosis, inflammation, severity of disease, or long COVID-19. We enrolled 92 hospitalised patients with COVID-19 between March and April 2020 who were tested for 18 different APLAs (IgG and IgM) with a single line-immunoassay test. A total of 30 healthy blood donors were used to set the cut-off for each APLA positivity. Of the 92 COVID-19 inpatients, 30 (32.61%; 95% CI [23.41-43.29]) tested positive for APLA, of whom 10 (33.3%; 95% CI [17.94-52.86]) had more than one APLA positivity. Anti-phosphatidylserine IgM positivity was described in 5.4% of inpatients (n = 5) and was associated with the occurrence of COVID-19-related thrombosis (p = 0.046). Anti-cardiolipin IgM positivity was the most prevalent among the inpatients (n = 12, 13.0%) and was associated with a recorded thrombosis in their clinical history (p = 0.044); however, its positivity was not associated with the occurrence of thrombosis during their hospitalisation for COVID-19. Anti-phosphatidylinositol IgM positivity, with a prevalence of 5.4% (n = 5), was associated with higher levels of interleukin (IL)-6 (p = 0.007) and ferritin (p = 0.034). Neither of these APLA positivities was a risk factor for COVID-19 severity or a predictive marker for long COVID-19. In conclusion, almost a third of COVID-19 inpatients tested positive for at least one APLA. Anti-phosphatidylserine positivity in IgM class was associated with thrombosis, and anti-phosphatidylinositol positivity in IgM class was associated with inflammation, as noticed by elevated levels of IL-6. Thus, testing for non-criteria APLA to assess the risk of clinical complications in hospitalised COVID-19 patients might be beneficial. However, they were not related to disease severity or long COVID-19.

The APSANTICO Study: A Prospective Observational Study to Evaluate Antiphospholipid Antibody Profiles in Patients with Thromboembolic Antiphospholipid Syndrome (APS) after COVID-19 Infection and/or Vaccination

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new virus discovered in December 2019 that causes coronavirus disease 19 (COVID-19) and various vaccinations have been developed. The extent to which COVID-19 infections and/or COVID-19 vaccinations alter antiphospholipid antibodies (aPL) in patients with thromboembolic antiphospholipid syndrome (APS) remains unclear. Eighty-two patients with confirmed thromboembolic APS were included in this prospective non-interventional trial. Blood parameters including lupus anticoagulants, anticardiolipin IgG- and IgM-antibodies, and anti-ß2-glycoprotein I IgG- and IgM-antibodies were assessed prior to and after COVID-19 vaccination and/or COVID-19 infection. No increases in aPL in the total study population were detected. In fact, low but significant decreases were observed for anticardiolipin IgG- and anti-β2-glycoprotein I IgG-antibodies, while anticardiolipin IgM- and anti-b2-glycoprotein I IgM-antibodies slightly increased only in patients with COVID-19 infection and vaccination. Although the investigated patient group is known to have a high risk of recurrent thrombosis, only one arterial thrombotic event was diagnosed (1.2%, 1/82). This low recurrence rate was probably due to the high vaccination rates prior to infections and a high rate of effective anticoagulation. Our data show that COVID-19 infections and/or vaccinations do not deteriorate the clinical course of anticoagulated thromboembolic APS patients.

Lupus Anticoagulant Is Associated with Critical Cases and High Mortality in COVID-19: A Literature Review

Background

In severe COVID-19 cases, a hypercoagulable state may occur. Antiphospholipid syndrome-related auto-antibodies (APSRAs) contribute to coagulopathy, but their role in COVID- 19 remains unclear. We aimed to investigate the prevalence of positive APSRAs and their effect on clinical outcomes in confirmed COVID-19 patients.

Materials and Methods

In this cross-sectional study, severe hospitalized COVID-19 cases were enrolled. Demographic and clinical data were obtained from the day of admission. APSRAs including IgG and/or IgM anticardiolipin (aCL) and anti-β2-glycoprotein1 (anti-β2GP1) as well as lupus anticoagulant (LAC) were measured.

Results

In this study, 54 severe COVID-19 cases with positive RT-PCR and chest CT scans were recruited. Positive APSRAs were found in 7 (12.9%) patients. Positive LAC was a more prevalent marker as compared to other tests (11.1%). The prevalence of positive aCL (IgM or IgG) and anti-ß2 GPI (IgM or IgG) was 1.8% (in an elderly woman). Lower oxygen saturation was found in the positive APSRAs group as opposed to the negative APSRAs group (70.3±9 vs. 84.8±9.7%). The mortality rate in the positive APSRAs group was significantly higher relative to the negative APSRAs group (83.3% vs. 27.1%; P-value: 0.01). Likewise, the mechanical ventilation requirement in the positive group was also higher (50% vs. 27.1%, P-value: 0.28).

Conclusion

This study indicated that LAC might be associated with critical cases and high mortality of COVID-19. Nonetheless, the mortality was not related to macrothrombotic incidence.

Longitudinal Analysis of Antiphospholipid Antibody Dynamics after Infection with SARS-CoV-2 or Vaccination with BNT162b2

Antiphospholipid antibodies (aPL) comprise a group of autoantibodies that reflect prothrombotic risk in antiphospholipid syndrome (APS) but may also be present in a small proportion of healthy individuals. They are often transiently elevated in infections, including SARS-CoV-2, and may also be associated with vaccine-induced autoimmunity. Therefore, we aimed to investigate the dynamics of aPL in COVID-19 patients and in individuals (healthcare professionals-HCPs) after receiving BNT162b2 vaccine and to compare aPL levels and positivity with those found in APS patients. We measured solid-phase identifiable aPL, including anticardiolipin (aCL), anti-β2 glycoprotein I (anti-β2GPI), and anti-prothrombin/phosphatidylserine (aPS/PT) antibodies in 58 HCPs before and after vaccination (at 3 weeks, 3, 6, and 9 months after the second dose, and 3 weeks after the third booster dose), in 45 COVID-19 patients hospitalized in the ICU, in 89 COVID-19 patients hospitalized in the non-ICU (at admission, at hospital discharge, and at follow-up), and in 52 patients with APS. The most frequently induced aPL in COVID-19 patients (hospitalized in non-ICU) were aCL (50.6% of patients had positive levels at at least one time point), followed by anti-β2GPI (21.3% of patients had positive levels at at least one time point). In 9/89 COVID-19 patients, positive aPL levels persisted for three months. One HCP developed aCL IgG after vaccination but the persistence could not be confirmed, and two HCPs developed persistent anti-β2GPI IgG after vaccination with no increase during a 1-year follow-up period. Solid-phase aPL were detected in 84.6% of APS patients, in 49.4% of COVID-19 patients hospitalized in the non-ICU, in 33.3% of COVID-19 patients hospitalized in the ICU, and in only 17.2% of vaccinated HCPs. aPL levels and multiple positivity were significantly lower in both infected groups and in vaccinated individuals compared with APS patients. In conclusion, BNT162b2 mRNA vaccine may have induced aPL in a few individuals, whereas SARS-CoV-2 infection itself results in a higher percentage of aPL induction, but the levels, persistence, and multiple positivity of aPL do not follow the pattern observed in APS.

COVID-19 and the antiphospholipid syndrome

Coronavirus disease 2019 (COVID-19) has resulted in a global pandemic. Most COVID-19 patients are asymptomatic or have flu-like symptoms. However, around 15% of the patients may have severe disease, including unilateral or bilateral pneumonia with acute respiratory distress syndrome and progressive hypoxemia that may require mechanical ventilation assistance. A systemic inflammatory response syndrome occurs in the most severe forms of COVID-19, with multiorgan involvement which can be life threatening caused by a cytokine storm. Although what best characterizes COVID-19 are the manifestations of the respiratory system, it has been shown that it also acts at the cardiovascular level, producing coagulation abnormalities, which causes thrombotic events mainly in the arteries/arterioles, microcirculation and venous system, and potentially increased mortality risk. This multiorgan vascular disease overlaps with other known microangiopathies, such as thrombotic microangiopathy or paroxysmal nocturnal hemoglobinuria, where complement overactivation plays an important role in the pathophysiology of thrombosis. Furthermore, coagulopathy secondary to COVID-19 occurs in the context of an uncontrolled inflammatory response, reminiscent of APS, especially in its catastrophic form. This review summarizes the current knowledge regarding the relationship between COVID-19 and the APS.

Autoimmune Diseases Affecting Hemostasis: A Narrative Review

Hemostasis reflects a homeostatic mechanism that aims to balance out pro-coagulant and anti-coagulant forces to maintain blood flow within the circulation. Simplistically, a relative excess of procoagulant forces can lead to thrombosis, and a relative excess of anticoagulant forces can lead to bleeding. There are a wide variety of congenital disorders associated with bleeding or thrombosis. In addition, there exist a vast array of autoimmune diseases that can also lead to either bleeding or thrombosis. For example, autoantibodies generated against clotting factors can lead to bleeding, of which acquired hemophilia A is the most common. As another example, autoimmune-mediated antibodies against phospholipids can generate a prothrombotic milieu in a condition known as antiphospholipid (antibody) syndrome (APS). Moreover, there exist various autoimmunity promoting environments that can lead to a variety of antibodies that affect hemostasis. Coronavirus disease 2019 (COVID-19) represents perhaps the contemporary example of such a state, with potential development of a kaleidoscope of such antibodies that primarily drive thrombosis, but may also lead to bleeding on rarer occasions. We provide here a narrative review to discuss the interaction between various autoimmune diseases and hemostasis.

Effect of stimulated platelets in COVID-19 thrombosis: Role of alpha7 nicotinic acetylcholine receptor

Since early 2020, SARS-CoV-2-induced infection resulted in global pandemics with high morbidity, especially in the adult population. COVID-19 is a highly prothrombotic condition associated with subsequent multiorgan failure and lethal outcomes. The exact mechanism of the prothrombotic state is not well understood and might be multifactorial. Nevertheless, platelets are attributed to play a crucial role in COVID-19-associated thrombosis. To date, platelets' role was defined primarily in thrombosis and homeostasis. Currently, more focus has been set on their part in inflammation and immunity. Moreover, their ability to release various soluble factors under activation as well as internalize and degrade specific pathogens has been highly addressed in viral research. This review article will discuss platelet role in COVID-19-associated thrombosis and their role in the cholinergic anti-inflammatory pathway. Multiple studies confirmed that platelets display a hyperactivated phenotype in COVID-19 patients. Critically ill patients demonstrate increased platelet activation markers such as P-selectin, PF4, or serotonin. In addition, platelets contain acetylcholine and express α7 nicotinic acetylcholine receptors (α7nAchR). Thus, acetylcholine can be released under activation, and α7nAchR can be stimulated in an autocrine manner and support platelet function. α7 receptor is one of the most important mediators of the anti-inflammatory properties as it is associated with humoral and intrinsic immunity and was demonstrated to contribute to better outcomes in COVID-19 patients when under stimulation. Hematopoietic α7nAchR deficiency increases platelet activation and, in experimental studies, α7nAchR stimulation can diminish the pro-inflammatory state and modulate platelet reactiveness via increased levels of NO. NO has been described to inhibit platelet adhesion, activation, and aggregation. In addition, acetylcholine has been demonstrated to decrease platelet aggregation possibly by blocking the e p-38 pathway. SARS-CoV-2 proteins have been found to be similar to neurotoxins which can bind to nAChR and prevent the action of acetylcholine. Concluding, the platelet role in COVID-19 thrombotic events could be explained by their active function in the cholinergic anti-inflammatory pathway.

COVID-19 and antiphospholipid antibodies

Antiphospholipid syndrome and the coagulopathy of COVID-19 share many pathophysiologic features, including endotheliopathy, hypercoagulability, and activation of platelets, complement pathways, and neutrophil extracellular traps, all acting in concert via a model of immunothrombosis. Antiphospholipid antibody production in COVID-19 is common, with 50% of COVID-19 patients being positive for lupus anticoagulant in some studies, and with non-Sapporo criteria antiphospholipid antibodies being prevalent as well. The biological significance of antiphospholipid antibodies in COVID-19 is uncertain, as such antibodies are usually transient, and studies examining clinical outcomes in COVID-19 patients with and without antiphospholipid antibodies have yielded conflicting results. In this review, we explore the biology of antiphospholipid antibodies in COVID-19 and other infections and discuss mechanisms of thrombogenesis in antiphospholipid syndrome and parallels with COVID-19 coagulopathy. In addition, we review the existing literature on safety of COVID-19 vaccination in patients with antiphospholipid antibodies and antiphospholipid syndrome.