Antiphospholipid antibodies, antiphospholipid syndrome and infections

Ab initio prediction of specific phospholipid complexes and membrane association of HIV-1 MPER antibodies by multi-scale simulations

A potent class of HIV-1 broadly neutralizing antibodies (bnAbs) targets the envelope glycoprotein's membrane proximal exposed region (MPER) through a proposed mechanism where hypervariable loops embed into lipid bilayers and engage headgroup moieties alongside the epitope. We address the feasibility and determinant molecular features of this mechanism using multi-scale modeling. All-atom simulations of 4E10, PGZL1, 10E8, and LN01 docked onto HIV-like membranes consistently form phospholipid complexes at key complementarity-determining region loop sites, solidifying that stable and specific lipid interactions anchor bnAbs to membrane surfaces. Ancillary protein-lipid contacts reveal surprising contributions from antibody framework regions. Coarse-grained simulations effectively capture antibodies embedding into membranes. Simulations estimating protein-membrane interaction strength for PGZL1 variants along an inferred maturation pathway show bilayer affinity is evolved and correlates with neutralization potency. The modeling demonstrated here uncovers insights into lipid participation in antibodies' recognition of membrane proteins and highlights antibody features to prioritize in vaccine design.

The serological dilemma: rethinking syphilis treatment evaluation

INTRODUCTION

Nontreponemal tests (NTT) constitute a significant method in syphilis detection, playing a crucial role in screening, diagnosing, and monitoring disease activity. However, recent discussions have cast doubt on the traditional belief that NTT are suitable for evaluating treatment efficacy, as inconsistencies between NTT results and syphilis treatment outcomes have been observed with some frequency.

AREAS COVERED

We have delineated the current status of serological methods for evaluating the therapeutic efficacy of syphilis treatment and summarized and discussed the exploration of biomarkers for syphilis therapy. A literature search was conducted in PubMed over all available dates for relevant published papers and conference abstracts with the search terms, 'Syphilis,' 'Treponema pallidum,' 'Serofast,' 'Treatment efficacy evaluation,' 'Nontreponemal,' 'RPR,' 'TRUST,' 'VDRL,' 'Neurosyphilis,' 'Pregnant syphilis,' 'Congenital syphilis,' 'Reinfection,' 'Cardiolipin,' 'Serology.'

EXPERT OPINION

Currently, the assessment of treatment efficacy through serological methods is limited to the use of the NTT. Therefore, it is imperative for clinicians to gain a deeper understanding of the significance and limitations of the NTT, as well as a focus on exploring more potential indicators for evaluating treatment efficacy.

Antiphospholipid Antibodies as Key Players in Systemic Lupus Erythematosus: The Relationship with Cytokines and Immune Dysregulation

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by an overproduction of cytokines, such as interleukins and interferons, contributing to systemic inflammation and tissue damage. Antiphospholipid syndrome is a thrombo-inflammatory autoimmune disease affecting a third of SLE patients. We performed an in-depth analysis of the available literature, and we highlighted the complex interplay between immunity, inflammation, and thrombosis, the three major pathogenic pathways that are trapped in a mutually reinforcing destructive loop.

Catastrophic Antiphospholipid Syndrome: A Review of Current Evidence and Future Management Practices

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by blood clots and pregnancy complications due to antiphospholipid antibodies. Catastrophic APS (CAPS), a severe variant, leads to multiorgan failure and is often fatal. Pathogenesis involves antiphospholipid antibodies, particularly anti-beta-2-glycoprotein I (aβ2GPI), which trigger endothelial cell (EC) activation, cytokine release, and a prothrombotic state. Infections, surgeries, and other triggers can precipitate CAPS, leading to widespread microthromboses and systemic inflammatory responses. CAPS predominantly affects younger patients and those with systemic lupus erythematosus (SLE), with a high mortality rate, though recent treatment advances have improved survival. Diagnosing CAPS involves identifying clinical manifestations, including rapid organ involvement and small vessel occlusions, confirmed by histopathology and high antiphospholipid antibody levels. The CAPS registry data indicate that commonly affected organs include kidneys, lungs, central nervous system, and the heart, with a high prevalence of lupus anticoagulant and anticardiolipin antibodies (aCL). Current management strategies focus on therapeutic anticoagulation, immunosuppressive therapies like corticosteroids, and adjunct treatments such as plasmapheresis and intravenous immunoglobulin (IVIG). Early use of glucocorticoids and combination therapy has significantly improved outcomes. In life-threatening cases, especially with microangiopathy, experts recommend performing plasma exchange (PE). Patients with associated autoimmune conditions or refractory cases may receive cyclophosphamide (CY) and rituximab while considering PE for treatment. Maintenance of anticoagulation with an appropriate international normalized ratio (INR) is crucial to prevent recurrence. This article reviews the pathogenesis and epidemiology of CAPS. It also examines the current management strategies, and discusses the challenges and controversies associated with these strategies. It hereafter offers recommendations for future management and outlines directions for further research.

Is lupus anticoagulant testing with dilute Russell's viper venom clotting times reliable in the presence of inflammation?

Background

Testing for lupus anticoagulant (LA) is not recommended in case of inflammation as C-reactive protein (CRP) can interfere in vitro with the phospholipids present in the activated partial thromboplastin time test used to detect an LA. However, the potential interference of an acute phase protein (ie, CRP) in LA testing using the dilute Russell's viper venom (DRVV) test is poorly studied.

Objectives

To study the effect of inflammation, as evidenced by increased CRP levels, on DRVV tests.

Methods

First, a retrospective analysis (2013-2023) was performed: data on all LA workups were retrieved, and the association between CRP levels and DRVV screen, mix, and confirm clotting times was studied. Second, data on DRVV panels and CRP levels were extracted from 2 prospective studies involving intensive care unit patients to study the association between both variables. Third, CRP was added to normal pooled plasma at 6 relevant concentrations (up to 416 mg/L) to study the association between CRP itself and DRVV coagulation times.

Results

In the retrospective analysis, DRVV screen and confirm clotting times significantly increased as CRP increased (increase of 0.11 seconds and 0.03 seconds per 1 mg/L increase of CRP level, respectively). In the prospective analysis, only DRVV screen was prolonged with high CRP levels (increase of 0.06 seconds for a 1 mg/L increase in CRP level); DRVV screen/confirm ratio was also increased with high CRP levels. In vitro, the addition of CRP did not significantly increase any DRVV clotting times.

Conclusion

LA testing should be performed with much caution in the presence of inflammation as it may be associated with prolongation of both activated partial thromboplastin time and DRVV clotting times.

Challenging in leprosy relapse with antiphospholipid syndrome diagnosis: A case report

Key Clinical Message

Infectious diseases like leprosy can cause antiphospholipid antibodies, leading to blood clots. Clinicians should consider this for patients with unusual thrombotic events and prior infectious disease history.

Abstract

This case report details the diagnostic challenge of a 42-year-old man with a history of treated leprosy who presented with clinical features suggestive of antiphospholipid syndrome (APS). Vascular angiography revealed thrombosis, and serological tests were positive for APS antibodies. However, the patient subsequently developed symptoms, including thenar atrophy, paresthesia, and hypopigmented skin patches, which prompted further investigation. Electromyography detected sensorimotor polyneuropathy, while a nerve biopsy indicated a resurgence or chronic presence of leprosy. Despite initial APS management, the case evolved into a leprosy relapse confirmation after 20 years of remission, underscoring the diagnostic intricacies when concurrent autoimmune antibodies and infectious disease manifestations are present. This report emphasizes the importance of considering a broad differential diagnosis, including the potential for infectious disease relapse, in the presence of antiphospholipid antibodies. It illustrates the necessity of an interdisciplinary treatment approach in complex clinical scenarios.

Targeting the tissue factor coagulation initiation complex prevents antiphospholipid antibody development

ABSTRACT

Antiphospholipid antibodies (aPL) in primary or secondary antiphospholipid syndrome (APS) are a major cause for acquired thrombophilia, but specific interventions preventing autoimmune aPL development are an unmet clinical need. Although autoimmune aPL cross react with various coagulation regulatory proteins, lipid-reactive aPL, including those derived from patients with COVID-19, recognize the endolysosomal phospholipid lysobisphosphatidic acid presented by the cell surface-expressed endothelial protein C receptor. This specific recognition leads to complement-mediated activation of tissue factor (TF)-dependent proinflammatory signaling and thrombosis. Here, we show that specific inhibition of the TF coagulation initiation complex with nematode anticoagulant protein c2 (NAPc2) prevents the prothrombotic effects of aPL derived from patients with COVID-19 in mice and the aPL-induced proinflammatory and prothrombotic activation of monocytes. The induction of experimental APS is dependent on the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex, and NAPc2 suppresses monocyte endosomal reactive oxygen species production requiring the TF cytoplasmic domain and interferon-α secretion from dendritic cells. Latent infection with murine cytomegalovirus causes TF cytoplasmic domain-dependent development of persistent aPL and circulating phospholipid-reactive B1 cells, which is prevented by short-term intervention with NAPc2 during acute viral infection. In addition, treatment of lupus prone MRL-lpr mice with NAPc2, but not with heparin, suppresses dendritic-cell activation in the spleen, aPL production and circulating phospholipid-reactive B1 cells, and attenuates lupus pathology. These data demonstrate a convergent TF-dependent mechanism of aPL development in latent viral infection and autoimmune disease and provide initial evidence that specific targeting of the TF initiation complex has therapeutic benefits beyond currently used clinical anticoagulant strategies.

From Co-Infections to Autoimmune Disease via Hyperactivated Innate Immunity: COVID-19 Autoimmune Coagulopathies, Autoimmune Myocarditis and Multisystem Inflammatory Syndrome in Children

Neutrophilia and the production of neutrophil extracellular traps (NETs) are two of many measures of increased inflammation in severe COVID-19 that also accompany its autoimmune complications, including coagulopathies, myocarditis and multisystem inflammatory syndrome in children (MIS-C). This paper integrates currently disparate measures of innate hyperactivation in severe COVID-19 and its autoimmune complications, and relates these to SARS-CoV-2 activation of innate immunity. Aggregated data include activation of Toll-like receptors (TLRs), nucleotide-binding oligomerization domain (NOD) receptors, NOD leucine-rich repeat and pyrin-domain-containing receptors (NLRPs), retinoic acid-inducible gene I (RIG-I) and melanoma-differentiation-associated gene 5 (MDA-5). SARS-CoV-2 mainly activates the virus-associated innate receptors TLR3, TLR7, TLR8, NLRP3, RIG-1 and MDA-5. Severe COVID-19, however, is characterized by additional activation of TLR1, TLR2, TLR4, TLR5, TLR6, NOD1 and NOD2, which are primarily responsive to bacterial antigens. The innate activation patterns in autoimmune coagulopathies, myocarditis and Kawasaki disease, or MIS-C, mimic those of severe COVID-19 rather than SARS-CoV-2 alone suggesting that autoimmunity follows combined SARS-CoV-2-bacterial infections. Viral and bacterial receptors are known to synergize to produce the increased inflammation required to support autoimmune disease pathology. Additional studies demonstrate that anti-bacterial antibodies are also required to account for known autoantigen targets in COVID-19 autoimmune complications.

Venous thromboembolism in viral diseases: A comprehensive literature review

Venous thromboembolism (VTE) is known to be a common respiratory and/or cardiovascular complication in hospitalized patients with viral infections. Numerous studies have proven human immunodeficiency virus infection to be a prothrombotic condition. An elevated VTE risk has been observed in critically ill H1N1 influenza patients. VTE risk is remarkably higher in patients infected with the Hepatitis C virus in contrast to uninfected subjects. The elevation of D-dimer levels supported the association between Chikungunya and the Zika virus and the rise of clinical VTE risk. Varicella-zoster virus is a risk factor for both cellulitis and the consequent invasive bacterial disease which may take part in thrombotic initiation. Eventually, hospitalized patients infected with the coronavirus disease of 2019 (COVID-19), the cause of the ongoing worldwide pandemic, could mainly suffer from an anomalous risk of coagulation activation with enhanced venous thrombosis events and poor quality clinical course. Although the risk of VTE in nonhospitalized COVID-19 patients is not known yet, there are a large number of guidelines and studies on thromboprophylaxis administration for COVID-19 cases. This study aims to take a detailed look at the effect of viral diseases on VTE, the epidemiology of VTE in viral diseases, and the diagnosis and treatment of VTE.

Map of thrombogenesis in viral infections and viral-driven tumours

Viruses are pathogenic agents responsible for approximately 10% of all human cancers and significantly contribute to the global cancer burden. Until now, eight viruses have been associated with the development of a broad range of malignancies, including solid and haematological tumours. Besides triggering and promoting oncogenesis, viral infections often go hand-in-hand with haemostatic changes, representing a potential risk factor for venous thromboembolism (VTE). Conversely, VTE is a cardiovascular condition that is particularly common among oncological patients, with a detrimental impact on patient prognosis. Despite an association between viral infections and coagulopathies, it is unclear whether viral-driven tumours have a different incidence and prognosis pattern of thromboembolism compared to non-viral-induced tumours. Thus, this review aims to analyse the existing evidence concerning the association of viruses and viral tumours with the occurrence of VTE. Except for hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infection, which are associated with a high risk of VTE, little evidence exists concerning the thrombogenic potential associated with oncoviruses. As for tumours that can be induced by oncoviruses, four levels of VTE risk are observed, with hepatocellular carcinoma (HCC) and gastric carcinoma (GC) associated with the highest risk and nasopharyngeal carcinoma (NPC) associated with the lowest risk. Unfortunately, the incidence of cancer-related VTE according to tumour aetiology is unknown. Given the negative impact of VTE in oncological patients, research is required to better understand the mechanisms underlying blood hypercoagulability in viral-driven tumours to improve VTE management and prognosis assessment in patients diagnosed with these tumours.

Antiphospholipid antibodies in patients with stroke during COVID-19: A role in the signaling pathway leading to platelet activation

Background

Several viral and bacterial infections, including COVID-19, may lead to both thrombotic and hemorrhagic complications. Previously, it has been demonstrated an "in vitro" pathogenic effect of "antiphospholipid" antibodies (aPLs), which are able to activate a proinflammatory and procoagulant phenotype in monocytes, endothelial cells and platelets. This study analyzed the occurrence of aPL IgG in patients with acute ischemic stroke (AIS) during COVID-19, evaluating the effect of Ig fractions from these patients on signaling and functional activation of platelets.

Materials and methods

Sera from 10 patients with AIS during COVID-19, 10 non-COVID-19 stroke patients, 20 COVID-19 and 30 healthy donors (HD) were analyzed for anti-cardiolipin, anti-β2-GPI, anti-phosphatidylserine/prothrombin and anti-vimentin/CL antibodies by ELISA. Platelets from healthy donors were incubated with Ig fractions from these patients or with polyclonal anti-β2-GPI IgG and analyzed for phospho-ERK and phospho-p38 by western blot. Platelet secretion by ATP release dosage was also evaluated.

Results

We demonstrated the presence of aPLs IgG in sera of patients with AIS during COVID-19. Treatment with the Ig fractions from these patients or with polyclonal anti-β2-GPI IgG induced a significant increase of phospho-ERK and phospho-p38 expression. In the same vein, platelet activation was supported by the increase of adenyl nucleotides release induced by Ig fractions.

Conclusions

This study demonstrates the presence of aPLs in a subgroup of COVID-19 patients who presented AIS, suggesting a role in the mechanisms contributing to hypercoagulable state in these patients. Detecting these antibodies as a serological marker to check and monitor COVID-19 may contribute to improve the risk stratification of thromboembolic manifestations in these patients.

Frequency of positive antiphospholipid antibodies in pregnant women with SARS-CoV-2 infection and impact on pregnancy outcome: A single-center prospective study on 151 pregnancies

Background

At the beginning of the SARS-CoV-2 pandemic, there was a lack of information about the infection’s impact on pregnancy and capability to induce de novo autoantibodies. It soon became clear that thrombosis was a manifestation of COVID-19, therefore the possible contribution of de novo antiphospholipid antibodies (aPL) raised research interest. We aimed at screening SARS-CoV-2 positive pregnant patients for aPL.

Methods

The study included consecutive pregnant women who were hospitalized in our Obstetric Department between March 2020 and July 2021 for either a symptomatic SARS-CoV-2 infection or for other reasons (obstetric complications, labour, delivery) and found positive at the admission nasopharyngeal swab. All these women underwent the search for aPL by means of Lupus Anticoagulant (LA), IgG/IgM anti-cardiolipin (aCL), IgG/IgM anti-beta2glycoprotein I (aB2GPI). Data about comorbidities, obstetric and neonatal complications were collected.

Results

151 women were included. Sixteen (11%) were positive for aPL, mostly at low titre. Pneumonia was diagnosed in 20 women (5 with positive aPL) and 5 required ICU admission (2 with positive aPL). Obstetric complications occurred in 10/16 (63%) aPL positive and in 36/135 (27%) negative patients. The occurrence of HELLP syndrome and preeclampsia was significantly associated with positive aPL (p=0,004). One case of maternal thrombosis occurred in an aPL negative woman. aPL positivity was checked after at least 12 weeks in 7/16 women (44%): 3 had become negative; 2 were still positive (1 IgG aB2GPI + IgG aCL; 1 IgM aB2GPI); 1 remained positive for IgG aCL but became negative for aB2GPI; 1 became negative for LA but displayed a new positivity for IgG aCL at high titre.

Conclusions

The frequency of positive aPL in pregnant women with SARS-CoV-2 infection was low in our cohort and similar to the one described in the general obstetric population. aPL mostly presented as single positive, low titre, transient antibodies. The rate of obstetric complications was higher in aPL positive women as compared to negative ones, particularly hypertensive disorders. Causality cannot be excluded; however, other risk factors, including a full-blown picture of COVID-19, may have elicited the pathogenic potential of aPL and contributed themselves to the development of complications.

Lupus anticoagulant associates with thrombosis in patients with COVID-19 admitted to intensive care units: A retrospective cohort study

Background

Thrombosis is a frequent and severe complication in patients with coronavirus disease 2019 (COVID‐19) admitted to the intensive care unit (ICU). Lupus anticoagulant (LA) is a strong acquired risk factor for thrombosis in various diseases and is frequently observed in patients with COVID‐19. Whether LA is associated with thrombosis in patients with severe COVID‐19 is currently unclear.

Objective

To investigate if LA is associated with thrombosis in critically ill patients with COVID‐19.

Patients/Methods

The presence of LA and other antiphospholipid antibodies was assessed in patients with COVID‐19 admitted to the ICU. LA was determined with dilute Russell's viper venom time (dRVVT) and LA‐sensitive activated partial thromboplastin time (aPTT) reagents.

Results

Of 169 patients with COVID‐19, 116 (69%) tested positive for at least one antiphospholipid antibody upon admission to the ICU. Forty (24%) patients tested positive for LA; of whom 29 (17%) tested positive with a dRVVT, 19 (11%) tested positive with an LA‐sensitive aPTT, and 8 (5%) tested positive on both tests. Fifty‐eight (34%) patients developed thrombosis after ICU admission. The odds ratio (OR) for thrombosis in patients with LA based on a dRVVT was 2.5 (95% confidence interval [CI], 1.1–5.7), which increased to 4.5 (95% CI, 1.4–14.3) in patients at or below the median age in this study (64 years). LA positivity based on a dRVVT or LA‐sensitive aPTT was only associated with thrombosis in patients aged less than 65 years (OR, 3.8; 95% CI, 1.3–11.4) and disappeared after adjustment for C‐reactive protein.

Conclusion

Lupus anticoagulant on admission is strongly associated with thrombosis in critically ill patients with COVID‐19, especially in patients aged less than 65 years.

Tuberculosis and Autoimmunity

Tuberculosis remains a common and dangerous chronic bacterial infection worldwide. It is long-established that pathogenesis of many autoimmune diseases is mainly promoted by inadequate immune responses to bacterial agents, among them Mycobacterium tuberculosis. Tuberculosis is a multifaceted process having many different outcomes and complications. Autoimmunity is one of the processes characteristic of tuberculosis; the presence of autoantibodies was documented by a large amount of evidence. The role of autoantibodies in pathogenesis of tuberculosis is not quite clear and widely disputed. They are regarded as: (1) a result of imbalanced immune response being reactive in nature, (2) a critical part of TB pathogenicity, (3) a beginning of autoimmune disease, (4) a protective mechanism helping to eliminate microbes and infected cells, and (5) playing dual role, pathogenic and protective. There is no single autoimmunity-mechanism development in tuberculosis; different pathways may be suggested. It may be excessive cell death and insufficient clearance of dead cells, impaired autophagy, enhanced activation of macrophages and dendritic cells, environmental influences such as vitamin D insufficiency, and genetic polymorphism, both of Mycobacterium tuberculosis and host.

Epidemiology of Antiphospholipid Syndrome in the General Population

Purpose of Review

The epidemiology of antiphospholipid syndrome (APS) is poorly understood. Here, we review the current understanding of the epidemiology of antiphospholipid syndrome in the general population and the frequency of antiphospholipid antibodies in the general population in patients with obstetric morbidity, arterial events, and venous thromboembolism.

Recent Findings

There have been few population-based studies that estimated the prevalence and incidence of APS. The estimated incidence and prevalence among most these studies ranged between 1 and 2 cases per 100,000 and 40 and 50 cases per 100,000 respectively. The prevalence of antiphospholipid antibodies in patients with obstetric morbidity was 6–9%, while in arterial events and venous thromboembolism is 9–10%. However, this data remains limited. Mortality of patients with APS is 50–80% higher than the general population.

Summary

The epidemiology of APS has been difficult to elucidate. Population-based studies patients with diverse age, racial, and ethnic backgrounds are needed.

SARS-CoV-2 Virus Infection-Related Arterial Thromboembolism Leading to Critical Limb Ischemia and Amputation

COVID-19 infection has been shown to increase risk for thromboembolism. With most studies reporting mainly venous thromboembolic events, there is a lack of literature regarding the incidence of arterial thromboses in patients with COVID-19 infection. We report a dramatic case of a 55-year-old male with confirmed COVID-19 infection who presented with acute left critical limb ischemia leading to amputation as a result of thromboembolism from a distal abdominal aortic thrombus. Our case report contributes to the limited body of literature on COVID-19-related arterial thromboembolism. The patient consented to publish this case.

Hepatitis-A Infection-Induced Secondary Antiphospholipid Syndrome With Neuro-ophthalmological Manifestations

Antiphospholipid syndrome (APS) is a multisystem autoimmune disorder that can affect children and adults alike, with a similar spectrum of thrombotic events, predominately deep vein thrombosis and stroke. It is characterized by recurrent arterial or venous thrombosis and recurrent fetal loss with the presence of antiphospholipid antibodies (aPL) like antibodies to beta-2-glycoprotein I (B-2-GPI) and anticardiolipin (aCL). The disease could be classified into primary APS in the absence of an underlying disease or secondary APS occurring secondary to autoimmune diseases, infections, malignancies, and sometimes medication use. In the absence of clinical manifestations of APS, transient non-thrombogenic antiphospholipid antibodies are seen more commonly in children, predominantly after childhood infections. Cases with clinical manifestations of APS associated with different types of infections have been reported in the literature to keep track of potential triggering causes and take measures to prevent or treat the disease manifestations. This case documents the case of hepatitis-A as a triggering viral infection, causing secondary APS in a child.

Risk of progression to autoimmune disease in severe drug eruption: risk factors and the factor-guided stratification

The identification of risk factors is key not only to uncover the pathogenesis of autoimmune disease but also to predict progression to autoimmune disease. Drug-induced hypersensitivity syndrome (DiHS)/ drug reaction with eosinophilia and systemic symptoms (DRESS) is likely the best prototypic example for analyzing the sequential events. We conducted a retrospective study of 55 patients with DiHS/DRESS followed for the possibility of later development of autoimmune disease ∼18 years after resolution. Nine patients progressed to autoimmune sequelae regardless of treatment. The generation of autoantibodies preceded by 8 years in 8 of the 9 patients. The combination of increases in lymphocyte counts, severe liver damage, a rebound increase in globulin, persistent reactivations of Epstein-Barr virus and human herpesvirus-6, and low interleukin (IL)-2 and IL-4 at the acute/subacute phases, were significant risk factors for the future development of autoimmune disease. Based on these factors, we established a scoring system that can identify high-risk patients. When stratified these patients into three risk categories (low/intermediate/high), occurrence of autoimmune disease was exclusively detected in the high group. Our data represent the new scoring system to identify patients at high-risk of developing autoimmune disease, although a larger study is required to validate the scoring system.

Pathogenic lipid-binding antiphospholipid antibodies are associated with severity of COVID-19

BACKGROUND

Coronavirus disease 19 (COVID-19)-associated coagulopathy is a hallmark of disease severity and poor prognosis. The key manifestations of this prothrombotic syndrome-microvascular thrombosis, stroke, and venous and pulmonary clots-are also observed in severe and catastrophic antiphospholipid syndrome. Antiphospholipid antibodies (aPL) are detectable in COVID-19 patients, but their association with the clinical course of COVID-19 remains unproven.

OBJECTIVES

To analyze the presence and relevance of lipid-binding aPL in hospitalized COVID-19 patients.

METHODS

Two cohorts of 53 and 121 patients from a single center hospitalized for PCR-proven severe acute respiratory syndrome-coronavirus 2 infection were analyzed for the presence of aPL and clinical severity of COVID-19.

RESULTS

We here demonstrate that lipid-binding aPL are common in COVID-19. COVID-19 patients with lipid-binding aPL have higher median concentrations of C-reactive protein and D-dimer, and are more likely to have a critical clinical course and fatal outcome. Lipid-binding aPL isolated from COVID-19 patients target the recently described cell surface complex of lysobisphosphatidic acid (LBPA) with the protein C receptor (EPCR) to induce prothrombotic and inflammatory responses in monocytes and endothelial cells. We show that B1a cells producing lipid-reactive aPL of the IgG isotype circulate in the blood of COVID-19 patients. In vivo, COVID-19 aPL accelerate thrombus formation in an experimental mouse model dependent on the recently delineated signaling pathway involving EPCR-LBPA.

CONCLUSIONS

COVID-19 patients rapidly expand B1a cells secreting pathogenic lipid-binding aPL with broad thrombotic and inflammatory effects. The association with markers of inflammation and coagulation, clinical severity, and mortality suggests a causal role of aPL in COVID-19-associated coagulopathy.

Not all that is 'full house' is systemic lupus erythematosus: a case of membranous nephropathy due to syphilis infection

We describe an unusual case of membranous nephropathy precipitated by syphilis infection in a patient without systemic lupus erythematosus (SLE). A previously healthy 20-year-old man presented with leg and facial swelling. Laboratory investigation revealed nephrotic range proteinuria, acute kidney injury, hypocomplementaemia and a highly positive rapid plasma reagin. Kidney biopsy showed membranous nephropathy with 'full-house' immunofluorescence (IgG, IgA, IgM, C1q and C3), mimicking lupus nephritis class Vb. However, the patient had no features of SLE and had negative antinuclear and anti-double-stranded DNA antibodies. He was treated with high-dose methylprednisolone and mycophenolate mofetil for lupus nephritis and with penicillin for syphilis. After 2 months of therapy, his proteinuria resolved, and his renal function and C4 level normalised. This case illustrates that syphilis infection can be a mimicker of lupus nephritis. A literature review suggests that ful-house nephropathy may occur independently of lupus nephritis and may or may not develop into SLE.

Like father, like son: Pulmonary thromboembolism due to inflammatory or hereditary condition? Two case reports

BACKGROUND

Venous thromboembolism, which includes deep venous thrombosis and pulmonary embolism, is a well-known causal disorder with high morbidity and mortality rates. Inherited or acquired conditions affecting components of coagulation and fibrinolysis systems have been linked to venous thromboembolism pathogenesis as they may lead to a pro-inflammatory state in human bodies. Toxoplasmosis is a zoonosis that potentially leads to acute systemic cachectic-inflammatory effects in experimental animal models but is not yet proven in humans. It is known that venous thrombosis can occur during acute inflammatory/infectious diseases, although it is not well established with regard to toxoplasmosis alone.

CASE SUMMARY

A 70-year-old Caucasian man and his 32-year-old son developed general malaise, chills, fever, and myalgia, having established a diagnosis of toxoplasmosis. Twenty days later, they presented dry cough leading to further investigations that revealed an incidental deep venous thrombosis plus pulmonary embolism in them both. Thrombophilia screening showed both patients had a factor V Leiden mutation heterozygosis. Father and son completely recovered without any sequalae after anticoagulant treatment. They have not presented symptom recurrence of either medical disorder during 1 year of follow-up.

CONCLUSION

Toxoplasmosis may enhance the risk of venous thromboembolism in patients showing factor V Leiden mutation heterozygosis.

Antiphospholipid antibodies in critically ill COVID-19 patients with thromboembolism: cause of disease or epiphenomenon?

Coronavirus 2019 disease (COVID-19) is associated with coagulation dysfunction that predisposes patients to an increased risk for both arterial (ATE) and venous thromboembolism (VTE) and consequent poor prognosis; in particular, the incidence of ATE and VTE in critically ill COVID-19 patients can reach 5% and 31%, respectively. The mechanism of thrombosis in COVID-19 patients is complex and still not completely clear. Recent literature suggests a link between the presence of antiphospholipid antibodies (aPLs) and thromboembolism in COVID-19 patients. However, it remains uncertain whether aPLs are an epiphenomenon or are involved in the pathogenesis of the disease.

Untangling the Intricacies of Infection, Thrombosis, Vaccination, and Antiphospholipid Antibodies for COVID-19

Advanced SARS-CoV-2 infections not uncommonly associate with the occurrence of silent or manifest thrombotic events which may be found as focal or systemic disease. Given the potential complexity of COVID-19 illnesses, a multifactorial causation is likely, but several studies have focused on infection-induced coagulopathy. Procoagulant states are commonly found in association with the finding of antiphospholipid antibodies. The correlation of the latter with thrombosis and/or clinical severity remains controversial. Although measures of antiphospholipid antibodies most commonly include assessments for lupus anticoagulant, anticardiolipin, and anti-ß2-glycoprotein-I antibodies, lesser common antibodies have been detected, and there remains speculation that other yet undiscovered autoimmune thrombotic events may yet be found. The recent discovery of post-vaccination thromboses associated with platelet factor 4 antibody has created another level of concern. The pathogenesis of antiphospholipid antibodies and their role in COVID-19-related thrombosis deserves further attention. The multifactorial nature of thrombosis associated with both infection and vaccination should continue to be studied as new events unfold. Even if a cause-and-effect relationship is variable at best, such dedicated research is likely to generate other valuable insights that are applicable to medicine generally.

Neurologic Manifestations of the Antiphospholipid Syndrome - an Update

PURPOSE OF REVIEW

In recent years, the spectrum of neurological manifestations of antiphospholipid syndrome (APS) has been growing. We provide a critical review of the literature with special emphasis on presentation, proposed mechanisms of disease, and treatment of neurological involvement in APS.

RECENT FINDINGS

Although stroke is the most common cause of neurological manifestations in patients with APS, other neurological disorders have been increasingly associated with the disease, including cognitive dysfunction, headache, and epilepsy. Direct oral anticoagulants have failed to show non-inferiority compared to vitamin K antagonists for the prevention of major thrombotic events. Antiphospholipid antibodies are often found in patients with acute COVID-19 but clear evidence supporting an association between these antibodies and the risk of thrombotic events, including stroke and cerebral venous thrombosis, is still lacking. APS patients may present with several distinct neurological manifestations. New criteria will facilitate the classification of patients presenting with increasingly recognized non-criteria neurological manifestations.

B cells in primary antiphospholipid syndrome: Review and remaining challenges

It is now widely accepted that antiphospholipid antibodies (aPL) have direct pathogenic effects and that B cells, notably through aPL production, play a key role in the development of antiphospholipid syndrome (APS). Recent findings strengthened the implication of B cells with the description of specific B cell phenotype abnormalities and inborn errors of immunity involving B cell signaling in APS patients. In addition, it has been shown in preclinical models that cross-reactivity between APS autoantigens and mimotopes expressed by human gut commensals can lead to B cell tolerance breakdown and are sufficient for APS development. However, B cell targeting therapies are surprisingly not as effective as expected in APS compared to other autoimmune diseases. Elucidation of the B cell tolerance breakdown mechanisms in APS patients may help to develop and guide the use of novel therapeutic agents that target B cells or specific immune pathway.

Impact of SARS-CoV-2 infection on the recovery of peripheral blood mononuclear cells by density gradient

SARS-CoV-2 virus infection is responsible for coronavirus disease (COVID-19), which is characterised by a hyperinflammatory response that plays a major role in determining the respiratory and immune-mediated complications of this condition. While isolating peripheral blood mononuclear cells (PBMCs) from whole blood of COVID-19 patients by density gradient centrifugation, we noticed some changes in the floating properties and in the sedimentation of the cells on density medium. Investigating this further, we found that in early phase COVID-19 patients, characterised by reduced circulating lymphocytes and monocytes, the PBMC fraction contained surprisingly high levels of neutrophils. Furthermore, the neutrophil population exhibited alterations in the cell size and in the internal complexity, consistent with the presence of low density neutrophils (LDNs) and immature forms, which may explain the shift seen in the floating abilities and that may be predictive of the severity of the disease. The percentage of this subset of neutrophils found in the PBMC band was rather spread (35.4 ± 27.2%, with a median 28.8% and IQR 11.6-56.1, Welch's t-test early phase COVID-19 versus blood donor healthy controls P < 0.0001). Results confirm the presence of an increased number of LDNs in patients with early stage COVID-19, which correlates with disease severity and may be recovered by centrifugation on a density gradient together with PBMCs.

Venous thromboembolism in people living with HIV infection (PWH)

The risk of venous thromboembolism (VTE) and of recurrent VTE remain elevated in people living with HIV compared to controls still with contemporary antiretroviral therapy (ART). The pathophysiology of VTE in HIV is multi factorial and includes an interplay among traditional risk factors, HIV-specific factors, behavioral factors, exposure to ART and other therapies, coinfections, and co-morbidities.

High Prevalence of Acquired Thrombophilia Without Prognosis Value in Patients With Coronavirus Disease 2019

Background Recent literature reports a strong thrombotic tendency in patients hospitalized for a coronavirus disease 2019 (COVID-19) infection. This characteristic is unusual and seems specific to COVID-19 infections, especially in their severe form. Viral infections can trigger acquired thrombophilia, which can then lead to thrombotic complications. We investigate for the presence of acquired thrombophilia, which could participate in this phenomenon, and report its prevalence. We also wonder if these thrombophilias participate in the bad prognosis of severe COVID-19 infections. Methods and Results In 89 consecutive patients hospitalized for COVID-19 infection, we found a 20% prevalence of PS (protein S) deficiency and a high (ie, 72%) prevalence of antiphospholipid antibodies: mainly lupus anticoagulant. The presence of PS deficiency or antiphospholipid antibodies was not linked with a prolonged activated partial thromboplastin time nor with D-dimer, fibrinogen, or CRP (C-reactive protein) concentrations. These coagulation abnormalities are also not linked with thrombotic clinical events occurring during hospitalization nor with mortality. Conclusions We assess a high prevalence of positive tests detecting thrombophilia in COVID-19 infections. However, in our series, these acquired thrombophilias are not correlated with the severity of the disease nor with the occurrence of thrombotic events. Albeit the strong thrombotic tendency in COVID-19 infections, the presence of frequent acquired thrombophilia may be part of the inflammation storm of COVID-19 and should not systematically modify our strategy on prophylactic anticoagulant treatment, which is already revised upwards in this pathological condition. Registration URL: https://www.clini​caltr​ials.gov; Unique identifier: NCT04335162.

A Covid-19 Patient with Complement-Mediated Coagulopathy and Severe Thrombosis

We report a patient with severe Covid-19-associated coagulopathy and type 2 diabetes mellitus who tested positive for antiphospholipid antibodies (aPL). Analysis of skin specimens suggested direct SARS-CoV-2 viral-induced and complement-mediated vascular injury and thrombosis, consistent with prior reports. Serial aPL testing demonstrated high levels of anticardiolipin antibodies (aCL) that declined to insignificant levels over a period of 5 weeks. SARS-CoV-2 RNA was detected in nasopharyngeal swab specimens on serial assays performed over the same 5-week period, though it was not detected thereafter. We hypothesize that SARS-CoV-2 viral-induced aPL contributed to severe Covid-19-associated coagulopathy in this patient.

Antiphospholipid syndrome

Antiphospholipid syndrome is one of the more common acquired causes of hypercoagulability. Its major presentations are thrombotic (arterial, venous, or microvascular) and pregnancy morbidity (miscarriages, late intrauterine fetal demise, and severe pre-eclampsia). Classification criteria include 3 different antiphospholipid antibodies: lupus anticoagulant, anticardiolipin, and anti-beta 2 glycoprotein I. Management includes both preventive strategies (low-dose aspirin, hydroxychloroquine) and long-term anticoagulation after thrombosis.

Positive Anti-SSA/Ro Antibody in a Woman with SARS-CoV-2 Infection Using Immunophenotyping: A Case Report

The clinical spectrum of novel coronavirus infection appears to be wide, encompassing asymptomatic infection, mild upper respiratory tract illness, and severe viral pneumonia, with respiratory failure and even death. Autoantibodies, especially antiphospholipid antibodies, can occur in severe infections. Other autoantibodies are seldom reported. Here, a 60-year-old female patient without dry-mouth symptoms detected positive for anti-60 kDa SSA/Ro antibodies on day 43 after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. To investigate this unique clinical case of SARS-CoV-2 infection, immunological characteristics of this case were detected by using flow cytometry and were compared to the other three groups of patients-health subjects, 2019 novel coronavirus disease (COVID-19) recovery patients, and Sjögren's syndrome (SS) patients. Monitoring the autoantibody level and the development of subsequently related autoimmune diseases are warranted after SARS-CoV-2 infection.

Flare of Antiphospholipid Syndrome in the Course of COVID-19

We report the case of a 48-year-old man followed since 2013 for primary antiphospholipid syndrome (APLS) revealed by venous thromboembolism in the presence of antiphospholipid antibodies (APL-Abs, anticardiolipin and anti-β-2-glycoprotein-1), who decompensated in the course of coronavirus disease (COVID-19). Despite efficient anticoagulation, he suffered bilateral adrenal glands hemorrhage and limb arterial ischemia. The tropism of severe acute respiratory syndrome coronavirus-2 for endothelium can lead to microangiopathy and increased risk for thrombosis. If APL-Abs positivity can be an epiphenomenon under inflammatory and prothrombotic conditions, COVID-19 was herein responsible for disseminated thrombosis and a threat of catastrophic APLS, despite efficient anticoagulation.

Autoimmunity as the comet tail of COVID-19 pandemic

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can give rise to different clinical manifestations that are directly related to viral tissue damage or indirectly induced by the antiviral immune response. Hyper-activation of the immune system in an attempt to eradicate the infection may trigger autoimmunity. Several immune-mediated disorders have been described in SARS-CoV-2-infected individuals. These include cutaneous rashes and vasculitis, autoimmune cytopenia, anti-phospholipid syndrome, central or peripheral neuropathy, myositis and myocarditis. On the other hand, rheumatic patients were reported to have similar coronavirus disease 2019 (COVID-19) incidence, morbidity and mortality rates compared to general population. This opinion review will summarize the crucial immunologic steps which occur during SARS-CoV-2-infection that may link autoimmunity to COVID-19 and provides an opportunity for further discussion regarding this association.

COVID-19-Related Stroke

The COVID-19 pandemic is associated with neurological symptoms and complications including stroke. There is hypercoagulability associated with COVID-19 that is likely a "sepsis-induced coagulopathy" and may predispose to stroke. The SARS-CoV-2 virus binds to angiotensin-converting enzyme 2 (ACE2) present on brain endothelial and smooth muscle cells. ACE2 is a key part of the renin angiotensin system (RAS) and a counterbalance to angiotensin-converting enzyme 1 (ACE1) and angiotensin II. Angiotensin II is proinflammatory, is vasoconstrictive, and promotes organ damage. Depletion of ACE2 by SARS-CoV-2 may tip the balance in favor of the "harmful" ACE1/angiotensin II axis and promote tissue injury including stroke. There is a rationale to continue to treat with tissue plasminogen activator for COVID-19-related stroke and low molecular weight heparinoids may reduce thrombosis and mortality in sepsis-induced coagulopathy.

Sudden Sensorineural Hearing Loss in Systemic Lupus Erythematosus and Antiphospholipid Syndrome: A Clinical Review

BACKGROUND

Sudden sensorineural hearing loss (SSNHL) is defined as a sudden loss of hearing, usually unilateral, of more than 30 dB in 3 contiguous frequencies of the tonal audiometry. SSNHL estimates an incidence ranging from 5 to 20 per 100.000 people per year. In approximately 75% of cases, a cause cannot be identified. However, it could be a clinical manifestation of Systemic lupus erythematosus (SLE) and Antiphospholipid Syndrome (APS).

OBJECTIVE

This review will focus on the clinical presentation, diagnosis, and management of the SLE and APS associated SSNHL.

METHODS

We searched in PubMed, Scopus, Lilacs, and Cochrane reviewing reports of Sudden sensorineural hearing loss in SLE and/or APS. Articles written in English and Spanish, and were available in full text, were included.

RESULTS

In patients with SLE, bilateral involvement was frequent. Antiphospholipid antibodies were positive in the majority of the patients. Corticosteroids were the mainstay of the treatment. The auditory prognosis was poor with total hearing loss recovery reached in only 22% of patients. On the other hand, most of the patients with SSNHL and APS were males and presented associated symptoms such as vertigo, tinnitus and/or headache, 75% had bilateral disease. Lupus anticoagulant and aCL were found in equal proportions, all patients were anticoagulated, and aspirin was associated in 25% of the cases. Complete resolution or improvement of symptoms was observed in 25% of the patients.

CONCLUSION

Sudden sensorineural hearing loss, can be a clinical feature of SLE and APS. Treating physicians should be aware of this devastating complication, especially when bilateral involvement occurs.

Advances in the Research on Anticardiolipin Antibody

Anticardiolipin antibody (ACA) is a kind of autoantibody and is one of the antiphospholipid antibodies (aPLs). Phospholipids with a negative charge on platelets and endothelial cell membranes are ACA target antigens. ACA is common in systemic lupus erythematosus and other autoimmune diseases and is closely associated with thrombosis, thrombocytopenia, and spontaneous abortion. In 1983, Harris established a method for detecting ACA, and research on the antibody has gained worldwide attention and has developed rapidly. For this review, we browsed articles that cover most of the ACA-related studies in the last 25 years and extracted influential ideas and conclusions in this field.

Environmental Triggers of Autoreactive Responses: Induction of Antiphospholipid Antibody Formation

Antiphospholipid antibodies (aPLs) comprise a diverse family of autoantibodies targeted against proteins with the affinity toward negatively charged phospholipids or protein-phospholipid complexes. Their clinical significance, including prothrombotic potential of anti-cardiolipin antibodies (aCLs), anti-β2-glycoprotein I antibodies (aβ2-GPIs), and lupus anti-coagulant (LA), is well-established. However, the ontogeny of these pathogenic aPLs remains less clear. While transient appearance of aPLs could be induced by various environmental factors, in genetically predisposed individuals these factors may eventually lead to the development of the antiphospholipid syndrome (APS). Since the first description of APS, it has been found that a wide variety of microbial and viral agents influence aPLs production and contribute to clinical manifestations of APS. Many theories attempted to explain the pathogenic potential of different environmental factors as well as a phenomenon termed molecular mimicry between β2-GPI molecule and infection-relevant structures. In this review, we summarize and critically assess the pathogenic and non-pathogenic formation of aPLs and its contribution to the development of APS.

Radionuclide imaging of inflammation in atherosclerotic vascular disease among people living with HIV infection: current practice and future perspective

People living with human immunodeficiency virus (HIV) infection have twice the risk of atherosclerotic vascular disease compared with non-infected individuals. Inflammation plays a critical role in the development and progression of atherosclerotic vascular disease. Therapies targeting inflammation irrespective of serum lipid levels have been shown to be effective in preventing the occurrence of CVD. Radionuclide imaging is a viable method for evaluating arterial inflammation. This evaluation is useful in quantifying CVD risk and for assessing the effectiveness of anti-inflammatory treatment. The most tested radionuclide method for quantifying arterial inflammation among people living with HIV infection has been with F-18 FDG PET/CT. The level of arterial uptake of F-18 FDG correlates with vascular inflammation and with the risk of development and progression of atherosclerotic disease. Several limitations exist to the use of F-18 FDG for PET quantification of arterial inflammation. Many targets expressed on macrophage, a significant player in arterial inflammation, have the potential for use in evaluating arterial inflammation among people living with HIV infection. The review describes the clinical utility of F-18 FDG PET/CT in assessing arterial inflammation as a risk for atherosclerotic disease among people living with HIV infection. It also outlines potential newer probes that may quantify arterial inflammation in the HIV-infected population by targeting different proteins expressed on macrophages.

The sexual dimorphism of anticardiolipin autoantibodies in acute Q fever patients

OBJECTIVES

Q fever is a zoonotic disease caused by Coxiella burnetii which affects men more than women (sex ratio men/women: 2.2). Acute Q fever complications are associated with elevation of anticardiolipin (aCL) antibodies. Here, we investigate the sexual dimorphism of aCL antibodies during acute C. burnetii infection.

METHODS

IgG aCL antibodies were evaluated at the time of Q fever serological diagnosis with enzyme-linked immunosorbent assay. Results were analysed according to sex.

RESULTS

Among the 1323 patients with Q fever tested for aCL, 1013 had acute Q fever (692 men/321 women) and 310 had persistent focalized infection (226 men/84 women). In cases of acute Q fever, men presented a significantly higher proportion of positive aCL antibodies (351/692, 50.7%) than women (113/321, 35.2%) (p <0.05). In addition, men had significantly higher aCL antibodies levels than women (p <0.001).

CONCLUSIONS

We highlight a relationship between sex and markers of autoimmunity during Q fever. Further investigations are necessary to better understand the mechanisms of this sexual dimorphism.

Diagnostic Utility of Separate Anti-Ro60 and Anti-Ro52/TRIM21 Antibody Detection in Autoimmune Diseases

Anti-SS-A antibodies are often sought for in autoimmune diseases diagnosis. Two different target proteins have actually been identified: Ro52 and Ro60. Clinical and immunological associations seem different depending on anti-Ro52 or anti-Ro60 antibodies presence. However, due to a heterogeneous presentation in the literature, some immunology laboratories in France have stopped providing anti-Ro52 antibody findings. We report here a new hospital study designed to determine the diagnostic utility of the separate detection of anti-Ro52 and anti-Ro60 antibodies. We conducted a retrospective, observational study, including every adult patient with positive antinuclear antibodies (ANA) tested in our immunology laboratory, and associated with anti-Ro52 and/or anti-Ro60 antibodies, between 2011 and 2014. Out of 13032 sera tested for ANA, 399 adults had antibodies to Ro52 and/or Ro60; 81.7% were female, with a mean age of 54.5 ± 17.0 years. Anti-Ro52 antibodies were found in 75.7% of the patients and anti-Ro60 antibodies in 56.9%. Among them, 43.1% were classified in the Ro52 + Ro60- group, 32.6% in the Ro52 + Ro60 + group and 24.3% in the Ro52-Ro60+ group. In the Ro52-Ro60+ group, systemic lupus was the most frequent diagnosis (48.5%), with a possible association with antiphospholipid antibodies (anti-cardiolipin antibodies: OR 2.5 (CI95 [1.0-5.0], p = 0.05) and lupus anticoagulant {OR 3.6 (CI95 [1.10-10.0] p = 0.02)}. In the Ro52+Ro60+, primary Sjögren Syndrome was the most likely (OR 4.2 95% CI [2.1-8.3] p < 10^-4), especially in patients Ro52+Ro60+La+. Patients with isolated anti-Ro52 had a wider variety of diseases associated, but among auto-immune diseases they were more prone to inflammatory myositis (OR 10.5 [1.4-81.7], p = 0.02) and inflammatory rheumatism (OR 4.6 [1.6-13.8], p = 0.006) in contrast to systemic lupus (OR 0.2 [0.1-0.3], p < 10^-4) or primary Sjögren's syndrome (OR 0.1 [0.06-0.2], p < 10^-4). We therefore suggest that, when anti-ENA antibodies are prescribed, it should include separate anti-Ro52 and anti-Ro60 antibodies determination. To go even further, we would like to suggest a change in ENA nomenclature to avoid confusion, abandoning the anti-SS-A label in favor of the anti-Ro52/TRIM21 or anti-Ro60 antibody for a clearer designation.

Antı-β2 Glycoprotein I Antibodies in Children with Rheumatologic Disorders

Anti-beta-2-glycoprotein I antibodies (anti-β2GPI) which are the main antiphospholipid antibodies that characterize the autoimmune "antiphospholipid syndrome" are pathogenic and are contributing to thrombosis. We aimed to evaluate the presence and the diagnostic importance of these antibodies in children with different rheumatologic diseases with or without thrombosis risk. A total of 100 children with different rheumatologic diseases evaluated retrospectively. The mean anti-β2GPI IgG (p = 0.108), IgA (p = 0.547), and IgM (p = 0.807) levels showed no statistically significant difference between different diagnosis groups. But anti-β2GPI IgA and IgM levels were higher in SLE patient group. The mean anti-β2GPI IgG (p = 0.375), IgA (p = 0.811), and IgM (p = 0.276) levels were not also showed difference between disease groups with/without predisposition to thrombosis even though concentrations were higher in thrombosis group. In children with rheumatological complaints, anti-β2GPI antibody measurements should not be the first diagnostic criteria if vasculitis is not thought as the primary defect underlying the clinical symptoms.

Considering hepatitis C virus infection as a systemic disease

Hepatitis C virus (HCV) infection has been demonstrated to result in several adverse hepatic outcomes and has been associated with a number of important extrahepatic manifestations. The scope of extrahepatic clinical possibilities includes systemic diseases such as vasculitis and lymphoproliferative disorders, cardiovascular disease, myalgia, arthritis, and sicca syndrome. These end-organ effects of HCV may dominate the clinical course beyond the hepatic complications and significantly worsen the long-term prognosis of infected patients. Until several years ago, the standard of care for the treatment of HCV infection had been interferon-alpha-based regimens, which not only had limited effectiveness in achieving a cure but were often poorly tolerated, especially in patients with kidney disease. In those HCV-infected patients with significant systemic manifestations, the interferon-based regimens were problematic given their association with a wide variety of toxicities. The development of highly effective direct-acting antiviral agents to treat HCV infection presented an opportunity to improve the HCV care cascade with the eradication of HCV in most infected patients and by reducing the burden of both hepatic and extrahepatic complications.

A case of syphilis presenting with prolonged etiology-unrevealed fever, accompanying activated partial thromboplastin time prolongation

A 58-year-old woman presenting with 3-week-prolonged fever was referred to our department. Her present history and physical examination results were unremarkable. Her activated partial thromboplastin time (APTT) was prolonged. Upon further investigation, anticardiolipin/beta2-glycoprotein I complex antibodies (CL-β2GPI) were detected, occasionally associated with syphilis. On day 14 of her fourth visit as an outpatient, serological tests confirmed the diagnosis, with newly appeared roseola on her palms and soles. She was in the transitional phase to secondary syphilis. Four months later, after successful treatment, her APTT was normalized with CL-β2GPI negative. Syphilis should be considered in patients with APTT prolongation.

Insights into the diagnosis and pathogenesis of the antiphospholipid syndrome

The Antiphospholipid syndrome (APS), formerly known as Anticardiolipin or Hughes syndrome, is a systemic autoimmune disorder characterized by obstetrical complications and thrombotic events affecting almost every organ-system in patients persistently testing positive for antiphospholipid antibodies (aPL). The contribution of the extra-criteria aPL to the pathogenesis of APS have exceeded the expectations of a simple, direct pathologic 'hit' leading to thrombogenesis or obstetrical complications, and more pathologic pathways are being linked directly or indirectly to aPL. The value of extra-criteria aPL is on the rise, and these antibodies are nowadays evaluated as markers for risk assessment in the diagnostic approach to APS. A diagnosis of APS should be considered in pediatric patients with suggestive clinical and laboratory picture. Management of APS remains mostly based on anticoagulation, while other drugs are being tested for efficacy and side effects. Low-dose aspirin may have a role in the management of thrombotic and obstetric APS. Due to the high variability in disease severity and complication recurrence outcomes, new tools are being developed and validated to assess the damage index and quality of life of APS patients.

Role of Infectious Diseases in the Antiphospholipid Syndrome (Including Its Catastrophic Variant)

PURPOSE OF REVIEW

The antiphospholipid syndrome (APS) is characterized by the development of thrombotic events and pregnancy morbidity in the presence of antiphospholipid antibodies (aPL). An infectious etiology for this syndrome has been postulated. The present review is aimed to summarize recent evidence about the role of infections and vaccines in the pathogenesis of the APS (including its catastrophic variant).

RECENT FINDINGS

There is an increased risk of developing aPL in various infections, particularly in viral infections. The most frequent infection related to aPL has been hepatitis C virus. These antibodies may be associated with thromboembolic events, including catastrophic APS. There is a link between vaccinations, such as the tetanus toxoid and aPL, due to molecular mimicry between the two molecules. Accumulated evidence supports that the presence of aPL is associated with a variety of infections, including viruses, bacteria, fungi, and parasites, and the main mechanism to explain this correlation is molecular mimicry. Moreover, a link between vaccinations, such as the tetanus toxoid, and APS has also been described.