Antiphospholipid syndrome associated with infections: clinical and microbiological characteristics

Antiphospholipid antibodies (aPL) were originally detected in human serum almost 100 years ago when the Venereal Disease Research Laboratory (VDRL) test was described. A phospholipid called cardiolipin was the major tissue extract utilized in performing these tests. In 1983, cardiolipin was used for the first time as the antigen in solid-phase aPL specific assays for the now termed antiphospholipid syndrome (APS). Since then, many infections have been found to be associated with aPL positivity, although a pathogenic role for these antibodies was not usually obvious except in a few isolated cases.     

Catastrophic antiphospholipid syndrome (CAPS): Descriptive analysis of a series of 280 patients from the “CAPS Registry”

ObjectiveTo describe the clinical and laboratory features, as well as the precipitating factors, treatment and outcome of patients with catastrophic antiphospholipid syndrome (APS).MethodsWe analyzed the 280 patients included until September 2008 in the website based international registry of patients with catastrophic APS (“CAPS Registry”) (http://www.med.ub.es/MIMMUN/FORUM/CAPS.HTM).ResultsThe entire series includes 201 (72%) female and 79 (28%) male patients with a mean age of 37 ± 14 years (range, 11–60 years). A total of 129 (46%) patients suffered from primary APS, 112 (40%) from systemic lupus erythematosus, 14 (5%) from lupus-like disease, and 25 (9%) from other autoimmune diseases. The catastrophic episode was the first manifestation of the APS in 129 (46%) patients. A precipitating factor was reported in 53% of the patients. The first clinical manifestation at the time of the catastrophic episode was a pulmonary complication in 24% of the cases, a neurologic feature in 18% and a renal feature in 18%. During the catastrophic episode, intraabdominal involvement was identified in the majority of patients, mainly consisting of renal (71%), hepatic (33%), gastrointestinal (25%), splenic (19%), adrenal (13%), and pancreatic (8%) manifestations. 123 (44%) patients died at the time of the catastrophic APS event but the higher recovery rate was achieved by the combination of anticoagulants plus corticosteroids plus plasma exchange (PE) and/or intravenous immunoglobulins (IVIG) (69% versus 54%).ConclusionsThe catastrophic APS is an uncommon but potentially life-threatening condition that needs high clinical awareness. The therapeutical connotation is that this may be corrected with the combination of anticoagulation plus steroids plus attempts at achieving a prompt reduction of antiphospholipid antibody titer (i.e. PE and/or IVIG).     

The antiphospholipid antibody syndrome: A riddle wrapped in a mystery inside an enigma

The antiphospholipid antibody syndrome (APS) is the association of certain clinical features with the presence of antiphospholipid antibodies (APA) in the serum or plasma of affected individuals. APS may be primary or secondary to another disease, typically autoimmune diseases such as systemic lupus erythematosus (SLE).The prototypic clinical features are thrombotic events (venous and arterial) and pregnancy morbidity (recurrent fetal loss, severe preeclampsia, eclampsia, and multiple spontaneous abortions). The term antiphospholipid antibody is a misnomer since it now appears that APA are actually directed against protein phospholipid complexes. APA may also occur secondary to infections however these APA seem to be directed at phopsholipid only and are transient. Particular phospholipid-binding proteins associated with APS include beta 2-glycoprotein I (B2GPI), prothrombin, and annexin V. A recent International Consensus Statement defines Definite APS as the presence of certain clinical findings (either a thrombotic event and/or pregnancy morbidity) and the presence and persistence of laboratory evidence of APA [either the lupus anticoagulant (LA) and/or anticardiolipin antibodies (ACL)]. Other clinical features associated with APS include thrombocytopenia, various skin conditions, cardiac valvular diseases, and diverse neurological conditions as outlined in the main text. These other features may be part of APS but require further evidence to establish their pathological and clinical validity. Other laboratory tests of interest include anti-B2GPI, antiprothrombin, and antiphosphatidylserine antibodies. The diagnostic and clinical importance of these additional laboratory tests remains to be determined.APA are estimated to be present in up to 5% of the general population, with the prevalence increasing with age. APA are estimated to be present in 12% or more of patients with thrombosis. ACL are present in 12 to 30% of patients with SLE and LA are present in 15 to 34% of patients with SLE. There is often concordance between LA and ACL however this is not always true. APA (both ACL and LA) are associated with thromboembolic events. Venous thrombosis is more common than arterial thrombosis and a minority of patients have both. LA is more strongly associated with thrombosis than ACL. The estimated yearly incidence of thrombosis in individuals with APA is 1% for those with no history of thrombosis, 4% for those with SLE, and 6% for those with high titer immunoglobulin G (IgG) ACL. The presence of LA, and possibly of medium to high titers of IgG ACL, help identify patients at risk for thrombosis.     

B-cell directed therapies in antiphospholipid antibody syndrome--new directions based on murine and human data

The increased awareness of the role of humoral immunophysiology in antiphospholipid syndrome (APS) has aroused interest in B cells as therapeutic targets in this disease. This paper reviews the literature on B cell directed therapies in human and experimental APS. The clinical data is limited to B cell depletion with rituximab and comprises case reports and case series. Murine studies include use of modulators of B cell function such as belimumab and abatacept. In both human and murine studies, B cell directed therapies appeared to have clinical and serologic beneficial effects including a decrease in the antiphospholipid antibody titers after treatment. Randomized controlled clinical trials are needed to determine whether B cell depletors and/or B cell modulators can be effective agents for treating patients with APS.     

Catastrophic antiphospholipid syndrome: therapeutic developments

The catastrophic antiphospholipid syndrome is a potentially life-threatening condition with a high mortality rate, the diagnosis of which requires a high degree of clinical awareness on the part of attending physicians. Patients with this syndrome have various symptoms in common: clinical evidence of multiple organ involvement developed over a very short time period, histopathological evidence of multiple small-vessel occlusions and laboratory confirmation of the presence of antiphospholipid antibodies, usually in high titers. The combination of high doses of intravenous heparin, steroids, γ-globulins and/or repeated plasma exchanges are the basic treatment of choice for all patients with this severe condition.     

Intravenous immunoglobulin therapy in antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disorder defined by the occurrence of venous and arterial thromboses and pregnancy morbidity, frequently accompanied by a moderate thrombocytopenia, in the presence of antiphospholipid antibodies. There is both laboratory and clinical evidence for the beneficial role of intravenous immunoglobulin (IVIg) in APS. Data on the use of IVIg in patients with APS have focused on its obstetric complications and antiphospholipid antibodies-positive patients undergoing in vitro fertilization, but there are also case reports about treatments of other clinical manifestations (mainly hematological) of the syndrome. Future research should determine when to use anticoagulation, IVIg, or both in the treatment of APS.     

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.     

Pregnancy: Low-dose aspirin for prevention of pregnancy losses in women with primary antiphospholipid syndrome

Pregnancy loss, often recurrent, is one of the most importantclinical manifestations associated with the primary antiphospholipidsyndrome. In these cases, pregnancy wastage is related to thepresence of antiphospholipid antibodies, namely lupus anticoagulantand anticardiolipin antibodies, but patients do not have featuresof systemic lupus erythematosus or any other well-defined autoimmunedisease. We report here on the outcome of 21 consecutive pregnanciesin 18 patients with the syndrome who were treated with low-doseaspirin (100 mg/day) from 1 month before attempting conceptionand throughout the pregnancy. Low-dose prednisone (15–30mg/day) was added for potentially non-obstetric (autoimmune-related)reasons in six pregnancies. Patients were monitored as havinghigh-risk pregnancies. Prior to therapy, the rate of live-bornbabies was 6.1% (46 previous fetal losses and three live-bornbabies), and after therapy, it was 90.5% (21 pregnancies and19 live-born babies). Pre-term delivery due to maternal or fetalindications was required in 15% (3/20) of the viable pregnancies.Except for prematurity (20% of viable pregnancies) and its potentialassociated complications, there were no significant adverseeffects to either mothers or babies. Our treatment modalityis advocated for prevention of pregnancy losses in patientswith the ‘obstetric’ primary antiphospholipid syndrome.     

APhL antibody ELISA as an alternative to anticardiolipin test for the diagnosis of antiphospholipid syndrome

Background

Persistent levels of antiphospholipid (aPL) antibodies [lupus anticoagulant (LA), anticardiolipin (aCL), anti-beta 2 glycoprotein I (aβ₂GPI) IgG and/or IgM] in association with clinical features of thrombosis and/or pregnancy associated morbidity are indicative of antiphospholipid syndrome (APS). Of the aPL antibodies, aCL is the most sensitive for APS, however, their lack of specificity constitute a laboratory and clinical challenge. IgG/IgM antibodies directed against APhL (a mixture of phospholipids) has been reported to predict APS more reliably than aCL tests. The main objective of this study was to evaluate the performance characteristics of the APhL IgG/IgM ELISA, relative to the aCL and aβ₂GPI tests.

Methods

Sixteen (16) clinically confirmed APS and 85 previously tested serum (PTS) samples for aCL and aβ₂GPI IgG/IgM antibodies were evaluated with the APhL IgG/IgM ELISA. Clinical specificity was determined in 100 serum samples (50 healthy and 50 infectious disease controls [parvo- and syphilis-IgG/IgM positive]).

Results

The IgG antibody prevalence for aCL and APhL in the APS and PST groups was comparable with marginal differences in clinical specificities. In contrast to the aCL IgM ELISA, the APhL test showed improved clinical specificities (72% aCL vs 94% APhL in the healthy controls; 38% aCL vs 78% APhL in the infectious disease controls) with implications for increased reliability in the diagnosis of APS. The overall agreement of the APhL with the aCL or aβ₂GPI for the IgG tests was 89% and 85% respectively, and that of the APhL IgM to the aCL or aβ₂GPI IgM tests was 72% and 86% respectively.

Conclusion

Routine use of the APhL IgG/IgM ELISA may substantially reduce the high number of false positives associated with the aCL test without loss in sensitivity for APS.     

Classification of primary antiphospholipid syndrome as systemic lupus erythematosus: Analysis of a cohort of 214 patients

Objectives

To assess the limitations of the SLICC (Systemic Lupus International Collaborating Clinics) classification criteria for systemic lupus erythematosus (SLE), in patients with primary antiphospholipid syndrome (PAPS).

IgG accumulates in inhibitory hippocampal neurons of experimental antiphospholipid syndrome

Mice immunized with β₂-glycoprotein I (β₂GPI) are an experimental model of the antiphospholipid syndrome (eAPS) displaying elevated titers of antiphospholipid antibodies (aPL). We presently studied whether the behavioral hyperactivity in eAPS mice is associated with in vivo binding and accumulation of IgG in the brain. At 6 weeks post immunization eAPS mice had significantly higher levels of aPL (1.32 ± 0.28 and 0.02 ± 0.01 AU, p < 0.001 by t-test) compared to adjuvant immunized controls, as measured by ELISA. Significant hyperactivity in a staircase test in the eAPS mice compared to controls was found in stair-climbing (18.4 ± 0.9 and 12.0 ± 1.7, respectively) and rearing measures (23.5 ± 2.1 and 12.5 ± 1.9, p < 0.01 by t-test). Immunofluorescence staining in eAPS mice revealed significant in vivo accumulation of IgG in cortical and hippocampal neurons which was not seen in controls. Staining for IgG was markedly intense in inhibitory interneurons co-stained for GAD67 in the hippocampus of eAPS mice. The integrity of the blood brain barrier (BBB) evaluated by injection of Evans blue (EB) was impaired in eAPS and adjuvant immunized mice compared to naïve mice. Electrophysiological recordings in hippocampal brain slices showed altered response to paired pulse stimulation as well as dysregulation of carbachol-induced γ- oscillations in eAPS mice compared to control. Penetration into the brain and direct interaction of aPL with inhibitory interneurons in the hippocampus may explain the hyperactive behavior of the eAPS mice. A direct role of aPL in causing CNS dysfunction points to these antibodies as an important therapeutic target in APS.     

Cardiac valvulopathy in the antiphospholipid syndrome

The Libman and Sacks non bacterial endocarditis was reported in 1924 in patients with SLE. Its relation to the anti cardiolpin syndrome has only been described as recently as the last decade. In this paper we review the deposition of theses antibodies on the valve with complement components initiating the deformation of the valve. The valvulopathy in APS is quite common and may lead to valve replacement. In addition, a diversity of manifestations are detailed. More awareness should be drawn to this new complication of APS.     

beta2-glycoprotein I, the playmaker of the antiphospholipid syndrome

From its discovery in the early 60s till the beginning of the 90s, there was not much interest in plasma protein beta2-glycoprotein I (beta2-GPI). The finding that beta2-GPI acts as an essential cofactor for the detection of antiphospholipid antibodies (aPL) tremendously increased the interest in beta2-GPI [Lancet 335 (1990) 1544; Lancet 336 (1990) 177; Proc. Natl. Acad. Sci. U. S. A. 87 (1990) 4120]. It is now generally accepted that autoantibodies directed towards beta2-GPI are not only a serological marker but that they are involved in the pathology of the antiphospholipid syndrome (APS). In this review, we will first discuss the biochemistry of the protein beta2-GPI and the influence that the antibodies have on the function of beta2-GPI. Next, we will discuss the problems that are faced when assays to detect the presence of the autoantibodies are performed, emphasizing the urgent need for standardization of the anti-beta2-GPI-ELISA. Finally, we will discuss our latest insights into beta2-GPI and its role in the pathology of APS. Thereby, we will focus on the role of dimerized beta2-GPI on platelet and endothelial cell function.     

Management of pregnant women with antiphospholipid antibodies

Introduction: Important advancements in pregnancy outcome have been reported in women with antiphospholipid antibodies (aPL), despite the fact that the treatment of aPL related pregnancy morbidity is not guided by consistent findings from well-designed trials.

Areas covered: The current study draws a picture of the studies in the literature by performing a Medline search of relevant English language articles and reports our experience in managing different subsets of obstetric antiphospholipid syndrome (APS), defined on the basis of their clinical and laboratory characteristics. The management of pregnant women with non-criteria APS manifestations and that of aPL carriers during their first pregnancy is also examined.

Expert commentary: A heparin/aspirin combination constitutes conventional treatment for APS affected pregnant women. As this strategy fails in approximately 20–30% of cases, uncovering other options for women refractory to conventional treatment or at high risk of pregnancy complications has become an urgent undertaking. Some attempts have been made to prescribe additional treatments in the effort to improve live birth rates and/or reduce pregnancy complications, which often occur even in patients treated conventionally. The evidence from some studies and an individual risk/benefit assessment should instead guide treatment decisions for pregnant patients with non-criteria APS manifestations and aPL carriers.     

Identification of a peptide mimicking the binding pattern of an antiphospholipid antibody

Our objective was to characterize monoclonal antiphospholipid antibodies (APL) and identify disease-associated antigens in patients with the antiphospholipid syndrome (APS). We used the monoclonal antibody HL-5B, derived from a patient with APS suffering from multiple ischemic events, to screen a 12-mer peptide phage display library (New England Biolabs, London, England). The identified phage clones were sequenced and the derived consensus peptide was synthesized. The peptide was used to perform competitive inhibition experiments for their ability to inhibit the binding of the monoclonal antibody and of serum antibodies to cardiolipin and phosphatidylserine. Additionally patients and control sera were screened for their binding reactivities to this peptide. Using this 12-mer phage display library the peptide APHKHKASLSIY as consensus peptide for the monoclonal antiphospholipid antibody HL-5B could be identified. In competitive inhibition studies we showed that this peptide is able to inhibit the binding of HL-5B to cardiolipin and phosphatidylserine and furthermore another antiphospholipid antibody used as control was also inhibited in its binding to phospholipids. Using 21 sera from APS patients 67% showed a binding to the peptide in a specific ELISA above the cutoff level, generated with sera from 20 healthy controls. Out of the reactive patients' sera we used two exemplarily to perform inhibition studies. Both sera could be inhibited more than 40% in their binding to cardiolipin in a commercially available antiphospholipid antibody assay (Aescu.diagnostics, Wendelsheim, Germany). The identified peptide APHKHKASLSIY simulates the antigenic structure recognized from a subpopulation of serum antiphospholipid antibodies. This might indicate that the diversity of the antiphospholipid antibodies is limited and only few epitopes or few common structures are responsible for the development of those antibodies. Tests using these epitopes will strongly improve laboratory diagnosis of the APS.     

HIBISCUS: Hydroxychloroquine for the secondary prevention of thrombotic and obstetrical events in primary antiphospholipid syndrome

The relapse rate in antiphospholipid syndrome (APS) remains high, i.e. around 20%–21% at 5?years in thrombotic APS and 20–28% in obstetrical APS [2, 3].Hydroxychloroquine (HCQ) appears as an additional therapy, as it possesses immunomodulatory and anti-thrombotic various effects [4–16].Our group recently obtained the orphan designation of HCQ in antiphospholipid syndrome by the European Medicine Agency.Furthermore, the leaders of the project made the proposal of an international project, HIBISCUS, about the use of Hydroxychloroquine in secondary prevention of obstetrical and thrombotic events in primary APS. This study has been launched in several countries and at now, 53 centers from 16 countries participate to this international trial.This trial consists in two parts: a retrospective and a prospective study.The French part of the trial in thrombosis has been granted by the French Minister of Health in December 2015 (the academic trial independent of the pharmaceutical industry PHRC N PAPIRUS) and is coordinated by one of the members of the leading consortium of HIBISCUS.     

The emerging role of multiple antiphospholipid antibodies positivity in patients with antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by clinical symptoms of vascular thrombosis and/or pregnancy morbidity in the presence of autoimmune antiphospholipid antibodies (aPL). Current laboratory APS criteria include the presence of at least one of the three relevant aPL: lupus anticoagulant, anticardiolipin antibodies and anti-β₂ glycoprotein I antibodies. Therefore, patients could have a single aPL pattern or combinations of aPL. Evidence arising from clinical experience indicates that patients having the highest aPL titer and simultaneous aPL detected by different tests have a worse prognosis and a higher probability of recurrence of the APS clinical features. In recent years, an emerging role of multiple aPL positivity in the identification of high-risk patients with aPL/APS is evident. This paper will review the current knowledge on the clinical relevance of having single or multiple aPL positivity.     

Clinical profiles and risk assessment in patients with antiphospholipid antibodies

Introduction: Antiphospholipid syndrome (APS) is an acquired autoimmune thrombophilia associated with the presence of persistent antiphospholipid antibodies (aPL). Owing to recent studies, not only APS patients but also incidentally-identified, asymptomatic aPL carriers are able to be stratified in terms of the risk of future thrombotic events, according to the variety and the titer of positive aPL tests and to the non-thrombotic, aPL-associated clinical manifestations.

Areas covered: Here, we critically review (1) criteria manifestations of APS, (2) non-criteria manifestations of APS, (3) risk assessment in patients with APS and in aPL carriers, and (4) the potential role of primary thrombosis prophylaxis in aPL carriers. In addition, we discuss what we are currently able to do and what we need to do in the future for primary prophylaxis against a first thrombotic event.

Expert commentary: We suggest a comprehensive algorithm to stratify thrombotic risk in aPL carriers, including criteria aPL, non-criteria aPL, their scoring systems, and non-criteria manifestations. However, further studies, particularly prospective randomized controlled trials, are highly warranted to establish an effective and tolerable treatment regimen for high risk aPL carriers.     

Update on the current recommendations and outcomes in pregnant women with antiphospholipid syndrome

Pregnancy morbidity is part of the clinical spectrum of the antiphospholipid syndrome (APS), a chronic autoimmune condition serologically characterized by the persistent positivity of antiphospholipid antibodies (aPL). Antiplatelet and anticoagulant agents are the mainstay of the treatment of obstetric APS. However, there is an ongoing debate about the optimal management of women with most severe aPL-mediated obstetric complications, women not fulfilling APS criteria and those with refractory disease. Unfortunately, the literature cannot provide definite answers to these controversial issues, being flawed by many limitations. The evidence supporting the recommended therapeutic management of different aPL-related obstetrical clinical manifestations is presented, with a critical appraisal of each approach.