Seronegative antiphospholipid syndrome

[Seronegative antiphospholipid syndrome, catastrophic syndrome, new anticoagulants: learning from a difficult case report]

INTRODUCTION

The diagnosis of the antiphospholipid syndrome (APS) is based on clinical and biological criteria including the persistent presence of antiphospholipid antibodies and thrombotic events or pregnancy morbidity. Heparins relayed by vitamin K antagonists (VKA) are the gold standard treatment for thrombosis.

CASE REPORT

We report a 17-year-old man who presented with an initially seronegative antiphospholipid syndrome, in whom the diagnosis was late, only obtained after anticoagulation withdrawing, when a catastrophic antiphospholipid syndrome (CAPS) with cutaneous lesions and disseminated intravascular coagulation syndrome occurred. For personal convenience, this patient was initially treated with fondaparinux followed by a new oral anticoagulant (rivaroxaban) before to return to the conventional VKA treatment.

CONCLUSION

The "seronegative" APS is a controversial concept reflecting the heterogeneity of antigenic targets for aPL. This diagnosis may be considered after a rigorous work-up, with the help of haemostasis laboratories testing new emerging aPL assays. In APS, the new anticoagulants represent an attractive option needing nevertheless prospective studies to evaluate their safety and efficacy. Lupus anticoagulant detection in patients treated by new oral anticoagulants is not easy by usually recommended coagulation tests.

Antiphospholipid syndrome in Sarawak: real world experience in a developing country

We performed a cross-sectional study of all antiphospholipid syndrome (APS) patients during an 8-year period (2006-2013) to describe the clinical features, serology profiles, treatment regimes, and outcomes in our center. There were a total of 59 patients in our study with the female to male ratio of 9:1. They have a mean age of 41.6 ± 12.1 years and a mean duration of illness of 38.4 ± 68.5 months. The majority of patients presented with vascular thrombosis (69.5 %) with equal arterial and venous involvements. Twenty-six patients (44.1 %) presented with obstetric complications with recurrent abortions (32.2 %) as the main manifestation. Most patients were on daily warfarin doses of 2-6 mg (91.0 %) with target INR of 2-3. There was neither recurrent thrombosis nor bleeding complications documented. There were 80 % live births following treatment in our patients.

Systemic lupus erythematosus: prediction by MRI of the subsequent development of brain lesions

RATIONALE AND OBJECTIVES

Many patients with systemic lupus erythematosus (SLE) manifest the recurrence of new brain lesions on follow-up magnetic resonance imaging (MRI) scans. We assessed whether the initial MRI findings help to predict the subsequent development of brain lesions in patients with SLE.

MATERIALS AND METHODS

We enrolled 64 patients with SLE who had undergone initial and follow-up MRI studies. Two radiologists reviewed and categorized the initial MRI findings and divided the patients into those with no lesions on the initial and follow-up MRI scans (group A, n = 18), those with lesions on the initial scans only (group B, n = 32), and those with lesions on the first and new lesions on the follow-up MRI scans (group C, n = 14). We then looked for independent predictors of the subsequent development of brain lesions, such as antiphospholipid syndrome (APS) and findings on the initial MRI studies.

RESULTS

The incidence of lacunar and localized cortical infarcts was significantly greater in group C than group B (50% vs. 0%, P < .001 and 50% vs. 9%, P < .05, respectively). Multivariate logistic regression analysis indicated that lacunar or localized cortical infarcts on the initial MRI scans were independent predictors of the subsequent development of brain lesions (odds ratio [OR]: 5.412, 95% confidence interval [CI]: 1.18-24.85, P = .03), whereas the presence of APS was not (OR: 0.621, 95% CI: 0.18-2.19).

CONCLUSIONS

The presence of lacunar and/or localized cortical infarcts on initial MRI scans may predict the development of new brain lesions in patients with SLE.

The current standing of diagnosis of antiphospholipid syndrome associated with systemic lupus erythematosus

The antiphospholipid syndrome was first described in the early 1980s. The term was first coined to describe patients presenting with recurrent arterial and venous thrombosis or pregnancy complications. Antiphospholipid syndrome was first reported in systemic lupus erythematosus patients, but later on it became obvious that systemic lupus erythematosus is not a necessary condition for its occurrence. It has been shown that antibodies to phospholipids are the main causative agents of the disease, hence its name. The diagnosis of the disease has witnessed a remarkable evolution over the course of the past 25 years. With the observation that clinical parameters would not be enough to accurately diagnose the disease, antiphospholipid antibodies were recognized to play a central role in this regard. The main hindrance to an accurate diagnosis was the lack of standardization between different laboratory parameters that tested for the antiphospholipid antibodies. Lately, a combination of tests has been acknowledged to play a crucial role in diagnosis.

Isolated IgA anti- β2 glycoprotein I antibodies in patients with clinical criteria for antiphospholipid syndrome

Seronegative antiphospholipid syndrome (SNAPS) is an autoimmune disease present in patients with clinical manifestations highly suggestive of Antiphospholipid Syndrome (APS) but with persistently negative consensus antiphospholipid antibodies (a-PL). IgA anti-β2 Glycoprotein I (aB2-GPI) antibodies are associated with APS. However, they are not currently considered to be laboratory criteria due to the heterogeneity of published works and the use of poor standardized diagnostic systems. We have aimed to assess aPL antibodies in a group of patients with clinical manifestations of APS (C-APS) to evaluate the importance of the presence of IgA aB2GPI antibodies in APS and its relation with other aPL antibodies. Only 14% of patients with C-APS were positive for any consensus antibody, whereas the presence of isolated IgA aB2GPI antibodies was found in 22% of C-APS patients. In patients with arterial thrombosis IgA aB2GPI, antibodies were the only aPL antibodies present. Serologic profile in primary APS (PAPS) is different from systemic autoimmune disorders associated APS (SAD-APS). IgA aB2GPI antibodies are more prevalent in PAPS and IgG aB2GPI antibodies are predominant in SAD-APS. The analysis of IgA aB2GPI antibodies in patients with clinical manifestations of PAPS might avoid underdiagnosed patients and provide a better diagnosis in patients with SAD-APS. Laboratory consensus criteria might consider including analysis of IgA aB2GPI for APS diagnosis.

The mosaic of "seronegative" antiphospholipid syndrome

In the clinical practice it is possible to find patients with clinical signs suggestive of antiphospholipid syndrome (APS), who are persistently negative for the laboratory criteria of APS, that is, anti-cardiolipin antibodies (aCL), anti-β2-GPI antibodies and lupus anticoagulant. Therefore, it was proposed for these cases the term of seronegative APS (SN-APS). In order to detect autoantibodies with different methodological approaches, sera from 24 patients with SN-APS were analysed for anti-phospholipid antibodies using TLC immunostaining, for anti-vimentin/cardiolipin antibodies by enzyme-linked immunosorbent assay (ELISA), and for anti-annexin V and anti-prothrombin antibodies by ELISA and dot blot. Control groups of our study were 25 patients with APS, 18 with systemic lupus erythematosus (SLE), and 32 healthy controls. Results revealed that 13/24 (54.2%) SN-APS sera were positive for aCL (9 of whom were also positive for lysobisphosphatidic acid) by TLC immunostaining, 11/24 (45.8%) for anti-vimentin/cardiolipin antibodies, 3/24 (12.5%) for anti-prothrombin antibodies, and 1/24 (4.2%) for anti-annexin V antibodies. These findings suggest that in sera from patients with SN-APS, antibodies may be detected using "new" antigenic targets (mainly vimentin/cardiolipin) or methodological approaches different from traditional techniques (mainly TLC immunostaining). Thus, SN-APS represents a mosaic, in which antibodies against different antigenic targets may be detected.

B-Cell Targeted Therapies in Autoimmune Cytopenias and Thrombosis

Ever since the advent of Rituximab and subsequently the emergence of other compounds targeting B cells, a cornucopia of medical applications have been found for this family of compounds. After their establishment as standard of care in many conditions such as rituximab in lymphoma and rheumatoid arthritis, they have been progressively found to aid in the treatment of many other conditions. This area constituted a fertile area of research in the past 12 years. Physicians have investigated the B-cell depleting agents use in cases of autoimmune hematologic cytopenias such as immune thrombocytopenia, Evans syndrome, cold and warm autoimmune hemolytic anemia, and other thrombophilic disorders such as the antiphospholipid syndrome and thrombocytopenic purpura. This chapter presents a historical perspective reviewing the various studies that have been published in this field. In addition, it offers a current assessment of the evidence regarding the use of B-cell depleting agents in the aforementioned conditions.

TLC immunostaining for detection of "antiphospholipid" antibodies

Thin-layer chromatography (TLC) is a nonquantitative technique, which has been employed in the detection of antiphospholipid (aPL) antibodies. Antiphospholipid syndrome (APS) is the most frequently acquired thrombophilia, characterized by thrombosis and obstetric manifestations associated to an autoimmune trait, represented by the positivity of antiphospholipid (aPL) antibodies. Immunoassays for anticardiolipin (aCL) and anti-β2 glycoprotein I (aβ2GPI) antibodies and clotting tests for lupus anticoagulant (LA) represent the standard tests for the routine detection of aPL. The term "seronegative APS" has been used to describe patients with clinical manifestation of APS and persistently negative aPL assessed with routine assays. TLC immunostaining is a useful method for the detection of different antigenic targets of "antiphospholipid" antibodies; it is able to identify the reactivity of serum aPL experimented with purified phospholipid molecules with a different exposure compared to ELISA methods. This method seems to be applicable in patients who repeatedly tested negative for the standard aPL, i.e., aCL, aβ2GPI, and LA. Therefore, this technique may be proposed as a second step test for the diagnosis of APS.

Catastrophic antiphospholipid syndrome: diagnosis and management in pregnancy

Catastrophic antiphospholipid syndrome (CAPS) is a potentially lethal variant of antiphospholipid syndrome, characterized by multiorgan thrombosis in a short period of time, affecting mainly small vessels. In approximately 50% of CAPS cases, the catastrophic event is preceded by a trigger, mainly infections, or surgery, anticoagulation withdrawal, lupus flares, neoplasm, or pregnancy and puerperium. Treatment of CAPS is based on expert opinion and relies on a combination of several strategies, including anticoagulation, steroids, plasma exchange sessions, and/or intravenous immunoglobulins.

Seronegative antiphospholipid syndrome

APS is an autoimmune disease that leads to arterial and/or venous thrombosis, recurrent pregnancy loss and persistently positive aPLs. Patients with clinical manifestations highly suggestive of APS but persistently negative conventional aPLs are classified as having seronegative APS. Ongoing research has revealed the existence of non-criteria antibodies proposed to be relevant to APS and that can be potentially included in the disease's classification criteria. We present a literature review on the most promising antibodies of this heterogeneous aPL family, which includes antibodies to a zwitterionic phospholipid, namely phosphatidylethanolamine, phospholipid-binding plasma proteins, phospholipid-protein complexes and anionic phospholipids other than cardiolipin. Although these molecules can increase the diagnostic yield of APS, their clinical relevance is still debatable and needs to be confirmed by interlaboratory efforts toward standardizing diagnostic tools, in addition to experimental data and larger longitudinal studies.

Cerebral venous thrombosis revealing primary sjögren syndrome: report of 2 cases

Sjögren syndrome (SS) is an autoimmune disease of the exocrine glands, characterized by focal lymphocytic infiltration and destruction of these glands. Neurologic complications are quite common, mainly involving the peripheral nervous system (PNS). The most common central nervous system (CNS) manifestations are myelopathy and microcirculation vasculitis. However, specific diagnostic criteria for CNS SS are still lacking. We report two cases of primary SS in which the revealing symptom was cerebral venous thrombosis (CVT) in the absence of genetic or acquired thrombophilias.

Birds, babies and blood

This is an autobiographical review describing the author's career in immunology research and summarizing his current understanding of the areas involved. Contributions to autoimmunity, immune deficiency, transfusion immunology, HLA-disease associations, reproductive immunology, cellular therapies, and innate immunity are included; also discussion of medical research ethics and various research-related activities.

Diagnosis of antiphospholipid syndrome in routine clinical practice

The updated international consensus criteria for definite antiphospholipid syndrome (APS) are useful for scientific clinical studies. However, there remains a need for diagnostic criteria for routine clinical use. We audited the results of routine antiphospholipid antibodies (aPLs) in a cohort of 193 consecutive patients with aPL positivity-based testing for lupus anticoagulant (LA), IgG and IgM anticardiolipin (aCL) and anti-ß₂glycoprotein-1 antibodies (aß₂GPI). Medium/high-titre aCL/aβ₂GPI was defined as >99th percentile. Low-titre aCL/aβ₂GPI positivity (>95^th< 99^th percentile) was considered positive for obstetric but not for thrombotic APS. One hundred of the 145 patients fulfilled both clinical and laboratory criteria for definite APS. Twenty-six women with purely obstetric APS had persistent low-titre aCL and/or aβ₂GPI. With the inclusion of these patients, 126 of the 145 patients were considered to have APS. Sixty-seven out of 126 patients were LA-negative, of whom 12 had aCL only, 37 had aβ₂GPI only and 18 positive were for both. The omission of aCL or aβ₂GPI testing from investigation of APS would have led to a failure to diagnose APS in 9.5% and 29.4% of patients, respectively. Our data suggest that LA, aCL and aβ₂GPI testing are all required for the accurate diagnosis of APS and that low-titre antibodies should be included in the diagnosis of obstetric APS.

Clinical advances of interest in the diagnosis and treatment of patients with antiphospholipid syndrome

In this paper we review recent studies and consensus documents that we consider relevant to the diagnosis and treatment of patients with antiphospholipid syndrome (APS). The diagnosis of APS is based on the Sydney classification criteria (2006), in which positive laboratory tests (anticardiolipin antibodies, anti-β2-glycoprotein I antibodies or lupus anticoagulant) are mandatory. However, it is not uncommon to see patients with clinical features highly suggestive of the syndrome in whom these antibodies are persistently negative. Therefore, we summarize the principal clinical and serological findings in a subgroup of patients with seronegative APS in the first series published up to date. In addition, a recent study draws attention to the safety and efficacy of the long-term use of low-molecular-weight heparins in patients with APS not susceptible to warfarin treatment. There is also a subgroup of women with APS and recurrent fetal loss with no response to the standard antithrombotic therapy; in this group the materno-fetal prognosis could be improved by the addition of low-dose prednisolone during the first trimester of pregnancy. Finally, we list the principal recommendations regarding thromboprophylaxis in APS drawn from the expert consensus document elaborated at the meeting held in Galvestone (2010).

Thin-layer chromatography immunostaining in detecting anti-phospholipid antibodies in seronegative anti-phospholipid syndrome

In clinical practice it is possible to find patients with clinical signs suggestive of anti-phospholipid syndrome (APS) who are persistently negative for the routinely used anti-phospholipid antibodies (aPL). Therefore, the term proposed for these cases was seronegative APS (SN-APS). We investigated the clinical usefulness of thin-layer chromatography (TLC) immunostaining in detecting serum aPL in patients presenting clinical features of SN-APS. Sera from 36 patients with SN-APS, 19 patients with APS, 18 patients with systemic lupus erythematosus (SLE), 20 anti-hepatitis C virus (HCV)-positive subjects and 32 healthy controls were examined for aPL using TLC immunostaining. Anti-β(2) -glycoprotein-I, anti-annexin II, anti-annexin V and anti-prothrombin antibodies were tested by enzyme-linked immunosorbent assays (ELISA). Eahy926, a human-derived endothelial cell line, was incubated with immunoglobulin (Ig)G fraction from SN-APS patients and analysis of phospho-interleukin (IL)-1 receptor-associated kinase (IRAK) and phospho-nuclear factor (NF)-κB was performed by Western blot, vascular cell adhesion molecule 1 (VCAM-1) expression by cytofluorimetric analysis and supernatants tissue factor (TF) levels by ELISA. TLC immunostaining showed aPL in 58·3% of SN-APS patients: anti-cardiolipin in 47·2%, anti-lyso(bis)phosphatidic acid in 41·7% and anti-phosphatidylethanolamine in 30·5%. Six of 36 patients showed anti-annexin II. Incubation of Eahy926 cells with IgG from SN-APS induced IRAK phosphorylation, NF-κB activation, VCAM-1 surface expression and TF cell release. TLC immunostaining could identify the presence of aPL in patients with SN-APS. Moreover, the results suggest the proinflammatory and procoagulant effects in vitro of these antibodies.

Clinical manifestations of antiphospholipid syndrome (APS) with and without antiphospholipid antibodies (the so-called 'seronegative APS')

OBJECTIVES

Although the medical literature currently provides a growing number of isolated case reports of patients with clinically well-defined antiphospholipid syndrome (APS) and persistently negative antiphospholipid antibodies (aPL), there are no studies including a series of patients addressing the clinical features of this condition.

METHODS

The authors assessed clinical manifestations of APS in 154 patients: 87 patients with seropositive APS and 67 patients with thrombosis and/or pregnancy morbidity persistently negative for aPL and presenting with at least two additional non-criteria manifestations of APS (the so-called 'seronegative APS', SN-APS). Patients were interviewed at the time of recruitment, and a retrospective file review was carried out.

RESULTS

There were no significant differences in the frequency of thrombotic events or obstetric morbidity in patients with SN-APS versus patients with seropositive APS: deep vein thrombosis (31.4% vs 31.0%), pulmonary embolism (23.8% vs 28.7%), stroke (14.9% vs 17.2%), transient ischaemic attack (11.9% vs 10.3%), early spontaneous abortions (67.1% vs 52.1%), stillbirths (62.5% vs 59.4%), prematurity (28.1% vs 21.7%) or pre-eclampsia (28.1% vs 23.1%).

CONCLUSIONS

Classic and SN-APS patients show similar clinical profiles. The results suggest that clinical management in patients with APS should not be based only on the presence of conventional aPL.

Does seronegative antiphospholipid syndrome really exist?

The diagnosis of seronegative (SN-) antiphospholipid syndrome (APS) has been suggested for patients with clinical manifestations indicative of APS but with persistently negative results in the commonly used assays to detect anti-cardiolipin (aCL) antibodies, anti-β2 Glycoprotein I antibodies (aβ2GPI), and lupus anticoagulant (LA). To date the best management of these patients is still unclear. New emerging anti-phospholipid (aPL) assays could improve our ability in diagnosing APS. However, the availability of aPL assays in routine laboratory practice is limited. In fact, even aβ2GPI is routinely tested in only a small number of laboratories, and other aPL, such as anti-prothrombin or anti-annexin antibodies, in only a few research laboratories. On the other hand transient or false negative aPL assay and other genetic or acquired pro-thrombotic conditions can further complicate this issue. This paper is focused on the arguments for and against the diagnosis of SN-APS and is aimed to help the clinician when approaching a patient with clinical manifestations consistent with APS diagnosis but with negative aPL using the commonly available tests.

Livedo reticularis and related disorders

OPINION STATEMENT

Livedo reticularis is a violaceous mottling of the skin with a "fishnet" reticular appearance. Primary and secondary etiologies exist, including a pathologic variant termed livedo racemosa. No evidence-based medicine exists to guide therapy for this disorder, but most patients with primary and secondary livedo reticularis are asymptomatic and do not require treatment. In the rare instance that a patient with primary livedo reticularis experiences mild symptoms such as episodic numbness and tingling, avoidance of cold and vasoconstricting substances should be encouraged. Lastly, judicious dosing of a vasodilator such as a calcium channel blocker can be prescribed. Patients with secondary livedo reticularis or livedo racemosa may benefit from these same therapeutic suggestions; however, treating the proximate cause of livedo with a systemic association is encouraged and is most likely to yield cutaneous improvement. Although antiplatelet and/or anticoagulant therapy is often required when treating a patient with the antiphospholipid antibody syndrome or Sneddon's syndrome, the attendant livedo racemosa typically remains unchanged or progresses despite this treatment.

[Antiphospholipid syndrome in neurology]

Antiphospholipid syndrome (APS) is an autoimmune disease with recurrent thromboses and pregnancy complications (90% are female patients) that can be primary and secondary (with concomitant autoimmune disease). Antiphospholipid antibodies are prothrombotic but also act directly with brain tissue. One clinical and one laboratory criterion is necessary for the diagnosis of APS. Positive serological tests have to be confirmed after at least 12 weeks. Clinical picture consists of thromboses in many organs and spontaneous miscarriages, sometimes thrombocytopaenia and haemolytic anaemia, but neurological cases are the most frequent: headaches, stroke, encephalopathy, seizures, visual disturbances, Sneddon syndrome, dementia, vertigo, chorea, balism, transitory global amnesia, psychosis, transversal myelopathy and Guillain-Barre syndrome. About 50% of strokes below 50 years of age are caused by APS. The first line of therapy in stroke is anticoagulation: intravenous heparin or low-weight heparins. In chronic treatment, oral anticoagulation and antiplatelet therapy are used, warfarin and aspirin, mostly for life. In resistant cases, corticosteroids, intravenous immunoglobulins and plasmapheresis are necessary. Prognosis is good in most patients but some are treatment-resistant with recurrent thrombotic events and eventually death.

Hughes syndrome (the antiphospholipid syndrome): a disease of our time

A pro-thrombotic condition was described in 1983 which was characterised by the presence of circulating antiphospholipid antibodies, as well as peripheral thrombosis (e.g. DVT), a tendency to internal organ involvement, repeated miscarriage, and, occasionally, thrombocytopenia (aPL) (Hughes, Br Med J 287:1088-1089, 1983). Previously, there had been a number of observations, mainly in patients with lupus having "false positive" tests for syphilis, miscarriage and circulating lupus anticoagulants. The description in 1983 had three notable features (a) a detailed comprehensive clinical picture of the syndrome; (b) this description differed from other coagulopathies in showing a propensity for arterial thrombosis (e.g. stroke and heart attack); and (c) this was a syndrome quite independent from lupus. There are indications that the primary antiphospholipid syndrome will turn out to be more common than lupus, though this could still be a reflection of referral practice.

Livedoid vasculopathy and recurrent thrombosis in a patient with lupus: seronegative antiphospholipid syndrome?

Livedoid vasculopathy is a rare condition which predominantly affects young women. It is characterized by intense painful purpuric maculae in the legs, ankles and feet, due to thrombosis of the small and medium-sized dermal vessels, in the absence of vasculitis. Livedoid vasculopathy has been frequently associated with hypercoagulable states and antiphospholipid syndrome. We describe a 34-year-old White woman suffering from systemic lupus erythematosus, livedo reticularis, haemolytic anaemia, severe thrombocytopenia and recurrent venous thrombosis who was admitted to the hospital for extremely painful purpuric lesions in her lower limbs. The clinical and histological findings were diagnostic of livedoid vasculopathy. Once the initial sub-therapeutic international normalized ratio levels were corrected, livedoid vasculopathy did not recur. Tests for antiphospholipid antibodies were repeatedly negative. This case, the first reported of livedoid vasculopathy in a patient with seronegative antiphospholipid syndrome and systemic lupus erythematosus, draws attention to livedoid vasculopathy, a thrombotic dermopathy that may be under-diagnosed in patients with antiphospholipid syndrome.

Vimentin/cardiolipin complex as a new antigenic target of the antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by arterial and venous thrombosis, recurrent abortions, and antiphospholipid antibodies (aPL). However, it is possible to find patients with clinical signs of APS who persistently test negative for aPL (seronegative APS, or SN-APS). The aim of this study was to identify new antigenic target(s) of autoantibodies in APS patients, which may also be recognized in SN-APS. We tested sera from patients with SN-APS with a proteomic approach by analyzing endothelial cell-surface membrane proteins. Sera from SN-APS patients revealed 2 reactive spots corresponding to vimentin, a protein that is shown to bind cardiolipin in vitro. Antivimentin/cardiolipin antibodies were tested in 29 SN-APS patients, 40 APS patients, 30 patients with systemic lupus erythematosus, 30 with rheumatoid arthritis, 30 with venous or arterial thrombosis, and 32 healthy control patients. We observed that not only a large proportion of SN-APS patients but also almost all the APS patients displayed the presence of antivimentin/cardiolipin antibodies. To verify the possible pathogenic role of these autoantibodies, we demonstrated that affinity-purified antivimentin/cardiolipin antibodies induced interleukin receptor-associated kinase phosphorylation and nuclear factor-κB activation in endothelial cells. Our results prompt to identify vimentin as a "new" cofactor for aPL, which may represent a useful tool mainly in SN-APS patients.

Antiphospholipid syndrome (Hughes syndrome): 10 clinical topics

This year in Galveston, Texas, Silvia Pierangeli hosts the 13th International Congress on Antiphospholipid Antibodies. Twenty-six years after the first antiphospholipid syndrome meeting, the number of interested colleagues has multiplied, and the subject has become more scientifically understood. So also has the clinical picture. In this short contribution, I will highlight a number of clinical observations which may, or may not, contribute to our understanding of antiphospholipid syndrome.

Rational Laboratory Diagnostics of Antiphospholipid Antibodies: Anti-Cardiolipin, Anti-β2-Glycoprotein I, Anti-Prothrombin and Anti-Annexin V Antibodies

A possible co-appearance of anticardiolipin (aCL), anti-β2-glycoprotein I (anti-β2-GPI), anti-prothrombin (aPT) and anti-annexin V (aANXV) antibodies of IgG, IgM and IgA class were studied in 58 patients with SLE alone and 32 patients APS in the view of rational laboratory diagnostics. The presence of anti-phospholipid antibodies (aPL) were defined by our in-house ELISA methods. Out of 17 aCL negative SLE patients 6 had other antigenically defined aPL antibodies. In 13 patients only IgA but not IgG and IgM anti-β2GPI were detected. Different combinations of aPL subsets were equally distributed in APS and SLE groups. The prevalence of aANXV were similar in APS and SLE patients which was not the case with other aPL. Our findings support the idea of measuring additional subsets of aPL (aPT and aANXV) in unclear cases. IgA (either aCL or anti-β2-GPI) improved neither the diagnostic specificity nor diagnostic sensitivity, but only increased the frequency of the total anti-β2-GPI.

Antiphosphatidylethanolamine antibodies and the antiphospholipid syndrome

The antiphospholipid antibodies included as laboratory criteria of the antiphospholipid syndrome (APS) are antibodies reacting with anionic phospholipids – anticardiolipin antibodies and lupus anticoagulant – and with β2-glycoprotein I. However, antibodies reacting with phosphatidylethanolamine (aPE), a zwitterionic phospholipid, have also been described to be associated with the main features of APS. The objectives of this review are to describe the characteristics of aPE and to bring attention to recent evidence that aPE are correlated with the main clinical features of APS, notably, in the absence of the laboratory criteria of this syndrome.

Clinical manifestations and outcomes of antithrombotic treatment of the Tan Tock Seng Hospital Singapore antiphospholipid syndrome cohort

To examine the clinical manifestations, intensity of oral anticoagulation and outcomes in the prevention of recurrent thromboses in patients with antiphospholipid syndrome (APS) in a tertiary rheumatology centre in Singapore. Retrospective case review of consecutive patients with APS attending a rheumatology clinic from 1st January 2004 to 31st December 2005. There were 59 (44%) patients with definite APS and 75 (56%) with probable APS. Systemic lupus erythematosus (SLE) was the most common cause of secondary APS. Hypertension and hyperlipidaemia were the most common cardiovascular comorbidities. The most common manifestations were haematological (thrombocytopaenia and haemolytic anaemia), neurological (seizure, headache) and pulmonary hypertension. Among those with definite APS, there were similar proportions with arterial and venous thromboses. Recurrent thromboses occurred in 14 (23.7%) patient with definite APS receiving warfarin, comprising 14 (73.7%) episodes of arterial and 5 (26.3%) episodes of venous thromboses. Recurrent arterial thromboses occurred at international normalized ratio (INR) of <2 in 5 (35.7%), INR 2–3 in 6 (42.9%), INR > 3 in 3 (21.4%) episodes, respectively. Recurrent venous thromboses occurred at INR < 2 in 4 (80.0%) and INR > 3 in 1 (20.0%) episode, respectively. Twenty-eight episodes of bleeding occurred in 21 (35.6%) patients, the majority (78.6%) being minor bleeding. Two-thirds of all major bleeds occurred at INR ≥ 3. Venous and arterial thromboses were equally common in our patients with definite APS, although recurrent thromboses were more common in the arterial circulation. Target INR > 3 was associated with lower rates of recurrent arterial thromboses but higher rates of major and recurrent bleeding. Target INR ≥ 2 appeared to be sufficient to prevent recurrent venous thromboses.

Antiphospholipid (Hughes) syndrome: beyond pregnancy morbidity and thrombosis

The antiphospholipid syndrome is an autoimmune disease characterised by recurrent arterial or venous thrombosis, pregnancy morbidity and the persistence of positive antiphospholipid antibodies. Many other clinical manifestations may occur including heart valve disease, livedo reticularis, thrombocytopenia and neurological manifestations such as migraine and seizures. We review a number of other manifestations including stenotic lesions, coronary artery disease and accelerated atherosclerosis, skeletal disorders and the concept of seronegative antiphospholipid syndrome.

Livedo racemosa as a marker of increased risk of recurrent thrombosis in patients with negative anti-phospholipid antibodies

BACKGROUND AND OBJECTIVE

Livedo reticularis racemosa and cerebrovascular lesions characterize Sneddon's syndrome. We report 23 patients with livedo racemosa and describe the association with thrombotic events. Our objective was to determine whether livedo racemosa may be an independent clinical marker for the development of thrombotic events in patients who test negative for anti-phospholipid antibodies.

METHODS

Twenty-three patients with widespread livedo racemosa were studied. None of the patients were positive for anti-phospholipid antibodies. The clinical protocol included a register of thrombotic events, fetal death or miscarriages, hypertension, and valvular heart disease. Cerebral MRI and echocardiography were systematically performed in all patients.

RESULTS

Nineteen patients (82.60%) had thrombotic events. Fifteen (65.21%) had arterial thrombosis and eleven (47.82%) presented venous occlusions. Seven patients (30.43%) had both arterial and venous thrombosis. Fetal losses were recorded in seven cases (30.43%), with a total number of 33; five patients had 3 or more fetal losses. Eleven out of 23 patients (47.82%) had valvular heart disease. Arterial hypertension was detected in 16 (69.56%) patients. Four patients did not have thrombotic events but had other clinical manifestations. After anti-coagulation therapy was withdrawn, a new thrombotic event was observed in 9 out of the 14 treated patients (64.28%).

CONCLUSIONS

Livedo racemosa seems to be a good clinical marker for the detection of hypercoagulable states even in the absence of anti-phospholipid antibodies or other known biologic markers of thrombosis. Long-term anti-coagulation is probably warranted in patients with livedo racemosa and a previous thrombotic event.

Sixth meeting of the European Forum on antiphospholipid antibodies. How to improve the understanding of the antiphospholipid syndrome?

The main objective of these meetings is to promote international collaboration in various clinical and research projects. This paper is the summary of the 2007 Ljubljana meeting, and offers an overview of the proposed projects. The technical and methodological details of the projects will be published on the forum’s web site (http://www.med.ub.es/MIMMUN/FORUM/STUDIES.HTM).

Diagnosis of antiphospholipid syndrome

Antiphospholipid syndrome is a multisystem autoimmune disease, characterized by recurrent vascular thrombosis and/or pregnancy losses in the presence of persistently positive antiphospholipid antibodies. In clinical practice, testing for anticardiolipin antibodies and lupus anticoagulant is mandatory for the laboratory diagnosis of antiphospholipid syndrome. Identification of patients with antiphospholipid syndrome is important, as prophylactic anticoagulant therapy may prevent thrombosis from recurring, and treatment during pregnancy can improve fetal and maternal outcome.

[Livedo: from pathophysiology to diagnosis]

PURPOSE

We propose a diagnostic approach when facing a livedo. First, the pathophysiology of the livedo is reviewed using key articles barely quoted in the literature. Then the topic is handled in two ways. Figures and tables allow a rapid reading convenient "at the patient's bedside". The subject is also reviewed thoroughly, and we emphasize the intricacy of the various pathophysiological mechanisms involved for each livedo's related disease. Diseases associated with livedo are then briefly described with emphasis on the key diagnostic features and prevalence. Usefulness of the main diagnostic procedures is discussed.

CURRENT KNOWLEDGE AND KEY POINTS

A livedo is a usually purplish-blue erythema, reticulated (small and complete meshes) or racemosa (large broken circular segments) which is related to a slowdown of the blood flow in the dermic venules. These venules form adjacent circles communicating with each other, parallel to the skin surface. The blood flow slowdown may be due to a local vasoconstriction (vasomotor livedo) or to an arteriolar occlusion. Arteriolar occlusion may be related to blood abnormalities (thrombosis, high viscosity, embolus) or to increased parietal thickness (vasculitis, calcic deposition, intimal hyperplasia). It is not always possible to clinically distinguish a vasomotor livedo from those associated with diseases. Diagnostic procedures should be oriented by the medical history, the features of the livedo, and associated symptoms. Usefulness of the skin biopsy is usually limited to the situations where the livedo is infiltrated or necrotic.

FUTURE PROSPECTS AND PROJECTS

To raise controversy about their importance and implications, some pathophysiological data are presented: intimal pseudohyperplasia in Sneddon's syndrome and antiphospholipid syndrome, and white cell activation in essential thrombocythemia.

The clinical spectrum of antiphospholipid syndrome

Antiphospholipid syndrome (APS) is a disorder characterized by a wide variety of clinical manifestations. Virtually any organ system or tissue may be affected by the consequences of large- or small-vessel thrombosis. There is a broad spectrum of disease among individuals with antiphospholipid antibodies (aPL). Patients may exhibit clinical features suggesting APS but not fulfill the International Criteria for a "definite" diagnosis. Seronegative APS patients demonstrate typical idiopathic thromboses but aPL are not initially detected. Patients defined with definite APS demonstrate nearly identical sites of venous and arterial thrombosis, regardless of the presence or absence of systemic lupus erythematosus. Microangiopathic APS may present with isolated tissue and organ injury or as the overwhelming "thrombotic storm" observed in catastrophic APS.