Task Force on Catastrophic Antiphospholipid Syndrome (APS) and Non-criteria APS Manifestations (I): catastrophic APS, APS nephropathy and heart valve lesions

Performance validation of the 2023 American College of Rheumatology/European League Against Rheumatism antiphospholipid syndrome classification criteria in an antiphospholipid syndrome cohort

BACKGROUND

The 2023 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) antiphospholipid syndrome (APS) classification criteria were developed with higher specificity but lower sensitivity compared with the 2006 Sydney revised classification criteria.

OBJECTIVES

To validate the performance of the 2023 ACR/EULAR APS classification criteria in a large Chinese APS cohort.

METHODS

This was a single-center cohort study. Inclusion criteria aligned with the entry criteria of 2023 criteria. APS classification by "expert consensus panel" served as the gold standard. Sensitivity and specificity were compared between the 2023 and 2006 criteria.

RESULTS

A total of 526 patients with a mean age of 38.55 ± 12.67 years were enrolled, of whom 366 (69.58%) were female and 182 (34.60%) had systemic lupus erythematosus (SLE). Among them, 407 (77.38%) patients were classified as APS by experts. The 2023 criteria demonstrated higher overall specificity than the 2006 criteria (0.983 vs 0.950), while sensitivity was relatively lower (0.818 vs 0.853). The sensitivity of the 2023 criteria improved for patients with SLE (0.860 vs 0.825), microvascular manifestations (0.867 vs 0.786), cardiac valve disease (0.903 vs 0.774), and thrombocytopenia (0.811 vs 0.790). Reduced sensitivity of the 2023 criteria was linked to the omission of certain microvascular manifestations, a stricter definition of pregnancy morbidity, and the exclusion of isolated thrombocytopenia and isolated IgM isotype antiphospholipid antibodies from meeting clinical and laboratory criteria, respectively.

CONCLUSION

The 2023 criteria offer higher overall specificity and improved sensitivity in specific patient subsets, such as those with SLE, microvascular manifestations, cardiac valve disease, and thrombocytopenia when compared with the 2006 criteria.

Heart valve disease in primary antiphospholipid syndrome

OBJECTIVES

APS-associated heart valve disease (HVD) is well described. Nonetheless, limited data exist on clinical parameters associated with the course of primary APS (pAPS) patients with HVD. The goal of this study was to assess clinical features and related outcomes in patients with APS-associated HVD.

METHODS

In this multicentre retrospective study, we identified 33 pAPS patients with HVD (pAPS-HVD group) and compared their clinical course with 128 pAPS patients with normal heart valves on echocardiography (pAPS-control group).

RESULTS

pAPS-HVD patients had more cerebrovascular events (56.3% vs 25%, P = 0.005) and livedo reticularis (24.2% vs 7.8%, P = 0.013) than pAPS-controls. Furthermore, catastrophic-APS (CAPS) (12.1% vs 2.4%, P = 0.034), recurrent thrombosis (33.3% vs 4.7%, P < 0.001) and need for advanced therapy (i.e. IVIG, plasmapheresis or rituximab) were more frequent in pAPS-HVD patients. Anti-β2-glycoprotein 1 IgG (84.8% vs 63.2%, P = 0.034), anti-cardiolipin IgG (90.9% vs 64.8%, P = 0.005) and triple positive aPL (75.8% vs 56.5%, P = 0.047) were commoner in pAPS-HVD patients vs pAPS-controls. Ten of the 33 patients with pAPS-HVD underwent valve surgery, which was associated with male gender, smoking, arterial limb ischaemia and livedo reticularis.

CONCLUSION

pAPS-HVD patients had a more severe APS clinical course including CAPS and thrombotic events as well as a specific serology, namely IgG isotype aPL antibodies and triple positivity. Our data suggest that pAPS-HVD represents a high-risk subgroup of APS patients.

Diagnosis and Management of Catastrophic Antiphospholipid Syndrome and the Potential Impact of the 2023 ACR/EULAR Antiphospholipid Syndrome Classification Criteria

Catastrophic antiphospholipid syndrome (CAPS) is a rare and life-threatening condition characterized by the persistence of antiphospholipid antibodies and occurrence of multiple vascular occlusive events. CAPS currently remains a diagnostic challenge and requires urgent treatment. The diagnosis of CAPS is made difficult by classification criteria used as diagnostic criteria in clinical practice, knowledge derived from retrospective data and case reports, confounding clinical and biological features, and its rapid onset and mortality. The absence of prospective studies of CAPS limits the strength of evidence for guideline treatment protocols. This comprehensive review summarizes the current understanding of the disease, and discusses how the 2023 ACR/EULAR Antiphospholipid Syndrome Classification Criteria impact the definition and therapeutic management of CAPS, which is considered the most severe form of APS. The correct integration of 2023 ACR/EULAR APS classification criteria is poised to facilitate CAPS diagnosis, particularly in critical situations, offering a promising avenue for improved outcomes.

Risk factors in antiphospholipid antibody-associated valvular heart disease: A 383-patient cohort study

Valvular heart disease (VHD) is a prevalent cardiac manifestation in antiphospholipid syndrome (APS) patients. However, risk factors and predictors for antiphospholipid antibody-associated VHD (aPL-VHD) remain vague. We aimed to assess the risk of developing aPL-VHD in aPL-positive patients, by establishing a clinical prediction model upon a cross-sectional cohort from APS-Shanghai database, including 383 APS patients and durable aPL carriers with transthoracic echocardiography investigation. The prevalence of aPL-VHD was 11.5%. Multivariate logistic regression analysis identified three independent risk factors for aPL-VHD: anti-β2GPI IgG (OR 5.970, P < 0.001), arterial thrombosis (OR 2.758, P = 0.007), and stratified estimated glomerular filtration rate levels (OR 0.534, P = 0.001). A prediction model for aPL-VHD, incorporating the three factors, was further developed, which demonstrated good discrimination with a C-index of 0.855 and 0.841 (after bootstrapping), and excellent calibration (P = 0.790). We provide a practical tool for assessing the risk of developing VHD among aPL-positive patients.

Antiphospholipid syndrome nephropathy: Current knowledge and unanswered questions

The definition of acute and chronic antiphospholipid syndrome (APS) nephropathy was recently updated using a multiphase methodology in the context of the development of the new APS classification criteria. Currently, there is no consensus for the treatment of APS nephropathy, which mainly relies on the general recommendations for the management of APS. Based on evidence from experimental studies and a few clinical studies and case series, targeted treatments such as B-cell depletion, anti-B-cell activating factor antibody, complement inhibition, mammalian target of rapamycin inhibition, and neutrophil extracellular traps or interferon targeting may show promise for the treatment of microvascular manifestations in APS, including APS nephropathy. Validation of the new APS nephropathy definition and/or efforts for improvement in proposed terminology, along with the assessment of the safety and efficacy of potential targeted treatments in randomized controlled trials, are major future research directions. In this review, we summarize the current knowledge of APS nephropathy and discuss unanswered questions.

French National Diagnostic and Care Protocol for antiphospholipid syndrome in adults and children

Antiphospholipid syndrome (APS) is a chronic autoimmune disease involving vascular thrombosis and/or obstetric morbidity and persistent antibodies to phospholipids or certain phospholipid-associated proteins. It is a rare condition in adults and even rarer in children. The diagnosis of APS can be facilitated by the use of classification criteria based on a combination of clinical and biological features. APS may be rapidly progressive with multiple, often synchronous thromboses, resulting in life-threatening multiple organ failure. This form is known as "catastrophic antiphospholipid syndrome" (CAPS). It may be primary or associated with systemic lupus erythematosus (associated APS) and in very rare cases with other systemic autoimmune diseases. General practitioners and paediatricians may encounter APS in patients with one or more vascular thromboses. Because APS is so rare and difficult to diagnosis (risk of overdiagnosis) any suspected case should be confirmed rapidly and sometimes urgently by an APS specialist. First-line treatment of thrombotic events in APS includes heparin followed by long-term anticoagulation with a VKA, usually warfarin. Except in the specific case of stroke, anticoagulants should be started as early as possible. Any temporary discontinuation of anticoagulants is associated with a high risk of thrombosis in APS. A reference/competence centre specialised in autoimmune diseases must be urgently consulted for the therapeutic management of CAPS.

Heart Valve Involvement in Patients with Antiphospholipid Syndrome: A Long-Term Follow-Up Study of a Single Centre

BACKGROUND

Valve involvement is the most common cardiac manifestation in antiphospholipid syndrome (APS). The objective of the study was to describe the prevalence, clinical and laboratory features, and evolution of APS patients with heart valve involvement.

METHODS

A retrospective longitudinal and observational study of all APS patients followed by a single centre with at least one transthoracic echocardiographic study.

RESULTS

144 APS patients, 72 (50%) of them with valvular involvement. Forty-eight (67%) had primary APS, and 22 (30%) were associated with systemic lupus erythematosus (SLE). Mitral valve thickening was the most frequent valve involvement present in 52 (72%) patients, followed by mitral regurgitation in 49 (68%), and tricuspid regurgitation in 29 (40%) patients. Female sex (83% vs. 64%; p = 0.013), arterial hypertension (47% vs. 29%; p = 0.025), arterial thrombosis at APS diagnosis (53% vs. 33%; p = 0.028), stroke (38% vs. 21%; p = 0.043), livedo reticularis (15% vs. 3%; p = 0.017), and lupus anticoagulant (83% vs. 65%; p = 0.021) were more prevalent in those with valvular involvement. Venous thrombosis was less frequent (32% vs. 50%; p = 0.042). The valve involvement group suffered from higher mortality (12% vs. 1%; p = 0.017). Most of these differences were maintained when we compared patients with moderate-to-severe valve involvement (n = 36) and those with no or mild involvement (n = 108).

CONCLUSIONS

Heart valve disease is a frequent manifestation in our cohort of APS patients and is associated with demographic, clinical and laboratory features, and increased mortality. More studies are needed, but our results suggest that there may be a subgroup of APS patients with moderate-to-severe valve involvement with its own characteristics that differs from the rest of the patients with mild valve involvement or without valve involvement.

Ethnicity and Antiphospholipid Syndrome in Israel

OBJECTIVE

Antiphospholipid syndrome (APS) is an acquired coagulopathy associated with the presence of antiphospholipid antibodies. Whether ethnicity modulates APS clinical course is not known. The aim of our study was to assess the interplay of ethnicity and APS in Israel.

METHODS

We retrospectively evaluated the ethnic distribution of APS patients from 3 medical centers in Israel compared to the general population. Ethnic groups were defined according to the Israeli Bureau of Statistics as Ashkenazi (European), former Union of Soviet Socialist Republics (USSR), North African, Asian (West Asia, Greece, and Turkey), Israeli Arab individuals, and others.

RESULTS

Our cohort included 382 patients. The prevalence of Ashkenazi and Asian ethnicities was more pronounced (33% versus 12.8% and 15.4% versus 7.7%, respectively; P < 0.001), while Israeli Arabs were less represented (5.2% versus 31.1%; P < 0.001) relative to their part in the general population. Arab patients were younger at presentation (mean ± SD 28 ± 10 years versus 34 ± 13 years; P < 0.001) and were more likely to present with venous thrombosis (50% versus 35%; P = 0.037) and to suffer from venous thrombotic recurrence (45% versus 16%; P < 0.001) compared to other ethnicities. Mortality was higher among patients of Asian ethnic origin (8.8% versus 1.1%; P = 0.005); intriguingly, this group experienced cardiovascular risk factors more often (i.e., dyslipidemia and hypertension).

CONCLUSION

Ethnicity may affect the prevalence and/or natural course of APS, which is less prevalent and differs clinically in Israeli Arab patients, while mortality was linked with Asian ethnicity.

Patterns of Recurrent Thrombosis in Primary Antiphospholipid Syndrome-Multicenter, Real-Life Long-Term Follow-Up

Background

Antiphospholipid syndrome (APS) is an acquired hypercoagulable condition associated with antiphospholipid antibody (aPL) presence. Data on re-thrombosis following APS-diagnosis are limited.

Methods

This is a retrospective analysis of new thrombotic events among primary APS (pAPS) patients followed for up to 15 years in three medical centers in Israel.

Results

Among 312 primary-APS patients, 143 (46%) had new thrombotic event classified to three patterns: (1) Arterial—associated with heart valve disease (OR 7.24, 95% C.I. 2.26–24.6), hypertension (OR 3, 95% C.I. 1.44–6.25), elevated anti-B2-GPI IgM (OR 1.04, 95% C.I. 0.996–1.08), arterial thrombosis at presentation (OR 1.74 95% C.I. 0.992–3.26), and older age (41 vs. 34 years, p < 0.001). (2) Venous—linked with venous thrombosis at presentation (OR 12.9, 95% C.I. 5.27–31.6, p < 0.001), heart valve disease (OR 9.81 95% C.I. 1.82–52.9, p = 0.018), aGAPSS (OR 1.15 95% C.I. 1.02–1.29), and younger age (31 vs. 36.5 years, p = 0.001); and (3) Combined pattern—associated with heart valve disease (OR 40.5 95% C.I. 7.7–212) and pulmonary embolism (OR 7.47 95% C.I. 1.96–28.5). A 4th variant “the Breakthrough pattern” defined by re-thrombosis despite prophylactic therapy was observed in 100/143 (70%) patients and linked with heart valve disease (OR 8. 95% C.I. 2.43–26.3), venous thrombosis at presentation (OR 2.61 95% C.I. 1.47–4.66), leg ulcers (OR 12.2, 95% C.I. 1.4–107), hypertension (OR 1.99, 95% C.I. 0.92–4.34), and higher aGAPSS (OR 1.08, 95% C.I. 0.99–1.18).

Conclusion

In this real-life observation, re-thrombosis was common among pAPS patients including in those recommended to receive prophylactic therapy. Different patterns of recurrence were identified and linked with presenting symptoms, specific serological markers, APS manifestations, and comorbidities. Studies that will address interventions to prevent recurrences of APS-related events are needed.

Long Term Follow up of Patients With Primary Obstetric Antiphospholipid Syndrome

Introduction: Primary obstetric antiphospholipid syndrome (OAPS) is defined by specific morbidities and/or losses of pregnancy in the presence of persistent antiphospholipid antibodies (aPL). This variant of APS is usually treated during pregnancy and the post-partum period. Data on occurrence of thrombotic event during long term follow-up of OAPS patients is limited.

Methods: A multi-centre retrospectively cohort of female patients with primary APS (pAPS) was assembled during 2004–2019. Patients were grouped according to disease presentation as pure OAPS or thrombotic APS (tAPS) for those presenting with thrombosis. Clinical and serological data were compared between groups.

Results: Of 219 pAPS female patients 67 (30.6%) were diagnosed with OAPS and 152 (69.4%) with tAPS. During >10 years of follow-up 24/67 (35.8%) OAPS and 71/152 (50%) tAPS suffered a new thrombotic event (p = 0.06), while obstetric morbidity was more likely in the OAPS group (31.3 vs. 10.5%, p < 0.001) respectively. Among patients with OAPS at presentation heart valve disease and the presence of ANA were related to thrombosis following diagnosis (25 vs. 4.7%, p = 0.02; and 45.8 vs. 20.8%, p = 0.04 respectively).

Conclusion: Thrombotic event following diagnosis were common among female patients with pAPS regardless of disease presentation. Heart valve disease and ANA positivity may be risk factors for thrombosis during follow-up of patients presenting with pure OAPS.

Kidney disease in antiphospholipid antibody syndrome: Risk factors, pathophysiology and management

Antiphospholipid antibody syndrome (APLS) is a rare autoimmune disease characterized by recurrent arterial and venous thromboembolic events, pregnancy related complications as well as the persistent detection of antiphospholipid antibodies at a 12 week interval. Renal complications tend to occur in 3% of APLS patients, with renal artery stenosis being the most common kidney related complication. Renal pathology may be subdivided into macro as well as microvascular thrombotic complications with stenosis, thrombosis and infarction representing the principle macrovascular events and APLS nephropathy representing the predominant microvascular complication. APLS related kidney disease may present with an array of heterogenous manifestations ranging from hematuria and non-nephrotic range proteinuria to hypertension or as part of a severe, life threatening and fulminant multiorgan failure disorder known as catastrophic antiphospholipid antibody syndrome (CAPS). Management of APLS related renal complications depends on the site of vascular injury, the thromboembolic risk profile based on the subtype, isotype and titer of the autoantibodies as well as the severity of the injury. Primary prophylaxis in these patients primarily revolves around the use of low dose aspirin, with prophylactic anticoagulation during events that increase thromboembolic like surgery and hospitalization. Anticoagulation is the cornerstone of treatment of APLS related kidney disease with INR targets varying depending on the associated venous or arterial thrombosis. Immunosuppression with the likes of rituximab, mTOR inhibitors, eculizumab and belimumab have been used with some success, but lack randomized control trial validation for their use. Pulsed corticosteroids with Plasmapheresis and intravenous immunoglobulins is the recommended treatment for CAPS.

Description of damage in different clusters of patients with antiphospholipid syndrome

OBJECTIVE

To identify the different clinical phenotypes of antiphospholipid syndrome (APS) by using cluster analysis and describe cumulative damage of disease clusters.

METHODS

This retrospective study includes patients with APS (±systemic lupus erythematosus (SLE)). Two-step cluster analysis was applied by considering clinical data. Damage was calculated for all patients by applying damage index for APS (DIAPS).

RESULTS

A total of 237 patients (198 females; median age of 43 years; median follow-up of 9.5 years) were classified into four clusters. Cluster 1 (n = 74) consisted of older patients with arterial-predominant thrombosis, livedo reticularis, and increased cardiovascular risk; cluster 2 (n = 70) of SLE+APS patients with thrombocytopenia and heart valve disease; cluster 3 (n = 59) of patients with venous-predominant thrombosis, less extra-criteria manifestations; and cluster 4 (n = 34) of patients with only pregnancy morbidity with lower frequency of extra-criteria features and cardiovascular risk. Patients with SLE+APS (n = 123) had the highest mean DIAPS. Regarding clusters, 1 and 2 had high cumulative damage. While cumulative survival rates of clusters did not differ, cluster 2 and 3 had lower survival rates at further years. There was no correlation between DIAPS and mortality.

CONCLUSION

SLE+APS patients with extra-criteria manifestations and older APS patients with arterial thrombosis and increased cardiovascular risk have higher cumulative damage. Effective treatment of SLE disease activity and control of cardiovascular risk may help to reduce cumulative damage in these patients.

Cerebral Vein Thrombosis in the Antiphospholipid Syndrome: Analysis of a Series of 27 Patients and Review of the Literature

(1) Background: The Antiphospholipid Syndrome (APS) is a systemic autoimmune disorder characterized by arterial and/or venous thrombosis, pregnancy morbidity and raised titers of antiphospholipid antibodies. Cerebral vein thrombosis (CVT) is a rare form of cerebrovascular accident and an uncommon APS manifestation; the information in the literature about this feature consists of case reports and small case series. Our purpose is to describe the particular characteristics of CVT when occurs as part of the APS and compare our series with the patients published in the literature. (2) Methods: We conducted a retrospective observational study collecting data from medical records in three referral centers for APS and CVT, and a systematic review of the literature for CVT cases in APS patients. (3) Results: Twenty-seven APS patients with CVT were identified in our medical records, the majority of them diagnosed as primary APS and with the CVT being the first manifestation of the disease; additional risk factors for thrombosis were identified. The review of the literature yielded 86 cases, with similar characteristics as those of our retrospective series. (4) Conclusions: To our knowledge, our study is the largest CVT series in APS patients published to date, providing a unique point of view in this rare thrombotic manifestation.

Antiphospholipid syndrome: the need for new international classification criteria

Introduction: As soon as the association of lupus anticoagulant (LAC) and anticardiolipin antibodies (aCL) with thrombosis and miscarriages was described in the 1980s, the definition of the antiphospholipid syndrome (APS) became a need. Early descriptions of the disease by members of the Graham Hughes team included broad categories and unexplained laboratory inclusions. Over time, new clinical and experimental data refined the criteria, especially the obstetric manifestations, as well as the laboratory criteria.Areas covered: The authors performed a review of the literature using the PubMed database, and the following keywords were used: 'antiphospholipid antibody', 'antiphospholipid syndrome', and 'criteria of antiphospholipid'. The history of antiphospholipid criteria, clinical and experimental advancements, and other expert opinions were included in this paper.Expert opinion: It has been 14 years since an international congress on antiphospholipid antibodies has generated new classification based on the recent extensive research performed in the field. Currently, there is a need to update the international APS classification taking into consideration the inclusion of new clinical criteria such as aPL-related nephropathy as well as new standardized antibody specificities (e.g., anti-phosphatidylserine/prothrombin antibodies) with the adoption of a standardized scoring system that can stratify APS patients.

Combined brain/heart magnetic resonance imaging in antiphospholipid syndrome-two sides of the same coin

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by arterial, venous, and/or small vessel thrombosis, pregnancy morbidity, and persistently elevated levels of antiphospholipid antibodies (aPL). Cardiovascular disease (CVD) in APS can present as heart valvular disease (HVD), macro-micro-coronary artery disease (CAD), myocardial dysfunction, cardiac thrombi, or pulmonary hypertension. Brain disease presents as stroke or transient ischemic attack (TIA) and less frequently as cerebral venous thrombosis, seizures, cognitive dysfunction, multiple sclerosis (MS)-like syndrome, or chorea. Infarcts and focal white matter hyperenhancement are the commonest brain (MRI) abnormalities, while myocardial ischemia/fibrosis, valvular stenosis/regurgitation, or cardiac thrombi are the main abnormalities detected by cardiovascular magnetic resonance. This review aims to present the existing evidence on brain/heart involvement and their interrelationship in APS and the role of brain/heart MRI in their evaluation. Embolic brain disease, due to HVD, CAD, and/or cardiac thrombus, or brain hypo-perfusion, due to myocardial dysfunction, are among the main brain/heart interactions in APS and they are considered determinants of morbidity and mortality. Currently, there is no evidence to support the use of combined brain/heart MRI in asymptomatic APS patients. Until more data will be available, this approach may be considered in APS patients at high risk for CVD/stroke, such as systemic lupus erythematosus with high-risk aPL profile or high scores in CVD risk prediction models; APS patients with HVD/thrombus, CAD, or heart failure; those with classic and non-criteria neurologic APS manifestations (seizures, cognitive dysfunction, MS-like syndrome); or with aggressive multi-organ disease. Key Points • Cardiovascular disease (CVD) in antiphospholipid syndrome (APS) can present as heart valvular disease (HVD), macro-micro-coronary artery disease (CAD), myocardial dysfunction, cardiac thrombi, or pulmonary hypertension. • Brain disease presents as stroke or transient ischemic attack (TIA), and less frequently as cerebral venous thrombosis, seizures, cognitive dysfunction, and multiple sclerosis (MS). • A combined brain/heart MRI may be considered in APS patients at high risk for CVD/stroke, such as systemic lupus erythematosus with high-risk aPL profile or high scores in CVD risks; APS patients with HVD/thrombus, CAD, or heart failure; those with classic and non-criteria neurologic APS manifestations (seizures, cognitive dysfunction, MS-like syndrome); or with aggressive multi-organ disease.

Treatment of antiphospholipid syndrome

Antiphospholipid syndrome (APS) is the most common acquired thrombophilia. The clinical manifestations of APS are mainly vascular thrombosis (venous and/or arterial) and/or recurrent pregnancy morbidity with the concomitant persistent presence of antiphospholipid antibodies (aPL). Therefore, the goals of the treatment of patients with APS are reducing the pregnancy morbidity and/or the prevention of thrombotic events during the follow-up. Optimal treatment of APS has long been discussed, due to the heterogeneity of the clinical manifestations and the consequent plurality in the medical specialties involved in managing this condition. This review summarizes the available evidence on primary thromboprophylaxis in aPL-positive individuals with no prior thrombotic events, secondary prophylaxis in patients with positive history for thrombotic events, the management of refractory or difficult cases and the current strategies for the management of APS during pregnancy.

Management of Non-criteria Manifestations in Antiphospholipid Syndrome

PURPOSE OF THE REVIEW

To review the available evidence on the management of a variety of non-criteria manifestations in antiphospholipid syndrome (APS), including valvular disease, alveolar hemorrhage, thrombocytopenia, hemolytic anemia, APS nephropathy, skin ulcers, livedo reticularis, cognitive dysfunction, and epilepsy.

RECENT FINDINGS

Current treatment relies on low-level evidence and mainly on expert consensus due to the rarity and the heterogeneity of non-criteria APS manifestations and the diversity in management approaches. Conventional anticoagulation and/or antiplatelet APS treatment do not adequately control most of non-criteria manifestations. Increasing knowledge about the contribution of inflammatory in addition to, or independently of, thrombotic mechanisms in non-criteria APS manifestations provides insight into the potential effect of novel therapies targeting B-cells, mammalian target of rapamycin, neutrophil, and complement or interferon pathways. Existing evidence is limited by lack of high-quality studies. Better understanding of the pathophysiology and clinical phenotypes of APS and well-designed prospective studies of homogenous populations are needed to provide evidence-based recommendations for the management of non-criteria APS manifestations.

A woman with systemic lupus erythematosus, multiple pregnancy complications, and cerebral infarction who was only positive for phosphatidylserine-dependent antiprothrombin antibodies

A woman with systemic lupus erythematosus (SLE) had a history of two abortions before the 10th week, two foetal deaths with normal morphology, and one premature before the 34th week with early-onset hypertensive disorder of pregnancy (HDP) and placental dysfunction. Although she did not have any conventional antiphospholipid antibodies (aPLs), antiphospholipid syndrome (APS) was strongly suspected based on her obstetric history and renal biopsy findings consistent with aPL-associated nephropathy (APLN). Eventually, she was found to be positive for phosphatidylserine-dependent antiprothrombin antibodies (aPS/PTs). A healthy baby was born with anticoagulation and intravenous immunoglobulin (IVIG) therapy during pregnancy. aPS/PT titres gradually increased after delivery. Cerebral infarction occurred at 9 years after birth. If APS is clinically suspected but the antibodies included in the classification criteria for APS are all negative, we should consider an association with unconventional aPLs and manage according to APS.

A 75-year-old woman with primary antiphospholipid syndrome presenting with livedoid vasculopathy

The clinical presentation of primary antiphospholipid syndrome (PAPS) can vary, often mimicking many other medical conditions. Therefore, it is difficult to diagnose at the first presentation because of the absence of classical symptoms. We described an unusual presentation of PAPS mimicking livedoid vasculopathy (LV), where the only diagnostic clue at the initial presentation was skin lesions in both lower legs. A 75-year-old Han Chinese woman presented with features mimicking LV, without clinically significant antiphospholipid syndrome (APS). After many relevant laboratory examinations and histopathological examination, the patient was finally diagnosed as having PAPS. LV should not be treated as an independent disease, but as a skin manifestation. A high degree of suspicion of APS is needed in patients presenting or diagnosed with LV. Early interventions are necessary to prevent and reduce the risk of thrombosis. This case presents a rare clinical manifestation and provides significant information on PAPS.

Antiphospholipid syndrome and the relationship between laboratory assay positivity and prevalence of non-bacterial thrombotic endocarditis: A retrospective cohort study

BACKGROUND

Nonbacterial thrombotic endocarditis (NBTE) is a potential complication of antiphospholipid syndrome (APS) manifesting as noninfectious lesions on one or more cardiac valves. There are limited tools to inform clinicians regarding which APS patients would benefit most from echocardiographic screening for this complication.

OBJECTIVES

We tested the hypothesis that the risk of both prevalent and incident NBTE is directly related to the number of positive laboratory assays for APS.

PATIENTS/METHODS

In this single-center, retrospective, cohort study design, consecutive patients with confirmed APS seen at Mayo Clinic Rochester, MN (1/1/1993-6/26/2016), were identified by searching a centralized electronic database. Demographic data, clinical presentation, echocardiographic features, laboratory findings, and survival data were scrutinized.

RESULTS

During the study period, 611 patients met the diagnostic criteria for APS and 386 (63%) underwent echocardiography. Of these, 58 (15%) were found to have NBTE. NBTE was more common in those with double (19.4%) and triple-positive laboratory criteria (27.0%) compared with single-positive disease (5.7%, P < .001). Survival free of NBTE diagnosis was significantly shorter in those patients with >1 positive laboratory assay (P < .01). Cox proportional hazard analysis suggests that patients with APS are more likely to be diagnosed with NBTE if they have >1 positive laboratory assay (relative risk 20.1; 95% confidence interval 1.3-316.6; P < .03).

CONCLUSION

Antiphospholipid syndrome carries a high prevalence of NBTE (15%). This prevalence is particularly high for patients with either double- or triple-positive laboratory criteria.

EULAR recommendations for the management of antiphospholipid syndrome in adults

The objective was to develop evidence-based recommendations for the management of antiphospholipid syndrome (APS) in adults. Based on evidence from a systematic literature review and expert opinion, overarching principles and recommendations were formulated and voted. High-risk antiphospholipid antibody (aPL) profile is associated with greater risk for thrombotic and obstetric APS. Risk modification includes screening for and management of cardiovascular and venous thrombosis risk factors, patient education about treatment adherence, and lifestyle counselling. Low-dose aspirin (LDA) is recommended for asymptomatic aPL carriers, patients with systemic lupus erythematosus without prior thrombotic or obstetric APS, and non-pregnant women with a history of obstetric APS only, all with high-risk aPL profiles. Patients with APS and first unprovoked venous thrombosis should receive long-term treatment with vitamin K antagonists (VKA) with a target international normalised ratio (INR) of 2-3. In patients with APS with first arterial thrombosis, treatment with VKA with INR 2-3 or INR 3-4 is recommended, considering the individual's bleeding/thrombosis risk. Rivaroxaban should not be used in patients with APS with triple aPL positivity. For patients with recurrent arterial or venous thrombosis despite adequate treatment, addition of LDA, increase of INR target to 3-4 or switch to low molecular weight heparin may be considered. In women with prior obstetric APS, combination treatment with LDA and prophylactic dosage heparin during pregnancy is recommended. In patients with recurrent pregnancy complications, increase of heparin to therapeutic dose, addition of hydroxychloroquine or addition of low-dose prednisolone in the first trimester may be considered. These recommendations aim to guide treatment in adults with APS. High-quality evidence is limited, indicating a need for more research.

Silent Myocardial Perfusion Abnormalities Detected by Stress Cardiovascular Magnetic Resonance in Antiphospholipid Syndrome: A Case-Control Study

Objective: To examine the prevalence of silent myocardial ischemia and fibrosis in antiphospholipid syndrome (APS), using stress cardiovascular magnetic resonance (CMR). Methods: Forty-four consecutive APS patients without prior cardiac disease (22 primary APS, 22 systemic lupus erythematosus (SLE)/APS, mean age 44 (12.9) years, 64% women) and 44 age/gender-matched controls were evaluated using CMR at 1.5 T. Steady-state free precession imaging for function assessment and adenosine stress-CMR for perfusion-fibrosis evaluation were employed. The myocardial perfusion reserve index (MPRI), and myocardial fibrosis expressed as late gadolinium enhancement (LGE), were evaluated. Coronary angiography was indicated in patients with LGE. Associations with APS characteristics, classic cardiovascular disease (CVD) risk factors, high-sensitivity CRP (hs-CRP) and high-sensitivity Troponin (hs-TnT) levels were tested. All patients were followed up for 12 months. Results: Median MPRI was significantly lower in APS patients versus controls [1.5 (0.9–1.9) vs. 2.7 (2.2–3.2), p < 0.001], independently of any LGE presence. LGE was detected in 16 (36.3%) patients versus none of controls (p < 0.001); 12/16 were subsequently examined with coronary angiography and only two of them had coronary artery lesions. In multivariable analysis, none of the APS-related and classic CVD risk factors, or hs-CRP and hs-TnT covariates, were significant predictors of abnormal MPRI or LGE. At the twelve month follow-up, three (6.8%) patients experienced coronary artery disease, notably those with the lowest MPRI values. Conclusions: Abnormal MPRI and LGE are common in asymptomatic APS patients, independently so of any APS-related and classic CVD risk factors, or coronary angiography findings in cases with LGE. Stress-CMR is a valuable tool to detect silent myocardial ischemia and fibrosis in APS.

Cardiac Manifestations of Antiphospholipid Syndrome With Focus on Its Primary Form

Antiphospholipid syndrome (APS) is a multisystem autoimmune disease most commonly associated with recurrent arterial and venous thromboembolism and recurrent fetal loss. Other possible antiphospholipid antibody (aPL)-related clinical manifestations include cardiac involvement. The heart can be involved through immune mediated and /or thrombotic mechanisms. Mortality due to cardiovascular problems is elevated in APS. However, the cardiovascular risk in patients with primary APS (PAPS) compared with lupus-related APS is yet to be established. Cardiac symptoms of APS include valve abnormalities (thickening and vegetations), coronary artery disease (CAD), myocardial dysfunction, pulmonary hypertension, and intracardiac thrombi. Heart valve lesions are the most common cardiac manifestation, observed in approximately one third of PAPS patients and usually do not cause hemodynamic significance. Deposits of immunoglobulins including anticardiolipin (aCL), and of complement components, are commonly observed in affected heart valves from these patients. This suggests that an inflammatory process is initiated by aPL deposition, eventually resulting in the formation of valvular lesion. aPL may have a direct role in the atherosclerotic process via induction of endothelial activation. Multiple traditional and autoimmune-inflammatory risk factors are involved in triggering an expedited atherosclerotic arterial disease evident in APS. It is imperative to increase the efforts in early diagnosis, control of risk factors and close follow-up, in the attempt to minimize cardiovascular risk in APS. Clinicians should bear in mind that a multidisciplinary therapeutic approach is of paramount importance in these patients. This article reviews the cardiac detriments of APS, including treatment recommendations for each cardiac complication.

Lupus Nephritis with Coexistent Antiphospholipid Antibodies Associated Nephropathy: A Case Report and Literature Review

Antiphospholipid syndrome (APS) associated nephropathy is a distinct clinical entity and can occur in patients with systemic lupus erythematosus (SLE) independent of or associated with lupus nephritis. Associated APS nephropathy in a patient with lupus predicts poor renal outcome, especially if left untreated. Recognizing a coexistent APS nephropathy in a patient with lupus nephritis is of utmost importance. Here, we present a patient with severe lupus nephritis with antiphospholipid antibodies (aPLs) who had no thrombotic manifestations of APS clinically. On renal biopsy, she was found to have APS nephropathy. Remission was achieved after 3 months of anticoagulation and immunosuppression. This case illustrates the importance of renal biopsy in a patient of SLE with aPLs. Renal biopsy often alerts a treating rheumatologist of the presence of thrombotic involvement in such patients, thereby altering the treatment of such patients.

Antiphospholipid Syndrome Nephropathy: From Pathogenesis to Treatment

Kidney damage is a well-recognized complication of the antiphospholipid syndrome (APS), either primary or systemic lupus erythematosus (SLE)-associated APS. Kidney involvement in APS involves a variety of manifestations, such as renal artery thrombosis or stenosis, renal vein thrombosis, allograft loss due to thrombosis after kidney transplantation, and injury to the renal microvasculature, also known as APS nephropathy. Biopsy in patients with APS nephropathy includes acute thrombotic microangiopathy lesions and chronic intrarenal vascular lesions such as interlobular fibrous intimal hyperplasia, arterial and arteriolar recanalizing thrombosis, fibrous arterial occlusion, and focal cortical atrophy. The most frequent clinical features are hypertension, microscopic hematuria, proteinuria (ranging from mild to nephritic levels), and renal insufficiency. It is uncertain whether antiphospholipid antibodies or other factors are implicated in the development of APS nephropathy, and whether it is driven mainly by thrombotic or by inflammatory processes. Experimental models and clinical studies of thrombotic microangiopathy lesions implicate activation of the complement cascade, tissue factor, and the mTORC pathway. Currently, the management of APS nephropathy relies on expert opinion, and consensus is lacking. There is limited evidence about the effect of anticoagulants, and their use remains controversial. Treatment approaches in patients with APS nephropathy lesions may include the use of heparin based on its role on complement activation pathway inhibition or the use of intravenous immunoglobulin and/or plasma exchange. Targeted therapies may also be considered based on potential APS nephropathy pathogenetic mechanisms such as B-cell directed therapies, complement inhibition, tissue factor inhibition, mTOR pathway inhibition, or anti-interferon antibodies, but prospective multicenter studies are needed to address their role.

Renal involvement in antiphospholipid syndrome

This is a review of scientific publications on renal involvement in antiphospholipid syndrome (APS), with focus on clinical and histopathological findings and treatment. A search for English-language articles on renal involvement in APS covering the period 1980-2017 was conducted in Medline/PubMed and Scopus databases using the MeSH terms "antiphospholipid syndrome", "antiphospholipid antibodies", "glomerulonephritis" and "thrombotic microangiopathy" (TMA). APS nephropathy is primarily the result of thromboses in renal arteries or veins, intraparenchymatous arteries and glomerular capillaries. On histology, APS nephropathy is characterized by TMA, but chronic vaso-occlusive lesions are also commonly observed (fibrous intimal hyperplasia, focal cortical atrophy, fibrous occlusions of arteries). Anticardiolipin and lupus anticoagulant are the most prevalent antibodies in patients with APS nephropathy. The spectrum of renal manifestations includes renal vein thrombosis, renal artery thrombosis/stenosis, TMA, increased allograft vascular thrombosis and malignant hypertension. Anticoagulation is the standard treatment of thrombotic events. In systemic lupus erythematosus (SLE) patients with antiphospholipid antibodies (aPL), kidney failure due to SLE nephritis (immune-complex disease) should be clearly distinguished from kidney failure due to APS-related TMA. In such cases, renal biopsy is mandatory. SLE nephritis requires immunosuppressive therapy, whereas APS nephropathy is usually treated with anticoagulants. Recently, eculizumab and sirolimus have been proposed as a rescue therapy. Based on our review, APS nephropathy appears to be a distinct clinical condition. TMA is a characteristic histopathological finding in APS and is strongly associated with the presence of aPL. This has important therapeutic implications and allows distinguishing APS nephropathy from lupus nephritis.

Antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by the presence of antiphospholipid antibodies, such as lupus anticoagulant, anticardiolipin antibodies and anti-β2-glycoprotein 1 antibodies. APS can present with a variety of clinical phenotypes, including thrombosis in the veins, arteries and microvasculature as well as obstetrical complications. The pathophysiological hallmark is thrombosis, but other factors such as complement activation might be important. Prevention of thrombotic manifestations associated with APS includes lifestyle changes and, in individuals at high risk, low-dose aspirin. Prevention and treatment of thrombotic events are dependent mainly on the use of vitamin K antagonists. Immunosuppression and anticomplement therapy have been used anecdotally but have not been adequately tested. Pregnancy morbidity includes unexplained recurrent early miscarriage, fetal death and late obstetrical manifestation such as pre-eclampsia, premature birth or fetal growth restriction associated with placental insufficiency. Current treatment to prevent obstetrical morbidity is based on low-dose aspirin and/or low-molecular-weight heparin and has improved pregnancy outcomes to achieve successful live birth in >70% of pregnancies. Although hydroxychloroquine and pravastatin might further improve pregnancy outcomes, prospective clinical trials are required to confirm these findings.

Use of eculizumab in a systemic lupus erythemathosus patient presenting thrombotic microangiopathy and heterozygous deletion in CFHR1-CFHR3. A case report and systematic review

The association of thrombotic microangiopathy (TMA) with systemic lupus erythematosus (SLE) has been described in 0.5 to 10% of cases, and patients present worse outcome. TMA is described as the association of microangiopathic hemolytic anemia, thrombocytopenia, and an organ injury, frequently the kidney. This study describes a successful case of use of eculizumab in a patient with SLE and TMA refractory to standard therapy, and provides a literature review. Case description and search in PubMed and MEDLINE using systemic lupus erythemathous and/or antiphospholipid syndrome (APS) and eculizumab retrieved 15 case reports. Eighteen-year-old female presented acute renal failure and TMA and was diagnosed with SLE. Steroids and IV cyclophosphamide were started together with plasma exchange. After 55 days, she still persisted with microangiopathic anemia, thrombocytopenia, and anuria, and eculizumab was introduced. She had rapid improvement in hematological parameters, and dialysis was discontinued 25 days after the first dose. Genetic analysis showed large heterozygous deletion encompassing the entire CFHR1 and CFHR3, a finding previously associated with patients presenting atypical hemolytic-uremic syndrome (aHUS). Twenty patients who received eculizumab with SLE and/or APS have been published to date: 11 were female and mean age at presentation was 31 years. Seven out of the 20 patients presented only SLE, 5 patients only APS and 8 patients both SLE and APS. Eighteen patients underwent plasma exchange, with a mean of 20 (4-120) sessions per patient. Thirteen patients received rituximab. Hematological response was evident in 100% and kidney recovery in 85% of patients. The terminal complement blockade with eculizumab is an optional treatment for patients with SLE and/or APS presenting TMA and refractory to current immunosuppression therapies. Genetic testing may help recognize patients with aHUS and SLE/APS and therefore help to determine length of treatment with eculizumab.

Autoantibodies to types I and IV collagen and heart valve disease in systemic lupus erythematosus/antiphospholipid syndrome

Introduction/objectives autoantibodies to types I and IV collagen have been described in rheumatic fever and infective endocarditis. We tried to elucidate if an autoimmune response against collagens I and IV exists, associated with heart valve disease in systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS). A cohort of 172 patients with SLE (n = 79), primary APS (PAPS, n = 83), and secondary APS (n = 10) were assessed for valvulopathy by transthoracic echocardiograms. Autoantibodies to types I and IV collagen were assessed in patients and 50 controls, setting autoantibody positivity at two standard deviations above the mean antibody level of controls. Positive anticollagen IV antibody rate was significantly higher in SLE patients (17.7%) in respect to the rest of groups (PAPS 2.4%, controls 2%; P = 0.001). Percentage of positive autoantibodies to collagen I was similar in SLE and APS cohort of patients with and without valvular disease (48.4 vs 51.6%, respectively; P = 0.45). Percentage of positive autoantibodies to collagen IV was increased but not significantly in SLE and APS cohort of patients with respect to those without valvular disease (62.5 vs 37.5%, respectively; P = 0.08). Mean (standard deviation) levels of positive anticollagen I and IV antibodies did not differ between patients with and without valvular disease (85.6 ± 55 vs 81 ± 85 U/ml, respectively; P = 0.86 for anticollagen I) (0.05 ± 0.02 vs 0.12 ± 0.16 U/ml, respectively; P = 0.34 for anticollagen IV). Our data indicate a lack of association of autoantibodies to types I and IV collagen with heart valve disease in SLE and APS.

[2016 review on catastrophic antiphospholipid syndrome]

The catastrophic antiphospholipid syndrome (CAPS) develops in at least 1% of patients with antiphospholipid syndrome, either primary or associated with systemic lupus erythematosus. CAPS reveals the antiphospholipid syndrome in about 50% of cases. The CAPS is characterized by rapidly-progressive widespread thromboses mainly affecting the microvasculature in the presence of antiphospholipid antibodies. In a few days, the patients develop multiorgan failure with renal insufficiency with severe hypertension, pulmonary, cerebral, cardiac, digestive and/or cutaneous involvement. The vital prognosis is frequently engaged. CAPS is often precipitated by infectious diseases, surgical procedures and/or withdrawal or modification of the anticoagulation. CAPS overall mortality rate has decreased and is currently below 30%. The main differential diagnoses are other thrombotic microangiopathies, and heparin-induced thrombocytopenia. The treatment of CAPS consists of the association of anticoagulation and steroids, plus plasma exchange and/or intravenous immunoglobulins. Cyclophosphamide is added only in patients with active systemic lupus erythematosus. The potential contribution of some additional therapies (rituximab, eculizumab or sirolimus) needs to be assessed. The prevention of CAPS is essential and is based upon the adequate management of the perioperative period when surgery cannot be avoided, the prompt treatment and the prevention with immunization of infections and the education of patients with antiphospholipid syndrome, especially for the management of oral anticoagulants.

Antiphospholipid Syndrome and the Kidney

The antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by a combination of arterial and/or venous thrombosis, pregnancy morbidity, and the persistent presence of circulating antiphospholipid antibodies (aPL). APS has been described as primary APS when it occurs in the absence of any features of other autoimmune disease, and as secondary in the presence of other autoimmune diseases, mainly systemic lupus erythematosus (SLE). There is a well-known link between SLE and APS; 40% of SLE patients have aPL, and, in turn, some, but only a minority of patients with APS, eventually will develop features of SLE. Because SLE and APS can target the kidneys independently or at the same time, discriminating between inflammatory or thrombotic lesions is crucial in planning therapy. We provide an overview of the renal manifestations associated with the presence of aPL in patients with SLE, and discuss the impact of aPL in selected scenarios such as lupus nephritis, end-stage renal disease, and pregnancy.

Antiphospholipid syndrome and kidney disease

The antiphospholipid syndrome is a common autoimmune disease caused by pathogenic antiphospholipid antibodies, leading to recurrent thrombosis and/or obstetrical complications. Importantly for nephrologists, antiphospholipid antibodies are associated with various renal manifestations including large renal vessel thrombosis, renal artery stenosis, and a constellation of intrarenal lesions that has been termed antiphospholipid nephropathy. This last condition associates various degrees of acute thrombotic microangiopathy, proliferative and fibrotic lesions of the intrarenal vessels, and ischemic modifications of the renal parenchyma. The course of the disease can range from indolent nephropathy to devastating acute renal failure. The pejorative impact of antiphospholipid antibody-related renal complication is well established in the context of systemic lupus erythematous or after renal transplantation. In contrast, the exact significance of isolated antiphospholipid nephropathy remains uncertain. The evidence to guide management of the renal complications of antiphospholipid syndrome is limited. However, the recent recognition of the heterogeneous molecular mechanisms underlying the progression of intrarenal vascular lesions in antiphospholipid syndrome have opened promising tracks for patient monitoring and targeted therapeutic intervention.

Antiphospholipid Syndrome (APS) - An Update on Clinical Features and Treatment Options

Antiphospholipid syndrome (APS) is an autoantibody disorder characterized by the presence of antiphospholipid (APL) antibodies and heterogeneous clinical manifestations. Patients may present with recurrent thrombosis, obstetric morbidity, cardiac valvular lesions, thrombocytopenia, skin lesions, renal or neurologic abnormalities. We provide a comprehensive review of these diverse clinical features except renal and obstetric complications. Treatment of APS can be challenging as one tries to balance the benefit of anticoagulation therapy in this hypercoagulable state while minimizing the risk of bleeding. We discuss the various therapeutic options including the role of aspirin, warfarin, low molecular weight heparin, new direct thrombin inhibitors, hydroxychloroquine, intravenous gamma globulin, rituximab and others. Lower risk APS patients (i.e. first venous thrombosis) should receive warfarin with a target INR of 2.0-3.0. Higher risk patients (i.e. arterial thrombosis or recurrent venous events) have a target INR of >3.0. Currently, warfarin remains the mainstay in treatment of APS. Because of lack of adequate data, the newer oral direct inhibitors should be considered only when there is a known allergy/ intolerance or poor control with warfarin. Additional vascular and thrombotic risk factors should be aggressively reduced. Further studies involving large number of APS patients, diagnosed according to accepted criteria, are needed to better define the role of newer anticoagulants and other novel therapies.

The relevance of "non-criteria" clinical manifestations of antiphospholipid syndrome: 14th International Congress on Antiphospholipid Antibodies Technical Task Force Report on Antiphospholipid Syndrome Clinical Features

The purpose of this task force was to critically analyze nine non-criteria manifestations of APS to support their inclusion as APS classification criteria. The Task Force Members selected the non-criteria clinical manifestations according to their clinical relevance, that is, the patient-important outcome from clinician perspective. They included superficial vein thrombosis, thrombocytopenia, renal microangiopathy, heart valve disease, livedo reticularis, migraine, chorea, seizures and myelitis, which were reviewed by this International Task Force collaboration, in addition to the seronegative APS (SN-APS). GRADE system was used to evaluate the quality of evidence of medical literature of each selected item. This critical appraisal exercise aimed to support the debate regarding the clinical picture of APS. We found that the overall GRADE analysis was very low for migraine and seizures, low for superficial venous thrombosis, thrombocytopenia, chorea, longitudinal myelitis and the so-called seronegative APS and moderate for APS nephropathy, heart valve lesions and livedo reticularis. The next step can be a critical redefinition of an APS gold standard, for instance derived from the APS ACTION registry that will include not only current APS patients but also those with antiphospholipid antibodies not meeting current classification criteria.

Catastrophic antiphospholipid syndrome: task force report summary

The Task Force on Catastrophic Antiphospholipid Syndrome (CAPS) aimed to assess the current knowledge on pathogenesis, clinical and laboratory features, diagnosis and classification, precipitating factors and treatment of CAPS. This article summarizes the main aspects of its final report.

14th International Congress on Antiphospholipid Antibodies Task Force Report on Catastrophic Antiphospholipid Syndrome

The 'Task Force on Catastrophic Antiphospholipid Syndrome (CAPS)' was developed on the occasion of the 14th International Congress on Antiphospholipid Antibodies. The objectives of this Task Force were to assess the current knowledge on pathogenesis, clinical and laboratory features, diagnosis and classification, precipitating factors and treatment of this condition in order to address recommendations for future research. This article summarizes the studies analyzed by the Task Force, its recommendations and the future research agenda.

Renal involvement in antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease defined by the presence of arterial or venous thrombotic events and/or pregnancy morbidity in patients who test positive for antiphospholipid antibodies (aPLs). APS can be isolated (known as primary APS) or associated with other autoimmune diseases, such as systemic lupus erythematosus (SLE; known as secondary APS). The kidney is a major target organ in APS and renal thrombosis can occur at any level within the vasculature of the kidney (renal arteries, intrarenal arteries, glomerular capillaries and renal veins); events reflect the site and size of the involved vessels. Histological findings vary widely, including ischaemic glomeruli and thrombotic lesions without glomerular or arterial immune deposits on immunofluorescence. Renal prognosis is affected by the presence of aPLs in patients with lupus nephritis and can be poor. In patients with SLE and aPLs, biopsy should be performed because inflammatory and thrombotic lesions require different therapeutic approaches. Renal involvement in patients with definite APS is treated by anticoagulation with long-term warfarin. The range of renal manifestations associated with APS is broadening and, therefore, aPLs have increasing relevance in end-stage renal disease, transplantation and pregnancy.