Spectrum of vascular pathology affecting patients with the antiphospholipid syndrome

Deciphering Mechanisms, Prevention Strategies, Management Plans, Medications, and Research Techniques for Strokes in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune rheumatic condition characterized by an unpredictable course and a wide spectrum of manifestations varying in severity. Individuals with SLE are at an increased risk of cerebrovascular events, particularly strokes. These strokes manifest with a diverse range of symptoms that cannot be solely attributed to conventional risk factors, underscoring their significance among the atypical risk factors in the context of SLE. This complexity complicates the identification of optimal management plans and the selection of medication combinations for individual patients. This susceptibility is further complicated by the nuances of neuropsychiatric SLE, which reveals a diverse array of neurological symptoms, particularly those associated with ischemic and hemorrhagic strokes. Given the broad range of clinical presentations and associated risks linking strokes to SLE, ongoing research and comprehensive care strategies are essential. These efforts are critical for improving patient outcomes by optimizing management strategies and discovering new medications. This review aims to elucidate the pathological connection between SLE and strokes by examining neurological manifestations, risk factors, mechanisms, prediction and prevention strategies, management plans, and available research tools and animal models. It seeks to explore this medical correlation and discover new medication options that can be tailored to individual SLE patients at risk of stroke.

Rethinking antiphospholipid syndrome to guide future management and research

Antiphospholipid syndrome (APS) consists of thrombotic, non-thrombotic and obstetric clinical manifestations developing in individuals with persistent antiphospholipid antibodies (aPL). Although researchers have made progress in characterizing different clinical phenotypes of aPL-positive people, the current approach to clinical management is still mostly based on a 'one size fits all' strategy, which is derived from the results of a limited number of prospective, controlled studies. With the 2023 publication of the ACR-EULAR APS classification criteria, it is now possible to rethink APS, to lay the groundwork for subphenotyping through novel pathophysiology-informed approaches, and to set a future APS research agenda guided by unmet needs in clinical management.

Antiphospholipid syndrome: advances in diagnosis, pathogenesis, and management

Antiphospholipid syndrome (APS) is a thrombo-inflammatory disease propelled by circulating autoantibodies that recognize cell surface phospholipids and phospholipid binding proteins. The result is an increased risk of thrombotic events, pregnancy morbidity, and various other autoimmune and inflammatory complications. Although antiphospholipid syndrome was first recognized in patients with lupus, the stand alone presentation of antiphospholipid syndrome is at least equally common. Overall, the diagnosis appears to affect at least one in 2000 people. Studies of antiphospholipid syndrome pathogenesis have long focused on logical candidates such as coagulation factors, endothelial cells, and platelets. Recent work has shed light on additional potential therapeutic targets within the innate immune system, including the complement system and neutrophil extracellular traps. Vitamin K antagonists remain the mainstay of treatment for most patients with thrombotic antiphospholipid syndrome and, based on current data, appear superior to the more targeted direct oral anticoagulants. The potential role of immunomodulatory treatments in antiphospholipid syndrome management is receiving increased attention. As for many systemic autoimmune diseases, the most important future direction is to more precisely identify mechanistic drivers of disease heterogeneity in pursuit of unlocking personalized and proactive treatments for patients.

Pulmonary arterial hypertension due to antiphospholipid syndrome initially mimicking chronic thromboembolic pulmonary hypertension

Pulmonary arterial hypertension (PAH) is the second most common lung complication in antiphospholipid syndrome (APS) patients. However, the concurrent development of APS-related nonthrombotic PAH is rarely reported. Lack of awareness for group 1 PAH in APS patient may contribute to underdiagnosis of this condition. Herein, we reviewed the case of a 56-year-old female who was diagnosed with PAH related to APS that mimicked chronic thromboembolic pulmonary hypertension (CTEPH). It is crucial to be aware of the possibility of a group 1 PAH diagnosis, even though patients have already been diagnosed with CTEPH. Furthermore, a multidisciplinary approach and serial follow-up right heart catheterization with echocardiography are important to make a timely diagnosis and provide optimal treatment for APS-related PAH in patients with CTEPH-like clinical features.

Mechanisms of immunothrombosis and vasculopathy in antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune thrombophilia propelled by circulating antiphospholipid antibodies that herald vascular thrombosis and obstetrical complications. Antiphospholipid antibodies recognize phospholipids and phospholipid-binding proteins and are not only markers of disease but also key drivers of APS pathophysiology. Thrombotic events in APS can be attributed to various conspirators including activated endothelial cells, platelets, and myeloid-lineage cells, as well as derangements in coagulation and fibrinolytic systems. Furthermore, recent work has especially highlighted the role of neutrophil extracellular traps (NETs) and the complement system in APS thrombosis. Beyond acute thrombosis, patients with APS can also develop an occlusive vasculopathy, a long-term consequence of APS characterized by cell proliferation and infiltration that progressively expands the intima and leads to organ damage. This review will highlight known pathogenic factors in APS and will also briefly discuss similarities between APS and the thrombophilic coagulopathy of COVID-19.

Myocardial involvement in anti-phospholipid syndrome: Beyond acute myocardial infarction

Anti-phospholipid antibodies (aPL) are the serological biomarkers of anti-phospholipid syndrome (APS), an autoimmune disorder characterized by vascular events and/or pregnancy morbidity. APS is a unique condition as thrombosis might occur in arterial, venous or capillary circulations. The heart provides a frequent target for circulating aPL, leading to a wide variety of clinical manifestations. The most common cardiac presentation in APS, valvular involvement, acknowledges a dual etiology comprising both microthrombotic and inflammatory mechanisms. We describe the cases of 4 patients with primary APS who presented a clinically manifest myocardiopathy without epicardial macrovascular distribution. We propose that microthrombotic/inflammatory myocardiopathy might be an overlooked complication of high-risk APS. As extensively hereby reviewed, the literature provides support to this hypothesis in terms of anecdotal case-reports, in some cases with myocardial bioptic specimens. In aPL-positive subjects, microthrombotic/inflammatory myocardial involvement might also clinically manifest as dilated cardiomyopathy, a clinical entity characterized by ventricular dilation and reduced cardiac output. Furthermore, microthrombotic/inflammatory myocardial involvement might be subclinical, presenting as diastolic dysfunction. Currently, there is no single clinical or imaging finding to firmly confirm the diagnosis; an integrated approach including clinical history, clinical assessment, laboratory tests and cardiac magnetic resonance should be pursued in patients with suggestive clinical presentation.

Small Bowel Necrosis Associated with Catastrophic Antiphospholipid Syndrome: A Case Report

Catastrophic antiphospholipid syndrome is a highly fatal condition characterized by widespread thromboembolism subsequent to a triggering factor (e.g., infection, trauma, and neoplasia) in antiphospholipid antibody-positive patients. This paper reports a case of a 29-year-old male without the underlying disease who developed extensive mesenteric thromboembolism and jejunal necrosis during the treatment for acute enteritis. The patient's condition was improved with low-molecular-weight heparin and an intravenous Ig treatment with emergency surgery. The serum antiphospholipid (anticardiolipin IgM) and lupus anticoagulant antibody tests showed positive results. Acute infectious enterocolitis is generally considered a mild disease. On the other hand, aggressive evaluation and treatment should be considered if the clinical conditions do not improve and deteriorate rapidly despite appropriate antibiotic treatment because of the possibility of acute immunological complications, such as catastrophic antiphospholipid syndrome.

Antiphospholipid syndrome

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

A glimpse into the history of description of the antiphospholipid syndrome

Prior to 1983, several landmark reports prepared the stage for a detailed description of the Antiphospholipid (Hughes) syndrome (APS). Formerly depicted as lupus-like, APS exhibits a wide spectrum of symptoms that overlap with Sjogren's, Hashimoto, and other autoimmune diseases. In this review, we take a glimpse into the history of description of APS, discussing the events that led to its recognition as one of the most common autoimmune diseases and the enormous impact of that recognition in the rheumatology field.

Stroke in systemic lupus erythematosus: epidemiology, mechanism, and long-term outcome

Objective

To determine stroke prevalence, mechanisms, and long-term outcome in a cohort of Hispanic patients with systemic lupus erythematosus (SLE).

Methods

We analyzed demographical data, the timing between SLE diagnosis and stroke onset, stroke type, recurrence, and outcomes from an institutional database of 4451 patients with SLE followed from 1993 to 2018.

Results

We observed 139 strokes (3.1%), for an incidence rate of 1.25 per 1000 person-years: 81 (58.3%) acute ischemic stroke (AIS), 19 (13.7%) subarachnoid hemorrhage (SAH), 17 (12.2%) cerebral venous thrombosis, 13 (9.4%) intracerebral hemorrhage (ICH), and 9 (6.5%) transient ischemic attack. Median time from SLE diagnosis to acute stroke was 60 months (interquartile range 12–132 months). AIS had a bimodal presentation with 26% occurring within the first year and 30% >10 years after SLE diagnosis. In contrast, 75% of ICH cases occurred >3 years (and 34% >10 years) after SLE diagnosis. The most important cause of AIS was secondary antiphospholipid syndrome (48%). Hypertension was associated with 69% of ICH cases, while aneurysmal rupture was observed in 78% of SAH cases. Excellent recovery at hospital discharge was observed in 65%. Stroke recurrence was observed in 7%. The long-term all-cause fatality rate was 8%.

Conclusions

The prevalence of stroke in this cohort was 3.1%. Ischemic strokes had a bimodal presentation, occurring either early after SLE diagnosis or after a several-year delay. Half of the hemorrhagic strokes occurred >10 years after the diagnosis of SLE. Clinical outcome was usually good with a relatively low recurrence rate.

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: Role of Vascular Endothelial Cells and Implications for Risk Stratification and Targeted Therapeutics

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by venous thromboembolism, arterial thrombosis, and obstetric morbidities in the setting of persistently positive levels of antiphospholipid antibodies measured on 2 different occasions 12 weeks apart. Patients with APS are at increased risk for accelerated atherosclerosis, myocardial infarction, stroke, and valvular heart disease. Vascular endothelial cell dysfunction mediated by antiphospholipid antibodies and subsequent complement system activation play a cardinal role in APS pathogenesis. Improved understanding of their pathogenic function could help in the risk stratification of patients with APS and provide new molecular therapeutic targets.

Kidney disease in primary anti-phospholipid antibody 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 aPL. APS can be isolated (primary APS) or associated with other autoimmune diseases. 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 vasculature and renal veins). Histological findings vary widely, including ischaemic glomeruli and thrombotic lesions without glomerular or arterial immune deposits on immunofluorescence. Renal involvement in patients with definite APS is treated with long-term anticoagulants as warfarin, but new treatments are being tried. The aim of this article is to review the links between primary APS and kidney disease.

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.

Nonthrombotic proliferative vasculopathy associated with antiphospholipid antibodies: A case report and literature review

A 20-year-old man presented with recurrent hemoptysis for seven months. A small subpleural nodule in his right lower lobe was found and excised surgically. Based on the presence of antiphospholipid antibodies (aPL) and vascular wall hypertrophy without vasculitis or an intraluminal thrombus, nonthrombotic proliferative vasculopathy (NTPV) affecting pulmonary arteries was diagnosed. Recently, aPL have been postulated to directly induce the proliferation of vascular cells in the intima and media, leading to NTPV. We review 5 cases of NTPV-associated aPL with critical ischemia in the lower extremities and gastrointestinal infarction. NTPV-associated aPL might be distinct from classic antiphospholipid syndrome and should be considered in aPL-positive patients who present with vascular occlusions of medium-sized vessels in the absence of atherosclerotic risk factors and systemic or local inflammation.

Inhibition of the mTORC pathway in the antiphospholipid syndrome

BACKGROUND

Although thrombosis is considered the cardinal feature of the antiphospholipid syndrome, chronic vascular lesions are common, particularly in patients with life-threatening complications. In patients who require transplantation, vascular lesions often recur. The molecular pathways involved in the vasculopathy of the antiphospholipid syndrome are unknown, and adequate therapies are lacking.

METHODS

We used double immunostaining to evaluate pathway activation in the mammalian target of rapamycin complex (mTORC) and the nature of cell proliferation in the vessels of patients with primary or secondary antiphospholipid syndrome nephropathy. We also evaluated autopsy specimens from persons who had catastrophic antiphospholipid syndrome. The molecular pathways through which antiphospholipid antibodies modulate the mTORC pathway were evaluated in vitro, and potential pharmacologic inhibitors were also tested in vitro. Finally, we studied the effect of sirolimus in kidney-transplant recipients with the antiphospholipid syndrome.

RESULTS

The vascular endothelium of proliferating intrarenal vessels from patients with antiphospholipid syndrome nephropathy showed indications of activation of the mTORC pathway. In cultured vascular endothelial cells, IgG antibodies from patients with the antiphospholipid syndrome stimulated mTORC through the phosphatidylinositol 3-kinase (PI3K)-AKT pathway. Patients with antiphospholipid syndrome nephropathy who required transplantation and were receiving sirolimus had no recurrence of vascular lesions and had decreased vascular proliferation on biopsy as compared with patients with antiphospholipid antibodies who were not receiving sirolimus. Among 10 patients treated with sirolimus, 7 (70%) had a functioning renal allograft 144 months after transplantation versus 3 of 27 untreated patients (11%). Activation of mTORC was also found in the vessels of autopsy specimens from patients with catastrophic antiphospholipid syndrome.

CONCLUSIONS

Our results suggest that the mTORC pathway is involved in the vascular lesions associated with the antiphospholipid syndrome. (Funded by INSERM and others.).

Eculizumab improves posttransplant thrombotic microangiopathy due to antiphospholipid syndrome recurrence but fails to prevent chronic vascular changes

Thrombotic microangiopathy (TMA) is one of the hallmark vascular lesions of antiphospholipid syndrome nephropathy (APSN). These lesions are at high risk of recurrence after kidney transplantation. The complement pathway is thought to be active in this process. We used eculizumab to treat three consecutive kidney transplant recipients with posttransplant TMA due to APSN recurrence that was resistant to plasmapheresis and explored the complement deposition and apoptotic and vascular cell markers on the sequential transplant biopsies. Treatment with eculizumab resulted in a rapid and dramatic improvement of the graft function in all three patients and in improvement of the TMA lesions within the graft. None of these patients had TMA flares after eculizumab was withdrawn. At the time of TMA diagnosis, immunofluorescence studies revealed intense C5b-9 and C4d depositions at the endothelial cell surface of the injured vessels. Moreover, C5b-9 colocalized with vessels exhibiting a high rate of apoptotic cells. Examination of sequential biopsies during eculizumab therapy showed that TMA lesions, C4d and apoptotic markers were rapidly cleared but the C5b-9 deposits persisted for several months as a footprint of the TMA. Finally, we noticed that complement inhibition did not prevent the development of the chronic vascular changes associated with APSN. Eculizumab seems to be an efficient method for treating severe forms of posttransplant TMA due to APSN recurrence. Terminal complement inhibition does not prevent the development of chronic APSN.

Interstitial lung diseases-can pathologists arrive at an etiology-based diagnosis? A critical update

Interstitial lung diseases (ILD) encompass a group of diseases with a wide range of etiologies and a variety of tissue reactions within the lung. In many instances, a careful evaluation of the tissue reactions will result in a specific diagnosis or at least in a narrow range of differentials, which will assist the clinician to arrive at a definite diagnosis, when combining our interpretation with the clinical presentation of the patient and high-resolution computed tomography. In this review, we will exclude granulomatous pneumonias as well as vascular diseases (primary arterial pulmonary hypertension and vasculitis); however, pulmonary hypertension as a complication of interstitial processes will be mentioned. Few entities of pneumoconiosis presenting as an interstitial process will be included, whereas those with granulomatous reactions will be excluded. Drug reactions will be touched on within interstitial pneumonias, but will not be a major focus. In contrast to the present-day preferred descriptive pattern recognition, it is the author's strong belief that pathologists should always try to dig out the etiology from a tissue specimen and not being satisfied with just a pattern description. It is the difference of sorting tissue reactions into boxes by their main pattern, without recognizing minor or minute reactions, which sometimes will guide one to the correct etiology-oriented interpretation. In the author's personal perspective, tissue reactions can even be sorted by their timeliness, and therefore, ordered by the time of appearance, providing an insight into the pathogenesis and course of a disease. Also, underlying immune mechanisms will be discussed briefly as far as they are essential to understand the disease.

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

The objectives of the 'Task Force on Catastrophic Antiphospholipid Syndrome (APS) and Non-criteria APS Manifestations' were to assess the clinical utility of the international consensus statement on classification criteria and treatment guidelines for the catastrophic APS, to identify and grade the studies that analyse the relationship between the antiphospholipid antibodies and the non-criteria APS manifestations and to present the current evidence regarding the accuracy of these non-criteria APS manifestations for the detection of patients with APS. This article summarizes the studies analysed on the catastrophic APS, APS nephropathy and heart valve lesions, and presents the recommendations elaborated by the Task Force after this analysis.

Trombose em artérias pulmonares pequenas e médias em granulomatose de Wegener: um estudo com microscopia confocal por varredura a laser

OBJETIVO: A granulomatose de Wegener (GW) pode causar dano nas células endoteliais e fenômenos tromboembólicos. Entretanto, poucos estudos analisaram a microcirculação pulmonar - artérias pulmonares de pequeno/médio calibre (APPMC) - em pacientes com GW. O objetivo deste estudo foi quantificar trombos de fibrina em amostras de APPMC de pacientes com GW. MÉTODOS: Analisamos 24 APPMC de seis pacientes com GW e 16 APPMC de quatro pacientes controles sem WG. Utilizamos CD34 para a marcação do endotélio em todas as amostras e microscopia confocal a laser para detectar trombos de fibrina intravasculares. Calculamos a área total do vaso, a área livre do lúmen e a área trombótica. RESULTADOS: A média da área total do vaso foi similar no grupo GW e no grupo controle (32.604 µm² vs. 32.970 µm², p = 0,8793). Trombos foram identificados em 22 das 24 APPMC (91,67%) no grupo GW, e em nenhuma do grupo controle (p < 0,0001; OR = 297 (IC95%: 13,34-6.612). A média da área trombótica foi maior no grupo GW do que no grupo controle (10.068 µm² vs. 0.000 µm², p < 0,0001). Em contraste, a média da área livre do lúmen foi menor no grupo GW que no grupo controle (6.116 µm² vs. 24.707 µm², p < 0,0001). CONCLUSÕES: A microscopia confocal a laser mostrou uma associação significante entre trombose microvascular pulmonar e GW. Isso sugere um possível papel da trombose microvascular na fisiopatologia da GW pulmonar, evocando o potencial benefício da anticoagulação na GW pulmonar. Entretanto, novos estudos são necessários para confirmar nossos achados, assim como um ensaio clínico randomizado a fim de testar o papel da anticoagulação no tratamento de pacientes com GW pulmonar.

Atherosclerosis in primary antiphospholipid syndrome

Antiphospholipid syndrome (APS) is the most common cause of acquired thrombophilia, but experimental and clinical evidence accumulated over the years suggest that the clinical manifestations of APS go beyond those of a simple hypercoagulable state. Although still a controversial topic, the elevated risk of atherosclerosis in systemic lupus erythematosus seems little accounted for by the presence of antiphospholipid antibodies, whereas premature atherosclerosis has been addressed in few series of patients with primary APS. The available data in primary APS suggest that traditional risk factors for atherosclerosis are less involved in arterial disease, rather antiphospholipid antibodies appear as major players. Their effect on the coagulation system, the vessel wall and on the antioxidant/oxidant balance impairs vascular homeostasis, leading to premature arterial thickening.

Twenty-year follow-up: an unusual case of nephropathy of antiphospholipid syndrome

Nephropathy of antiphospholipid antibody syndrome (NAPS) is an increasingly well-recognized aspect of antiphospholipid syndrome. The most characteristic histopathology is that of thrombotic microangiopathy, and thrombosis occurring in the renal vasculature is thought to be the initiating event. Other less common pathologies have been reported, and the mechanisms of these are unclear. Therapy has been largely empiric. We report a case of NAPS in a patient with atypical pathology, who has declined therapy with immunosuppressive agents and anticoagulants and who has maintained normal renal function in 20 years of follow-up.

[Acquired idiopathic thrombotic thrombocytopenic purpura: arguments for an autoimmune disease]

Thrombotic thrombocytopenic purpura (TTP) is a severe form of thrombotic microangiopathy (TMA) characterized by systemic platelet clumping, hemolytic anemia, and multiorgan failure. TTP results from a defect in ADAMTS13, a plasma enzyme specifically involved in the cleavage of highly hemostatic unusually large (UL) von Willebrand factor (vWF) multimers into smaller and less adhesive vWF forms. Failure to degrade these UL-vWF multimers leads to excessive platelet aggregation and capillary occlusion. ADAMTS13 deficiency is related to mutations of the encoding gene in hereditary TTP, whereas in acquired forms it results from autoantibodies that may alter the protein function. This latter finding strongly suggests that acquired idiopathic TTP corresponds to an autoimmune disease. Acquired idiopathic TTP appears to be associated with clinical features suggestive of autoimmunity in one third of cases. In two thirds, autoantibodies such as antinuclear antibodies may be observed. This review, based on an analysis of the literature and on French experience with TMA, focuses on the different autoimmune manifestations that may be observed in TTP, as well as the putative pathophysiological link between autoimmune manifestations and TTP.

[Antiphospholipid syndrome]

Antiphospholipid syndrome (APS) is characterized by recurrent arterial or venous thromboembolism or pregnancy loss in association with antibodies directed against anionic phospholipids or plasma proteins bound to anionic phospholipids. A common cause of the huge variety of clinical manifestations is vaso-occlusive disease and not vasculitis in venous or arterial blood vessels of different sizes and sites (i.e. deep vein thrombosis, pulmonary embolism, cerebrovascular disease). In accordance with this, fetal abortion, typically beyond the tenth week of gestation, is also caused by infarctions of blood vessels in the placenta. Establishing the correct diagnosis of APS is not easy. To estimate the risk of thrombotic complications is challenging, as well as the questions of, which, how long and in what strength anticoagulation is recommended. This paper should enable the reader to apply international consensus classification criteria correctly, to interpret the different laboratory tests for anti-phospholipid antibodies and to gain an awareness of the different forms of anticoagulation in order to stratify therapeutic decisions.

Antiphospholipid syndrome and the kidneys

OBJECTIVES

To study the relationship between antiphospholipid antibodies and kidney diseases.

METHODS

We reviewed the medical literature from 1968 to 2005 using MEDLINE and the keywords antiphospholipid syndrome, anticardiolipin antibodies, lupus anticoagulant, hypertension, renal artery stenosis, renal vascular thrombosis, thrombotic microangiopathy, and glomerulonephritis.

RESULTS

The renal manifestations of the antiphospholipid syndrome may result from thrombosis occurring at any location within the renal vasculature, that is, in the renal artery trunk or branches, intraparenchymal arteries and arterioles, glomerular capillaries, and the renal veins. The spectrum of these manifestations includes renal artery stenosis and/or malignant hypertension, renal infarction, renal vein thrombosis, thrombotic microangiopathy, increased allograft vascular thrombosis, and reduced survival of renal allografts. More recently nonthrombotic conditions like glomerulonephritis have also been reported.

CONCLUSION

The kidney appears to be a major target organ in both primary and secondary APS. Early detection of renal involvement may improve the prognosis of these patients.

Diffuse large and small bowel necrosis in catastrophic antiphospholipid syndrome

The catastrophic variant is an accelerated form of the antiphospholipid syndrome resulting in multiorgan failure because of multiple small vessel occlusions. We report a case of catastrophic antiphospholipid syndrome in a patient with subacute cutaneous lupus erythematosus and ischemic bowel, who presented with acute abdominal pain due to diffuse right colon and small bowel necrosis requiring large resection, associated with acute respiratory distress syndrome, thrombocytopenia and disseminated intravascular coagulation. Histopathological examination of resected tissues showed diffuse arteriolar and venous thrombosis but no vasculitis, and mesenteric artery lumen severely narrowed by intimal fibrosis. The patient died 15 days after admission despite treatment with anticoagulation, steroids, continuous hemofiltration and plasma exchange. Ischemic bowel and diffuse intestinal necrosis may be secondary to the antiphospholipid syndrome, and a high level of suspicion and an early diagnosis are required.

Idiopathic Pulmonary Fibrosis Related to Endothelial Injury and Antiendothelial Cell Antibodies

Mechanisms underlying idiopathic pulmonary fibrosis are not well understood. This paper presents data supporting the hypothesis that microvascular endothelial cell injury and antiendothelial cell antibodies play roles in human idiopathic pulmonary fibrosis. Serologic and pathologic features of 40 patients diagnosed with idiopathic pulmonary fibrosis were evaluated. All patients had open lung biopsies indicating either usual or nonspecific interstitial pneumonitis. All biopsies had morphologic evidence of microvascular injury to the endothelium, and direct immunofluorescence testing revealed variable deposition of IgG, IgM, or IgA within septal microvasculature suggestive of humorally mediated microvascular injury. Ultrastructural studies revealed changes of endothelial cell injury and necrosis and evidence of repetitive episodes of microvascular injury characterized by basement membrane zone collagen deposition and lamellation. Serum samples demonstrated reactivity to multiple endothelial cell antigenic epitopes, and indirect immunofluorescent testing demonstrated a prominent pattern of fluorescence in pulmonary endothelial cell preparations. Serum samples were positive in 37/40 patients for antiphospholipid antibodies with one fourth having positive lupus anticoagulant tests accompanied by thrombotic episodes. In patients with idiopathic pulmonary fibrosis, Factor VIII levels and C-reactive protein levels were also elevated, supporting the presence of endothelial cell injury and inflammation. These data underscore a potential role for immune-based microvascular injury in the evolution of usual or nonspecific interstitial pneumonitis and indicate that those patients have evidence of microvascular injury and endothelial cell necrosis. The high prevalence of antiphospholipid antibodies in these patients may lead to an inherent thrombophilic tendency.

Catastrophic antiphospholipid syndrome in a 14-year-old child

Antiphospholipid syndrome (APS) is an autoimmune disease. Less than 1% of patients with APS present with life-threatening catastrophic APS (CAPS). We report here a case of CAPS in a young girl with cardiac, gastrointestinal and renal involvement. Although the management was complicated, the outcome was better than expected. We suggest that CAPS be included in the differential diagnosis of acute renal failure in children with multi-organ involvement and prolonged phospholipid-dependent coagulation time and promptly treated with immunomodulating agents and anticoagulants.

Antiphospholipid syndrome nephropathy in patients with systemic lupus erythematosus and antiphospholipid antibodies: Prevalence, clinical associations, and long-term outcome

OBJECTIVE

To evaluate the prevalence, clinical associations, and outcome of antiphospholipid syndrome (APS) nephropathy in patients with systemic lupus erythematosus (SLE) and antiphospholipid antibodies (aPL) and in SLE patients without aPL.

METHODS

Kidney biopsy specimens obtained from 81 patients with aPL (18 of whom had APS) and 70 patients without aPL were retrospectively examined for the presence of APS nephropathy. Clinical and serologic data obtained at the time of kidney biopsy and during a mean followup of 7 years were recorded. In cases for which serial kidney biopsy specimens were available, the evolution of APS nephropathy was examined.

RESULTS

APS nephropathy existed in 39.5% of patients with aPL, compared with only 4.3% of patients without aPL. APS nephropathy was associated with both lupus anticoagulant and anticardiolipin antibodies. Among aPL-positive SLE patients, APS nephropathy was found in two-thirds of those with APS and in one-third of those without APS. A strong association between APS nephropathy and the presence of arterial thrombosis and livedo reticularis was noted. Patients with APS nephropathy had a higher frequency of hypertension and elevated serum creatinine levels at the time of kidney biopsy but did not have a higher frequency of renal insufficiency, end-stage renal disease, or death at the end of followup. Serial kidney biopsy specimens were available from 11 patients and showed progression of APS nephropathy lesions. During followup, manifestations of APS (especially arterial thromboses) developed more frequently in the SLE/non-APS patients with APS nephropathy than in those without APS nephropathy.

CONCLUSION

Among patients with SLE, APS nephropathy occurs almost exclusively in those with aPL, suggesting an important role of aPL in the pathogenesis of APS nephropathy. Patients with APS nephropathy develop hypertension, raised serum creatinine levels, and progression of histologic lesions, all of which are associated with a poor renal outcome. Manifestations of APS also tend to develop in these patients. APS nephropathy should be included in the APS classification criteria, and the use of appropriate anticoagulant therapy should be tested.

Antiphospholipid syndrome

Antiphospholipid syndrome has received considerable attention from the medical community because of its association with a number of serious clinical disorders, including arterial and venous thromboembolism, acute ischemic encephalopathy, recurrent pregnancy loss, thrombocytopenia, and livido reticularis. It can occur within the context of several diseases, mainly autoimmune disorders, and is then called secondary antiphospholipid syndrome. However, it may be also be present without any recognizable disease, or so-called primary antiphospholipid syndrome. There is no defined racial predominance for primary antiphospholipid syndrome, although a higher prevalence of systemic lupus erythematosus (SLE) occurs in African Americans and the Hispanic population. Multiple terms exist for this syndrome, some of which can be confusing. Lupus anticoagulant syndrome, for example, is a misleading term, because patients may not necessarily have SLE, and it is associated with thrombotic rather than hemorrhagic complications. To avoid further confusion, antiphospholipid syndrome is currently the preferred term for this clinical syndrome. Antiphospholipid antibodies are found in 1% to 5% of young healthy control subjects; however, the incidence increases with age and coexistent chronic disease. The syndrome occurs most commonly in young to middle-aged adults; however, it also can occur in children and the elderly. Among patients with SLE, the prevalence of antiphospholipid antibodies is high, ranging from 12% to 30% for anticardiolipin antibodies, and 15% to 34% for lupus anticoagulant antibodies. In general, anticardiolipin antibodies occur approximately five times more often then lupus anticoagulant in patients with antiphospholipid syndrome. This syndrome is the most common cause of acquired thrombophilia, associated with either venous or arterial thrombosis or both. It is characterized by the presence of antiphospholipid antibodies, recurrent arterial and venous thrombosis, and spontaneous abortion. Rarely, patients with antiphospholipid syndrome may have fulminate multiple organ failure, or catastrophic antiphospholipid syndrome. This is caused by widespread microthrombi in multiple vascular beds, and can be devastating. Patients with catastrophic antiphospholipid syndrome may have massive venous thromboembolism, along with respiratory failure, stroke, abnormal liver enzyme concentrations, renal impairment, adrenal insufficiency, and areas of cutaneous infarction. According to the international consensus statement, at least one clinical criterion (vascular thrombosis, pregnancy complications) and one laboratory criterion (lupus anticoagulant, antipcardiolipin antibodies) should be present for a diagnosis of antiphospholipid syndrome. The hallmark result from laboratory tests that defines antiphospholipid syndrome is the presence of antibodies or abnormalities in phospholipid-dependent tests of coagulation, such as dilute Russell viper venom time. There is no consensus for treatment among physicians. Overall, there is general agreement that patients with recurrent thrombotic episodes require life-long anticoagulation therapy and that those with recurrent spontaneous abortion require anticoagulation therapy and low- dose aspirin therapy during most of gestation. Prophylactic anticoagulation therapy is not justified in patients with high titer anticardiolipin antibodies with no history of thrombosis. However, if a history of recurrent deep vein thrombosis or pulmonary embolism is established, long-term anticoagulant therapy with international normalized ratio (INR) of approximately 3 is needed.

Antiphospholipid antibodies in thromboangiitis obliterans

Thromboangiitis obliterans (TAO) and antiphospholipid syndrome (APS) share the clinical characteristics of arterial thrombosis and recurrent thrombophlebitis. Although the association of anticardiolipin antibodies (aCLa) and TAO has been previously recognized, the prevalence and the clinical impact of this association remains unclear. aCLa were measured by double ELISA in patients with TAO (n = 47), premature atherosclerosis (pASO) (n=48) and otherwise healthy individuals (n = 48). Antibody status was then compared to clinical presentation and outcomes in patients meeting the diagnostic criteria for TAO. The prevalence of aCLa was significantly higher in patients with TAO (36%) compared to either pASO (8%; p = 0.01) or healthy individuals (2%; p < 0.001). Patients with TAO and a high antibody titer tended to be younger and suffer a significantly higher rate of major amputations compared to those without the antibody (100% versus 17%; p = 0.003). Clinical features of TAO not significantly altered by the presence of aCLa included upper limb involvement, digital necrosis, superficial thrombophlebitis (or deep venous thrombosis). Protein C, protein S, and anti-thrombin III were normal in all individuals. TAO is associated with an increased prevalence of aCLa. The presence of a high antibody titer in these patients is associated with increased morbidity, including major limb amputation. In patients meeting the diagnostic criteria for TAO, screening for aCLa should be considered. Although attractive, the efficacy of chronic anticoagulation in this setting remains to be proven.

Primary anti-phospholipid antibody syndrome (APS): current concepts

Primary anti-phospholipid syndrome (APS) is a thrombophilic state characterized by recurrent arterial and venous thrombosis, recurrent pregnancy loss, and the presence of circulating anti-phospholipid antibodies that may be responsible for thrombophilia and pregnancy morbidity. Ophthalmologic features are present in 15-88% of the patients with primary APS, thus ophthalmologists are one of the first physicians to whom the patient will present. An accurate diagnosis may save the patient from recurrent, potentially life-threatening thrombosis. In the U.S.A., an estimated 35,000 new cases of APS-related venous thrombosis occur each year in a population that is several decades younger than the patient population typically affected by thrombosis. Clinical features, such as chorea, transverse myelitis, cardiac valvular lesions, and accelerated atherosclerosis, are hypothesized to be due to a direct tissue-antibody interaction and cannot be explained purely by thrombosis. The use of recently proposed, well-defined diagnostic criteria, and better standardization of laboratory assays for the anti-phospholipid antibodies should help enable epidemiological surveys to establish the prevalence of these antibodies in patients with thrombosis and in the general population. Diagnosis of APS should be considered in all patients with recurrent systemic or ocular thrombosis in the absence of known risk factors. Several well-designed prospective studies show an increased risk of thrombosis in the presence of medium to high antibody level. With ocular involvement in as many as 88% of APS patients, an ophthalmic assessment should be an integral part of the clinical work-up of any patient with suspected or confirmed APS. The presence of isolated ocular thrombophilia with persistently elevated anti-phospholipid antibodies or lupus coagulant should confirm the diagnosis of APS. Management of these patients must be a multi-disciplinary effort with either a rheumatologist or a hematologist having the overall responsibility for coordinating treatment and monitoring the patient's immune status and anticoagulation. Treatment of isolated ocular thrombophilia in the presence of moderate to high titers of antiphospholipid antibodies should be on the same principles as patients with APS to prevent recurrent ocular or cerebral thrombosis.

Antiphospholipid syndrome nephropathy in systemic lupus erythematosus

In the course of the antiphospholipid syndrome (APS), the existence of vaso-occlusive lesions capable of affecting numerous organs is now well established. The renal involvement attributable to primary APS, APS nephropathy (APSN), corresponds to vaso-occlusive lesions of the intrarenal vessels, associating side-by-side, acute thromboses with chronic arterial and arteriolar lesions, leading to zones of cortical ischemic atrophy. A retrospective study of 114 lupus patients undergoing renal biopsy was undertaken to determine the following: (1) if APSN can be found in the course of systemic lupus erythematosus (SLE); (2) if certain clinical and biologic factors can permit the prediction of the presence of APSN; and (3) if APSN is a superadded renal morbidity factor in lupus patients. This study shows the following: (1) APSN occurs in SLE (32% of patients with renal biopsies) in addition to, and independently of, lupus nephritis; (2) APSN is statistically associated with lupus anticoagulant but not with anticardiolipin antibodies; (3) APSN is associated with extrarenal APS, mainly arterial thromboses and obstetrical fetal loss, but not with the venous thromboses of APS; (4) APSN is an independent risk factor, over and above lupus nephritis, that contributes to an elevated prevalence of hypertension, elevated serum creatinine, and increased interstitial fibrosis. Thus, it seems likely that, because of its associations with hypertension, elevated serum creatinine, and increased interstitial fibrosis, APSN may worsen the prognosis in these patients. APSN may also have therapeutic significance in that its recognition should permit a better balance between immunosuppressor and antithrombotic and/or vasoprotective therapy. Finally, this study suggests that APSN should be considered as an element to be included in the classification criteria of APS.

The cutaneous pathology of lupus erythematosus: a review

The presentation of lupus erythematosus (LE) ranges from a skin rash unaccompanied by extracutaneous stigmata to a rapidly progressive lethal multiorgan disease. The diagnosis and subclassification is traditionally based on the correlation of serological and clinical findings. The latter include a photoinduced skin rash, arthralgia, arthritis, fever, Raynaud's phenomenon, anemia, leukopenia, serositis, nephritis and central nervous sysdtem disease. The conventional classification scheme includes systemic, subacute cutaneous and discoid LE. Recent advances in our understanding of the cutaneous histopathology which correlates with the traditional forms of LE, along with certain novel LE subtypes, are the focus of this review. In addition to the main subtypes of LE, we will discuss associated vasculopathic lesions and the contribution of immunofluorescence microscopy to the diagnosis of LE and related connective tissue disease syndromes. Consideration will be given to unusual variants of LE such as anti-Ro/SSA-positive systemic lupus erythematosus (SLE), bullous SLE, lymphomatoid LE, lupus erythematosus profundus, drug induced LE, linear cutaneous LE, chiblains LE and parvovirus B19-associated LE.

Morphology of vascular, renal, and heart lesions in the antiphospholipid syndrome: relationship to pathogenesis

A growing body of evidence suggests that aPL are not only serological markers of the antiphospholipid syndrome (APS), but may also directly contribute to the development of thrombosis and other manifestations, including the APS vasculopathy. The latter has been documented in leptmeninges, lung, skin, myocardium, peripheral arteries, and kidney. Renal lesions, a common feature of primary antiphospholipid syndrome (PAPS), include occlusion of principal renal arteries or their main branches, TMA, cortical ischemia, and renal vein thrombosis. Within the cardiac manifestations associated with aPL, valvular involvement is the most common. Histologic findings in valve specimens are consistent with a noninflammatory lesion characterized by intravalvular capillary thrombosis, laminar or verrucous superficial thrombosis, vascular proliferation, fibrosis, and calcification. Even though there is general consensus that endothelial damage triggers the chain of events that results in valve thickening, fusion, rigidity, and ultimately functional abnormalities, we believe that more experimental work remains to be done on the initial valve insult in APS.

Primary antiphospholipid antibody syndrome: neuroradiologic findings in 11 patients

OBJECTIVE

To describe the neuroradiologic findings of primary antiphospholipid antibody syndrome (PAPS).

MATERIALS AND METHODS

During a recent two-year period, abnormally elevated antiphospholipid antibodies were detected in a total of 751 patients. In any cases in which risk factors for stroke were detected-hypertension, diabetes mellitus, hyperlipidemia, smoking, and the presence of SLE or other connective tissue diseases-PAPS was not diagnosed. Neuroradiologic studies were performed in 11 of 32 patients with PAPS. We retrospectively reviewed brain CT (n = 7), MR (n = 8), and cerebral angiography (n = 8) in 11 patients with special attention to the presence of brain parenchymal lesions and cerebral arterial or venous abnormalities.

RESULTS

CT or MR findings of PAPS included nonspecific multiple hyper-intensity foci in deep white matter on T2-weighted images (5/11), a large infarct in the territory of the middle cerebral artery (4/11), diffuse cortical atrophy (2/11), focal hemorrhage (2/11), and dural sinus thrombosis (1/11). Angiographic findings were normal (5/8) or reflected either occlusion of a large cerebral artery (2/8) or dural sinus thrombosis (1/8).

CONCLUSION

Neuroradiologic findings of PAPS are nonspecific but in young or middle-aged adults who show the above mentioned CT or MR findings, and in whom risk factors for stroke are not present, the condition should be suspected.

CT features of abdominal manifestations of primary antiphospholipid syndrome

PURPOSE

The purpose of this work was to evaluate the CT features of the abdominal manifestations of primary antiphospholipid syndrome (PAPS).

METHOD

Of the 32 patients who were confirmed to have PAPS among 751 patients with elevated antiphospholipid antibodies during a 2 year period, we retrospectively reviewed the 14 patients who underwent abdominal CT. The clinical indications for abdominal CT included abdominal pain, abdominal distension, or lower leg swelling. CT findings were analyzed with regard to the abdominal vascular system and abdominal organ involvement patterns as well as ancillary findings.

RESULTS

Of the 14 patients with PAPS, 10 had involvement of the venous system (72%), 2 of the arterial system (14%), and 2 of both systems (14%). Of the 12 patients who had venous system involvement, 4 had thrombosis in the inferior vena cava (IVC), 2 in both the IVC and the hepatic vein, 1 in the IVC and splenic and portal veins, 1 in the IVC and hepatic and adrenal veins, 1 in the hepatic, portal, and renal veins, and 3 in the portal and superior mesenteric veins. Budd-Chiari syndrome developed in five of the nine patients who had thrombosis of the IVC or hepatic vein. Arterial thrombosis was noted in four patients, hepatic artery in two, aorta in one, renal artery in one, pancreatic arcade in one, and splenic artery in one, with infarct of multiple organs including the liver, jejunum, colon, kidney, and adrenal gland. Seven of the 14 patients (50%) manifested thrombosis or infarct of multiple extra-abdominal organs.

CONCLUSION

PAPS should be included in the differential diagnosis when CT demonstrates infarcts in multiple organs or patients have recurrent episodes of venous or arterial thrombosis.