Reduced prostacyclin activity in systemic lupus erythematosus

Lupus anticoagulant in patients with peripheral vascular disease: a prospective study

OBJECTIVE

To assess the incidence of lupus anticoagulant (LAC) in patients with peripheral vascular disease.

DESIGN

Prospective clinical study.

SETTING

University Hospital.

MATERIALS

20 patients with claudication (group 2), 20 patients with critical ischaemia (group 3) and 20 patients prior to elective abdominal aortic aneurysm surgery (group 4) were compared to 20 general surgical controls (group 1).

CHIEF OUTCOME MEASURES

Venous blood samples for coagulation assay.

MAIN RESULTS

Positive results for LAC by the Dilute Russell's viper venom time (DRVVT) with the platelet neutralisation procedure were present in 26 out of 60 vascular patients compared with none of the 20 general surgical controls. The three vascular groups showed a similar prevalence of LAC and this differed significantly from that in the control group (chi 2 = 10.94, p = 0.0009). Of the 26 positive results only three were associated with an abnormal activated partial thromboplastin time (APTT), which has previously been used as a marker for the presence of LAC activity. Fibrinogen levels were raised in seven of 20 patients in group 2 but were normal in the remaining vascular groups (p = 0.001). The mean factor VII level (124.1 units dl-1) in group 2 was higher than the mean of the remaining vascular patients (109.3 units dl-1, p < 0.05).

CONCLUSIONS

The high prevalence of LAC in patients with peripheral vascular disease and the associated increased risk of early graft thrombosis may justify routine testing by DRVVT prior to reconstructive vascular surgery. Treatment of these patients with antiplatelet agents or formal anticoagulation perioperatively should be considered.

Antiphospholipid antibodies and thrombosis

Antiphospholipid antibodies are a diverse group of immunoglobulins initially thought to have specificity to phospholipid epitopes. It is apparent that autoimmune anticardiolipin antibodies require a serum cofactor beta-2-glycoprotein I (beta 2GPI) for their binding to phospholipids. Lupus anticoagulant also may bind to phospholipids by beta 2GPI or by prothrombin. The description of binding to protein-phospholipid epitopes may explain several perplexing features of these antibodies both in vitro and in vivo. Antiphospholipid antibodies have a well-established association with clinical disease--in particular thrombosis, thrombocytopenia and recurrent fetal loss. The mechanism of the predisposition to thrombosis seen with these antibodies is poorly understood. It has been suggested that they may cause endothelial dysfunction by causing increased tissue factor expression, by inhibiting prostacyclin secretion or by inhibiting fibrinolysis. Various platelet-activating activities have also been described. The evidence that antiphospholipid antibodies promote thrombosis by effects on endothelium or platelets is inconclusive. Inhibition of protein C activation, or of activated protein C action, has been demonstrated in vitro. A poor correlation between thrombosis in vivo and these inhibitory effects has been found. Beta-2-glycoprotein I has been identified as a cofactor for binding to phospholipid by thrombogenic anticardiolipin antibodies. That beta 2GPI may be a natural anticoagulant of importance remains to be proved. Inhibition by antiphospholipid antibodies of this anticoagulant function could explain the propensity to thrombosis seen in association with these antibodies.

Livedo reticularis in a patient with systemic lupus erythematosus and anticardiolipin antibodies

This report describes a case of livedo reticularis associated with increased titres of anticardiolipin antibodies (aCL) in a patient with systemic lupus erythematosus. A 38-year-old woman presented with fever, malaise, arthritis and livedo reticularis in a severe form. Antibodies to native DNA and an increased level of aCL were found. A significant positive correlation exists between livedo reticularis and elevated serum antiphospholipid activity in patients with systemic lupus erythematosus. aCL are shown to play a possible pathogenetic role in thrombotic events. This suggests that thrombosis is the underlying cause of livedo in these patients. A biopsy performed in a patient at the site where livedo was most marked showed no evidence of thrombi. It is postulated that the mechanism of livedo in lupus patients with aCL consists of both thrombosis and dysfunction in the regulation of the tone of the peripheral vascular bed.

Pulmonary hypertension in MCTD: report of two cases with anticardiolipin antibody

We report on 2 patients with well-documented mixed connective tissue disease (MCTD) accompanied by severe pulmonary hypertension (PH) due to thrombosis or thromboembolism. In a previous report we indicated (1) that patients with MCTD complicated by PH have a significantly worse prognosis than patients with other connective tissue disease (CTD) complicated by PH. Both our patients had anticardiolipin antibody (a-CL) in the initial stages of the disease. We also studied the relationship of a-CL to PH in patients with other CTD. Patients of either MCTD or SLE with high levels of a-CL had significantly higher values of mean pulmonary arterial pressure than patients without a-CL. Several factors were suggested for the pathogenesis of PH such as vasospasm, arteritis, platelet dysfunction, and thrombosis or thromboembolism. The presence of a-CL may be one of important factors in development of PH among patients with MCTD with recurrent pulmonary thrombosis or thromboembolism.

Concurrent protein C deficiency and lupus anticoagulants

An inherited deficiency of protein C, a recognized hypercoagulable state, may cause a clinically significant deep venous thrombosis. Only some persons with a deficiency of protein C experience thrombosis, and almost always the thrombotic event occurs in the venous circulation. Warfarin-induced skin necrosis, a rare event observed in some patients soon after treatment with warfarin is begun, is believed to be another manifestation of this deficiency. We describe a young woman whose basal functional and antigenic levels of protein C were about 45% and who experienced both deep venous thrombosis and warfarin-induced skin necrosis in a clinically severe course. Evidence for lupus anticoagulants was present, with prolonged activated partial thromboplastin time that was corrected when lysed platelets were added, prolonged Russell's viper venom time, anticardiolipin antibodies, and other laboratory evidence. Lupus anticoagulants are associated also with a significant incidence of thrombosis, including arterial thrombosis, and this patient developed concurrently arterial thrombosis. The combined effects of protein C deficiency and lupus anticoagulants, exacerbated by other potentially thrombogenic conditions, are believed responsible for the severe thrombotic events experienced by this patient.

Lupus anticoagulant: interference with in vivo prostaglandin production and with platelet sensitivity to prostacyclin

The hypothesis has been made that inhibition of prostacyclin (PG12) production may play a role in the pathogenesis of thrombosis in patients with the lupus anticoagulant (LA), but so far no evidence of reduced PG12 levels in vivo has been produced. We have tested the plasma levels of PG12 and thromboxane A2 (TXA2) and the platelet sensitivity to PG12 in 14 patients with and without LA and in 14 healthy controls. No significant difference in the prostanoid basal levels was detected among the groups; however, in some patients PG12 increments seemed to parallel the clinical course of the disease. Platelet sensitivity to exogenous PG12 was significantly enhanced in the LA + patients and correlated with PG12 values. We suggest that in these subjects additional factors, other than reduced PG12, may predispose to thrombosis.

Immunology and clinical importance of antiphospholipid antibodies

Having reviewed the literature on the association of aPL antibodies with clinical manifestations, it is clear that this group of autoantibodies are of considerable importance. The presence of aPL antibodies in some but not all individuals confers a risk of a clinical syndrome characterized by recurrent arterial or venous thrombosis, thrombocytopenia, hemolytic anemia, or positive Coombs' test, and in females, recurrent idiopathic fetal loss. In SLE, the risk is approximately 40%, compared with a risk of 15% in the absence of aPL antibodies. However, only one half of persons possessing these antibodies have SLE, and overall the risk is around 30%. In some circumstances, such as in chlorpromazine or infection-associated aPL antibodies, there appears to be no increased risk. At the other end of the spectrum are seen patients whose only clinical manifestations comprise features of this clinical syndrome, and this entity has been designated the primary antiphospholipid syndrome (PAPS). aPL antibodies are also important because they are not uncommon. They have been found frequently in women with idiopathic recurrent fetal loss (30%), in non-autoimmune patients with ischemic heart disease (20%), or venous thrombosis (up to 30%), or stroke (4-47%), and in chronic immune thrombocytopenia (30%). These autoantibodies can be detected using sensitive solid-phase immunoassays employing the CL antigen, or in appropriate coagulation tests to detect LA activity. These assays are simple to perform but require care in selection of the best test and in interpretation of results. Current tests do not distinguish between those persons at risk of the clinical events and those not at risk. Detection of specific isotypes (especially IgG) and antibody level may aid in such a designation. Treatment of aPL antibody-associated syndromes remains a controversial subject. Since thromboses are associated with significant morbidity and potential mortality, there is a good argument for long-term preventive antithrombotic therapy, at least for as long as the antibodies are detectable, in those patients in whom clinical complications have previously occurred. It is not generally recommended that this treatment be offered to individuals in whom aPL antibodies are detected but who have not suffered previous thromboses, since the risk of such events does not appear to be equal within a group of aPL antibody-positive persons. This particularly applies to pregnant women, since live births and uncomplicated pregnancies are observed regularly in the presence of aPL antibodies without specific treatment. A previous history of at least one unexplained, late fetal loss is considered a prerequisite before intervention in subsequent pregnancies.(ABSTRACT TRUNCATED AT 400 WORDS)

Lupus anticoagulant inhibition of in vitro prostacyclin release is associated with a thrombosis-prone subset of patients

PURPOSE

The effect of lupus anticoagulant-containing sera on endothelial prostacyclin generation (both basal and after thrombin stimulation) was determined. Subsets of patients who had experienced arterial, venous, or no thrombosis were compared with respect to the quantitation of antiphospholipid antibody and effects on prostacyclin production.

PATIENTS AND METHODS

Serum antiphospholipid antibodies were detected in 26 patients by immunologic (enzyme-linked immunosorbent assay) and kinetic (anticoagulant) assays. Cultured human endothelial cells were exposed to patient or normal serum, and the release of prostacyclin was determined by radioimmunoassay of supernatants. Release was determined in the absence and presence of the secretagogue, thrombin (1 U/mL), corrected for interassay variation, and correlated with other clinical and laboratory variables.

RESULTS

The normal prostacyclin response was a 2.5-fold increase after thrombin (1 U/mL) compared to basal production. Patients with a history of arterial thrombosis (Group 1, n = 10) had the highest IgG anticardiolipin antibody titers (449 +/- 115 [OD x 1,000]), most prolonged kaolin clotting times (140 +/- 15 seconds), and the least prostacyclin response to thrombin (1.36-fold). Patients with venous thrombosis (Group 2, n = 6) had lower titers (329 +/- 120), intermediate clotting times (125 +/- 19 seconds), and slightly impaired prostacyclin responses (2.18-fold). Patients with no history of thrombosis (Group 3, n = 10) had low antibody titers (220 +/- 20), mildly prolonged clotting times (108 +/- 6 seconds), and normal prostacyclin responses (2.33-fold). Patient serum did not alter basal or arachidonate-induced prostacyclin production. Group 1 had significantly lower platelet counts (99 +/- 19) compared to Group 2 (167 +/- 35) or Group 3 (167 +/- 34), but were similar in age and associated diagnoses.

CONCLUSIONS

Inhibition of prostacyclin responses is commonly found in serum from patients with lupus anticoagulants, and is likely to be present in patients with high IgG anticardiolipin antibodies, strong lupus anticoagulants, low platelet counts, and a recent arterial thrombosis.

The 'antiphospholipid syndrome' and the 'lupus anticoagulant'

In recent years an association has been described between, on the one hand, an in vitro prolongation of phospholipid-dependent coagulation tests (the 'lupus anticoagulant') or the demonstration of antiphospholipid antibodies and, on the other, clinical events, particularly recurrent thrombosis (usually venous but sometimes arterial), thrombocytopenia, and also recurrent mid-term fetal loss. Other less well-documented associations with haemolytic anaemia, livedo reticularis, strokes and other neurological syndromes have been suggested. The antibodies are present temporarily in many infections, are usually of IgM isotype and thrombosis does not occur. However, they are persistently present and mainly of IgG isotype in a number of auto-immune disorders associated with thrombosis, in particular systemic lupus erythematosus, in which 50% of patients will show antibody of one isotype or another. The strongest association is with antinuclear factor-negative lupus and 'lupus-like' disorders in which a full diagnosis of classical lupus cannot be made. The clotting test abnormality and antiphospholipid antibodies may be found also in otherwise normal individuals suffering thrombosis or fetal loss--the so-called primary antiphospholipid syndrome. These data raise important questions for management, but many details are controversial despite a decade's work; this review examines the present position and outlines some of the difficulties, particularly from the point of view of nephrology and paediatrics.

Systemic lupus erythematosus circulating anticoagulant: report of a case

A patient without lupus erythematosus in whom a routine presurgical work-up resulted in discovery of the SLE circulating antibody is described. The diagnosis and treatment are discussed.

Chlorpromazine-induced anticardiolipin antibodies and lupus anticoagulant: absence of thrombosis

Anticardiolipin antibodies were determined in 96 psychiatric patients treated chronically with chlorpromazine by an enzyme-linked immunosorbent assay using anti-IgM and anti-IgG (fab'2 fragment) as the second antibody. Fifty-four of these patients had an IgM-lupus anticoagulant, and the remaining 42 were followed as controls. Elevated IgM-anticardiolipin antibodies (ACA) levels were detected in 31 patients with the lupus anticoagulant and in 5 controls (p less than 0.001). During a median followup of 5 years, single episodes of deep vein thrombosis or pulmonary embolism occurred in three patients; one had the lupus anticoagulant and the other two had low-level ACA. Contrary to the reported experience in systemic lupus erythematosus and related autoimmune disorders, chlorpromazine-induced lupus anticoagulant and anticardiolipin antibodies levels appear not to be associated with an increased incidence of thrombosis.

Primary sclerosing cholangitis in the presence of a lupus anticoagulant

Lupus anticoagulant, an immunoglobulin that prolongs the partial thromboplastin time, has been associated with thrombotic events, including deep venous thrombosis, pulmonary emboli, and Budd-Chiari syndrome. In this report, primary sclerosing cholangitis was diagnosed in a man with a 10-year history of multiple thrombotic events related to a circulating lupus anticoagulant. Progressive jaundice and pruritus developed, and sclerosing cholangitis was confirmed by direct cholangiography. Sclerosing cholangitis is the second hepatobiliary disease reported in association with a lupus anticoagulant.

Recurrent cerebral infarctions in two brothers with antiphospholipid antibodies that block coagulation reactions

Inhibitors blocking coagulation reactions, often called lupus anticoagulants, are readily identifiable but rarely considered as risk factors for cerebral infarction. These inhibitors are inconsistently found in a number of diseases (often autoimmune) and after treatment with ceretain drugs and appear to be closely associated with, or identical to, antibodies to certain phospholipids. We have observed two brothers with these inhibitors who both experienced recurrent cerebral infarctions. Such familial occurrence has rarely been reported. In addition, some other family members were found to have depressed factor XII levels. Using the technique of double immunodiffusion, we found that the serum from these brothers formed precipitin lines against certain phospholipid substrates, lending further support to the antiphospholipid nature of this inhibitor.

The lupus anticoagulant, pulmonary thromboembolism, and fatal pulmonary hypertension

A patient with a circulating lupus anticoagulant in the absence of systemic lupus erythematosus developed recurrent deep venous thromboses and pulmonary emboli. Pulmonary emboli recurred despite prolonged oral anticoagulant therapy and resulted in fatal pulmonary arterial hypertension. Extended anticoagulant therapy alone may not prevent recurrent thromboembolism in patients with a lupus anticoagulant. Pulmonary thromboembolism may be an important factor in the pathogenesis of pulmonary hypertension in patients with a lupus anticoagulant.

Systemic vascular lesions and prognosis in systemic lupus erythematosus

The purpose of this paper is to show the relationship of systemic vascular lesions to the clinical manifestations and prognosis in SLE. Thirty-four autopsied cases of SLE formed the subject material for this study. Histopathological tissue studies were made on vascular lesions from almost all organs. Vascular lesions were separated into three groups according to the size of the involved vessel: 1) medium-sized artery (9 cases), 2) small artery (12 cases) and 3) (13 cases) without systemic vascular lesions. Vascular lesions were also separated into five groups (a) fibrinoid degeneration (10 cases), b) intimal thickening (6 cases), c) thrombosis (6 cases), d) sclerosis (7 cases) and e) (13 cases) without systemic vascular lesions. Patients with involvement of medium-sized arteries had a low female incidence, photosensitivity, and positive LE cell incidence, and the cause of death in these patients was cerebral vascular involvement. The cause of death in patients with vascular fibrinoid degeneration and thrombosis was mainly uremia, whereas patients with sclerosis more often died from infection. Regarding systemic vascular lesions in SLE, the prognosis for the patients with thrombosis and vascular involvement of medium-sized arteries was the most grave.

Thrombosis in systemic lupus erythematosus: striking association with the presence of circulating lupus anticoagulant

The lupus anticoagulant was found in the plasma of 31 of 60 patients with systemic lupus erythematosus and other connective tissue disorders (mixed connective tissue disease, systemic vasculitis, polyarteritis nodosa, primary sicca syndrome, discoid lupus, Behcet's syndrome, and systemic sclerosis). Strong associations were found with biological false positive seroreaction for syphilis and thrombocytopenia. The most striking association, however, was with the high prevalence of thrombosis. This tendency to thrombosis was independent of disease activity of systemic lupus erythematosus. The lupus anticoagulant appears to be a useful marker for a subset of patients with systemic lupus erythematosus at risk for the development of thromboembolic complications.

Gangrene developing after minor surgery in a patient with undiagnosed systemic lupus erythematosus and lupus anticoagulant

We report a case of progressive peripheral ischaemia and gangrene as a presenting feature of systemic lupus erythematosus. It developed in a previously asymptomatic 40-year-old woman following minor surgery to her toe. Eventually she required a below-knee amputation and despite systemic corticosteroids continued to deteriorate, presenting later with signs of systemic intravascular thromboses. Histopathology and immunofluorescence on vessels repeatedly failed to demonstrate any evidence for vasculitis. A full coagulation screen confirmed the presence of 'lupus' anticoagulant. A plasma exchange was performed to remove circulating immunoglobins and she made a rapid and sustained recovery. Peripheral gangrene has not previously been described in association with lupus anticoagulant. We would suggest that in all cases of systemic thrombosis or unexplained peripheral vascular ischaemia lupus anticoagulant should be considered.

Deficiency of a plasma factor stimulating vascular prostacyclin generation in patients with lupus nephritis and glomerular thrombi and its correction by ancrod: in-vivo and in-vitro observations

Glomerular thrombi occur frequently in active lupus nephritis. Their presence has been correlated with low platelet counts and with subsequent development of glomerular sclerosis. We have examined the plasma PGI2 generating capacity of 8 patients with active lupus nephritis with thrombi that were to undergo defibrination therapy with ancrod. PGI2 generation by these plasma samples was significantly decreased as compared both to normals and to 6 individuals with lupus nephritis and no glomerular thrombi. Significant improvement in the capacity to generate PGI2 was seen in the post-ancrod treatment plasma samples. the pathogenesis of this defect is discussed.

Stroke as an early manifestation of systemic lupus erythematosus

Both stroke and transient cerebral ischaemic attacks occurring in younger patients may be due to systemic lupus erythematosus. Other clinical features of the disease may be absent. Initially the ESR may be normal, as may serological tests. Seizures may occur at or near the time of the vascular events. Systemic lupus erythematosus may be the cause of an asymptomatic cerebral infarct or multi-infarct dementia.

Arterial thrombosis, intrauterine death and "lupus" antiocoagulant: detection of immunoglobulin interfering with prostacyclin formation

In a 31-year-old woman with a history of recurrent arterial thrombosis, both of whose pregnancies had resulted in intrauterine death at 23 and 24 weeks, a "lupus" anticoagulant was identified. The patient's IgG fraction, containing the lupus anticoagulant, reduced the release of prostacyclin (PGI2) from rat aorta rings or pregnant human myometrium. This inhibitory effect was abolished in the presence of arachidonic acid. The production of 6-keto-PGF1 alpha by cultured bovine endothelial cells was also decreased in the presence of the patient's IgG fraction. The plasma level of 6-keto-PGF1 alpha was reduced. An antibody in this patient may interfere with the production or release of PGI2 by the vessel wall, possibly by interfering with the availability of arachidonic acid. This mechanism could play a role in this patient's arterial disease and obstetric problems.