Novel diagnostic and therapeutic frontiers in thrombotic anti-phospholipid syndrome

The anti-phospholipid syndrome (APS) is an autoimmune disorder characterized by vascular thrombosis and/or pregnancy morbidity, associated with a persistent positivity for anti-phospholipid antibodies (aPL). The current classification criteria for APS include three laboratory tests: lupus anti-coagulant (LA), anti-cardiolipin (aCL), and anti-β2 glycoprotein-I (β2GPI). To date, the therapeutic approach for thrombotic APS mainly centers on long-term anti-coagulation with a vitamin K antagonist (VKA). APS management may represent a challenge for the treating physicians. Patients with different aPL profiles need a tailored risk-stratified approach. Moreover, in patients with recurrent thrombotic events despite therapy with VKA, or in those with microvascular involvement, new therapeutic options are highly needed. In this review, we aim to elucidate recent findings about new aPL specifities, available risk scoring models, and novel therapeutic approaches in APS management.

Lupus anticoagulant-hypoprothrombinemia syndrome presenting with co-existing cerebral venous thrombosis and subdural hemorrhage

The lupus anticoagulant-hypoprothrombinemia syndrome (LA-HPS) - the association of acquired factor II deficiency and lupus anticoagulant - is a rare disease that may cause a predisposition not only to thrombosis but also to severe bleeding. We are reporting on a 36-year-old female patient presenting with co-existing cerebral venous thrombosis and subdural hemorrhage. The coagulation screening showed a prolonged prothrombin time (PT), activated partial thromboplastin time (aPTT), and a normal fibrinogen level and platelet count. Evaluation of the clotting factors revealed decreased levels of factors II (37%). Factors V, VIII, IX and XI were normal. Lupus anticoagulant (LA) was demonstrated by the Dilute Russell's Viper Venom Test (DRVVT). Immunological work-up was positive for IgG type anticardiolipines antibodies (aCL). Successful management consisted first of oral prednisone (60mg/d). Thus, anticoagulation was introduced once factor II had stabilized.

A new-generation dilute Russell’s viper venom time assay system for lupus anticoagulants: evaluation of detection utilising frozen reagents and controls

The dilute Russell's viper venom time (DRVVT) is one of the most widely used assays to detect lupus anticoagulants (LAs). Variation in diagnostic performance exists between DRVVT reagents from various manufacturers due to a variety of factors such as antibody heterogeneity, reagent phospholipid composition, venom heterogeneity, assay methodology and analytical technique. Recently, a new-generation DRVVT assay system has become available that utilises frozen reagents and controls that offer potential benefits to the diagnostic laboratory in terms of reagent quality and convenience of use. This study evaluates the diagnostic and analytical performance of these CryoCheck reagents and controls on a commonly employed automated coagulation analyser, the Sysmex CA 1500. Sensitivity is assessed by analysis of 60 samples shown to contain LAs by combinations of an alternative DRVVT, LA-sensitive dilute activated partial thromboplastin time and activated seven lupus anticoagulant assay. Specificity is assessed using 30 samples negative for LA, eight plasmas from non-LA orally anticoagulated patients and also immunodepleted factor-deficient plasmas. The CryoCheck reagents generated comparable diagnostic performance data to that previously reported for other reagents. There was a marked improvement in sensitivity when the BCSH recommended percent correction of ratio calculation for assessment of phospholipid dependence was employed in place of the manufacturer suggested test/confirm ratio. Slightly better diagnostic performance was achieved when using a frozen pooled normal control in place of a lyophilised normal control to generate sample/control ratios, giving sensitivity, specificity, positive predictive and negative predictive values of 88.2%, 86.8%, 90% and 85.2%, respectively. The combination of CryoCheck reagents and the Sysmex CA 1500 analyser provides a sensitive and specific LA detection technique comparable to those currently available.

Laboratory methods to detect antiphospholipid antibodies

This chapter reviews several important themes pertaining to the antiphospholipid syndrome (APS), including a description of the clinical features, a discussion of the main autoantigen, beta 2-glycoprotein I (β2GPI), and insights into the characteristics of the pathogenic anti-β2GPI autoantibodies. Evidence-based considerations for when to test for APS are explored, along with the clinical significance of patients testing positive on multiple APS assays, so-called triple positivity. A detailed review of recently published laboratory guidelines for the detection of lupus anticoagulant and the solid-phase anticardiolipin and anti-β2GPI ELISAs is undertaken. Finally, a brief review of nonclassification criteria laboratory assays with potential future diagnostic utility is presented.

Risk assessment in patients with antiphospholipid antibodies

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by the association of antiphospholipid antibodies (aPL) with thrombosis and/or pregnancy loss: classification criteria were defined in the updated international consensus held in Sidney in 2005. Vascular and obstetric manifestations display partially different pathogenetic mechanisms. Thrombosis develop as a result of local procoagulative changes upon triggers influence (second-hit theory). Pregnancy morbidity is thought to be dependent on placental thrombosis and complement activation. The laboratory tests include Lupus Anticoagulant (LA), a functional assay, and anticardiolipin (aCL) and anti-β2-glycoprotein I antibodies detected by solid phase enzyme-linked immunosorbent assay (ELISA). The LA testing is relatively standardized while there's still significant interlaboratory discrepancy in ELISA tests. Current APS criteria are under discussion: since for vascular and obstetric APS, different pathogenetic mechanisms have been shown, some criteria variation could also be contemplated. What is the weight of aPL antibodies in provoking thrombosis and which contribution could be expected from aPL per se is debated. As thrombosis is generally considered to be multi-factorial, each case needs a risk-stratified approach. Any primary prophylaxis, intensity and duration of secondary prophylaxis should take into account aPL profile, other cardiovascular risk factors and systemic autoimmune diseases associated. We look forward to the publication of recommendations of the leading experts in the field, developed during the recent 14th International Congress in Rio de Janeiro, Brazil.

Lupus anticoagulant testing

Antiphospholipid antibodies are a heterogenous group of autoantibodies directed against glycoproteins in concert with anionic phospholipids. In clinical laboratory practice, antiphospholipid antibody evaluations usually consist of a combination of the following: anticardiolipin antibody assay, anti-beta 2 glycoprotein I assay, and at least two lupus anticoagulant assays with an appropriate confirmatory test. Lupus anticoagulants produce their laboratory effect by prolonging recalcification times in assays within which phospholipid content is limited. Although many assays are available, all are based on the fundamental principle of demonstrating normalization of prolonged recalcification times with the addition of exogenous phospholipid. The antibody specificity of an individual lupus anticoagulant is difficult or impossible to determine; however a small proportion do demonstrate avidity for selected proteins such as prothrombin or beta 2 glycoprotein I. The mechanism by which these antibodies cause their clinical manifestations remains unknown; however their relationship to increased risk of thrombosis, pregnancy loss, and autoimmune thrombocytopenia is undoubted. There is no correlation between the "strength" of lupus anticoagulants and the level of thrombotic risk; thus it is important to identify both "weak" and "strong" lupus anticoagulants.

[Laboratory evaluation of lupus anticoagulant in Israel]

Lupus anticoagulants (LAC) are antibodies which are detected by a prolongation of phospholipid-dependent coagulation assays, and are associated with thrombotic events and pregnancy complications in patients with the antiphospholipid syndrome. The antiphospholipid syndrome is defined by arterial or venous thrombosis and/or pregnancy morbidity and by laboratory diagnosis of antiphospholipid antibodies. The laboratory diagnosis is based on LAC and/or anticardiolipin and/or anti-beta2-glycoprotein I antibodies present in plasma, on two or more occasions at least 12 weeks apart. ALthough the presence of LAC correlates best with thrombosis, the Laboratory testing of LAC is not well standardized. In this article, the Laboratory evaluation of LAC will be explained, including the different tests that are recommended by the Israeli Sub-committee of Thrombosis and Hemostasis Laboratories, the possibility to evaluate LAC in patients treated with antithrombotic therapy, and how to report and interpret the results.

Placental histomorphology in unexplained foetal loss with thrombophilia

BACKGROUND & OBJECTIVES

Acquired and genetic thrombotic conditions, both organ and non organ specific, are associated with increased foetal wastage. This study was carried out to examine the placenta from women with abnormal pregnancies and a history of unexplained foetal loss, and to associate with maternal thrombophilia status.

METHODS

Placentas from eight women with history of unexplained foetal loss were analyzed for histopathological characteristics. All the women were simultaneously screened for the common acquired and genetic thrombophilia markers i.e., lupus anticoagulants ( LA), IgG / IgM antibodies for anticardiolipin (ACA), beta2 glycoprotein 1 (beta2GPI) and annexin V, protein C (PC), protein S (PS), antithrombin III (AT III), factor V Leiden ( FVL) mutation, prothrombin (PT) gene G20210A, methylene tetrahydrofolate reductase (MTHFR) C 677T, endothelial protein C receptor (EPCR) 23 bp insertion and plasminogen activator inhibitor ( PAI-1 4G/5G) polymorphisms

RESULTS

Six of eight women were positive for one or more thrombophilia markers. The placenta in all the cases except one, showed the characteristic features of infarct fibrin deposition and calcification. Among two women who were negative for thrombophilia, one showed clear evidence of thrombus in the placental sections while the other did not show any characteristic infarcts in the placental sections.

INTERPRETATION & CONCLUSION

Our findings showed that the histopathological examination of the placentas confirmed thrombophilia as the aetiological cause of thrombosis in 6 of the 8 women. The presence of thrombus in a negative thrombophilia woman suggests yet unidentified thrombophilia markers or probably non-haemostatic factors causing thrombosis.

The Activated Seven Lupus Anticoagulant Assay Detects Clinically Significant Antibodies

Lupus anticoagulants are a heterogeneous group of autoantibodies detected by their effects on phospholipid-dependent coagulation assays. Persistent lupus anticoagulants are associated with thrombotic disease, but not all are clinically significant. Antibody heterogeneity and reagent and test variability dictate that at least 2 tests, of different types, should be used to screen lupus anticoagulants. The objective of this study was to investigate whether the activated seven lupus anticoagulant assay detects clinically significant antibodies. Eighty-two patients with antiphospholipid syndrome (APS) and 32 with systemic lupus erythematosus + positive for activated seven lupus anticoagulant and who were without thrombosis, who were positive by activated seven lupus anticoagulant assay, were investigated for lupus anticoagulants by dilute Russell's viper venom time, dilute activated partial thromboplastin time, and Taipan snake venom time, and for anticardiolipin antibodies. Fifty-seven of the APS patients were positive for lupus anticoagulants in multiple assays, 25 in activated seven lupus anticoagulant alone. Fourteen of the latter group were previously positive in other antiphospholipid antibodies assays, and 11 had only been positive for lupus anticoagulants by activated seven lupus anticoagulant. Twenty-eight had elevated anticardiolipin antibodies, 6 of whom were from the group that was positive in activated seven lupus anticoagulant only. Eight of the systemic lupus erythematosus + lupus anticoagulants (without thrombosis) patients were positive for lupus anticoagulant by activated seven lupus anticoagulant alone and had only been positive in activated seven lupus anticoagulant previously, and none had elevated anticardiolipin antibodies. The remaining 24 patients were lupus-anticoagulant positive in multiple assays, and 9 had elevated anticardiolipin antibodies. Dilute Russell's viper venom time and Dilute activated partial thromboplastin time are widely used to detect lupus anticoagulants and are considered to detect clinically significant antibodies. Activated seven lupus anticoagulant detected antibodies in APS patients who were positive by these assays and also lupus anticoagulants undetectable by the dilute Russell's viper venom time/dilute activated partial thromboplastin time reagents used, demonstrating its utility as a first-line or second-line assay.

[The antiphospholipid syndrome, an update]

The antiphospholipid syndrome is an antibody mediated hypercoagulable state characterized by recurrent venous and arterial thromboembolic events. Several studies have determined that the frequency of antiphospholipid syndrome in patients presenting with a venous thromboembolic event is between 4% and 14%. Classical criteria include the presence of anticardiolipin antibody or lupus anticoagulant with typical complications of thrombosis or pregnancy loss. Other common associated manifestations include livedo reticularis, thrombocytopenia, valvular heart disease, and nephropathy with renal insufficiency, hypertension and proteinuria. Because of the high risk for recurrent thromboembolism in these patients, current recommendations suggest a longer, potentially lifelong, course of antithrombotic therapy following an initial event. For an initial venous thromboembolic event, a target INR of 2.0 to 3.0 is supported by two prospective, randomized clinical trials. In contrast, relatively limited data exist for an initial arterial thromboembolic event in patients who have the antiphospholipid syndrome, and therapeutic recommendations range from aspirin to warfarin with a high target INR. Recurrent thromboembolic events can be extremely difficult to treat, and some patients may benefit from the addition of immunosuppressive therapies. It is very important to evaluate in this setting additional, coincident prothrombotic risk factors.

Antiphospholipid antibody syndrome: the flow cytometric annexin A5 competition assay as a diagnostic tool

The mechanism underlying hypercoagulability in antiphospholipid antibody syndrome (APS) is uncertain. Here, we present a flow-cytometric assay (FCA) based on the hypothesis that anti-platelet-anionic-phospholipid autoantibodies (aPL) interfere with the activity of the natural anticoagulant protein annexin A5, thereby accelerating platelet procoagulant activity. This study assessed the clinical utility of the feasible FCA, which demonstrates the competition of the patient's aPL with the binding of annexin A5 to the platelet-anionic-phospholipids, in the diagnosis of APS. Sixty-two (94%) of 66 APS patients, 20 (51%) of 39 patients with systemic lupus erythematosus and two (4%) of 49 healthy individuals were positive by FCA. Compared with the anticardiolipin (aCL) assay, the relative sensitivity was 82% and the specificity 73.3%. However, 19 (25%) aCL-negative patients were positive by FCA; 12 were positive for lupus-anticoagulant (LA). Compared with LA assay, the relative sensitivity was 85% and the specificity 72.2%. However, 21 (26%) LA-negative patients were FCA-positive, 12 were positive for aCL. The FCA was particularly sensitive for APS patients with arterial (97.0%) and gestational vascular complications (100%) with overall sensitivity of 95% and specificity of 97%. Our findings suggest that the FCA is practical, sensitive and specific for the detection of clinically relevant aPL in the diagnosis of APS.

[Cardiac abnormalities in antiphospholipid syndrome]

OBJECTIVE

To investigate the clinical manifestations, treatment and prognosis of antiphospholipid syndrome (APS).

METHODS

The cases of 72 patients with defined APS admitted from Jan 1990 to Jan 2006 were analyzed retrospectively.

RESULTS

21 patients with primary APS and 51 patients with secondary APS were studied. Vascular thrombosis was present in 43 (59.7%) of the 72 patients in this study. Cardiac abnormalities could be observed in 48 patients (66.6%). Lesions most frequently involved left-sided valves, mitral (35.4%) more commonly affected than aortic (16.7%). Cardiac involvement was significantly related to thrombosis (P = 0.007) and prolonged activated partial thromboplastin time (APTT) (P = 0.026). Valvular involvement was significantly related to brain infarcts (P = 0.008) and thrombosis (P = 0.029). 20 APS patients with cardiac abnormalities and thrombosis received anticoagulation therapy and thrombosis did not happen any more during follow-up.

CONCLUSION

Cardiac manifestations of APS are valve abnormalities (valve thickening and vegetations), occlusive arterial disease (atherosclerosis and myocardial infarction), ventricular dysfunction and pulmonary hypertension. Cardiac abnormalities in APS are likely to be related to hypercoagulability.

Lupus anticoagulant and anticardiolipin antibodies in polytransfused beta thalassemia major

The currently used therapeutic strategies in beta thalassemia have prolonged the survival for many patients; this longer survival has been accompanied by the development of a number of unexpected complications, these include hemostatic derangements. The presence of anti-phospholipid antibodies (APA) (lupus anticoagulant, LA and anti-cardiolipid antibody, ACA) has recently been reported in polytransfused patients of beta thalassemia. In this study 50 patients with beta thalassemia major (beta-TM) who had received at least 20 transfusions were evaluated for presence of antiphospholipid antibodies and correlated with a number of clinical and hemostatic parameters. About 32% cases had developed a minor bleeding tendency and one also showed ecchymotic patch. None of the patients had thromboembolic episodes. LA was seen in 16% of cases. The mean age and number of transfusions were higher in LA positive patients as compared to LA negative patients however the results were not statistically significant. IgM ACA were detected in 6% of patients but no statistically significant correlation was found with age, number of transfusions, platelet count and coagulation parameters. IgG ACA were detected in 30% of cases and showed a significant correlation with number of blood transfusions (p = 0.016) and age (p = 0.031). Anti HCV antibodies were detected in 30% of patients out of which 1 had IgM ACA and 10 had IgG ACA. The latter showed a significant correlation with HCV infection. An increased incidence of LA and IgG ACA is found in polytransfused patients with beta-TM when compared to the normal healthy population but their clinical significance is yet not clearly understood.

Sudden sensorineural hearing loss and antiphospholipid syndrome

The antiphospholipid syndrome is the association between the presence of antiphospholipid antibodies, thrombosis and/or pregnancy morbidity and mortality. This report presents two cases of antiphospholipid antibodies and sensorineural hearing loss and discusses the probable causative link. We recommend that patients presenting with sudden sensorineural hearing loss are investigated for evidence of antiphospholipid antibodies. Life long anticoagulation is necessary to prevent life threatening thrombotic or thromboembolic events.

Significance of antiphospholipid antibodies in lupus nephritis

BACKGROUND

Some autoantibodies have been associated with lupus nephritis but the role of antiphospholipid antibodies (APA) is controversial.

OBJECTIVE

The present study was to explore the role of APA by comparing demographic profiles and the presence of anticardiolipin antibody (aCL) and lupus anticoagulant (LA) in systemiclupus erythematosus 1 (SLE) patients with and without nephritis.

MATERIAL AND METHOD

The cross-sectional study in a tertiary center was conducted in 77 SLE patients. All patients attended our renal or rheumatology clinics between June 2002 and December 2003.

RESULTS

Sixty-three (82%) of the 77 SLE patients had nephritis. The prevalence of antiphospholipid syndrome (APS) was 10% (8 patients), positive aCL (IgG) was 26% (20 patients) and positive LA was 26% (20 patients). The receiver operating characteristic (ROC) method was applied to assess the significance of aCL in both nephritis and non-nephritis groups. Area under the ROC curve was 0.538 (95%CI 0.312-0.765), a cutoff value of 20.5 GPL had a sensitivity of 75% and a specificity of 53%. In univariate analysis, neither positivity for anticardiolipin antibody nor lupus anticoagulant was associated with lupus nephritis. Analyzed in only the lupus nephritis group, LA-positive lupus nephritis patients had higher systolic blood pressure (SBP) (133.7 vs 121.9 mmHg, p = 0.005), lower platelet count (209.8 vs 264.4 x 10(3)/microL, p = 0.02) and higher 24-hr urine protein excretion (2.6 vs 1.4 g, p = 0.02) than LA-negative lupus nephritis patients. Serum creatinine was higher in LA-positive lupus nephritis than LA-negative (233.0 vs 94.9 micromol/L), but did not reach statistical significance.

CONCLUSION

APA are frequently seen in SLE patients, but not associated with lupus nephritis. However lupus anticoagulant tends to associate with lupus nephritis. Detection of LA in lupus nephritis patients could identify patients who had increased risk to develop bad renal outcomes (elevated SBP and 24-hr urine protein excretion).

[When to start the long-term anticoagulation if antiphospholipid antibodies are present in high concentration--case report of the twin brothers]

The authors describe the observation of twin brothers with high concentrations of antiphospholipid anibodies in both of them, and the clinical manifestation of antiphospholipid syndrome (APS) and later systemic lupus erythematosus in first, without any clinical signs and symptoms in the other. The literature reports of twins with APS were analyzed and the discussion about long-term anticoagulation beginning proposed.

Use of a new silica clotting time for diagnosing lupus anticoagulant in patients who meet the clinical criteria for antiphospholipid syndrome

The silica clotting time (SCT) is a phospholipid-dependent coagulation assay used for the laboratory diagnosis of lupus anticoagulant (LA) antibodies. The sensitivity and specificity of a new commercial SCT for identifying LA in patients who meet the clinical criteria for antiphospholipid syndrome (APS), and its association with thrombotic events were evaluated here. Forty-five patients who met the clinical criteria for APS according to the Sapporo International Consensus Statement were examined. Sixty-nine patients who did not meet the clinical criteria for APS, and 20 blood donors were used as controls. Plasma samples from the patients and controls were tested for LA using a new commercial SCT with low and high synthetic phospholipid concentrations. The results were compared with those obtained by diluted Russell's viper venom time (dRVVT) and activated partial thromboplastin time (APTT). SCT's sensitivity for identifying LA in patients who met the clinical criteria of APS was higher compared to APTT and dRVVT (53.3% vs. 31.1% and 31.1%), and the specificities of these assays were 96.6%, 100%, and 98.9%, respectively. When dRVVT was combined with SCT, and dRVVT was combined with APTT their sensitivities were 57.7% and 48.8%, and their specificities were 96.6% and 98.9%, respectively. A stepwise logistic regression analysis indicated that the combination of dRVVT with SCT was associated with total thrombotic events (odds ratio (OR)=11.5, 95% confidence interval (CI)=1.25-106.3, P=0.031) as well as with venous thrombosis (OR=4.09, 95% CI=1.16-14.43, P=0.028). According to our results, SCT is the most sensitive assay for identifying LA in patients who meet the clinical criteria for APS. Moreover, the highest sensitivity was reached with a combination of SCT and dRVVT. The method's association with total thrombotic events and venous thrombosis was in fact significant.

Changes in autoimmune markers of the anti-cardiolipin syndrome on days of extreme geomamagnetic activity

The possible relation between various biological or medical phenomena and changes in environmental physical activity, such as Solar, Geomagnetic Activity (GMA); Cosmic Ray; Proton, and other particle flux, have been reported. These phenomena seem to be reflected, among others, in the immune system, resulting in changes in immunoglobulin (Ig) levels or outbursts of epidemics.

AIM

to examine a possible association of GMA with another aspect of the immune system--autoimmunity. Fluctuations of levels of anticardiolipin (IgG; IgM, IgA subtypes) and lupus anticoagulant (Kaulin clotting time and Dilute Russell's viper venom time) autoantibodies, serving as anticardiolipin syndrome (ACLS) markers, were monitored during days of severe GMA storms and compared with those of lowest/quiet GMA days. Cosmophysical data were obtained from the NOAA National Space Service Center and the National Geophysical Data Center, USA.

RESULTS

A significant rise in the levels of anti beta2Gp1-IgA (p = 0.0001); and KCT (p = 0.019) was observed on days of the GMA storms.

CONCLUSION

On days of major GMA storms, significant changes in the autoimmune marker levels of ACLS were observed compared with quiet days. An involvement of those changes in clinical events related to GMA storms is possible.

Clinicopathological features of lupus anticoagulant; experience at AFIP during last seven years

BACKGROUND

The lupus anticoagulant (LA) belongs to family of immunoglobulins, most commonly an IgG isotype. These antibodies have been identified most frequently in association with thromboembolic events, recurrent fetal loss and thrombocytopenia. The aim of the present study was to evaluate the presenting clinical and pathological features in patients LA positive presenting at AFIP Rawalpindi over the period of Jan 1993 to Nov 2000.

MATERIAL/METHODS

Retrospective analysis of patients presenting with positive LA was carried out.

RESULTS

1583 suspected cases were screened for LA including 1370 females and 213 males. 1024 cases presented with history of recurrent abortions, 292 with thrombosis, 152 with thrombotic strokes before the age of 45 years, 52 with thrombocytopenia and 63 with miscellaneous disorders. Out of 1024 patients tested for recurrent abortions, 130 (13%) females were positive for lupus anticoagulant. Ten (6.5%) of 152 patients presenting with strokes were found positive. Out of 292 cases presenting with thrombosis 17 (5.9%) were found positive.

CONCLUSIONS

The lupus anticoagulant prevalence in Pakistani patients with recurrent fetal loss, stroke and thrombosis is statistically significant. Clinicians should be made aware of association of LA with various diseases. The successful management of these patients depends upon close liaison with obstetricians, physicians and haematologists.

Diagnosis of antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by recurrent vascular thrombosis and pregnancy losses. Laboratory diagnosis of APS relies on the demonstration of a positive anticardiolipin antibody test by an in-house or commercially available enzyme-linked immunosorbent assay, or on the presence of lupus anticoagulant by a coagulation-based test. Persistence of the positive results must be demonstrated, and other causes and underlying factors considered. Although it is universally recognized that the routine screening tests (anticardiolipin antibody or lupus anticoagulant) might miss some cases of APS, careful differential diagnosis and repeat testing are mandatory before the diagnosis of 'seronegative APS' can be made. Correct identification of patients with APS is important because prophylactic anticoagulant therapy can prevent thrombosis from recurring and treatment of affected women during pregnancy can improve fetal and maternal outcome.

[Antiphospholipid syndrome and stroke]

Antiphospholipid syndrome is characterized by arterial or venous thrombosis, and the presence of antiphospholipid antibodies (aPL). APL are considered to be a cause of an acquired hypercoagulable state leading to stroke and transient ischemic attack (TIA). We examined the causes in 50 young patients with ischemic stroke. The most prevalent cause was atherosclerosis and the incidence of APS was 12.5%. APL comprise a heterogeneous group of autoantibodies, such as beta2-glycoprotein I dependent anticardiolipin antibody (beta2-GPIaCL), lupus anticoagulant (LA), and other antiphospholid-protein antibodies. We examined the incidence and the pathogenic role of antiphospholipid protein antibodies. The subjects comprised 250 patients (155 male, 95 females) with ischemic stroke, aged 26 to 92 years (mean 72 years). We measured beta2-GPI aCL, IgG aCL, LA, phosphatidyserine dependent antiprothrtombin antibody (PS-PT), antiphosphatidyl-serine antibody (PS), antiphosphatidyl-inositol antibody (PI) in each patient. The incidence of beta2-GPI aCL, IgG aCL, LA, phosphatidyserine, PS-PT, PS, and PI was 2.8%, 12%, 9.2%, 7.2%, 9.6%, and 8.8%, respectively. The incidence of young stroke patients under 50 years was 5.2%. Among 13 young stroke patients, 5 had SLE. Among 23 patients with LA., 18 (78%) patients had PS-PT. Anti-PS-PT antibody is closely related to LA. Antinuclear antibody was detected in 79% of the patients with aPS and/or aPI. We compared the carotid ultrasonographic findings in positive aPI or aPS patients with those in negative ones. Increased IMT, plaque score and carotid stenosis were more common in aPI and aPS-positive patients than in negative ones Three of 5 patients who showed positive beta2-GPI, aCL and LA, simulataneously, had sysyemic lupus erythematosus as an immulological background. Two of 3 patients with PI and/or PS and beta2-GPI and/or LA were patients with SLE. Antiphospholipid antibody was considered to be a risk factor of stroke, especially in SLE and/or young female patients. The incidence of lupus anticoagulant is more common than beta2-GPI aCL in ischemic stroke. In SLE patients with stroke, multi-antiphospholipid-protein antibodies was inclined to be present. LA is closely related to ant-PS-PT and aPI and aPS are associated with anti-nuclear antibody and precipitation of atherosclerosis.

[Autoimmune thrombophilia]

Antibodies against phospholipids and phospholipid-binding proteins, especially anti-cardiolipin and anti-beta2-glycoprotein I antibodies, are important diagnostic markers of autoimmune thrombophilia. These autoantibodies are quite common among patients with systemic lupus erythematosus but can also be found in individuals without concurrent rheumatic conditions. Apart from thromboembolic disease, these antibodies are linked to recurring fetal loss and intrauterine fetal death. In patients with recurring thrombotic events in whom anti-phospholipid antibodies or prolonged aPTT (as a sign of lupus anticoagulant activity) is found, long-term or even lifelong anticoagulation therapy should be considered. Habitual spontaneous abortions and other obstetric complications are often preventable with LMW heparin in combination with low-dose acetylsalicylic acid. In this review, we outline a diagnostic strategy for uncovering autoimmune thrombophilia supplemented with functional and genetic tests for hypercoagulability.

Investigation and current management of recurrent IVF treatment failure in the UK

OBJECTIVE

To determine current practice in the management of recurrent in vitro fertilisation (IVF) treatment failure in licensed UK infertility centres.

DESIGN

National postal questionnaire study and literature review.

SETTING

University Hospital, Centre for Reproductive Medicine, Coventry, UK.

SAMPLE

Human Fertilisation and Embryology Authority licensed centres providing IVF/intracytoplasmic sperm injection (ICSI) in the UK (n = 79).

METHODS

A survey was designed that sought to determine how recurrent treatment failure was defined and which, if any, investigations were initiated. Furthermore, we asked which therapeutic options were subsequently recommended.

MAIN OUTCOME MEASURES

Definition of recurrent treatment failure. Investigations undertaken. Clinical or embryology changes recommended following recurrent treatment failure.

RESULTS

The response rate was 82%. The most common definition was three unsuccessful IVF cycles (range 2-6). Nineteen percent included frozen embryo replacements (FERs) in this figure. Anticardiolipin antibodies and lupus anticoagulant were the most frequent investigations suggested, followed by hysteroscopy and karyotype. A majority of centres would use a different treatment strategy in a subsequent cycle with blastocyst culture and assisted hatching being most popular.

CONCLUSIONS

The results of this survey suggest that there is considerable variation in the approach to investigation and management of recurrent IVF treatment failure in the UK, although in some areas (e.g. the definition) there was broad concordance. Not all of these approaches are evidence based.

Long-term follow-up in 128 patients with primary antiphospholipid syndrome: do they develop lupus?

We retrospectively studied a large cohort of patients with primary antiphospholipid syndrome (APS) from 4 different referral centers to analyze the clinical and serologic features and, specifically, to determine the number of patients going on to develop systemic lupus erythematosus (SLE) or other autoimmune disease after long-term follow-up. The study included 128 unselected patients with primary APS who fulfilled the Sapporo International Criteria from 4 different tertiary hospitals in the United Kingdom, Mexico, and Spain. The patients had attended the referral centers between January 1987 and July 2001. We reviewed clinical and serologic characteristics according to a pre-established protocol. We used univariate analysis with the chi-squared or Fisher exact test and logistic regression to analyze possible factors related to the coexistence of SLE and APS. Ninety-seven female and 31 male patients fulfilled the criteria, with a median age of 42 +/- 12 years (range, 16-79 yr), and with a mean follow-up of 9 +/- 3 years (range, 2-15 yr). The main manifestations included deep vein thrombosis in 62 patients (48%), arterial thrombosis in 63 (49%) patients, pregnancy loss in 177/320 (55%) cases, and pulmonary embolism in 37 (30%) patients. Other clinical manifestations were migraine in 51 (40%) patients, thrombocytopenia in 48 (38%), livedo reticularis in 47 (37%), and valvular disease in 27 (21%). Serologic findings were anticardiolipin antibodies (aCL) IgG positive in 110 (86%) patients, aCL IgM in 36 (39%), lupus anticoagulant in 71 (65%), antinuclear antibodies in 47 (37%), and positive Coombs test in 5 (4%) patients. During the follow-up and after a median disease duration of 8.2 years (range, 1-14 yr), 11 (8%) patients developed SLE, 6 (5%) developed lupus-like disease, and 1 (1%) developed myasthenia gravis. The remaining 110 patients (86%) continued to have primary APS. After the univariate analysis, a family history of lupus, the presence of Raynaud phenomenon, migraine, psychiatric features, multiple sclerosis-like features, hemolytic anemia, low C3 and C4, and Coombs positivity conferred a statistically significant risk for the subsequent development of SLE (p < 0.05). Only the presence of Coombs positivity had statistical significance (odds ratio, 66.4; 95% confidence interval, 1.6-2714; p = 0.027) after the logistic regression evaluation. The current study confirms that progression from primary APS to SLE or lupus-like disease is unusual, even after a long follow-up. Only 3 patients developed anti-dsDNA antibodies. The presence of a positive Coombs test might be a marker for the development of SLE in patients with primary APS.

Learning from peer assessment: the role of the external quality assurance multilaboratory thrombophilia test process

The quality control process is a critical feature of pathology best practice. In addition to internal quality control processes applied on a test-to-test or day-to-day basis, the participation of laboratories in external quality assurance programs (QAPs) is critical to achieving ongoing test accuracy. There are several such programs operating in the international arena. With respect to thrombophilia, these include the Australia-based Royal College of Pathologists of Australia QAP, the United Kingdom-based National External Quality Assessment Service, and the International Thrombophilia External Quality Assessment Scheme, based in the Netherlands. Although there are some similarities between the programs, some diversity is also apparent. Each of the programs assess for the common markers of congenital thrombophilia, such as antithrombin, protein C, protein S, and activated protein C resistance. Testing of some acquired markers of thrombophilia, such as lupus anticoagulant, and genetic tests such as factor V Leiden and prothrombin G20210A mutation, are also available. This report focuses on some recent trends from these programs.

Antiphospholipid Syndrome: Review

Antiphospholipid syndrome spans many medical disciplines. Classic criteria include the presence of anticardiolipin antibody or lupus anticoagulant with typical complications of thrombosis or pregnancy loss. Other common associated manifestations include livedo reticularis, thrombocytopenia, valvular heart disease, and nephropathy with renal insufficiency, hypertension, and proteinuria. Treatment of serious complications with anticoagulation is standard; generally warfarin for thrombosis and aspirin/heparin for pregnancy prophylaxis. Detailed recommendations regarding precise intensity and duration of anticoagulation are still a subject of debate.

Identification of Thrombin Antibodies in Patients with Antiphospholipid Syndrome

Venous or arterial thrombosis, abortion, and the presence of antiphospholipid antibodies (aPL) define the criteria for the antiphospholipid syndrome (APS). A heterogeneous group of antibodies against phospholipids and plasma proteins may influence several coagulation pathways and lead to thrombophilia. We investigated the presence of antibodies to thrombin (Thr) in patients with aPL and reviewed their clinical manifestations. IgG and IgM titers of aPL were measured by ELISA (Aesku.Diagnostics, Wendelsheim, Germany). Lupus anticoagulants (LA) were measured according to the criteria of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis. One hundred twenty patients were identified with LA or anticardiolipin (aCL). Of the 120 patients, 98 (82%) had primary APS and 22 (18%) had secondary APS. Further, 76/120 (63%) were suffering from thromboembolic manifestations, mostly venous thrombosis. Anti-thrombin-IgG was detected in 20%, and anti-thrombin-IgM was detected in 23% of the patients. The presence of anti-thrombin antibodies was closely related to the presence of anti-beta(2)-glycoprotein-I (beta(2)-GP-I) (96%), aCL (97%), and LA (87%), and less well to the presence of anti-phosphatidylserine/prothrombin (Ser/Pro) antibodies (71%) or anti-prothrombin antibodies (Pro) (50%). Sixty-seven percent of the patients with anti-Thr-IgG suffered from thromboembolic complications, mostly arterial thrombosis. The rate of thrombosis was higher for these patients than for patients with anti-beta(2)-GP-I antibodies (37/60, 62%), LA (50/79, 63%), or anti-Ser/Pro antibodies (18/28, 64%). Anti-thrombin antibodies were found in 20% of patients with aPL; 67% of these patients were admitted with thrombotic manifestations of APS. The presence of anti-thrombin antibodies was closely associated with the presence of aCL and anti-beta(2)-GP-I antibodies. The sensitivity of the test for anti-thrombin antibodies for the diagnosis of APS was higher than the sensitivity of the anti-prothrombin assay and similar to the sensitivity of the anti-Ser/Pro assay.

Risk of thromboembolism in patients with idiopathic autoimmune hemolytic disease and antiphospholipid antibodies: results from a prospective, case-control study

During a period of 4 years, 21 consecutive patients with newly diagnosed idiopathic autoimmune hemolytic disease (IAHD) and 42 healthy, sex- and age-matched subjects, were tested for the presence of antiphospholipid antibodies (APA). At diagnosis, APA were detected in 10/21 (47.6%) patients and in 2/42 (4.76%) controls (p< 0.01). No thromboembolic events were registered during the follow-up period.

Clinical characteristics of stroke patients with antiphospholipid antibodies

BACKGROUND

Antiphospholipid syndrome is important as a cause of ischemic stroke, although clinical characteristics of the syndrome are not well documented.

METHODS

We analyzed differences in clinical characteristics between 40 antiphospholipid-antibody (aPL)-positive and 40 aPL-negative stroke patients.

RESULTS

Stroke patients with aPL were significantly younger and were more likely to be women in comparison with stroke patients without aPL. Valvular heart disease, neurological complications and hematological disorders were more frequent in the aPL-positive group. The mean value of thrombin-antithrombin III complex was significantly lower in the aPL-positive group. Cerebral infarctions in the carotid system were less and large-artery lesions more frequent in the aPL-positive patients.

CONCLUSIONS

Stroke patients with aPL have clinical characteristics distinct from stroke patients without aPL.

Antiphospholipid syndrome: association between laboratory tests and clinical practice

Antiphospholipid antibodies are a wide and heterogeneous group of immunoglobulins, whose presence inpatients with arterial and venous thrombosis, and obstetrical complications defines the antiphospholipid syndrome. We systematically reviewed published articles on this syndrome to investigate the association between thrombosis and the most common antiphospholipid antibodies. Lupus anticoagulants were a clear risk factor for thrombosis, irrespective of the site and type of thrombosis, the presence of systemic lupus erythematosus, and the methods used to detect them. Anticardiolipin and anti 2-glycoprotein I antibodies were possible risk factors of thrombosis, at least in some selected situations. Conversely, the measurement of antiprothrombin antibodies was not helpful to define the patient's risk of thrombosis. These results are mainly due to the still far from optimal standardization of the methods to detect the various antiphospholipid antibodies.

Anti-oxLDL antibodies--marker for arterial thromboses in antiphospholipid syndrome?

Antibodies against oxidized low-density lipoproteins (anti-oxLDL antibodies) are involved in the development of atherosclerosis in animal models, but their role in humans is not clear. The aim of this study was to explore the relationship between the presence of anti-oxLDL antibodies and the presence of anti-beta2glycoprotein I (beta2gpI) antibodies, anticardiolipin antibodies and lupus anticoagulant. We also analyzed the relationship between the appearance of anti-oxLDL antibodies and clinical signs of antiphospholipid syndrome. This study included three groups of patients: 27 patients with primary antiphospholipid syndrome, 20 with secondary antiphospholipid syndrome associated with systemic lupus erythematosus and 13 patients with systemic lupus erythematosus. Levels of anti-oxLDL, anticardiolipin and anti-beta2gpI antibodies were detected by ELISA. The presence of lupus anticoagulant was detected by coagulation tests. We found that the presence of anti-oxLDL antibodies was associated with a history of arterial thromboses in patients with secondary antiphospholipid syndrome (chi2 = 8.89, p < 0.01) and in patients with primary antiphospholipid syndrome (chi2 = 4.64, p < 0.05). Also, the appearance of anti-oxLDL antibodies was associated with the presence of anti-beta2gpI antibodies (chi2 = 4.25, p < 0.05), which was not dependent on diagnosis. These preliminary observations have to be confirmed in a larger study.

Effect of subcutaneous administration of dalteparin on lupus anticoagulant assays

INTRODUCTION

Treatment with unfractionated heparin (UH) is known to affect screening tests for lupus anticoagulant (LA). False positive test results are common because confirmatory steps lack sufficient specificity to distinguish between LA and the presence of heparin. In this study, we wanted to see if therapeutic levels of low-molecular weight heparin (LMWH) may cause false positive tests for LA or alter the LA test results in LA-positive patients. We also wanted to evaluate the need to include heparin-neutralizing agents in the reagents.

MATERIALS AND METHODS

Six healthy subjects without LA and six LA-positive patients were given 100 IU/kg dalteparin subcutaneously (s.c.). Samples for three in-house and two commercially available LA tests were taken before and 4 h after the injection. LA test results were calculated as normalized screening/confirm ratios or as recommended by the manufacturers.

RESULTS

With both healthy subjects and LA patients, only small and clinically unimportant differences in mean clotting times and final test results were seen 4 h after subcutaneous dalteparin injections, at anti-FXa activities within the therapeutic range.

CONCLUSIONS

Our study with dalteparin suggests that LMWH therapy with plasma concentrations within the therapeutic range does not cause false positive tests for LA when normalized screening/confirm ratios are applied; nor do test results for LA-positive patients seem to be significantly altered. Heparin-neutralizing agents did not influence test performance.

Alteration in the laboratory profile of a lupus anticoagulant in a patient with non-Hodgkin's lymphoma

We describe a patient with non-Hodgkin's lymphoma who developed a lupus anticoagulant (LA) detectable by activated partial thromboplastin time (APTT), dilute Russell's viper venom time (DRVVT) and kaolin clotting time (KCT). IgM anticardiolipin antibodies (ACA) were elevated. At a later admission, and following treatment for the lymphoma, routine coagulation screening showed an elevated prothrombin time (PT) without correction in mixing tests using a recombinant thromboplastin. Routine APTT was below the reference range and ACA levels were normal. Raw data for one-stage factor assays demonstrated the presence of an inhibitor. Analysis for LA was undertaken by DRVVT, KCT, activated seven lupus anticoagulant assay, Taipan snake venom time, platelet neutralisation procedures (PNP), Ecarin time and PT using rabbit brain thromboplastin. The results revealed a LA capable of prolonging the clotting times of the PNPs and PT using recombinant thromboplastin, but that was corrected using Ecarin venom, modified PNP and brain thromboplastin. The antibody also demonstrated the lupus anticoagulant co-factor effect. The factor VIII: C was markedly raised which may have masked the LA in the APTT. The changing laboratory profile over time demonstrates the effects of LA heterogeneity and variations in sensitivity and specificity of assays for the detection of antiphospholipid antibodies.

Lupus anticoagulant testing using plasma spiked with monoclonal antibodies: performance in the UK NEQAS proficiency testing programme

We report here results from a United Kingdom National Quality Assessment Scheme (UK NEQAS) exercise in which both plasma spiked with monoclonal antibodies and plasma from a patient known to have lupus anticoagulant (LA) were distributed to 245 hemostasis laboratories with a request for them to test for possible LA using their routine screening procedure. In general, good agreement was seen in the diagnosis of samples spiked with monoclonal antibodies against beta2-glycoprotein 1 (beta2GP1) and prothrombin, the LA-positive patient sample, and a normal pooled plasma; over 87% of centers correctly identified each sample. However, methods employing platelet neutralizing procedures were associated with a higher proportion of false-negative responses with the antiprothrombin-spiked sample, and it is important to recognize that sensitivity and responsiveness of different methods may vary between artificial plasmas and different LA-positive patient plasmas.

Epileptic seizures in systemic lupus erythematosus

OBJECTIVE

To evaluate the frequency and risk factors of epileptic seizures in a large cohort of patients with systemic lupus erythematosus (SLE).

METHODS

Five hundred nineteen consecutive patients with SLE were studied, with follow-up ranging from 4 to 7.8 years. The type and frequency of risk factors associated with acute and recurrent epileptic seizures in SLE were determined.

RESULTS

Sixty (11.6%) patients with epileptic seizures were identified. Epileptic seizures occurred at the onset of SLE symptoms in 19 (31.6%) and after the onset of SLE in 41 of 60 (68.3%) patients. Fifty-three of 60 (88.3%) patients had acute symptomatic epileptic seizures, and 7 of 60 (11.7%) had recurrent epileptic seizures. Variables associated with acute epileptic seizures at SLE onset were stroke (p = 0.0004) and antiphospholipid antibodies (p = 0.0013). Epileptic seizures during follow-up were related to nephritis (p = 0.001), antiphospholipid antibodies (p = 0.005), and epileptic seizures at disease onset (p = 0.00001). All seven patients who presented recurrent epileptic seizures had antiphospholipid syndrome and interictal epileptic abnormalities on EEG.

CONCLUSIONS

Epileptic seizures were observed in 11.2% of systemic lupus erythematosus (SLE) patients. Antiphospholipid antibodies and stroke were related to epileptic seizures at SLE disease onset. Patients with renal flares, epileptic seizures at SLE disease onset, and antiphospholipid antibodies were at greater risk for acute symptomatic seizures during follow-up. Recurrence of epileptic seizures occurred in 1.3% of patients and was associated with antiphospholipid syndrome.

Thrombotic thrombocytopenic purpura with severe ADAMTS-13 deficiency in two patients with primary antiphospholipid syndrome

Arterial thrombotic events, thrombocytopenia, and hemolytic anemia with schistocytes may be encountered in the setting of both thrombotic thrombocytopenic purpura (TTP) and primary antiphospholipid syndrome (APS). We report 2 cases of TTP occurring in patients with definite primary APS. We also describe the results of tests for ADAMTS-13 activity in 20 consecutive patients with primary APS, as well as tests for antiphospholipid antibodies in 26 patients who had TTP, severe ADAMTS-13 deficiency, and ADAMTS-13-inhibiting antibodies. In both of the patients with primary APS and TTP, ADAMTS-13 activity was undetectable, and ADAMTS-13-inhibiting antibodies were present. None of the 26 patients with TTP and severe ADAMTS-13 deficiency was positive for the lupus anticoagulant. One of these patients had a low level of anticardiolipin antibodies (22 IgG phospholipid units). In the 20 patients with primary APS, mean ADAMTS-13 activity was 116% (range 44-250%), and no severe deficiency (< 5%) was observed. Our findings suggest that primary APS must be added to the list of autoimmune disorders that can be complicated by TTP.

Induction of endothelial cell apoptosis by heat-shock protein 60-reactive antibodies from anti-endothelial cell autoantibody-positive systemic lupus erythematosus patients

OBJECTIVE

To determine whether anti-endothelial cell autoantibodies (AECAs) from systemic lupus erythematosus (SLE) patients with the antiphospholipid syndrome are involved in the initial endothelial cell (EC) membrane perturbation effect that is postulated to provide a target for antiphospholipid antibody (aPL) binding and, hence, to trigger the thrombotic cascade. To identify the AECA antigenic target on ECs and to determine the mechanism whereby the EC membrane is disrupted.

METHODS

AECAs from SLE patients were assayed for binding to ECs by flow cytometry. Positive AECAs were assayed by immunoblotting, and a consensus antigen was identified by mass spectrometry. This candidate antigen was tested in recombinant form for AECA recognition. AECAs were affinity-purified on this antigen and incubated with ECs to determine their physiologic effects. Anti-Hsp60 antibody titers were determined by enzyme-linked immunosorbent assay. The relationship of anti-Hsp60 status and lupus anticoagulant (LAC) status to thrombotic manifestations between disease onset and the last followup visit were analyzed.

RESULTS

Most of the SLE sera (73%) possessed IgG that bound to the surface of ECs. These positive IgG shared reactivity against a 60-kd EC surface polypeptide that was identified as human Hsp60. The presence of Hsp60 at the EC surface was established using anti-Hsp60 antibodies from commercial sources or affinity-purified from SLE sera that bound ECs. Incubation of ECs with these anti-Hsp60 antibodies induced apoptosis in a time- and dose-dependent manner, as determined by Hoechst 33342 dye staining of condensed nuclei and by annexin V binding to surface phosphatidylserine. Anti-Hsp60 antibodies were not restricted to SLE patients, but were found in patients with other autoimmune diseases. However, anti-Hsp60 antibodies were significantly associated with an increased frequency of thrombosis when present in combination with LAC in the SLE patients.

CONCLUSION

The presence of Hsp60 at the surface of ECs serves as a target for the anti-Hsp60 antibodies in SLE sera. These anti-Hsp60 antibodies bind to ECs and induce apoptosis, particularly phosphatidylserine exposure, thus providing a target for the binding of aPL and inducing the subsequent thrombotic cascade.

Spinal Dural Arteriovenous Fistulas Are Not Associated With Prothrombotic Factors

Background and Purpose— The cause of spinal dural arteriovenous fistulas (SDAVF) is unknown. In intracranial dural arteriovenous fistulas, an association with factor V Leiden mutation has been found. Therefore, we studied the association between prothrombotic factors and SDAVF.

Methods— Factor V Leiden mutation, factor II mutation, protein S, protein C, factor VIII, von Willebrand factor, antithrombin III, and lupus anticoagulant were determined by means of standard laboratory tests in 40 patients and 119 control subjects matched for sex and age.

Results— Factor V Leiden mutation was not found in the patient group and was found twice in the control group. Factor II mutation was found in 1 patient and in none of the control subjects. There was no decreased activity of protein S, protein C, factor VIII, von Willebrand factor, or antithrombin III in patients in comparison with controls. Lupus anticoagulant was not found in the patient group and once in the control subjects.

Conclusions— We conclude that it is unlikely that prothrombotic factors are involved in the pathogenesis of spinal dural arteriovenous fistulas, but subtle associations are not ruled out.

Antiprothombin antibodies and the diagnosis of antiphospholipid syndrome

The preliminary classification criteria for definite antiphospholipid syndrome (APS) include the presence of anticardiolipin antibodies (aCL) and/or lupus anticoagulant (LA) as laboratory criteria. However, antiphospholipid antibodies (aPL) are a heterogeneous group of antibodies comprising also antibodies against phospholipid-binding proteins or their complexes with phospholipids. Prothrombin is one of the antigen recognized by aPL. In the last decade, there has been increasing interest in antibodies against prothrombin alone and those against phosphatidylserine-prothrombin complex. The latter, phosphatidylserine-dependent antiprothrombin antibodies (aPT), have been closely associated with APS and LA. In this paper, we review the properties of antiprothrombin antibodies.

Nailfold videocapillaroscopy in primary antiphospholipid syndrome (PAPS)

OBJECTIVES

To evaluate microcirculatory changes (functional and morphological) in primary antiphospholipid syndrome (PAPS) patients.

METHODS

Thirty-one patients were examined using nailfold videocapillaroscopy (18 PAPS patients and 13 healthy subjects). The patients were subdivided into two subgroups, with lupus anticoagulant (n = 8) and with anticardiolipin (n = 10) antibodies. Capillary morphology was determined; diameters ( micro m) and functional capillary density (FCD, number capillaries/mm2) were measured in control conditions. Blood flow velocity (CBFV, mm/s) was also evaluated at rest and after release of 60 s arterial occlusion.

RESULTS

The percentage of subjects with at least one morphological alteration in the observed capillaries was 77.8% for patients and 21.3% for healthy subjects. Capillary diameters ( microm) [afferent (AD), apical (APD) and efferent (ED)] were significantly smaller (mean +/- s.d.: AD-PAPS, 7.4 +/- 2.1; control, 9.1 +/- 2.6, P = 0.063; APD-PAPS, 11.6 +/- 2.3; control, 14.4 +/- 3.8, P = 0.015; ED-PAPS, 8.4 +/- 2.0; control, 10.9 +/- 3.2, P = 0.011) in PAPS patients compared with controls. FCD (PAPS, 8.5 +/- 3.2; control, 8.3 +/- 2.9, P +/- 0.862), mean resting CBFV (PAPS, 0.73 +/- 0.31; control, 0.88 +/- 0.41, P = 0.278), mean peak CBFV after occlusion (PAPS, 1.07 +/- 0.52; control, 1.59 +/- 0.91, P = 0.063) and mean time (s) to reach it (PAPS, 5.2 +/- 1.7; control, 4.6 +/- 1.8, P = 0.101) were not statistically different between the two groups.

CONCLUSION

Our results suggest that nailfold capillary morphology is altered in patients with PAPS, but these changes could not be correlated to impairment of functional parameters.