[Antiphospholipid antibodies in megakaryocytic thrombopenias]

We investigated the prevalence of antiphospholipid antibodies (APA) in megakaryocytic thrombopenias in order to establish their clinical significance and prognostic value. We studied 82 thrombopenic patients: 38 women and 44 men (age: 17-91 years). We assessed circulating lupus antibody (LA) through thromboplastin inhibition test (TIT), anticardiolipin antibodies (ACL) through ELISA and antiplatelet antibodies through flow cytometer. We conducted a statistical study RSIGMA, comparing patients with ACL + against ACL-. We found ACL positive in 21%, LA in 33% and antiplatelet antibodies in 42%. We observed a direct correlation (p < 0.05) between ACL and LA and between ACL and anticore antibodies, but not between ACL and antiplatelet antibodies. There was also a significant correlation between ACL and abortion, thrombosis and bleeding in thrombopenic patients. We conclude that APAs are present in 39% of the megakaryocytic thrombopenias and that they are not correlated with antiplatelet antibodies. Positivity of APA in thrombopenic patients is associated to poor prognosis and long term follow-up.

Antiphospholipid antibodies and risk of intrauterine late fetal death

STUDY OBJECTIVE

Goal of the study was to analyze the relationship between anticardiolipin antibodies, lupus anticoagulant and the risk of intrauterine late fetal death.

DESIGN

A case-control study was conducted in a network of general and teaching hospitals in northern Italy. Cases studied were 99 women (median age 27 years), without clinical evidence of systemic lupus erythematosus or other immunological disorders who had an 'unexplained' intrauterine fetal death at or after the 20 weeks of gestation. The control subjects were 85 women (median age 28 years) who gave birth at term (> 37 weeks gestation) to healthy infants on randomly selected days at the same hospitals where cases had been identified.

RESULTS

The presence of lupus anticoagulant was detected in four of the 99 cases (4%, 95% confidence interval 2%-15%) and none of the 85 controls. A total of 10 out of the 89 cases (11%, 95 confidence interval 6%-23%), but none of the 79 controls for whom anticardiolipin antibodies value was available had elevated anticardiolipin antibodies; this difference was statistically significant (chi 2(1) = 9.38, p < 0.01).

Severe postpartum pulmonary, cardiac, and renal syndrome associated with antiphospholipid antibodies

BACKGROUND

The antiphospholipid antibody syndrome has been associated with thromboembolic events, thrombocytopenia, fetal death, fetal growth retardation, and early-onset severe preeclampsia.

CASE

A postpartum woman developed fever, pulmonary infiltrates, cardiac conduction defects, and renal insufficiency following severe preeclampsia. She tested positive for lupus anticoagulant and anticardiolipin antibody, and responded to steroid therapy and plasmapheresis.

CONCLUSION

The postpartum multi-system involvement suggests that a variety of clinical presentations may be associated with antiphospholipid antibodies. Treatment with plasmapheresis or corticosteroids may be of value in similar cases.

[Determination of antiphospholipid antibodies in serum using ELISA]

The authors compare two ELISA methods for the assessment of antiphospholipid antibodies, classes IgG and IgM, in serum: ELISA Pin Plate System ALPHA DIALAB Co. and the ELISA method developed in the Research Institute of Rheumatic Diseases. Both methods use cardiolipin as antigen. In the Pin Plate test the immunochemical reaction antigen/antibody does not take place at the surface of the pits of the microtitration plates but on the tip of the next plate. The results of examinations of antiphospholipid antibodies obtained by the tested methods are comparable, the Pin Plate test is quicker and more sensitive, but its price limits routine use.

A prospective epidemiological study on the occurrence of antiphospholipid antibody: the Montpellier Antiphospholipid (MAP) Study

The objective of this study was to determine the prevalence and clinical significance of elevated antiphospholipid antibodies (APA) in a large series of patients admitted to a department of Internal Medicine. At the end of entry phase, 1014 patients were tested (488 males-526 females, mean age: 66.7 years, range 18-97). Seventy-two (7.1%) patients were found APA positive at least once: 44 males and 28 females, mean age 69 years, range 23 to 94. Twenty fulfilled the criteria of Primary Antiphospholipid Antibody Syndrome: 10 patients were referred for deep vein thrombosis, 3 had history of deep vein thrombosis, 1 had both arterial thrombosis and a history of venous thrombosis; 2 had thrombocytopenia; 3 had stroke, 1 had a history of a stroke. One patient had SLE according to ARA classification. The most frequent associated disease was cancer: 14 patients, 9 had evolutive malignant disease, 5 were in clinical remission of neoplasia. Other clinical conditions included chronic and/or acute alcoholic intoxication (n = 8), severe atherosclerosis (n = 4), leg ulcer (n = 4). Insufficient data are available about the evolution, but 7 patients died in the year following diagnosis. Eight patients had fluctuations in APA detection: 2 initially APA positive became negative, 5 initially negative became positive and 1 patient was alternatively positive, negative and positive without steroid treatment. Thus, as expected, APA occur in a variety of clinical disorders. The association with cancer or alcoholic intoxication deserves further investigations.

Diagnosis of antiphospholipid antibodies

The antiphospholipid antibody syndrome consists of a presentation with venous thrombosis, arterial thrombosis (or vasculopathy), recurrent pregnancy loss, or thrombocytopenia, in the setting of high-titer anticardiolipin antibody or lupus anticoagulant. Characteristics of the lupus anticoagulant (an antibody detected by a functional assay) and anticardiolipin antibody are reviewed, in light of new information on the role of plasma proteins, especially B2-glycoprotein I. The advantages and disadvantages of screening and confirmatory assays for lupus anticoagulant are detailed, as well as modifications of the anticardiolipin antibody assay to improve sensitivity and specificity.

Anti-glycoprotein Ib/IX and IIb/IIIa antibodies in patients with antiphospholipid antibodies

Antiphospholipid antibodies, namely lupus anticoagulant (LA), anticardiolipin (aCL) type A and type B antibodies, are frequently associated with immune-mediated thrombocytopenia. Antiphospholipid antibodies have been suggested to bind to the phospholipids of the platelet membrane, thus participating to the process of platelet destruction, which leads to thrombocytopenia. However, a clear antiphospholipid (aPL) demonstration of such a role has never been given for antibodies. Conversely, autoantibodies directed against membrane-associated glycoproteins (GP) have been shown to be pathogenetically linked to the development of thrombocytopenia in patients with idiopathic thrombocytopenic purpura. For this reason, we have measured anti-GPIb/IX and GPIIb/IIIa IgG in the plasma of 68 patients with aPL antibodies by ELISA. The monoclonal antibody-specific immobilization of platelet antigen (MAIPA) assay was used. Twenty-seven out of 68 patients with antiphospholipid antibodies (40%) had increased plasma levels of anti-GP antibodies. In particular, 7 of them had elevated anti-GPIIb/IIIa levels only, 6 had anti-GPIb/IX antibodies only, whereas in the remaining 14 cases both types of autoantibodies were found elevated. The level of anti-GP antibodies in plasma did not correlate with age, sex, clinical associated conditions, history of thrombosis, IgG aCL titer or the presence of a phospholipid-dependent inhibitor of coagulation. In contrast, a statistically significant association between thrombocytopenia and high anti-GP antibody titer was observed (p = 0.0458). To establish whether there was cross-reactivity between antiphospholipid and anti-GP antibodies, adsorption experiments were performed using cardiolipin-containing liposomes or washed, normal, resting platelets.(ABSTRACT TRUNCATED AT 250 WORDS)

[Emboligenic mitral papillary fibroelastoma and positive antiphospholipid antibodies]

Cardiac papillary fibroelastoma has been associated to high levels of antiphospholipid antibodies, either primary or in the context of systemic lupus erythematosus. We present the case of a young female with several episodes of peripheral emboli. Two-dimensional echocardiography demonstrated a tumor on the anterior mitral leaflet. The mass was resected and histologically showed a papillary architecture covered by hyperplasic endocardial cells on a layer of connective tissue and a central core of collagen and elastic fibers. The immunologic study demonstrated high titers of anticardiolipin antibodies, complement consumption and positive antinuclear antibodies. The patient keep high anticardiolipin antibodies titers at follow-up but embolization has not recurred and has no symptoms.

Incidence of antiphospholipid antibodies in patients with monoclonal gammopathy of undetermined significance

The incidence of antiphospholipid antibodies in patients with monoclonal gammopathy of undetermined significance (MGUS) was studied. Antiphospholipid antibodies were measured in the sera of 93 patients (49 women, 44 men; mean age 70 [+/- 21] years) with MGUS by using an enzyme-linked immunosorbent assay (ELISA). The phospholipids tested were cardiolipin (CL), phosphatidylserine (PS), phosphatidylinositol (PI), phosphatidylglycerol (PG), phosphatidic acid (PA), phosphatidylcholine (PC), and phosphatidylethanolamine (PE). Positive results were defined as a value higher than the number of multiples of the mean per phospholipid, which included 76 of 80 (95%; 20 age-matched) control individuals. The immunoglobulin-G (IgG) or IgM antiphospholipid antibodies isotype varied among the patients, as did the phospholipid specificity. For IgG, PI was found elevated in 32% of the MGUS samples, whereas the other phospholipid antigens ranged from 9% to 15%. The percentage of patients with IgM antiphospholipid antibodies was higher. The authors observed PS, PI, PA, and PC as positive in 45%, 35%, 25%, and 25% of patients, respectively. Of the 12 sera studied for IgA isotype, three (25%) were positive for PS, six (50%) for CL, and none for PE. Patients with MGUS manifested a significantly higher (P < .01) incidence of antiphospholipid antibodies in their blood than did the control persons. No difference in the incidence of antiphospholipid antibodies was seen between younger and older (age-matched) control patients. No correlation was found between serum levels of immunoglobulins and optical density reading of the blank plates used as ELISA controls.

Some recent developments with lupus anticoagulants

Lupus anticoagulants (LA) have been defined as phospholipid-interfering antibodies. Testing for them has become a frequently requested procedure in coagulation laboratories and new methods have recently become available. Activated partial thromboplastin time (aPTT) reagents with reduced levels or different types of phospholipid provide high sensitivity. Correction procedures resistant to heparin and based on aPTT and dilute Russell's viper venom time (DRVVT) tests with added hexagonal phase phospholipids have improved the specificity of testing. Simplified tests based on venom activators of factor X and prothrombin improve the reliability of LA testing and may facilitate the further categorization of circulating anticoagulants. Recent studies on the mechanism of LA derived from various patients have confirmed their heterogeneity, principally in the protein cofactors involved in their interactions with phospholipids. Perhaps one-third of LA require beta 2-glycoprotein 1 to exert an anticoagulant effect. The remainder may require human prothrombin as suggested from studies with reconstituted clotting factor systems.

Antiphospholipid syndrome associated with immunotherapy for patients with melanoma

BACKGROUND

Immunotherapy for patients with cancer is associated with severe side effects, including the possible induction of autoantibodies. The latter was proven for antithyroid microsomal and antithyroglobulin antibodies.

METHODS

This study was designed to evaluate antiphospholipid antibodies (APA) in 30 patients receiving three different forms of immunotherapy for disseminated melanoma using interleukin-2 (IL-2), alpha-interferon (alpha-interferon) or the combination of both.

RESULTS

APA were detected in none of 18 patients treated with IL-2 alone, 2 of 4 (50%) treated with alpha-interferon alone, and 3 of 8 (37.5%) treated with the combination of both. In the last group, increased concentrations of APA were observed, while the patients were still receiving alpha-interferon alone. APA levels were not detected in any of 10 patients with melanoma who were not treated with alpha-interferon or IL-2. In patients with increased APA, five of five (100%) had a prolongation of the partial thromboplastin time and 4 or five (80%) had deep venous thrombosis, which in one patient was followed by pulmonary embolism.

CONCLUSIONS

The high incidence of therapy-induced elevated APA concentrations suggests that these should be carefully monitored in all patients receiving immunotherapy with alpha-interferon.

Antiphospholipid antibodies in predicting adverse pregnancy outcome. A prospective study

OBJECTIVE

To determine if the presence of antiphospholipid antibody (aPL) in healthy pregnant women is associated with adverse pregnancy outcome, including 1) intrauterine fetal loss, 2) maternal pregnancy complications, 3) low birth weight, and 4) low 5-minute Apgar scores.

DESIGN

Prospective cohort study in women with normal pregnancies.

SETTING

Obstetrics clinic at the University of Colorado Health Sciences Center.

PATIENTS

Eligible patients included 451 low-risk, nulliparous pregnant women who came to the obstetrics clinic before 25 weeks gestation; 408 were enrolled and 389 had blood drawn at the first prenatal visit and completed clinical follow-up.

MEASUREMENTS

Blood for six aPL measures was drawn at the first prenatal visit and for 239 patients at delivery.

RESULTS

Ninety-five patients (24.4%) had elevated aPL levels by one or more measures at the first prenatal visit: 15.8% of the aPL-positive and 6.5% of the aPL-negative patients experienced fetal loss (relative risk, 2.44; 95% CI, 1.29 to 4.62). However, an elevated IgG anticardiolipin antibody level at the first prenatal visit was the only aPL measurement that was significantly associated with fetal loss (relative risk, 3.5; CI, 1.56 to 8.07). Adjustment for confounding variables decreased the relative risk of aPL for fetal loss slightly, but the difference remained statistically significant. Neither a positive aPL result at the initial visit nor a positive result at delivery was associated with maternal complications of pregnancy, low birth weight, or low Apgar scores.

CONCLUSIONS

Patients with elevated aPL levels at their initial prenatal visit had an increase in fetal loss but no increase in maternal pregnancy complications, low birth weight, or low Apgar scores. Immunoglobulin G anticardiolipin antibody was the only single test of aPL significantly associated with fetal loss.

Clinical consequences of antiphospholipid antibodies: an historic cohort study

OBJECTIVE

To determine the risk of antiphospholipid antibody-related disorders in women with elevated levels of these antibodies.

METHODS

We used an historic cohort study design. Surveys of medical and obstetric histories for the interval from initial antibody testing to the time of patient interview were used to calculate age-adjusted rates for the development of medical disorders associated with antiphospholipid antibodies. The cohort included 130 women with lupus anticoagulant, medium to high levels of immunoglobulin G anticardiolipin antibodies, or both.

RESULTS

The median interval of study was 3.2 years (range 0.7-9.5, mean 3.7). Sixty-three subjects (48%) developed at least one new disorder during the study interval. The age-adjusted rates (per 1000 patient-years; +/- standard error) for the development of the disorders studied were as follows: thrombosis (156.8 +/- 30.0), cerebrovascular accident (93.8 +/- 25.1), amaurosis fugax (57.1 +/- 23.2), transient ischemic attack (170.4 +/- 27.6), systemic lupus erythematosus (9.8 +/- 3.8), and autoimmune thrombocytopenia (56.0 +/- 22.2). Of the 34 thrombotic events that occurred during the study interval, eight were associated with pregnancy and eight occurred while the patients were taking anticoagulant medications.

CONCLUSIONS

Our subjects developed complications associated with antiphospholipid antibodies at a substantial rate, and almost half suffered at least one new event during the study interval. The high rate of thrombosis in individuals with antiphospholipid antibodies, especially associated with pregnancy, underscores the need to evaluate long-term anticoagulation in these patients.

Cerebrovascular and neurological disorders associated with antiphospholipid antibodies in CSF and serum

Paired serum and cerebrospinal fluid (CSF) samples from 70 patients with inflammatory and non-inflammatory neurological diseases, as well as 10 sera from patients with primary antiphospholipid syndrome (PAS), six of which presented with cerebrovascular ischemic syndromes, were studied for the presence of anticardiolipin antibodies (ACA) of the G and M classes. PAS sera and some selected paired CSF and serum specimens, were also analyzed for the presence of anti-phosphatidylserine (PS) and anti-phosphatidylethanolamine (PE) antibodies. High levels of IgG and IgM ACA were synthesized intrathecally only in patients with neurosyphilis. Patients with other infectious or inflammatory neurological diseases very rarely showed detectable levels of ACA in serum and/or CSF. ACA were found not only in patients with untreated PAS but also in the serum of 3/7 patients with migraine, thus confirming a relationship between ACA and vascular disorders. The search for PS and PE antibodies disclosed that in PAS patients the serum titers of these antibodies mirrored ACA IgG and IgM titers, while they were never found in the CSF.

Familial Sneddon's syndrome: clinical, hematologic, and radiographic findings in two brothers

We present the clinical, hematologic, and radiographic findings in two brothers with Sneddon's syndrome (stroke and livedo reticularis) and antiphospholipid antibodies. Patient 1 had anticardiolipin antibody and patient 2 had lupus anticoagulant, which we detected only upon repeated blood testing. One should test for both anticardiolipin antibody and lupus anticoagulant and repeat the screenings before determining a Sneddon's syndrome patient's antiphospholipid antibody status. Both Sneddon's syndrome and the primary antiphospholipid antibody syndrome are potentially familial causes of stroke. In familial cases, an inherited predisposition to antiphospholipid antibody production may be involved in disease pathogenesis.

High levels of anti-phospholipid antibodies in uncomplicated and severe Plasmodium falciparum and in P. vivax malaria

The majority (75%) of adult patients with uncomplicated Plasmodium falciparum and P. vivax malaria are positive for anti-phospholipid antibodies (aPLA) as demonstrated by ELISA using a panel of anionic and cationic phospholipids. The highest IgG and IgM binding was to the anionic phospholipids, phosphatidylserine (PS), phosphatidic acid (PA) and cardiolipin (CL), but excluding phosphatidylinositol (PI) to which only low antibody levels were found. Comparison of the mean IgG and IgM aPLA showed a trend for anti-PA > CL > PS > PC > PE > PI. Anti-PI levels were compared in two groups of African children, one group with non-severe and the other with severe (cerebral) falciparum malaria. Children with cerebral disease had significantly lower IgM anti-PI. The results are discussed with the view that serum-derived aPLA may have a role in 'anti-disease' immune responses. Their possible role in the opsonization and phagocytosis of parasitized erythrocytes and in thrombocytopenia is also considered.

Antibodies against platelet-activating factor in patients with antiphospholipid antibodies

We have studied the specificity of antiphospholipid antibodies in 148 patients with autoimmune diseases, 120 patients with systemic lupus erythematosus and 28 with the primary antiphospholipid syndrome. In addition, 20 patients suffering from syphilis were studied. As a control group, 64 healthy volunteers were investigated. Patient and control serum samples were tested for binding to seven different phospholipid antigens by ELISA. Interestingly, 90% of the sera from syphilis patients and 6% of the autoimmune patients exhibited a significant binding to platelet-activating factor (PAF), a molecule similar to the structure of phosphatidylcholine. In addition, the IgG fraction from one of the lupus patients, which showed a high binding activity to PAF, was further affinity-purified using both liposomes and an affinity chromatography column. Preincubation of these antibodies with PAF inhibited subsequent binding to immobilized PAF. These observations might suggest a putative interaction of antiphospholipid autoantibodies with PAF 'in vivo', which may have, in some patients, important pathophysiological consequences.

Prevalence, significance, and specificity of antibodies to phospholipids in Q fever

A cross-sectional study of the prevalence, significance, and specificity of antibodies to phospholipids (aPL) in patients with Q fever was undertaken in a university-based tertiary care medical center. The results of the lupus anticoagulant (LA) test, VDRL test, fluorescent treponemal antibody absorption test, and ELISA with different phospholipid antigens were determined for 26 patients with Q fever diagnosed by clinical and serological criteria. Plasma from four patients with Q fever and antibodies to cardiolipin (aCL) was purified by affinity chromatography in a cardiolipin column and tested against all phospholipids. For 17 patients with high levels of aCL, a modified ELISA without fetal calf serum was performed to determine if the serum cofactor was needed for a CL activity. Fisher's exact test was used for the statistical analysis. From the results of our study we conclude the following: patients with Q fever have a high incidence of aPL, with techniques with aCL or LA being the most sensitive to determine aPL (these antibodies can help diagnose Q fever presenting only as a fever); antibodies (phase II) to Coxiella burnetii and aCL are different antibodies; and the aCL activity in patients with Q fever is cofactor-independent.

Antiphospholipid antibodies (aPL) in systemic lupus erythematosus. Are they specific tools for the diagnosis of aPL syndrome?

OBJECTIVE

Antiphospholipid antibody (aPL) specificity for aPL-related events was evaluated in systemic lupus erythematosus (SLE).

METHODS

A study was carried out on 105 patients affected with SLE comparing the prevalence of lupus anticoagulant (LA) and IgG and IgM anticardiolipin antibodies (aCL) between patients with and without features of antiphospholipid syndrome (APS). Antiphospholipid antibody profile was subsequently evaluated in the aPL positive patients with and without aPL-related events, thus excluding the patients with complications of APS possibly due to factors other than aPL.

RESULTS

LA showed a strong association with thrombosis and livedo reticularis, and IgG aCL with thrombosis and neurological disorders, while no clinical features were associated with IgM aCL. A considerable number of aPL positive patients with no aPL-related manifestations was also observed, suggesting the low specificity of aPL assays (54.4%). When studying the 60 aPL positive patients, LA was specific (91.3%) for the diagnosis of aPL-related thrombosis, whereas aCL were not specific, although IgG aCL mean levels were higher in patients with arterial thrombosis than in those without APS features.

CONCLUSIONS

LA but not aCL positivity is a specific tool for the diagnosis of thrombotic complications due to aPL in SLE.

Antiphospholipid and thrombosis syndromes

ACAs and the lupus anticoagulant are strongly associated with thrombosis and appear to be the most common of the acquired blood protein defects causing thrombosis. Although the precise mechanism or mechanisms whereby antiphospholipid antibodies alter hemostasis to induce a hypercoagulable state remain unclear, several theories, as previously discussed, have been advanced. The most common thrombotic events associated with ACAs are DVT and PE (type I syndrome), coronary or peripheral artery thrombosis (type II syndrome), cerebrovascular or retinal vessel thrombosis (type III syndrome), and occasionally patients present with mixtures (type IV syndrome). The relative frequency of ACAs in association with arterial and venous thrombosis strongly suggests that these should be looked for in any patient with unexplained thrombosis; all three idiotypes (IgG, IgA, and IgM) should be assessed. Also, the type of syndrome (I through IV) should be defined, if possible, because this may dictate both type and duration of both immediate and long-term anticoagulant therapy. Unlike those with ACAs, patients with primary lupus anticoagulant thrombosis syndrome usually have venous thrombosis. Since the aPTT is unreliable in patients with lupus anticoagulant and is not usually prolonged in patients with ACAs, definitive tests (ELISA for ACA and the dRVVT for lupus anticoagulant) should be immediately ordered when suspecting antiphospholipid syndrome or in patients with otherwise unexplained thrombotic or thromboembolic events.

Serologic tests for connective tissue diseases and the primary vasculitides

This article provides a brief historical perspective on the development of tests for antiphospholipid antibodies, antinuclear antibodies, myositis-specific antibodies, and antineutrophil cytoplasmic antibodies in the clinical laboratory. Tests presently available in most clinical laboratories that are used in the diagnosis and treatment of the connective tissue diseases and the vasculitides are discussed. Mention is made of antibodies under study in the research laboratories.

Activity of antiphospholipid antibody ELISA cofactor in different animal sera

A plasma protein cofactor, beta 2-glycoprotein I (beta 2GPI), also known as apolipoprotein H, is necessary to detect certain antiphospholipid antibodies (aPA) to negatively charged phospholipids (PL) in the ELISA. Inasmuch as sera are diluted 1:100 before testing, the concentration of native beta 2GPI may be insufficient to provide an optimal aPA ELISA signal. Therefore, many laboratories add adult bovine serum (ABS) to the diluent buffer to provide a consistent level of cofactor for optimal aPA binding. To determine if other animal sera can provide the cofactor, cat, chicken, dog, horse, goat, guinea pig, mouse, pig, rat, and sheep were tested as diluent supplements in the aPA ELISA. To measure cofactor activity in these animal sera, ELISA for aPA to anionic phospholipids were performed. Two aPA positive patient plasmas were selected for study; one with cofactor-dependent and one with cofactor-independent aPA. Only four of the animal sera tested (bovine, pig, sheep, and cat) supported the cofactor-dependent aPA in ELISA. The cofactor-independent aPA was positive in the presence of each animal serum except bovine and rat. In order to determine whether these animal sera contain a beta 2GPI-like molecule, Western blot analyses were performed. By using a polyclonal antiserum produced to human beta 2GPI, specific beta 2GPI-like cross-reactivity was observed with all animal sera except the chicken. In summary, cofactor activity in animal sera varied significantly; however, bovine and pig sera appear to allow optimal binding of cofactor dependent aPA.

Characterization of antiphospholipid antibodies in women with recurrent spontaneous abortions

Antiphospholipid antibodies are important in the etiology of recurrent pregnancy loss. To date, most studies have concentrated on antibodies to cardiolipin specifically. In this study, the serum of 352 women with recurrent pregnancy loss was studied by enzyme-linked immunosorbent assay for antibodies to six phospholipid epitopes: cardiolipin, phosphoserine, phosphoglycerol, phosphoethanolamine, phosphatidic acid and phosphoinositol. Of these women, 59.1% had either an IgG or IgM antibody to one of the six phospholipids. This compared to only 4.6% in the control group. Approximately 75% of the isotypes were IgM. The most common phospholipid epitope was phosphoserine. However, in patients with antibodies to only one phospholipid, phosphoethanolamine was the most common. These findings support recent evidence that antiphospholipid antibodies may interfere with the formation of syncytiotrophoblasts in the placenta. In addition, antiphospholipid antibodies occur more frequently in patients who suffer recurrent miscarriages than was previously thought.

Antiphospholipid antibodies in coronary artery disease: a review

APAs present a clinical problem that is now recognized to be a significant causative factor of both fatal and nonfatal myocardial infarction as well as other coronary syndromes. Similar to the thrombotic complications of APAs in the cerebrovascular system, the result can be life-threatening or fatal. Correct diagnosis requires a high index of suspicion, especially in patients with known prior thrombotic events and in those who present with myocardial ischemia or infarction without underlying risk factors and at a young age. In these patients an aggressive laboratory evaluation must be performed, including testing for APAs. The treatment of the coronary syndrome must progress along currently accepted approaches, including the aggressive and early use of thrombolytic therapy followed by anticoagulation with heparin, porcine heparin, or possibly low molecular weight heparin. Intermediate and long-term therapy with some form of heparin or high-intensity warfarin anticoagulation is essential to have any chance of preventing coronary reocclusion and recurrent myocardial infarction as well as other thrombotic events. Although the precise incidence of APAs in the general and coronary artery disease population is not known and although in the individual patient early disease may be difficult to detect, an enhanced awareness of the possibility of the association of APAs with coronary artery disease may allow earlier diagnosis and may save lives. Studies of larger numbers of patients over extended time periods with various pharmacological approaches to anticoagulation are needed to define more clearly optimal management.

Antinuclear and antiphospholipid antibodies in healthy women with recurrent spontaneous abortion

PROBLEM

To determine the presence of absence of subclinical autoimmunity in healthy women with first trimester recurrent spontaneous abortion (RSA), the sera of 72 healthy women with a history of three or more consecutive abortions were analyzed for the presence of antibodies to phospholipid and nuclear antigens.

METHOD

Lupus anticoagulant was determined, as were antibodies to cardiolipin. An indirect immunofluorescent antinuclear test was performed and specific antinuclear antibodies to double-stranded DNA, ribonucleoprotein, Smith antigen, and Sjogren's syndrome A and B antigens were tested.

RESULTS

Nine women (13.2%) had low levels of antinuclear antibodies, none of which were specific. Four women (5.6%) had moderate to high levels of aCL antibodies.

CONCLUSION

We conclude that the prevalence of aCLs and antinuclear antibodies in healthy women with first trimester RSA is low. Subclinical autoimmunity is not a common cause of first trimester RSA.

Antiphospholipid antibodies in patients with idiopathic autoimmune haemolytic anemia

Isolated cases of anti-phospholipid antibody (aPL)-associated idiopathic autoimmune haemolytic anemia (IAHA) have been recently described. To assess the significances of this association, we studied by ELISA the presence of aPL in sera from 18 patients with IAHA and 14 patients with non-autoimmune haemolysis (NON-AH). Four IAHA cases and none of the NON-AH controls showed IgM anticardiolipin antibodies (aCL) that crossreacted extensively with zwitterionic as well as with other anionic phospholipids. IgG aCL were detected in 6 patients with IAHA and in 1 patient with NON-AH; there was little cross-reactivity with other phospholipids. Our results suggest that antiphospholipid antibodies are present in a substantial number of patients with IAHA. This humoral response does not seem to be secondary to the haemolysis proper. The potential pathogenic significance of this finding is discussed.

Can tests for IgA, IgG, or IgM antibodies to cardiolipin or phosphatidylserine substitute for lupus anticoagulant assays in screening for antiphospholipid antibodies?

Antiphospholipid antibodies (APL) are detected by both ELISA and tests for lupus anticoagulants (LA). We evaluated ELISA tests for IgG, IgM, and IgA isotopes of antibodies binding cardiolipin (CL) and phosphatidylserine (PS) in samples from LA patients presenting with recurrent miscarriages. All values were expressed in multiples of the normal median (MOM). In 32% (11/34) of cases, not only were all ELISA values at or below 2.5 MOM, but the distribution of these ELISA MOM values within the normal range was similar to distribution of values from LA negative controls with the same history. Neither the use of PS as the antigen nor the addition of IgA assays improved the correlation of ELISA results with the presence of LA. ELISAs are inadequate as the sole screening test for these separate, but often associated, families of APL.

Cutaneous expressions of antiphospholipid syndromes

The cutaneous clinical signs of antiphospholipid syndromes are expressed as stagnation of blood flow as livedo reticularis, purplish erythematous macules of acral areas, or end result of thrombosis as ulcers and necrosis (Fig. 6) (Table 1). Corresponding histological signs are reflected as thrombosis of dermal blood vessels (Fig. 7).

Detection of beta-2-glycoprotein-I-dependent antiphospholipid antibodies and anti-beta-2-glycoprotein-I antibody in patients with systemic lupus erythematosus and in patients with syphilis

We investigated whether or not antiphospholipid antibodies (aPLs; antiphosphadidylserine antibody, aPS; antiphosphatididylinositol antibody, aPI; antiphosphatidic acid antibody, aPA, and antiphosphadidylethanolamine antibody, aPE) were beta 2-glycoprotein-I (GPI)-dependent antibodies like anticardiolipin antibody (aCL) in patients with systemic lupus erythematosus (SLE). None of the patients with syphilis or healthy controls was positive for any GPI-dependent aPL. By contrast, GPI-dependent aCL (40%), aPS (20%), aPI (18%), aPA (12%) and aPE (8%) were detected in patients with SLE. Among these, 4 patients were negative for aCL, but positive for aPS. Those who were positive for more than 2 types of aPL, along with lupus anticoagulant, had a high incidence of arteriovenous thrombosis, fetal loss, thrombocytopenia and biological false-positive reaction to syphilis. From these findings we conclude that GPI-dependent aPLs, other than aCL, are present in patients with SLE, and we should examine more than 2 types of aPL, such as a combination of aCL and aPS, to avoid overlooking aPL. Furthermore, we confirmed that GPI-independent aPL was not rare in SLE patients, but the clinical significance of this type of aPL in this clinical setting is unclear.

Serodiagnosis of tuberculosis: assessment of kaolin agglutination test

Kaolin agglutination test (KAT), for the detection of anti-tuberculophospholipid antibodies for the serodiagnosis of tuberculosis, was performed on the sera of 137 pulmonary and 276 extra pulmonary tuberculosis patients and 140 controls. The sensitivity and specificity of KAT was 86.9% and 100%, respectively, at the titre of 1:128 and more.

[Cardiac anomalies in systemic lupus erythematosus: their prevalence and relation to duration, disease activity and the presence of antiphospholipid antibodies]

We conducted an echocardiographic study to determine the incidence and spectrum of morphologic and functional cardiac abnormalities in systemic lupus erythematosus (SLE) and to relate these findings to the disease activity and duration, and the presence of antiphospholipid (APL) antibodies. Thirty consecutive patients with LES (5 male and 25 female, mean age 37 +/- 11 years) were studied with a clinical cardiovascular examination and M-mode, 2-D Doppler echocardiogram. All patients fulfilled the American Rheumatism Association criteria for diagnosis of SLE. Disease activity was scored using the "Lupus Activity Criteria Count". The duration of the disease was less than 1 year in 5 patients (16.7%), between 1 and 5 years in 7 (23.3%), and superior to 5 years in 18 (60%). No patient had a history of rheumatic fever or infective endocarditis. All patients had received steroid therapy. In 26.7% of patients the disease was active, and in 33.3% APL antibodies were present. Patients were matched by number, age and sex with the control group. In 73.3% of the patients the echocardiogram resulted abnormal; valvular disease occurred in 30% and the echocardiographic features were of diffuse thickening, with 4 mitral and 2 aortic regurgitations. No valvular dysfunctions were significant, nor was Libman-Sacks endocarditis present. Pericardial disease, effusion or thickening was detected in 33.3% of the echocardiograms. Furthermore, there was one patient with left ventricular mild hypertrophy; 2 with a mild enlargement of the left ventricle with no segmental abnormalities of wall motion and no systolic disfunction; 8 patients (26.7%) were normal. Compared with the control group, patients with SLE had an increased prevalence of echocardiographic abnormalities, especially pericardial (p < 0.001) and valvular (p < 0.01). No association was found between activity, duration of the disease and prevalence of cardiac abnormalities. On the contrary, an association between the presence of APL antibodies and cardiac abnormalities at the echocardiographic examination was evident (p < 0.05).

Detection of antitrophoblast antibodies in the sera of patients with anticardiolipin antibodies and fetal loss

Women with anticardiolipin antibodies (ACLA) are at increased risk for fetal loss. One potential explanation for this outcome is that sera from these individuals contain antibodies reactive with trophoblast cells, which are involved in the establishment of the uteroplacental vasculature and maintenance of placental blood fluidity. To examine this hypothesis, we compared the incidence of trophoblast-reactive antibodies in 27 patients with ACLA and a history of fetal loss with that in 29 normal pregnant women. Sera from 20 patients, but only one control, contained trophoblast-reactive antibodies (P < .001). These antibodies were not directed against major histocompatibility class I antigens, and reacted with both term and first-trimester trophoblast cells. In most cases, sera from which ACLA were adsorbed by cardiolipin-containing liposomes maintained reactivity against cells. In addition, patient Ig fractions immunoprecipitated an approximately 62-kD protein from the trophoblast cell surface, stimulated the release of arachidonic acid and thromboxane A2 by trophoblasts, and inhibited the binding of prourokinase to trophoblast urokinase receptors. These observations show that sera from women with ACLA and a history of fetal loss contain antitrophoblast antibodies. These antibodies may be serologically distinct from ACLA, and may contribute to the pathogenesis of fetal demise.

[Pregnancy and systemic lupus erythematosus]

BACKGROUND

The interrelations between systemic lupus erythematosus (SLE) and pregnancy are reason for debate. Patients with SLE may present antiphospholipid antibodies (APL), anti-Ro (a-Ro) or anti-La (a-La) with their influence in pregnancy not being well defined.

METHODS

The pregnancies in a series of 96 fertile age women with SLE, followed during the period of 1975-1991 with a mean follow up of 6.2 years were studied. The spontaneous or provoked abortions, prematurity and the number of flares of the disease during pregnancy and during the year after birth were analyzed. The number of flares was compared with that presented by a control group of women with SLE of similar clinical features followed over the same time period.

RESULTS

Twenty-seven patients had 35 pregnancies with 23 full term pregnancies, 5 spontaneous abortions and 7 provoked abortions. Twenty-six percent of the deliveries were premature. One or two flares related with 43% of the pregnancies with viable fetus (11 flares in total) were registered. The number of flares in the control group was 6%. The difference was not statistically significant (p = 0.55) but the relative risk was of 1.6. No relation was found between the presence of APL, a-Ro and a-La and the course of the pregnancy. No case of lupus neonatorum was observed.

CONCLUSIONS

Pregnancy is not advised in patients with systemic lupus erythematosus in remission. Patients should be more frequently controlled during pregnancy and post partum. The presence of antiphospholipid antibodies or anti-Ro does not modifies the prognosis.

Detection of antiphospholipid antibodies by flow cytometry: rapid detection of antibody isotype and phospholipid specificity

Laboratory diagnosis of antiphospholipid antibodies is important in patients with clinical features of the antiphospholipid syndrome, such as thrombosis and fetal loss. We have developed a novel method for the detection of antiphospholipid antibodies using flow cytometry. Anionic phospholipids cardiolipin, phosphatidylserine and phosphatidylinositol are coated onto polystyrene beads of different sizes, allowing detection and semiquantitation of their respective phospholipid antibody isotypes. The results of the flow cytometric method closely correlate those of the standardised anticardiolipin enzyme-linked immunosorbent assay (ELISA), but the method is quicker and is versatile in its ability to detect IgG, IgM and IgA antibody isotypes at the same time. The method promises to be useful in evaluating the significance of phospholipid specificity and antibody isotypes in patients with the antiphospholipid syndrome.

Antibodies to beta 2-glycoprotein I inhibit phospholipid dependent coagulation reactions

Lupus anticoagulants are antibodies that inhibit phospholipid dependent coagulation reactions in vitro. These antibodies are of clinical interest because of their association with a variety of clinical manifestations characterized by microvascular thrombosis. Although these antibodies were originally thought to be directed at negatively charged phospholipid, recent studies have suggested that they may be directed at phospholipid-protein complexes. The effect of antibodies directed against beta 2-glycoprotein I (beta 2-GP I, apolipoprotein H) on phospholipid-dependent coagulation reactions has been studied. Polyclonal and monoclonal antibodies to beta 2-GP I were found to inhibit thrombin generation in a dose dependent manner. Inhibition of thrombin formation was due to specific interaction with beta 2-GP I. There was no evidence that inhibition was due to crossreactivity with other proteins involved in the prothrombinase complex. These findings document that antibodies directed against beta 2-GP I can have anticoagulant activity analogous to lupus anticoagulant activity and are consistent with the recent observation of such activity in lupus anticoagulant patient samples.

Antiphospholipid antibodies enhance thrombin-induced platelet activation and thromboxane formation

In a group of 6 patients with lupus anticoagulant (LA) and antiphospholipid (aPL) antibodies detected by ELISA overnight urine and blood were simultaneously collected. A significantly increased urinary excretion of the platelet-derived thromboxane (TX) metabolite 11-dehydro-TXB2 was found in this group, as compared to 12 healthy individuals. In contrast, a small but significant reduction of the vascular prostacyclin (PGI2) metabolite 2,3-dinor-6-keto-prostaglandin F1 alpha was observed. To further elucidate the effect of these antibodies on platelet activation we isolated the F(ab')2 fragments from IgG of the 6 patients and 5 controls, and we evaluated the effect of these fragments on the responses of isolated normal platelets to thrombin. Patients' F(ab')2 increased platelet aggregation and serotonin release of platelets stimulated by low dose thrombin (0.01 U/ml). At threshold thrombin concentration (0.05 U/ml) an enhanced TXB2 production was also observed. In summary, our results show, in addition to the altered TXA2/PGI2 balance observed in vivo, a direct stimulatory effect of aPL antibodies on platelet activation in vitro. This effect is related to recognition of phospholipid epitopes on platelets as shown by its neutralization upon preincubation with phospholipids. This phenomenon may be relevant for the thrombotic tendency of these patients.

Antiphospholipid antibodies: prevalence, clinical significance and correlation to cytokine levels in acute myeloid leukemia and non-Hodgkin's lymphoma

This study was designed to explore the prevalence and clinical significance of elevated antiphospholipid antibodies (APA) titres in patients affected by acute myeloid leukemia (AML) and high-grade non-Hodgkin's lymphoma (NHL). We also analyzed possible correlations with circulating levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and the soluble form of the receptor for interleukin-2 (sIL-2r). Nineteen patients with de novo AML and 14 patients with newly-diagnosed NHL were investigated. Tests for APA included the measurement of anticardiolipin antibodies (ACA) with a solid-phase immunoassay, and the detection of the lupus-like anticoagulant (LA) activity. Five patients with AML (26.3%) and 5 patients with NHL (35.7%) presented elevated APA at diagnosis, as compared to 3 of 174 persons of the control group (p < 0.0001). APA titres became normal in all patients responding to treatment, whereas non-responders retained elevated levels. In addition, 6 patients (4 with AML and 2 with NHL), who had normal APA at diagnosis and were either refractory to treatment or in relapse, subsequently developed LA and/or ACA positivity. At presentation, the mean levels of IgG- and IgM-ACA in patients were not significantly different from controls, and concordance between ACA and LA results reached just 30%. With regard to the clinical course, we were not able to detect any statistically significant difference between patients with normal and elevated APA. Pretreatment concentrations of IL-6 and TNF-alpha in AML, and sIL-2r in NHL were found significantly elevated compared to controls (p = 0.003, p = 0.009 and p = 0.024 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)