APS--controversies in diagnosis and management, critical overview of current guidelines

Profiles of criteria and non-criteria anti-phospholipid autoantibodies are associated with clinical phenotypes of the antiphospholipid syndrome

Background

Specific anti-phospholipids antibodies (aPLs) are used as classification criteria of the antiphospholipid syndrome (APS). These aPLs, although essential for diagnosis, do not predict disease phenotypes, which may require specific therapies. Non-criteria aPLs are rarely evaluated and their role is yet to be defined. In the current study, we aimed to examine the association between criteria and non-criteria aPLs and APS phenotypes.

Methods

Serum samples from 188 subjects, 130 APS patients and 58 controls were analyzed for the presence of 20 aPLs (IgG and IgM isotypes to cardiolipin (CL), beta2-glycoprotein1 (β2GP1), phosphatidic acid (P-acid), phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylinositol (PI), phosphatidylserine (PS), annexin-5 (AN) and prothrombin (PT) using a line immunoassay (GA Generic Assays, Germany). Sero-positivity to the different aPLs/aPLs profiles was correlated to APS phenotypes (i.e. arterial thrombosis, CNS manifestations, venous thrombosis, relapsing disease, obstetric morbidity).

Results

In this cohort, arterial thrombosis was associated with accumulative number of ≥ 7/20 aPLs evaluated (OR 4.1; CI 95% 1.9–96, p = 0.001) as well as the sole presence of aPT (IgG) (OR 2.3;CI 95% 1.1–5.1, p = 0.03). CNS manifestations were linked with a profile of 4 aPLs (IgG): aPT, aPG, aPI and aAN (OR 2.6;CI 95% 1.1–6.3, p = 0.03). Symptom-free period of ≥ 3 years was linked with lower number of aPLs and the presence of aPI (IgG) (OR 3.0;CI 95% 1.08–8.1, p < 0.05) or aAN (IgG) (OR 3.4;CI 95% 1.08–10.9, p < 0.05). APS related pregnancy morbidity correlated with a profile of 2 aPLs (IgG): aCL and aPS (OR 2.9; CI 95% 1.3–6.5, p < 0.05) or the sole presence of aAN (IgG) (OR 2.8; CI 95% 1.02–8, p = 0.05).

Conclusion

In this study, we observed an association between specific criteria/non-criteria aPLs or aPLs profiles and clinical phenotypes of APS. Our data suggest that examination of a wider variety of aPLs may allow better characterization of APS.

Tetra positive thrombotic antiphospholipid syndrome: Major contribution of anti-phosphatidyl-serine/prothrombin antibodies to lupus anticoagulant activity

BACKGROUND

The concurrent presence of lupus anticoagulant, anticardiolipin, and anti β2-glycoprotein I antibodies (triple positive profile) identifies patients at high risk of thromboembolic events. These patients are also positive for anti-phosphatidyl-serine/prothrombin antibodies (tetra-positive profile).

OBJECTIVE

Understand which antibody among anti-β2-glycoprotein I and anti-phosphatidyl-serine/prothrombin is responsible for lupus anticoagulant activity.

PATIENTS/METHODS

Affinity purified anti-β2-glycoprotein I antibodies from plasma of 14 tetra-positive patients spiked into normal pooled plasma were tested.

RESULTS AND CONCLUSIONS

Anti-β2-glycoprotein I antibodies did not prolong the diluted Russell viper venom time and silica clotting time (median ratio 0.98, interquartile ratio [IQR] 0.9-1.06; and 1.0, IQR 0.91-1.03, respectively). Anticoagulant activity remained in the flow-through that was deprived of anti-β2 glycoprotein I antibodies (median ratio 1.88, IQR 1.58-2.77; and 1.75, IQR 1.17-2.9, respectively). This material was loaded on size-exclusion chromatography Sephacryl S-300 column and showed that anticoagulant activity and anti-phosphatidyl-serine/prothrombin antibodies coeluted in the same fractions. Besides, the flow through was poured into a prothrombin affinity column. Protein yield in three patients ranged from 54 to 91 μg/mL and showed strong positivity in phosphatidyl-serine/prothrombin ELISA. The affinity purified material prolonged the coagulation time of normal pooled plasma: the diluted Russell viper venom ratio in the three patients was 2.09, 1.21, and 1.35; that of silica clotting time was 2.05, 1.5, and 2.13. In conclusion, under the assay conditions used, anticoagulant activity in tetra-positive antiphospholipid syndrome patients may largely be attributable to anti-phosphatidyl-serine/prothrombin antibodies.

Antiphospholipid antibodies detected by line immunoassay differentiate among patients with antiphospholipid syndrome, with infections and asymptomatic carriers

BACKGROUND

Antiphospholipid antibodies (aPL) can be detected in asymptomatic carriers and infectious patients. The aim was to investigate whether a novel line immunoassay (LIA) differentiates between antiphospholipid syndrome (APS) and asymptomatic aPL+ carriers or patients with infectious diseases (infectious diseases controls (IDC)).

METHODS

Sixty-one patients with APS (56 primary, 22/56 with obstetric events only, and 5 secondary), 146 controls including 24 aPL+ asymptomatic carriers and 73 IDC were tested on a novel hydrophobic solid phase coated with cardiolipin (CL), phosphatic acid, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylserine, beta2-glycoprotein I (β2GPI), prothrombin, and annexin V. Samples were also tested by anti-CL and anti-β2GPI ELISAs and for lupus anticoagulant activity. Human monoclonal antibodies (humoAbs) against human β2GPI or PL alone were tested on the same LIA substrates in the absence or presence of human serum, purified human β2GPI or after CL-micelle absorption.

RESULTS

Comparison of LIA with the aPL-classification assays revealed good agreement for IgG/IgM aß2GPI and aCL. Anti-CL and anti-ß2GPI IgG/IgM reactivity assessed by LIA was significantly higher in patients with APS versus healthy controls and IDCs, as detected by ELISA. IgG binding to CL and ß2GPI in the LIA was significantly lower in aPL+ carriers and Venereal Disease Research Laboratory test (VDRL) + samples than in patients with APS. HumoAb against domain 1 recognized β2GPI bound to the LIA-matrix and in anionic phospholipid (PL) complexes. Absorption with CL micelles abolished the reactivity of a PL-specific humoAb but did not affect the binding of anti-β2GPI humoAbs.

CONCLUSIONS

The LIA and ELISA have good agreement in detecting aPL in APS, but the LIA differentiates patients with APS from infectious patients and asymptomatic carriers, likely through the exposure of domain 1.

Presence of Antiphospholipid Antibodies as a Risk Factor for Thrombotic Events in Patients with Connective Tissue Diseases and Idiopathic Thrombocytopenic Purpura

OBJECTIVE

Antiphospholipid syndrome (APS) is a well-known complication of habitual abortion and/or thrombosis and is frequently associated with autoimmune diseases.

METHODS

We retrospectively investigated the relationships between the presence of antiphospholipid antibodies (aPLs) and the incidence of thrombotic events (THEs) in 147 patients with various connective tissue diseases (CTD) suspected of having APS and 86 patients with idiopathic thrombocytopenic purpura (ITP). THEs were observed in 41 patients, including 14 cases of venous thrombosis, 21 cases of arterial thrombosis and eight cases of complications of pregnancy.

RESULTS

The prevalence of THE was significantly high in the systemic lupus erythematosus (SLE) patients compared with the other CTD patients and ITP patients. The frequency of lupus anticoagulant (LA), anticardiolipin antibodies (aCL)-β2-glycoprotein (GPI) complex IgG and aPL was significantly high in the SLE patients compared with the ITP patients. Subsequently, the rate of development of THE was significantly high in the patients with aPLs. In particular, the incidence of THE was significantly high in the SLE or ITP patients with LA, aCL-β2GPI IgG or aPL. The optimal cut-off values for LA, aCL IgG and aCL-β2GPI complex IgG for the risk of THEs were higher in the SLE patients in comparison to the values obtained when using the kit provided by the manufacturer.

CONCLUSION

Although aPLs is frequently associated with SLE and is a causative factor for thrombosis, the optimal cut-off value for aPL for predicting the occurrence of THEs varies among different underlying diseases.

Both IgG and IgM anti-beta2 glycoprotein I antibodies assays are clinically useful to the antiphospholipid syndrome diagnosis

OBJECTIVES

The aim of our study was to evaluate the clinical values of anti-beta2 glycoprotein I antibodies (anti-beta2GPI) IgG and IgM comparing with lupus anticoagulant (LA), anticardiolipin antibodies (aCL) in the two clinical groups of antiphospholipid syndrome (APS), vascular thrombosis (VT) and pregnancy morbidity (PM).

METHODS

Eighty patients who fulfilled the APS clinical criteria, VT n = 34; PM n = 40, both VT and PM n = 6 were included. LA, aCL and three anti-beta2GPI ELISA kits were tested.

RESULTS

Sensitivities of LA, aCL and anti-beta2GPI assays were found respectively 62, 26 and 41% in VT, and 28, 28 and 30% in PM. The sensitivity for the APS diagnosis could reach to 63% using triple tests. The presence of LA (P<0·01, OR = 4·3) or anti-beta2GPI IgG alone (P<0·05, OR = 8·4) was significantly associated with VT. IgM isotype was found more frequent in PM (92%) than in VT (57%) among all positive anti-beta2GPI cases.

CONCLUSION

Both IgG and IgM anti-beta2GPI assays were useful when clinical features of APS presented, even its standardization is ongoing. A decreased by half sensitivity of LA in PM compared with that in VT underlines the importance of adding anti-beta2GPI in PM of APS, especially IgM isotype although recent review questioned its significance.

Leg ulcers in antiphospholipid syndrome secondary to systemic lupus erythematosus treated with intravenous immunoglobulin

BACKGROUND

Despite encouraging reports on the efficacy of intravenous immunoglobulin (IVIg) in antiphospholipid syndrome, the clinical value of this treatment is not well established, and most of the data are based on case reports and small series of patients.

OBSERVATION

We describe the significant improvement of leg ulcers with IVIg in a 61-year-old female, with diabetes mellitus, venous peripherical insufficiency and secondary antiphospholipid syndrome to systemic lupus erythematosus.

CONCLUSIONS

This case illustrates a rare cause of leg ulcers and documents that IVIg may be an effective adjuvant treatment in the management of selected patients with antiphospholipid syndrome when conventional strategies using subcutaneous heparin and low-dose aspirin are insufficient.

Renal transplantation dramatically reduces IgA anti-beta-2-glycoprotein I antibodies in patients with endstage renal disease

IgA anti-beta-2-glycoprotein I (aB2GPI) antibodies have been related to vascular pathology in the general population and mainly in hemodialyzed patients (prevalence 33%) in whom an elevated incidence of thrombosis and mortality is found. In this paper we have studied the presence of IgA aB2GPI antibodies at pretransplant and their evolution after transplantation with a cross-sectional-based follow-up study of a cohort of 288 endstage renal disease (ESRD) patients treated with kidney transplantation. Pretransplant IgA aB2GPI levels were elevated 31.7 ± 4.2 U/mL without differences in age or type of dialysis. Patients with different etiologies of ESRD showed higher levels of IgA aB2GPI than blood donors, except the groups of non-IgA glomerular disease and systemic erythematosus lupus, whose nonsignificant differences were observed. IgA aB2GPI antibodies dropped immediately after transplantation (10.7 ± 1.0 U/mL, P < 0.0001), coinciding with a high degree of immunosuppression, and remained significantly lower than that observed in pretransplant status. Prevalence of patients with elevated antibodies was also less in transplanted patients (8.9% versus 30.4%, P < 0.0001). Among, positivity for IgA aB2GPI was higher than in patients who had received their first transplant that those were retransplanted. This finding could have important clinical implications and can suggest new therapeutic strategies in patients with IgA aB2GPI antibodies.

The current standing of diagnosis of antiphospholipid syndrome associated with systemic lupus erythematosus

The antiphospholipid syndrome was first described in the early 1980s. The term was first coined to describe patients presenting with recurrent arterial and venous thrombosis or pregnancy complications. Antiphospholipid syndrome was first reported in systemic lupus erythematosus patients, but later on it became obvious that systemic lupus erythematosus is not a necessary condition for its occurrence. It has been shown that antibodies to phospholipids are the main causative agents of the disease, hence its name. The diagnosis of the disease has witnessed a remarkable evolution over the course of the past 25 years. With the observation that clinical parameters would not be enough to accurately diagnose the disease, antiphospholipid antibodies were recognized to play a central role in this regard. The main hindrance to an accurate diagnosis was the lack of standardization between different laboratory parameters that tested for the antiphospholipid antibodies. Lately, a combination of tests has been acknowledged to play a crucial role in diagnosis.

Antiphospholipid syndrome: a clinical and laboratorial challenge

Antiphospholipid syndrome (APS) is an acquired autoimmune thrombophilia characterized by the presence of a heterogeneous family of antibodies that bind to plasma proteins with affinity for phospholipid surfaces. The two major protein targets of antiphospholipid antibodies are prothrombin and β2-glycoprotein I (β2GPI). APS leads to aprothrombotic state, and it is characterized by the occurrence of arterial, venous or microvascular thrombosis or recurrent fetal loss. The diagnosis of APS is based on a set of clinical criteria and the detection of lupus anticoagulant (LA), anticardiolipin antibodies (ACA) or anti-β2GPI in plasma. Although laboratory tests are essential for APS diagnosis, these tests have limitations associated with the robustness, reproducibility and standardization. The standardization of diagnostic tests for detection of APLAs has been a challenge and a variety of results have been obtained using different commercial kits and in-house techniques. An increased sensitivity of the ELISA kits for detection of ACA effectively has contributed to APS diagnosis. However, the lack of specificity associated with a high number of false-positive results is a clinical and laboratorial challenge, since such results may lead to mistaken clinical decisions, such as prescription of oral anticoagulant, leading to the risk of hemorrhaging. Furthermore, clinicians are often unfamiliar with these tests and have difficulty interpreting them, requiring interaction between clinical and laboratory professionals in order to ensure their correct interpretation.

Presence of antiphospholipid antibody is a risk factor in thrombotic events in patients with antiphospholipid syndrome or relevant diseases

Antiphospholipid antibodies (aPL) including lupus anticoagulant (LA), anticardiolipin antibodies (aCL) IgG and aCL-β2-glycoprotein I (β2GPI) complex IG are causative factors for thrombotic event (THE). We retrospectively investigated relationships between aPLs and THE in 458 patients suspected of having antiphospholipid syndrome. THEs were observed in 232 of 458 patients, including 148 cases of venous thrombosis, 59 of arterial thrombosis, 18 of microthrombosis, and 20 of complications of pregnancy. The frequency of THE was significantly high in patients positive for LA and/or aPL. In patients with autoimmune disease (AID), the frequency of THE was significantly high in patients with any types of aPLs. Additionally, risk of THE was significantly increased in patients with more than two types of aPLs. Prolonged activated partial thromboplastin time indicated a high risk for THE. However, neither thrombocytopenia nor AID was a risk for THE. In conclusion, the presence of aPL is an indicator for high risk of THE in patients in whom THE was suspected. However, the risk of THE in aPL-positive patients varied among patients with different underlying diseases.

Clinical accuracy for diagnosis of antiphospholipid syndrome in systemic lupus erythematosus: evaluation of 23 possible combinations of antiphospholipid antibody specificities

OBJECTIVES

To evaluate the clinical accuracy of antiphospholipid antibody (aPL) specificities both individually and/or in combination, in a wide cohort of systemic lupus erythematosus (SLE) patients in an attempt to identify a panel of tests that may provide the best accuracy for diagnosing antiphospholipid syndrome (APS).

PATIENTS AND METHODS

This study included 230 patients (218 women, mean age 42.7 ± 11.9 years, mean disease duration 12.2 ± 8.7 years), all fulfilling the 1982 criteria for SLE. All patients were tested for lupus anticoagulant (LA), anti-cardiolipin (aCL), anti-β(2) glycoprotein I (anti-β2GPI), solid phase anti-prothrombin (aPT), anti-phosphatidylserine/prothrombin (aPS/PT), and anti-phosphatidylethanolamine (aPE) antibodies. Sensitivity, specificity and predictive values were calculated. The diagnostic accuracy for each combination of tests was assessed by ROC and their area under the curve analysis as well as by the Youden's index (YI).

RESULTS

Testing for six aPL derived 23 possible combinations of results. Among them, LA + anti-β(2)GPI + aPS/PT had the best diagnostic accuracy for APS as a whole and individually for both thrombosis and pregnancy loss (AUC 0.712, OR 3.73 [95% CI 1.82-5.38], P = 0.0001, YI = 0.32 and AUC 0.709, OR 3.75 [95% CI 2.13-6.62], P = 0.0001, YI = 0.37 and AUC 0.677, OR 4.82 [95% CI 2.17-10.72], P = 0.0007, YI = 0.38, respectively) and the best specificity when compared with all the other obtainable combination of tests. Triple positivity for LA + anti-β(2)GPI + aPS/PT was more strongly associated with clinical events (thrombosis and/or PL) when compared with double or single positivity (OR 23.2 [95% CI 2.57-46.2] vs. OR 7.3 [95% CI 2.21-25.97], OR 5.7 [95% CI 2.12-17.01] or OR 3.11 [95% CI 1.56-7.8] for single positivity for LA, aPS/PT and anti-β(2)GPI, respectively).

CONCLUSIONS

Combining LA, anti-β(2)GPI and aPS/PT improves the diagnostic power and helps in stratifying the risk for each patient, according to their aPL profile.

8-isoprostane, prostaglandin E2, C-reactive protein and serum amyloid A as markers of inflammation and oxidative stress in antiphospholipid syndrome: a pilot study

OBJECTIVE

To test the inflammation and oxidative stress hypothesis in antiphospholipid syndrome (APS) patients and to identify possible associations with clinical and laboratory features of the disease.

METHODS

Serum amyloid A (SAA), C-reactive protein (CRP), 8-isoprostane and prostaglandin E2 (PGE) were assayed in the sera of 45 APS patients and then compared to control groups made up of 15 antiphospholipid antibody (aPL) negative patients with systemic lupus erythematosus, 15 aPL negative subjects with pregnancy-related morbidity, 15 aPL negative patients with thrombosis, 15 subjects with persistently positive aPL with no signs or symptoms of APS, and 15 healthy volunteers from among the hospital staff.

RESULTS

APS patients showed significantly higher CRP (p = 0.01), SAA (p < 0.01), 8-isoprostane (p = 0.05) and PGE2 (p = 0.001) plasma levels as compared to controls. Among APS subjects, significantly higher 8-isoprostane and PGE2 levels were observed in patients with triple positivity for aPL (lupus anticoagulant, anticardiolipin and anti-beta2-glycoprotein I antibodies) compared to APS patients with single or double aPL positivity.

CONCLUSION

Both inflammation and oxidative stress, as measured by SAA, CRP, 8-isoprostane and PGE2, occur in APS and seem to be related to triple positivity for aPL.

[Advances in the prevention, diagnosis and therapy of vascular diseases]

Atherosclerosis is a systemic disease affecting the coronary, carotid, intracerebral, renal and peripherial arteries. The early morphological and functional impairments could be detected in the second or third decades of life and their progression depend on the number and severity of risk factors and individual susceptility. Although the vascular risk factors (smoking, overweight, age, unhealthy diet, lack of physical exercise, hypertension, diabetes mellitus, chronic kidney disease and dyslipidemia) are the same and common in the different vascular diseases, the present clinical routine artificially classifies the diagnosis and therapy of different vascular diseases into different subfields of medicine with the negative impact of possible polypragmasia. Recently, worldwide health surveys (e.g. REACH registry) have proven the usefulness of a holistic approach in the diagnosis and therapy of multiorgan-affected vascular patients. This review summarizes the multidisciplinary advances and future perspective of vascular diseases.

Prevalence of annexin A5 resistance in children and adolescents with rheumatic diseases

OBJECTIVE

The underlying mechanism(s) by which antiphospholipid antibodies (aPL) result in thrombosis remains poorly understood. A significant body of evidence has evolved to support the hypothesis that antibody-mediated disruption of an annexin A5 anticoagulant shield may play a role in the pathogenesis; this proposed mechanism has not been previously studied in children.

METHODS

We investigated the association between aPL and resistance to annexin A5 anticoagulant activity in 90 children with a variety of rheumatic diseases using a novel mechanistic assay, the annexin A5 resistance assay (A5R).

RESULTS

Patients with a diagnosis of primary aPL syndrome, systemic lupus erythematosus, and mixed connective tissue disease demonstrated lower mean A5R levels (p = 0.030), higher prevalence of positive aPL (p < 0.001), and more thrombotic events (p = 0.014) compared to those with other diagnoses. Patients with persistently positive aPL had significantly lower mean A5R compared to patients with no aPL (mean A5R = 203% ± 44% vs 247% ± 35%; p < 0.001), whereas patients with transient aPL did not. Patients with thrombosis had lower A5R levels compared to those without thrombosis (mean A5R = 207% ± 36% vs 237% ± 46%; p = 0.048).

CONCLUSION

Children and adolescents with rheumatic diseases and persistent aPL have reduced annexin A5 anticoagulant activity, whereas transient, nonpathogenic aPL have less effect on annexin A5 activity.