Clinical performance of non-criteria antibodies to phospholipids in Chinese patients with antiphospholipid syndrome

Profile and clinical relevance of non-criteria antiphospholipid antibodies in patients diagnosed with or highly suspected of APS

OBJECTIVE

This study investigates the positivity and relevance of non-criteria aPLs with clinical phenotypes in patients highly suspected of or diagnosed with APS.

METHODS

Outpatient cases were included from a prospectively maintained database, and patients were grouped into APS (n = 168), seronegative APS (SNAPS, n = 9), those meeting the diagnostic criteria for clinical events without laboratory results (only-event, n = 15), those that had aPL positivity without clinical manifestations (asymptomatic APA, n = 39), and healthy controls (n = 88). Criteria aPL results and APS-related clinical features were extracted. Sixteen non-criteria aPLs were tested and analysed.

RESULTS

LA, aCL and anti-β2 glycoprotein-I were positive in 84.5%, 61.3% and 74.4% of APS patients, and 61.5%, 59.0% and 74.4% of asymptomatic APA patients, respectively. In patients negative for criteria serological tests, 23 out of 24 were positive for at least one non-criteria aPL. Triple-positive patients also had significantly higher tests of some aPLs in comparison with other groups. Stroke was associated with anti-phosphatidyl-inositol (aPI) IgG and anti-phosphatidyl-glycerol (aPG) IgG. Late embryonic loss correlated with aPI IgM, and premature birth/eclampsia was associated with aPI IgG and aPG IgG. There were also positive associations between heart valve lesions and anti-phosphatidylserine-prothrombin (aPS/PT) IgM, APS nephropathy and anti-phosphatidyl-choline IgG or aPS/PT IgG, and livedo reticularis and anti-phosphatidyl-ethanolamine IgM.

CONCLUSION

The prevalence of non-criteria aPLs differed from diagnostic biomarkers in patients diagnosed with or suspected of APS. Detection of aPLs provided additive value in the evaluation of APS-related clinical manifestations.

Levels and avidities of antiphosphatidylethanolamine antibodies in patients with thrombotic events and immunologically-mediated diseases

AIMS

Antiphosphatidylethanolamine antibodies (aPE) represent one type of antiphospholipid antibody (aPL) directed against the neutral phospholipids - phosphatidylethanolamines. The aim of this study was to evaluate levels and avidities of aPE in several groups of patients and compare them with conventional aPLs.

METHODS

aPE were analysed in a cohort consisting of 68 hospitalized patients. The other cohort comprised 22 patients with immunologically-mediated diseases. The control group consisted of 20 healthy persons. ELISA methods were used for determination of aPL. Avidities of aPE were tested by modified ELISA with urea as a chaotropic agent.

RESULTS

aPE IgG/IgM were significantly higher in the group of patients with venous thromboembolism than those with non-thrombotic internal disorders (P=0.02 for both Ig classes). aPE IgG/IgM elevated above cut-off values were found in 10.8% of patients with venous thromboembolism and as a single aPL in 6.5%. Levels of aPE IgG higher than our limit (>6 U/mL) were detected in 29% of patients with immunologically-mediated diseases with other positive aPL. Low-, intermediate- and high-avidity aPE IgG were found in patients of both cohorts. The avidities of aPE IgG differed from those of anticardiolipin antibodies IgG. Neither aPE IgG levels nor avidity dynamics significantly changed during follow-up.

CONCLUSION

aPE may be related to venous thromboembolism and may be part of the repertoire of aPL in immunologically-mediated diseases. There are patients with thrombosis negative for conventional aPL but positive for aPE. aPE IgG may have different avidities.

Criteria and Non-Criteria Antiphospholipid Antibodies in Antiphospholipid Syndrome: How Strong Are They Correlated?

The place of non-criteria antiphospholipid antibodies (aPLs) in the diagnosis of antiphospholipid syndrome (APS) is still debatable. The aim of this research was to evaluate the correlations between the titres of non-criteria aPLs (anti-phosphatidylethanolamine (aPE), anti-phosphatidylserine (aPS), and anti-prothrombin (aPT) antibodies), and the ones of the already studied criteria aPLs (anti-cardiolipin (aCL) and anti-β2 glycoprotein I-aβ2GPI antibodies). Altogether, 72 APS (30 primary and 42 secondary) patients were included in our study. High correlation coefficients (rs) were found between aPS IgM and aCL IgM, overall (0.77, p < 0.01), as well as in the primary (0.81, p < 0.01), and secondary (0.75, p < 0.01) APS subgroups. Low or statistically insignificant correlations were observed between IgG/IgM isotypes of aPT and aCL, or aβ2GPI, in the entire study population, and when evaluating the subgroups. Therefore, moderate correlations were mainly identified between the tested non-criteria antibodies and the criteria ones, suggesting little added value for the use of the tested non-criteria aPLs, with the exception of aPT, which seems to have different kinetics and might be a promising APS diagnostic tool.

Pregnancy complicated with adrenal adenoma causing ACTH-independent Cushing's syndrome, accompanied by obstetric antiphospholipid syndrome and severe pre-eclampsia: case report and literature review

This case report shares the management experience of a patient with pregnancy combined with adrenal adenoma causing ACTH-independent Cushing's syndrome (CS), accompanied by obstetric antiphospholipid syndrome (OAPS) and severe pre-eclampsia. The case was a 26-year-old that presented with typical clinical symptoms and signs of CS. The patient had a history of 4 spontaneous abortions in the last 4 years. The 24-hour urinary free cortisol was significantly increased, an abnormal cortisol circadian rhythm was demonstrated by a high late-night salivary cortisol, blood ACTH was suppressed (< 1ng/dL), anticardiolipin antibody was positive, and imaging examination showed an adrenal tumor. The patient underwent laparoscopic adrenal tumor resection under general anesthesia at 23 weeks of gestation. The tumor was pathologically confirmed to be an adrenocortical adenoma. The patient underwent a cesarean section at 39 weeks of gestation to give birth to a healthy baby girl with an Apgar score of 10. Pregnancy complicated by CS is clinically rare, easily masked by normal physiological changes of pregnancy, and is difficult to diagnose. The determination of 24-hour urinary free cortisol, the circadian rhythm of serum cortisol, ultrasound, and MRI can be helpful in the diagnosis of CS during pregnancy. Surgery is the first choice for the treatment of CS during pregnancy. As a subtype of antiphospholipid syndrome, patients with OAPS are prone to thrombotic events and recurrent miscarriages if not treated accordingly. To our knowledge no cases of CS with OAPS and severe pre-eclampsia have been reported. We summarize the experience of the treatment of this patient and review the literature to improve clinicians' awareness of this disease.

High-throughput sequencing technology facilitates the discovery of novel biomarkers for antiphospholipid syndrome

Antiphospholipid syndrome (APS) is characterized by arterial and venous thrombosis and/or morbid pregnancy, accompanied by persistent antiphospholipid antibody (aPL) positivity. However, due to the complex pathogenesis of APS and the large individual differences in the expression of aPL profiles of patients, the problem of APS diagnosis, prognosis judgment, and risk assessment may not be solved only from the antibody level. It is necessary to use new technologies and multiple dimensions to explore novel APS biomarkers. The application of next-generation sequencing (NGS) technology in diseases with a high incidence of somatic mutations, such as genetic diseases and tumors, has been very mature. Thus, we try to know the research and application progress of APS by NGS technology from genome, transcriptome, epigenome and other aspects. This review will describe the related research of NGS technology in APS and provide more reference for the deep understanding of APS-related screening markers and disease pathogenesis.

Extra-criteria antiphospholipid antibodies in patients with small vessel brain lesions and clinical manifestations associated with antiphospholipid syndrome

OBJECTIVES

Neurological manifestations compatible with small vessel brain lesions (SVBL), such as migraine, cognitive impairment, seizures, and transverse myelitis, may be related to antiphospholipid syndrome (APS) and patients could need APS therapies even though they do not fit into thrombosis or obstetric morbidity. Furthermore, extra-criteria antiphospholipid antibodies (aPL) provide an increase in sensitivity in patients with clinical manifestations related to APS but negative for IgG/IgM anticardiolipin (aCL), anti-β2 glycoprotein I (aβ2GPI), and lupus anticoagulant, which are the antibodies included in the classification criteria for APS.

METHODS

We determined extra-criteria aPL in 65 SVBL patients with neurological traits and Magnetic Resonance Imaging suggestive of APS but negative for APS classification criteria, 47 of whom were prospectively followed and tested over three years. A group of 95 patients with autoimmune diseases (AD) but without clinical traits of APS was also studied.

RESULTS

A persistent presence of extra-criteria aPL was detected in 27.7% of patients: 12.77% IgM anti- prothrombin (PT), 6.38% IgG anti-PT, 6.38% IgM anti-phosphatidylethanolamine (PE), 4.26% IgA aβ2GPI, 2.13% IgG anti-phosphatidylserine/prothrombin (PS/PT) and 2.13% IgM anti-PS/PT. There was a tendency towards a higher prevalence of these aPL in SVBL patients than in AD - especially for IgA aβ2GPI - and a lack of IgG aPS/PT positivity in the AD group. We found no SVBL patient positive for IgA aCL, IgG anti-PE, annexin V, or aβ2GPI domain I.

CONCLUSIONS

Extra-criteria aPL can improve sensitivity for APS diagnosis in patients with SVBL, especially IgA aβ2GPI and IgG anti-PS/PT antibodies.

Prevalence and diagnostic value of non-criteria antiphospholipid antibodies for antiphospholipid syndrome in Chinese patients

Background

The presence of antiphospholipid antibodies (aPLs) plays a pivotal role in the pathogenesis of antiphospholipid antibody syndrome (APS). This study aimed to examine the diagnostic value of a set of non-criteria aPLs and their relevance with APS-related criteria and extra-criteria manifestations.

Methods

From a prospectively constructed database, consecutive APS patients consisting of 114 primary APS (PAPS group), 54 with APS secondary to SLE (SAPS group), 9 seronegative APS (SNAPS), as well as 209 patients with systemic lupus erythematosus (SLE) and 88 healthy controls were included in this study. Levels of criteria aPLs, baseline information, and APS-related criteria and extra-criteria features were extracted from the database. Serum levels of non-criteria aPLs including aPC IgG/IgM, aPI IgG/IgM, aPE IgG/IgM/IgA, aPG IgG/IgM/IgA, anti-phosphatidic acid (aPA) IgG/IgM, aSM IgG/IgM, and aPS/PT IgG/IgM were analyzed with AESKULISA® ELISA Test Kits.

Results

The addition of aPC IgG/M, aPI IgG/M, aPE IgG/M/A, aSM IgG/M, and aPA IgG/M to aCL or aβ2GPI IgG/M could significantly increase diagnostic sensitivity and accuracy. A significant difference between PAPS or SAPS and HC was presented in all non-criteria aPLs except for aSM IgM and aPG IgA. Eight out of nine SNAPS patients were positive for at least 1 aPL. Pregnancy morbidity was associated with aSM IgM (r = 0.22) and aSM IgG (r = 0.15). Pre-eclampsia or premature birth was associated with aSM IgG (r = 0.16), aPI IgG (r = 0.22), aPC IgG (r = 0.16), and aPG IgG (r = 0.18). Stroke was associated with aPI IgG (r = 0.2). The clinical association was also observed in DVT with aPS/PT IgG (r = 0.17). Valve lesion was positively associated with aSM IgM (Fisher test p = 0.039), APS nephropathy was associated with aPC IgG (OR 3.797), and livedo reticularis was associated with aPE IgM (OR 15.391).

Conclusion

Additional detection of non-criteria aPLs including aPC IgG/M, aPE IgG/M/A, aPI IgG/M, aSM IgG/M, and aPA IgG/M could assist in APS diagnosis. The positivity of certain aPLs was statistically associated with both criteria and extra-criteria APS clinical manifestations.

Non-criteria antiphospholipid antibodies in antiphospholipid syndrome: Diagnostic value added

Objective

Non-criteria antiphospholipid antibodies (aPLs) increase the diagnostic value for antiphospholipid syndrome (APS) and contribute to better recognition of seronegative APS (SNAPS). However, the clinical utility and the diagnostic value of non-criteria aPLs are inconsistent. This study aimed to investigate the prevalence and clinical significance of 7 non-criteria aPLs in a large APS cohort.

Methods

Seven non-criteria aPLs, including anti-phosphatidylserine/prothrombin (aPS/PT) antibodies IgG/IgA/IgM, anti-phosphatidylethanolamine antibodies (aPE) IgG/IgA/IgM, anti-Annexin V antibodies (aAnnexinV) IgG/IgA/IgM, anti-phosphatidylserine antibodies (aPS) IgM, aPS IgG, antibodies directed against a mixture of phospholipids (APhL) IgG, and APhL IgM were tested among 175 patients with APS, 122 patients with other autoimmune diseases (as disease controls), and 50 healthy controls.

Results

In the present study, the highest prevalence of non-criteria aPLs was seen in aAnnexinV (58.86%). APhL IgG and aPS IgM showed the highest specificity (95.35%) and aPS/PT showed the highest Youden index (0.3991) for the diagnostic value of APS. The aAnnexinV also showed the highest prevalence in SNAPS (43.3%), followed by APhL IgM (21.7%), aPE (16.7%) and aPS/PT (16.7%). APhL IgG, aPS/PT, and aPS IgG showed positive association with thrombotic events in APS patients [APhL IgG: odds ratio (OR) = 2.26, 95% confidence interval (CI) 1.18-4.34, p = 0.013; aPS/PT: OR = 2.48, 95% CI: 1.32-4.69, p = 0.004; aPS IgG: OR = 1.90, 95% CI 1.01-3.60, p = 0.046; respectively). The inclusion of the non-criteria aPLs increased the accuracy of APS diagnosis from 65.7% to 87.4%.

Conclusion

Our data provide evidence that adding the non-criteria aPLs can improve the diagnostic accuracy in APS. APhL IgG, aPS/PT, and aPS IgG may be potential biomarkers to predict the risk of thrombosis in APS.

Seronegative autoimmune diseases: A challenging diagnosis

Autoimmune diseases (AID) are increasingly prevalent conditions which comprise more than 100 distinct clinical entities that are responsible for a great disease burden worldwide. The early recognition of these diseases is key for preventing their complications and for tailoring proper management. In most cases, autoantibodies, regardless of their potential pathogenetic role, can be detected in the serum of patients with AID, helping clinicians in making a definitive diagnosis and allowing screening strategies for early -and sometimes pre-clinical- diagnosis. Despite their undoubted crucial role, in a minority of cases, patients with AID may not show any autoantibody, a condition that is referred to as seronegative AID. Suboptimal accuracy of the available laboratory tests, antibody absorption, immunosuppressive therapy, immunodeficiencies, antigen exhaustion, and immunosenescence are the main possible determinants of seronegative AID. Indeed, in seronegative AID, the diagnosis is more challenging and must rely on clinical features and on other available tests, often including histopathological evaluation and radiological diagnostic tests. In this review, we critically dissect, in a narrative fashion, the possible causes of seronegativity, as well as the diagnostic and management implications, in several AID including autoimmune gastritis, celiac disease, autoimmune liver disease, rheumatoid arthritis, autoimmune encephalitis, myasthenia gravis, Sjögren's syndrome, antiphospholipid syndrome, and autoimmune thyroid diseases.

VWF, Platelets and the Antiphospholipid Syndrome

The antiphospholipid syndrome (APS) is characterized by thrombosis and/or pregnancy morbidity with the persistent presence of antiphospholipid antibodies (aPLs). Laboratory criteria for the classification of APS include the detection of lupus anticoagulant (LAC), anti-cardiolipin (aCL) antibodies and anti-β2glycoprotein I (aβ2GPI) antibodies. Clinical criteria for the classification of thrombotic APS include venous and arterial thrombosis, along with microvascular thrombosis. Several aPLs, including LAC, aβ2GPI and anti-phosphatidylserine/prothrombin antibodies (aPS/PT) have been associated with arterial thrombosis. The Von Willebrand Factor (VWF) plays an important role in arterial thrombosis by mediating platelet adhesion and aggregation. Studies have shown that aPLs antibodies present in APS patients are able to increase the risk of arterial thrombosis by upregulating the plasma levels of active VWF and by promoting platelet activation. Inflammatory reactions induced by APS may also provide a suitable condition for arterial thrombosis, mostly ischemic stroke and myocardial infarction. The presence of other cardiovascular risk factors can enhance the effect of aPLs and increase the risk for thrombosis even more. These factors should therefore be taken into account when investigating APS-related arterial thrombosis. Nevertheless, the exact mechanism by which aPLs can cause thrombosis remains to be elucidated.

Anti-phospholipid antibodies and reproductive failures

Anti-phospholipid syndrome (APS) recapitulates the link between autoimmunity and pregnancy failure: Acquired anti-phospholipid antibodies (aPL) play a pathogenic role in pregnancy complications. The diagnosis of obstetric APS can easily be pursued when women present with laboratory and clinical features fulfilling the international classification criteria. Standard therapeutic approach to obstetric APS consists in the association of anti-platelet agents and anticoagulants. Most patients achieve a live birth thanks to conventional treatment; however, approximately 20% fail to respond and are managed with additional therapeutic tools added on the top of conventional treatment. Surely, a refinement of risk stratification tools would allow early identification of high-risk pregnancies that warrant tailored treatment. In real life, obstetricians and rheumatologists face complex diagnostic scenarios including women with pregnancy morbidities other than those mentioned in classification criteria such as one or two early losses and premature birth after 34 weeks due to preeclampsia or placental insufficiency, women with low-titer aPL not fulfilling criteria laboratory requirements, women with positive non-criteria aPL, asymptomatic aPL carriers, and infertile women found to be aPL-positive. This review focuses on some of the several unanswered questions related to diagnostic, prognostic, and therapeutic aspects in obstetric APS.

Seronegative antiphospholipid syndrome: refining the value of "non-criteria" antibodies for diagnosis and clinical management

Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by arterial and venous thrombotic manifestations and/or pregnancy-related complications in patients with persistently high antiphospholipid antibodies (aPL), the most common being represented by anticardiolipin antibodies (aCL), anti-beta 2 glycoprotein-I (aβ2GPI), and lupus anticoagulant (LAC). A growing number of studies have showed that, in some cases, patients may present with clinical features of APS but with temporary positive or persistently negative titers of aPL. For these patients, the definition of seronegative APS (SN-APS) has been proposed. Nevertheless, the negativity to classic aPL criteria does not imply that other antibodies may be present or involved in the onset of thrombosis. The diagnosis of SN-APS is usually made by exclusion, but its recognition is important to adopt the most appropriate anti-thrombotic strategy to reduce the rate of recurrences. This research is in continuous development as the clinical relevance of these antibodies is far from being completely clarified. The most studied antibodies are those against phosphatidylethanolamine, phosphatidic acid, phosphatidylserine, phosphatidylinositol, vimentin/cardiolipin complex, and annexin A5. Moreover, the assays to measure the levels of these antibodies have not yet been standardized. In this review, we will summarize the evidence on the most studied non-criteria aPL, their potential clinical relevance, and the antithrombotic therapeutic strategies available in the setting of APS and SN-APS.