Lessons from the “Euro-Phospholipid” project

Perioperative management of a patient with systemic lupus erythematosus-associated antiphospholipid syndrome undergoing mandibular third molar surgery

Antiphospholipid syndrome (APS) is a systemic autoimmune condition characterised by recurrent venous or arterial thrombosis and pregnancy complications, with persistent antiphospholipid autoantibodies. APS is often found in conjunction with other autoimmune diseases, such as systemic lupus erythematosus (SLE). SLE-associated APS patients may require dental procedures like tooth extractions. Due to the complex nature of this autoimmune disorder, perioperative management requires a comprehensive approach involving various medical specialists.These patients are frequently taking medications like anticoagulants, antiplatelet drugs, disease-modifying drugs and immunosuppressants. This medication regimen can increase their risk of postoperative complications, including bleeding, thrombosis, delayed healing and postoperative infections. Currently, there are no established guidelines for performing tooth extractions in individuals with SLE-associated APS.We report a case of SLE-associated APS with pericoronitis requiring surgical extraction. The purpose of this report is to offer practical recommendations for the perioperative management of dental procedures and alteration in medications used in such cases.

Immunogenicity, safety, and antiphospholipid antibodies after SARS-CoV-2 vaccine in patients with primary antiphospholipid syndrome

Objective

Coronavirus disease 19 (COVID-19) has an increased risk of coagulopathy with high frequency of antiphospholipid antibodies (aPL). Recent reports of thrombosis associated with adenovirus-based vaccines raised concern that SARS-CoV-2 immunization in primary antiphospholipid syndrome (PAPS) patients may trigger clotting complications. Our objectives were to assess immunogenicity, safety, and aPL production in PAPS patients, after vaccinating with Sinovac-CoronaVac, an inactivated virus vaccine against COVID-19.

Methods

This prospective controlled phase-4 study of PAPS patients and a control group (CG) consisted of a two-dose Sinovac-CoronaVac (D0/D28) and blood collection before vaccination (D0), at D28 and 6 weeks after second dose (D69) for immunogenicity/aPL levels. Outcomes were seroconversion (SC) rates of anti-SARS-CoV-2 S1/S2 IgG and/or neutralizing antibodies (NAb) at D28/D69 in naïve participants. Safety and aPL production were also assessed.

Results

We included 44 PAPS patients (31 naïve) and 132 CG (108 naïve) with comparable age (p=0.982) and sex (p>0.999). At D69, both groups had high and comparable SC (83.9% vs. 93.5%, p=0.092), as well as NAb positivity (77.4% vs. 78.7%, p=0.440), and NAb-activity (64.3% vs. 60.9%, p=0.689). Thrombotic events up to 6 months or other moderate/severe side effects were not observed. PAPS patients remained with stable aPL levels throughout the study at D0 vs. D28 vs. D69: anticardiolipin (aCL) IgG (p=0.058) and IgM (p=0.091); anti-beta-2 glycoprotein I (aβ2GPI) IgG (p=0.513) and IgM (p=0.468).

Conclusion

We provided novel evidence that Sinovac-CoronaVac has high immunogenicity and safety profile in PAPS. Furthermore, Sinovac-CoronaVac did not trigger thrombosis nor induced changes in aPL production.

Avoiding misclassification of thrombotic primary antiphospholipid syndrome as systemic lupus erythematosus (SLE): What are the best-performing SLE classification criteria?

BACKGROUND

Systemic lupus erythematosus (SLE) and Primary Antiphospholipid Syndrome (PAPS) overlap clinical and immunological features. Therefore, misclassification of PAPS patients as SLE is a concern. The ACR/EULAR 2019 SLE classification has never been studied in PAPS.

OBJECTIVE

To verify if the ACR/EULAR 2019 SLE classification can correctly classify a PAPS patient as not having SLE and compare its performance with the SLICC 2012 SLE classification. Methods: One-hundred thrombotic PAPS patients who fulfilled the Sidney criteria were consecutively screened and those who attended the inclusion criteria were submitted to ACR/EULAR 2019 and SLICC 2012 classifications.

RESULTS

Sixty-seven PAPS patients were included in this study. The majority was female (89.6%) with median age at study inclusion of 45 years (35-53) and median PAPS disease duration of 13 years (8-19). PAPS correct classification was observed more often with ACR/EULAR 2019 than SLICC 2021 criteria (94.0% vs. 64.2%; p < 0.001). The 4 misclassified patients in ACR/EULAR 2019 were also misclassified in SLICC 2012. The comparison of misclassified patients to those correctly not classified as SLE resulted, for both criteria, in higher frequencies of hematological domain [ACR/EULAR 2019 (100% vs. 28.6%, p = 0.010) and SLICC 2012 (95.8% vs. 11.6%, p < 0.001)]. Further analysis of hematological manifestations revealed that for the ACR/EULAR 2019 leukopenia (100% vs. 22.2%, p = 0.004) and for the SLICC 2012 leukopenia/lymphopenia (91.7% vs. 7%, p < 0.001) were more frequent in misclassified group. Proteinuria (20.8% vs. 0%, p = 0.004) and low complement (45.8% vs. 20.9%, p = 0.033) were also more often observed in the incorrectly SLICC 2012 classified patients.

CONCLUSION

ACR/EULAR 2019 had high accuracy for distinguishing PAPS from SLE, whereas the SLICC 2012 incorrectly classified more than one third of the PAPS patients as having SLE.

Cardiovascular Considerations in Anesthetic Management for a Patient With Antiphospholipid Syndrome and Decreased Cardiac Function: A Case Study

This case report describes the prolonged general anesthetic management of a 41-year-old woman with antiphospholipid syndrome (APS), systemic lupus erythematosus, and previously undiagnosed decreased cardiac function who underwent planned partial resection of the left tongue, tracheostomy, neck dissection, and pedicled flap reconstruction. This was immediately followed by emergent surgery to salvage the flap, and 1 month later, revision of the soft tissue flap was performed. A preoperative echocardiogram was performed because of her various risk factors, which identified lateral wall hypokinesis and reduced left ventricular ejection fraction of 40%, despite no known cardiovascular disease. However, cardiology consult determined no additional treatment was needed before the surgery. Multiple antithrombotic strategies were used, including elastic stockings, intermittent pneumatic compression devises, and heparin bridging. During the general anesthetic, stroke volume variation (SVV) was used to assess cardiac function and guide fluid management. There were no signs of systemic thrombosis, although the free flap reconstruction was abandoned because of a thrombus in the vascular anastomosis. Cardiac function can deteriorate in APS patients because of coronary and/or microvascular thrombosis. Therefore, it is necessary to evaluate cardiac function, regardless of a known history of cardiovascular disease. Moreover, additional monitoring (ie, SVV) may be useful during prolonged general anesthetics for patients with APS and cardiac dysfunction.

The antiphospholipid syndrome in patients with systemic lupus erythematosus

The antiphospholipid syndrome (APS) is an autoimmune disease characterized by the occurrence of venous and/or arterial thrombosis and pregnancy morbidity in the presence of pathogenic autoantibodies known as antiphospholipid antibodies (aPL). APS may be associated with other diseases, mainly systemic lupus erythematosus (SLE). The presence or absence of SLE might modify the clinical or serological expression of APS. Apart from the classical manifestations, APS patients with associated SLE more frequently display a clinical profile with arthralgias, arthritis, autoimmune hemolytic anemia, livedo reticularis, epilepsy, glomerular thrombosis, and myocardial infarction. The management of patients with SLE and APS/aPL should include an accurate stratification of vascular risk factors. Low dose aspirin and hydroxychloroquine should be considered as primary prophylaxis. In high risk situations, such as surgery, prolonged immobilization, and puerperium, the prophylaxis should be potentiated with low molecular weight heparin. The challenge of treating patients with a previous vascular event (secondary prophylaxis) is the choice of treatment (anti-platelet agents, anticoagulation with vitamin K antagonists or combined therapy) and its duration, based on individual risk stratification and the site of vascular presentation. The role of novel anticoagulants in APS patients is still to be clearly defined. Novel approaches are needed since the prognosis of SLE patients with APS/aPL is still worse than that of SLE patients with negative aPL. The goal for the future is to improve the outcome of these patients by means of early recognition and optimal preventative treatment.

Antiphospholipid Antibodies: From General Concepts to Its Relation with Malignancies

Antiphospholipid syndrome (APS) is an adquired autoimmune pro-thrombotic disease characterized by arterial and/or venous thrombosis and/or fetal losses associated with the persistent presence of antiphospholipid antibodies (aPL) detectable by solid phase assays (anticardiolipin (aCL) and anti-β2 glycoprotein I, β2GPI) and/or functional coagulation test (lupus anticoagulant (LA)). Most patients with typical APS manifestations have the presence of one or more of conventional aPL, but, some patients might exhibit clinical features related with APS but with persistent negative determinations of "classic" aPL (seronegative APS). Expanding the network of autoantibodies in patients highly suspected of having APS but who have normal results from a conventional test using new antibodies (i.e., phosphatidylserine/prothrombin and β2GPI domain 1) would increase the diagnosis. Thrombosis is one of the leading causes of death among patients with cancer, representing up to 15% of all deaths. Cancer increases the risk of thrombosis and chemotherapy is further associated with a higher risk of thrombosis. In addition, aPL may contribute to an increased risk of thrombosis in patients with malignancies, although the levels do not seem to reflect their pathogenicity. Several malignancies, particularly hematological and lymphoproliferative malignancies, may indeed be associated with the generation of aPL but do not necessarily enhance the thrombophilic risk in these patients.

Primary prophylaxis to prevent obstetric complications in asymptomatic women with antiphospholipid antibodies: a systematic review

OBJECTIVE

Obstetric complications are common in patients with antiphospholipid syndrome. However, the impact of antiphosholipid antibodies (aPL) in the pregnancy outcomes of asymptomatic aPL carriers is uncertain. The aim of this systematic review is to assess whether primary prophylaxis is beneficial to prevent obstetric complications during pregnancy in asymptomatic women positive for aPL who have no history of recurrent pregnancy loss or intrauterine fetal death.

METHODS

Studies evaluating the effect of prophylactic treatment versus no treatment in asymptomatic pregnant aPL carriers were identified in an electronic database search. Design, population and outcome homogeneity of studies was assessed and meta-analysis was performed. The pooled Mantel-Haenszel relative risk of specific pregnancy outcomes was obtained using random effects models. Heterogeneity was measured with the I(2) statistic. All analyses were conducted using Review Manager 5.3.

RESULTS

Data from five studies involving 154 pregnancies were included and three studies were meta-analysed. The risk ratio and 95% confidence interval (CI) of live birth rates, preterm birth, low birth weight and overall pregnancy complications in treated and untreated pregnancies were 1.14 (0.18-7.31); 1.71 (0.32-8.98); 0.98 (0.07-13.54) and 2.15 (0.63-7.33),respectively. Results from the meta-analysis revealed that prophylactic treatment with aspirin is not superior to placebo to prevent pregnancy complications in asymptomatic aPL carriers.

CONCLUSION

This systematic review did not find evidence of the superiority of prophylactic treatment with aspirin compared to placebo or usual care to prevent unfavourable obstetric outcomes in otherwise healthy women with aPL during the first pregnancy.

A polymorphism in TLR2 is associated with arterial thrombosis in a multiethnic population of patients with systemic lupus erythematosus

OBJECTIVE

Thrombosis is a serious complication of systemic lupus erythematosus (SLE). Studies that have investigated the genetics of thrombosis in SLE are limited. We undertook this study to assess the association of previously implicated candidate genes, particularly Toll-like receptor (TLR) genes, with pathogenesis of thrombosis.

METHODS

We genotyped 3,587 SLE patients from 3 multiethnic populations for 77 single-nucleotide polymorphisms (SNPs) in 10 genes, primarily in TLRs 2, 4, 7, and 9, and we also genotyped 64 ancestry-informative markers (AIMs). We first analyzed association with arterial and venous thrombosis in the combined population via logistic regression, adjusting for top principal components of the AIMs and other covariates. We also subjected an associated SNP, rs893629, to meta-analysis (after stratification by ethnicity and study population) to confirm the association and to test for study population or ethnicity effects.

RESULTS

In the combined analysis, the SNP rs893629 in the KIAA0922/TLR2 region was significantly associated with arterial thrombosis (logistic P = 6.4 × 10(-5) , false discovery rate P = 0.0044). Two additional SNPs in TLR2 were also suggestive: rs1816702 (logistic P = 0.002) and rs4235232 (logistic P = 0.009). In the meta-analysis by study population, the odds ratio (OR) for arterial thrombosis with rs893629 was 2.44 (95% confidence interval 1.58-3.76), without evidence for heterogeneity (P = 0.78). By ethnicity, the effect was most significant among African Americans (OR 2.42, P = 3.5 × 10(-4) ) and European Americans (OR 3.47, P = 0.024).

CONCLUSION

TLR2 gene variation is associated with thrombosis in SLE, particularly among African Americans and European Americans. There was no evidence of association among Hispanics, and results in Asian Americans were limited due to insufficient sample size. These results may help elucidate the pathogenesis of this important clinical manifestation.

Antiphospholipid-related chorea

Chorea is a movement disorder which may be associated with immunologic diseases, in particular in the presence of antiphospholipid antibodies (aPL). Choreic movements have been linked to the isolated presence of plasmatic aPL, or to primary, or secondary antiphospholipid syndrome. The highest incidence of aPL-related chorea is detected in children and females. The presentation of chorea is usually subacute and the course monophasic. Choreic movements can be focal, unilateral, or generalized. High plasmatic titers of aPL in a choreic patient can suggest the diagnosis of aPL-related chorea; neuroimaging investigation does not provide much additional diagnostic information. The most relevant target of aPL is β2-glycoprotein I, probably responsible for the thrombotic manifestations of antiphospholipid syndrome. Etiology of the movement disorder is not well understood but a neurotoxic effect of aPL has been hypothesized, leading to impaired basal ganglia cell function and development of neuroinflammation. Patients affected by aPL-related chorea have an increased risk of thrombosis and should receive antiplatelet or anticoagulant treatment.

Systemic lupus erythematosus one disease or many?

Systemic lupus erythematosus (SLE) characterizes by a variety of clinical manifestations and the presence of a wide profile of autoantibodies. This clinical and serological heterogeneity raised the question: is SLE a single disease with varied phenotypes, or a similar phenotype shared by different diseases with diverse pathogenic mechanisms? Herein we debate the clinical, genetic, hormonal and serological differences typically observed in SLE on the one hand, and the numerous similarities between subtypes of this disease on the other. Leading to the conclusion that SLE may be considered not as a single disease but rather as a single syndrome, which defines by a set of signs, symptoms, or phenomena that occur together and suggest a particular abnormality. Additionally, the accumulated knowledge on gene expression pathways, autoantibodies clusters, hormonal and environmental factors associated with SLE may allow a better classification of this syndrome and updating of SLE criteria. This may further allow targeted biologics and other therapies as well as "personalized medicine" to begin.

Catastrophic antiphospholipid syndrome: updated diagnostic algorithms

The catastrophic antiphospholipid syndrome (APS) is the most severe form of APS with acute multiple organ involvement and small vessel thrombosis. During the 13th International Congress on Antiphospholipid Antibodies (aPL) a "Catastrophic APS Task Force" was developed to discuss the challenges in the diagnosis and management of catastrophic APS. The purpose of this paper is to summarize the diagnostic challenges (false-positive/negative aPL results and overlap with other thrombotic microangiopathies) and propose updated diagnostic algorithms for catastrophic APS. Important steps of the diagnostic algorithms include: a) history of APS or persistent aPL-positivity; b) three or more organ new thrombosis developing in less than a week; c) biopsy diagnosis of microthrombosis; and d) other explanations for multiple organ thromboses and/or microthrombosis.

Pregnancy in autoimmune rheumatic diseases: the importance of counselling for old and new challenges

Rheumatic diseases can affect women during their childbearing age. Therefore, physicians should introduce a discussion with the patients about pregnancy and its problems. Lupus pregnancies can be successful, even in patients with renal disease, when planned in remission state; the use of low dose aspirin was shown to be an independent predictor of good outcome, so it can be suggested as a preventive measure. Pregnancies in women with Antiphospholipid Syndrome can fail even if properly treated, especially when associated with a systemic autoimmune disease, a history of both thrombosis and pregnancy morbidity, and a triple positivity of antiphospholipid antibody assays. Women with systemic sclerosis have generally a good obstetric outcome, except for an increase rate of preterm deliveries. Severe disease complications were sometimes reported, but their relationship with gestation is not clear yet. Although data on human pregnancy are still preliminary, anti-TNF agents are classified as non teratogens in contrast to methotrexate and leflunomide. So women affected by aggressive chronic arthritis may be treated with anti-TNF in the pre-conceptional period, discontinuing the drug as soon as pregnancy starts. In order to increase maternal compliance and cope with difficult cases, a multidisciplinary team (rheumatologists/internists, obstetricians and neonatologists) should take care of patients during pregnancy.

Management of the antiphospholipid syndrome

Antiphospholipid syndrome (APS) is characterized by recurrent venous or arterial thromboses, fetal losses and thrombocytopenia in the presence of antiphospholipid antibodies, namely lupus anticoagulant, anticardiolipin antibodies or antibodies directed to various proteins, mainly β2 glycoprotein I, or all three. There is consensus in treating patients with APS and first venous thrombosis with oral anticoagulation to a target international normalized ratio (INR) of 2.0-3.0. A recent systematic review recommended a target INR of >3.0 in those patients with APS and arterial thrombosis. The approach in women with obstetric manifestations of APS is based on the use of aspirin plus heparin. The best treatment for patients with the catastrophic variant of the APS is a combination of anticoagulation, corticosteroids, and plasma exchange or intravenous immunoglobulins.

Hormonal therapy in a patient with ovarian agenesis and possible SLE: a choice to be made

Systemic lupus erythromatosus (SLE) is an autoimmune disease, which affects mainly women in the reproductive age and is influenced by hormonal changes. Therefore, hormone supplementation for patients with SLE either as contraceptives or as postmenopausal supplementation remains a controversial issue. Herein, we report a case of a 22-year-old woman with a history of ovarian agenesis, treated for several years with hormone therapy in order to reduce the risk of osteoporosis and other estrogen-deficient disorders. At the current evaluation, she met 3 of 11 diagnostic criteria for SLE along with a strong familial autoimmune predisposition. Precipitation of SLE in patients treated with hormonal therapy has been previously described. This prompted us to seek alternative drug therapies that prevent both the onset of overt SLE as well as the progression of estrogen-deficient phenomena. This unique case illustrates the dilemma of using hormone therapy in patients at risk to develop SLE and the current therapeutic alternatives.

Geo-epidemiology and autoimmunity

Autoimmune disease (AD) affects approximately 3% of the population. This is an enormous number, but ironically the study of autoimmunity has not taken on the significance of many other diseases because so many of the ADs are relatively uncommon. Indeed, despite enormous advances in the diagnosis and the treatment of AD, there is still a paucity of data on the etiological events that lead to the clinical pathology. For most other human diseases, the etiology is addressed and often solved by the use of epidemiology. Epidemiology consists of the study of prevalence of a disease, coupled with analysis of genetic factors and detection of environmental agents. In the context of autoimmune conditions, preclinical epidemiology has recently been favored, as a consequence of the discovery that autoantibody precedes overt disease. The idea of a North-South gradient in the prevalence of ADs, with a reciprocal gradient in that of infectious injuries has proven to be debatable. More importantly, environmentally-induced changes have been shown to modify certain diseases giving rise to the key concept of epigenetics. However, it is clear that major voids exist. Some of these voids were hoped to be solved by the use of genome-wide associations. This, however, has proven very problematic, as the genetic basis of AD is considerably more complicated than once believed. We now base our hopes on next generational sequencing as a brut force undertaking to partially decipher the genetic code that predisposes individuals to AD. This volume is a compilation of papers in Autoimmunity Reviews and the Journal of Autoimmunity and presented as part of the 7th International Congress on Autoimmunity in Ljubljana, Slovenia. It is clearly impossible to present data on the geoepidemiology of all of the AD. Instead, we attempted to generate interest amongst immunologists to generate papers that are thought provoking but also contemporary reviews.

The geoepidemiology of the antiphospholipid antibody syndrome

Antiphospholipid antibodies (aPL) can be detected by functional (lupus anticoagulant) and/or by solid phase assays (anti-cardiolipin and anti-beta2 glycoprotein I). Although detectable in 1-5% of asymptomatic apparently healthy subjects, persistent aPL are significantly associated with recurrent arterial/venous thrombosis and with pregnancy morbidity. Such an association is the formal classification tool for the antiphospholipid syndrome (APS). The prevalence of the syndrome with no associated systemic connective tissue diseases (primary APS) in the general population is still a matter of debate since there are no sound epidemiological studies in the literature so far. aPL display higher prevalence in systemic lupus erythematosus and rheumatoid arthritis than in other systemic autoimmune diseases. However not all the aPL positive lupus patients display the clinical manifestations. Comparable findings may be found in the paediatric population, although anti-beta2 glycoprotein I antibodies are detected in healthy children more frequently than in adults. High prevalence of aPL has been also reported in clinical manifestations that are not formal APS classification criteria: heart valve disease, livedo reticular, nephropathy, neurological manifestations, and thrombocytopenia. Antiphospholipid antibodies can be associated with infectious processes, active vaccination, drug administration and malignancies. Their prevalence and titres are lower and the relationship with the APS clinical manifestations are less strong than in the previously mentioned conditions. Ethnicity was also reported to influence the prevalence of aPL.

Catastrophic antiphospholipid syndrome: treatment, prognosis, and the risk of relapse

The "catastrophic" variant of the antiphospholipid syndrome (APS) is characterized by multiple vascular occlusive events, usually affecting small vessels and developing over a short period of time. Although patients with catastrophic APS represent less than 1% of all patients with APS, they are usually in a life-threatening situation with a 50% mortality rate. The purpose of this paper is to review the treatment strategies and prognostic factors in patients with catastrophic APS. A detailed description of the clinical and laboratory features of the syndrome can be found in the other articles of this issue.

Pro-inflammatory genotype as a risk factor for aPL-associated thrombosis: Report of a family with multiple anti-phospholipid positive members

OBJECTIVE

Inflammation might represent a second hit for anti-phospholipid antibody (aPL)-mediated thrombosis. Inflammatory responses have been linked to gene polymorphisms of several cytokines and Toll Like Receptors (TLRs). We examined IL1 beta, TNFalpha, TGFbeta, IL6, IFN gamma, IL10, tlr4 gene polymorphisms in a family with several members positive for IgG anti-beta2 glycoprotein I (beta 2GPI) antibodies but with recurrent thrombosis in one member only.

METHODS

Lupus anticoagulant, anti-cardiolipin, anti-beta 2GPI IgG/IgM antibodies, IL1beta, TNFalpha, TGF beta1, IL6, IL10, IFN gamma, tlr4 gene polymorphisms (by allele-specific polymerase chain reaction) in addition to standard thrombophilic risk factors and cytokine serum levels (IL-1 beta, TNFalpha, IL-10) were evaluated.

RESULTS

Recurrent thrombotic events was reported only in the proband, but not in three healthy siblings persistently positive for IgG anti-beta2GPI antibodies, respectively. The wild type tlr4 gene and cytokine polymorphisms associated with a high pro-inflammatory response (IL-1 beta promoter-511C/T; TNFalpha G/A; TGFbeta+10T/C, +25C/G; IL-6 -174C/G) were found only in the proband. Serum cytokine levels were normal.

CONCLUSION

This case report confirms that protective tlr4 gene polymorphisms are more frequent in asymptomatic aPL carriers. In line with the role of inflammatory mediators as second hits for aPL-associated thrombosis, the polymorphisms of cytokines linked to higher inflammatory response were found in the proband only.

Antiphospholipid syndrome

Antiphospholipid syndrome is diagnosed when arterial or venous thrombosis or recurrent miscarriages occur in a person in whom laboratory tests for antiphospholipid antibodies (anticardiolipin antibodies and/or lupus anticoagulant and/or anti-beta 2-glycoprotein I) are positive. Despite the strong association between antiphospho-lipid antibodies and thrombosis, their pathogenic role in the development of thrombosis has not been fully elucidated. Novel mechanisms involving both the complement pathway and micro-particles have been described. The knowledge of these new pathogenic approaches might identify novel therapeutic targets and therefore may improve the management of these patients.

The physiopathology of the catastrophic antiphospholipid (Asherson's) syndrome: compelling evidence

Catastrophic antiphospholipid (Asherson's) syndrome (cAPS) was described in the past as a severe variant of the antiphospholipid syndrome (APS). Currently growing evidence suggests it is a unique condition. This statement is based on several clinical and physiopathological features that although not well understood define cAPS by itself. The remarkable features of cAPS are the presence of antiphospholipid antibodies (aPLAs) and microthromboses. Additional physiopathological features are the presence of anemia and thrombocytopenia, which are also often described in similar autoimmune conditions. A strong association with concomitant infection is thought to act as the main trigger of microthromboses in cAPS. Several theories have been proposed to explain these physiopathological features. Some of them suggest the possibility of molecular mimicry between components of infectious microorganisms and natural anticoagulants, which might be involved in the production of cross-reacting aPLAs in cAPS. Some genetic risk factors have also been suggested to be implicated in the onset of cAPS, however they have not been defined yet. Herein, we review the remarkable physiopathological features commonly described in cAPS hitherto. We concluded that although they are not completely understood, it is possible to differentiate them from similar conditions. Nevertheless further studies on these physiopathological mechanisms of the disease are needed.

Predictive, protective, orphan autoantibodies: the example of anti-phospholipid antibodies

Anti-phospholipid antibodies (aPL) are one of the most recent examples of autoantibodies that can appear even long time before any clinical manifestation can be associated with them. There is a general agreement that they may represent a strong risk factor for recurrent thrombosis and/or fetal losses. Anti-phospholipid antibodies represent a necessary but not sufficient factor (first hit) for thrombosis, and require additional triggering factors (second hit) to disclose the thrombogenic activity. Several factors may affect the predictive value of aPL, including titre, immunoglobulin isotype, fine antigenic specificity and affinity binding activity. Their careful evaluation is suggested in order to characterize the true predictive value of aPL.