Clinical Application of Revised Laboratory Classification Criteria for Antiphospholipid Antibody Syndrome: Is the Follow-Up Interval of 12 Weeks Instead of 6 Weeks Significantly Useful?

Antiphospholipid Antibody Testing: An Audit on Testing Practices in a Public Tertiary Care Center

BACKGROUND

Antiphospholipid antibodies (aPLs) are antibodies directed against cell membrane components and can be associated with clinical features or be asymptomatic. Testing and interpreting these antibodies is associated with many challenges and pitfalls in clinical practice.

OBJECTIVE

To review all antiphospholipid antibody testing and describe the testing practices, indications for testing and interpretation of results to infer local challenges with aPL testing and subsequently address ways to overcome those challenges.

METHODS

This is a retrospective analysis of all aPL testing done in a tertiary center between 2014 and 2018. Characteristics of study patients collected through chart review were described using the mean and standard deviation for continuous variables and proportion for categorical variables. Group differences were compared between patients with any aPL-positive result and those with no positive result using chi-square or Fisher's exact test as appropriate for categorical variables and a simple regression model for numerical variables.

RESULTS

Among 414 patients undergoing aPL testing, mainly adult females, 62 (14.9%) patients had at least one positive antibody, of those, 26 (42%) had repeat testing done. Testing was mostly done for obstetric indication (107, 25.8%), with 36 patients having one or two early pregnancy losses <10 weeks as their testing indication. A total of 27 (6.5%) patients were labeled with APS/possible APS based on chart review, but on review of the testing of those patients according to classification criteria, only nine patients satisfied the criteria for APS.

CONCLUSION

This study highlights the clinical challenges associated with aPL testing, including the controversies around indication for testing, the low rates of repeat testing to confirm persistence, and the common misinterpretation of results. Having an aPL testing profile, explicit reference ranges, results commentary, and close interaction between ordering physicians and laboratory staff might be starting points to overcome these challenges.

Severe Abdominal Pain and Multi-Organ Involvement in a Young Woman With Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by diverse clinical manifestations and a broad spectrum of disease course and prognosis. Often presenting over an extended period, delays in diagnosis can significantly influence patient management and survival, particularly when faced with rare complications such as digestive system manifestations. This case report uniquely highlights the diagnostic and therapeutic challenges posed by severe abdominal pain in a young woman suspected of SLE, with a symptom often masked by steroid therapy or immunosuppression. The diagnostic journey, which led to the identification of SLE as the cause of abdominal pain, involved differentiating SLE from various abdominal pathologies including abdominal vasculitis, gastrointestinal syndrome, antiphospholipid antibody syndrome, pancreatitis, urinary tract infections, and obstetric-gynecological abnormalities. This case underlines the critical need for accurate, timely diagnosis, and targeted therapy in managing SLE, emphasizing the potential implications of such complexities on patient outcomes.

Risk factors for persistent positive anticardiolipin antibodies in women with recurrent pregnancy loss

Antiphospholipid syndrome (APS) is an established cause of recurrent pregnancy loss (RPL). It is necessary to detect persistently positive antiphospholipid antibodies to diagnose APS. This study aimed to explore risk factors for persistent anticardiolipin (aCL) positivity. Women with a history of RPL or with a history of one or more intrauterine fetal deaths after 10 weeks underwent examinations to determine the causes of RPL, including antiphospholipid antibodies. If aCL-IgG or aCL-IgM antibodies were positive, retests were performed at least 12 weeks apart. Risk factors for persistent aCL antibody positivity were retrospectively investigated. The number and percentage of cases above the 99th percentile were 74/2399 (3.1%) for aCL-IgG, and 81/2399 (3.5%) for aCL-IgM. Of the initially tested cases, 2.3% (56/2399) for aCL-IgG and 2.0% (46/2289) for aCL-IgM were ultimately positive above the 99th percentile in retests. Retest values after 12 weeks were significantly lower than the initial values for both IgG and IgM immunoglobulin classes. Initial aCL antibody titers were significantly higher in the persistent-positive group than in the transient-positive group for both IgG and IgM immunoglobulin classes. The cut-off values for predicting persistent positivity of aCL-IgG antibodies and aCL-IgM antibodies were 15 U/mL (99.1 percentile) and 11 U/mL (99.2 percentile), respectively. The only risk factor for persistently positive aCL antibodies is a high antibody titer during the initial test. When the aCL antibody titer in the initial test exceeds the cut-off value, therapeutic strategies can be defined in subsequent pregnancies without waiting for 12 weeks.

Loss of antiphospholipid antibody positivity post-thrombosis in SLE

Background/Purpose

Loss of positivity of antiphospholipid antibodies has been observed in clinical practice post-thrombosis in patients with SLE with secondary antiphospholipid syndrome (APS). Our study defined the frequency of this loss and the duration before positivity recurred.

Methods

In this prospective study, patients with SLE having at least two positive antiphospholipid markers prior to thrombosis and at least 1 year of follow-up after thrombosis were included. Antiphospholipid markers included lupus anticoagulant (dilute Russell viper venom test >45 s followed by mixing and confirmatory tests) and/or anticardiolipin titre (aCL IgG ≥20, aCL IgM ≥20 and/or aCL IgA ≥20). The percentage of visits with positive antiphospholipid markers after thrombosis was calculated. For patients with a negative antiphospholipid marker any time after thrombosis, survival estimates were performed to calculate the time to return of antiphospholipid positivity.

Results

In APS due to SLE, complete loss of antiphospholipid positivity post-thrombosis was up to 41% for aCL IgG, 51% for IgM and 50% for IgA, but only 20% for those with lupus anticoagulant. Of those who at some point lost aCL IgG or became negative for lupus anticoagulant, the majority (60% and 76%, respectively) reacquired the antibody within 5 years. In contrast, of those who lost aCL IgM or IgA, fewer reacquired it within 5 years (37% and 17%, respectively).

Conclusion

Intermittent positivity of antiphospholipid antibodies is present in APS due to SLE. These fluctuations make it difficult to decide on length of anticoagulation. Lupus anticoagulant is more likely to persist post-thrombosis.

Evaluation of different ways to identify persistent positivity of lupus anticoagulant in systemic lupus erythematosus

Objective

Persistent positivity for lupus anticoagulant has been associated with an increased risk of thrombosis among patients with SLE. Persistent positivity is often defined as having two positive assessments separated by more than 90 days. Our objective was to determine whether frequent repeated lupus anticoagulant testing would identify more patients with persistent positivity, and whether the additional patients identified were still at increased risk of thrombosis.

Methods

Using a large longitudinal cohort with frequent lupus anticoagulant testing, we compared three different hypothetical clinical strategies for identifying persistent positivity: (1) assessment of lupus anticoagulant twice more than 90 days apart; (2) assessment of lupus anticoagulant annually, with repeat testing if an annual assessment was positive; and (3) assessment of lupus anticoagulant 16 times (approximately quarterly for 4 years). The prevalence of persistent positivity was compared between the approaches and by demographic subgroups. Subgroups based on these definitions were compared with respect to the risk of thrombosis in subsequent follow-up using discrete survival analysis.

Results

Among the 785 patients included in our analysis, the prevalence of persistent lupus anticoagulant as defined by the first two patient assessments was 4.3%. Annual assessment resulted in a prevalence of 6.6%, and using all 16 assessments resulted in a prevalence of 10.5%. The prevalence was substantially higher in men than in women, and in Caucasians than in African-Americans (p<0.01 for all comparisons). The rate of thrombosis was significantly elevated among those with persistently positive lupus anticoagulant by any definition (HR ranging from 2.75 to 3.42) relative to those without persistently positive lupus anticoagulant.

Conclusion

While there are other risk factors for thrombosis (including other antiphospholipid subtypes), more frequent testing (not limited to twice over 3 months) for lupus anticoagulant would be useful for identifying more patients with SLE at elevated risk for thrombosis.

Anti-phospholipid antibodies in women presenting with preterm delivery because of preeclampsia or placental insufficiency

Objective:

To assess the proportion of women presenting with preterm delivery because of preeclampsia or placental insufficiency (PREPI) with anti-phospholipid antibodies (APLA).

Material and Methods:

This was a prospective cohort study conducted at an obstetrics and gynecology department. Women, aged 20-40 years, with preeclampsia who delivered before 34 weeks were cases while those who delivered before 34 weeks but did not have preeclampsia acted as controls. Both groups had APLA measured at diagnosis and 12-weeks postnatally. Anti-phospholipid antibody syndrome (APS) was diagnosed according to Sapporo’s criteria.

Results:

The study included 98 cases and 106 controls. Both cases and controls were similar in terms of age, gestational age and parity. The frequency of APS positivity was 17.3% in cases but only 3.8% in controls (p=0.001). Cases were more likely to be of Baloch ethnicity (34.7% vs. 11.3%, p=0.001), have a history of miscarriage (25.5% vs. 13.2%, p=0.026), use aspirin (p<0.001) or low molecular weight heparin (p<0.001), and be obese (p<0.001) than controls. Cases were more likely to have lupus anticoagulant antibodies (82.4% vs. 75%).

Conclusion:

Our study confirms a high prevalence of APLA in women who have preterm delivery due to PREPI. An opportunity to screen these women should be made, so that proper counselling can be given and future pregnancies can be managed in an appropriate and timely manner.

Antiphospholipid syndrome: the need for new international classification criteria

Introduction: As soon as the association of lupus anticoagulant (LAC) and anticardiolipin antibodies (aCL) with thrombosis and miscarriages was described in the 1980s, the definition of the antiphospholipid syndrome (APS) became a need. Early descriptions of the disease by members of the Graham Hughes team included broad categories and unexplained laboratory inclusions. Over time, new clinical and experimental data refined the criteria, especially the obstetric manifestations, as well as the laboratory criteria.Areas covered: The authors performed a review of the literature using the PubMed database, and the following keywords were used: 'antiphospholipid antibody', 'antiphospholipid syndrome', and 'criteria of antiphospholipid'. The history of antiphospholipid criteria, clinical and experimental advancements, and other expert opinions were included in this paper.Expert opinion: It has been 14 years since an international congress on antiphospholipid antibodies has generated new classification based on the recent extensive research performed in the field. Currently, there is a need to update the international APS classification taking into consideration the inclusion of new clinical criteria such as aPL-related nephropathy as well as new standardized antibody specificities (e.g., anti-phosphatidylserine/prothrombin antibodies) with the adoption of a standardized scoring system that can stratify APS patients.

Immunosuppressive Treatment in Antiphospholipid Syndrome: Is It Worth It?

The antiphospholipid syndrome (APS) is characterized by the development of venous and/or arterial thrombosis and pregnancy morbidity in patients with persistent antiphospholipid antibodies (aPL). Catastrophic antiphospholipid syndrome (CAPS) is a life-threatening form of APS occurring in about 1% of cases. Lifelong anticoagulation with vitamin K antagonists remains the cornerstone of the therapy for thrombotic APS, but frequently the use of anticoagulation may be problematic due to the increased risk of bleeding, drug interactions, or comorbidities. Immunosuppressant drugs are widely used to treat several autoimmune conditions, in which their safety and effectiveness have been largely demonstrated. Similar evidence in the treatment of primary APS is limited to case reports or case series, and studies on a large scale lack. Immunomodulatory drugs may be an emerging tool in managing such particular situations, like refractory obstetrical complications, CAPS, or so-called APS non-criteria manifestations. In addition, immunomodulatory drugs may be useful in patients experiencing recurrent thromboembolic events despite optimized anticoagulant therapy. We did a comprehensive review of literature analyzing the possible role of immunomodulation in primary APS to provide a broad overview of potentially safe and effective target treatments for managing this devastating disease.

The Laboratory Diagnosis of the Antiphospholipid Syndrome

The Antiphospholipid Syndrome (APS) is classified based on the presence of both clinical and laboratory criteria. Both sets of criteria are subject to much review and intense research as it is becoming increasingly clear that no single test is specific for defining this autoimmune disorder. A number of leading international bodies have released guidelines in an attempt to improve the laboratory testing and reporting. The current review is an appraisal of some of the literature pertaining to the laboratory testing.