What is known about pediatric antiphospholipid syndrome?

The Antiphospholipid Syndrome in the Pediatric Population

Pediatric antiphospholipid syndrome (APS) is characterized by autoantibodies directed against protein complexes on cellular membranes and leads to a prothrombotic, proinflammatory state. A child with APS may present with venous, arterial, or small vessel thrombosis. Other manifestations of APS include nonthrombotic manifestations, such as hematologic and neurologic symptoms. APS may be a primary condition or related to other autoimmune diseases. If APS-related thrombosis is unrecognized, the child may suffer recurrent thrombotic events after the withdrawal of anticoagulation. Thus, it is important to consider APS as a cause of thrombosis in children. Appropriate testing confirms the diagnosis and directs further care.

Pediatric antiphospholipid syndrome: clinical features and therapeutic interventions in a single center retrospective case series

BACKGROUND/PURPOSE

Pediatric antiphospholipid syndrome (APS) is a thromboinflammatory disease characterized by the presence of circulating antiphospholipid antibodies and either thrombotic events or pregnancy morbidity. The objective of this study was to review a large institution's experience to better understand the characteristics of children with APS.

METHODS

We conducted a retrospective review of pediatric APS at a tertiary referral center. The electronic medical record system was queried from 2000 through 2019, and 21 cases were included based on meeting the revised Sapporo Classification criteria by age 18 or younger. Comparisons between primary and secondary APS patients were made with two-tailed t-tests.

RESULTS

Twenty-one patients were included with a median age at diagnosis of 16 years and median follow-up of 5.8 years. Secondary APS was slightly more common than primary APS (11 vs. 10 cases) and was primarily diagnosed in the context of systemic lupus erythematosus. Two thirds of patients (67%) also had "non-criteria" manifestations of APS including thrombocytopenia, autoimmune hemolytic anemia, and livedo reticularis/racemosa. Almost half of patients (43%) had recurrent thrombosis, typically when patients were subtherapeutic or non-adherent with anticoagulation. Damage Index in Patients with Thrombotic APS (DIAPS) scores indicated a chronic burden of disease in both primary and secondary APS patients.

CONCLUSION

This case series of pediatric APS provides important context regarding disease phenotypes displayed by children with APS. High prevalence of non-criteria clinical manifestations highlights the need to consider these characteristics when developing pediatric-specific classification criteria and when considering this relatively rare diagnosis in pediatric practice.

Primary antiphospholipid syndrome in pediatrics: beyond thrombosis. Report of 32 cases and review of the evidence

OBJECTIVE

Describe the frequency of thrombotic and non-thrombotic clinical manifestations, laboratory, treatment and prognosis in patients with pediatric primary antiphospholipid syndrome.

MATERIAL AND METHODS

A retrospective study was carried out in patients with a diagnosis of primary antiphospholipid antibody syndrome, under 16 years of age, under follow-up by the pediatric rheumatology service of the General Hospital, National Medical Center, La Raza, from January 2013 to December 2020. The antiphospholipid syndrome was defined when it met the laboratory criteria of the Sidney criteria and the presence of thrombosis or non-criteria manifestations of the disease (hematological, neurological, cutaneous, renal, cardiac or pulmonary). Demographic, clinical, laboratory, treatment, and prognosis data were collected.

RESULTS

We report 32 patients, 21 female (65%) and 11 male (35%), mean age 11.75 years, evolution time 16 weeks. Thrombosis 9 patients (28%), 1 arterial and 8 venous. Non-thrombotic manifestations; Hematologic: thrombocytopenia 22 patients (69%), autoimmune hemolytic anemia 13 (40%), Fisher-Evans syndrome 6 (19%), lupus anticoagulant with hypoprothrombinemia syndrome 2 (6%). Dermatological: livedo reticularis 20 (62%), skin ulcers 2 (6%), Raynaud's phenomenon 8 (25%). Neurological: epilepsy 1 (3%), migraine 3 (9%), chorea 1 (3%) and cognitive impairment 3 (9%). Renal in 4 (13%). Laboratory: prolonged aPTT 30 (93%), lupus anticoagulant 32 (100%), positive IgG anticardiolipin 20 (62%), positive IgM anticardiolipin 19 (60%). AntiB2GPI was performed in only 3 patients, being positive in all.

TREATMENT

anticoagulation in patients with thrombosis, antiplatelet in 23 (72%), steroid 30 (94%), immunosuppressant 30 (94%) and rituximab 4 (12.5%). No deaths were reported.

CONCLUSIONS

The clinical characteristics of patients with pediatric primary antiphospholipid syndrome differ from those presented in adults, since non-thrombotic manifestations are more frequent in children, for which classification criteria that include these manifestations are necessary for a better characterization of the disease in pediatric population.

Managing Antiphospholipid Syndrome in Children and Adolescents: Current and Future Prospects

Pediatric antiphospholipid syndrome (APS) is a rare acquired multisystem autoimmune thromboinflammatory condition characterized by thrombotic and non-thrombotic clinical manifestations. APS in children and adolescents typically presents with large-vessel thrombosis, thrombotic microangiopathy, and, rarely, obstetric morbidity. Non-thrombotic clinical manifestations are frequently seen in pediatric APS and may be present even before the vascular thrombotic events occur. We review insights into the pathogenesis of APS and discuss potential targets for therapy. The identification of multiple immunologic abnormalities in patients with APS reveals molecular targets for current or future treatment. Management strategies, especially for APS in adolescents, require screening for additional prothrombotic risk factors and consideration of counseling regarding contraceptive strategies, lifestyle recommendations, treatment adherence, and mental health issues associated with this autoimmune thrombophilia. The main goal of therapy in pediatric APS is the prevention of thrombosis. The management of acute thrombosis events in children and adolescents is the same as for primary APS, which involves isolated occurrences, and secondary APS, which is seen in association with another autoimmune disease, e.g., systemic lupus erythematosus. A pediatric hematologist should be consulted so other differential thrombophilic conditions can be eliminated. Therapy includes unfractionated heparin or low-molecular-weight heparin followed by vitamin K antagonists. Treatment of catastrophic APS involves triple therapy (anticoagulation, intravenous corticosteroid pulse therapy, and plasma exchange) and may include intravenous immunoglobulin for children and adolescents with this condition. New drugs such as eculizumab and sirolimus seem to be promising drugs for APS.

Identifying additional risk factors for arterial and venous thrombosis among pediatric antiphospholipid antibodies carriers

BACKGROUND

Antiphospholipid antibodies (aPL) have been extensively reported in children, but investigations into thrombotic risks associated with aPL positivity in pediatric patients is scarce. Positive aPL are not uncommon in pediatric connective tissue diseases (CTD), but identification and management of these patients is challenging due to lack of validated criteria and a paucity of data. In this study, we identify potential additional risk factors for thrombosis in a unique cohort of pediatric aPL positive carriers.

METHODS

Retrospective chart review was performed on 491 pediatric patients with CTD seen in our institution from 2001 to 2019. Patients without persistently moderate to high titer aPL at least 12 weeks apart were excluded. Univariate analysis was performed to evaluate correlation between different risk factors and thrombotic events.

RESULTS

Seventy-one aPL positive children with underlying CTD are included in this cohort. The majority (87%) are female and of Hispanic ethnicity (56%). Mean age of the cohort at the diagnosis of connective tissue disease is 12.7 (SD 2.6) years, and mean age of first positive aPL is 13.3 (SD 2.5) years. Average length of follow-up is 4.3 (SD 2.5) years. Four (5.6%) patients experienced arterial thrombosis, and 11 (15.5%) had venous thrombosis. Fifty-seven (80.3%) patients did not have any thromboembolic events. Among traditional risk factors and signs of endothelial injury, only Raynaud's phenomena demonstrated significant association with arterial thrombosis (OR = 8.4, 95%CI 1.13-111, P = 0.039), and hypertension or anti-hypertensive use demonstrated significant association with venous thrombosis (OR = 8.387, 95%CI 1.2 - 94, P = 0.02).

CONCLUSION

Data from our cohort suggest that Raynaud's phenomenon is a potential predictor of arterial thrombosis while the presence of hypertension or anti-hypertensive medication use is a potential predictor of venous thrombosis in aPL positive pediatric carriers. Further studies investigating pediatric aPL profiles and risk factors for development of thrombosis are needed to help guide clinicians in caring for these challenging patients.

Pediatric Antiphospholipid Syndrome: from Pathogenesis to Clinical Management

PURPOSE OF REVIEW

Elucidating the pathogenic mechanisms mediated by antiphospholipid antibodies (aPL) might exert important clinical implications in pediatric antiphospholipid syndrome (APS).

RECENT FINDINGS

aPL are traditionally regarded as the main pathogenic players in APS, inducing thrombosis via the interaction with fluid-phase and cellular components of coagulation. Recent APS research has focused on the role of β2 glycoprotein I, which bridges innate immunity and coagulation. In pediatric populations, aPL should be screened in appropriate clinical settings, such as thrombosis, multiple-organ dysfunction, or concomitant systemic autoimmune diseases. Children positive for aPL tests often present non-thrombotic non-criteria manifestations or asymptomatic aPL positivity. In utero aPL exposure has been suggested to result in developmental disabilities, warranting long-term follow-up. The knowledge of the multifaceted nature of pediatric APS should be implemented to reduce the risk of underdiagnosing/undertreating this condition. Hopefully, recent pathogenic insights will open new windows of opportunity in the management of pediatric APS.

Antiphospholipid syndrome and its role in pediatric cerebrovascular diseases: A literature review

Antiphospholipid syndrome (APS) or Hughes syndrome is an acquired thromboinflammatory disorder. Clinical criteria of APS diagnosis are large- and small-vessel thrombosis as well as obstetric problems; laboratory criteria are the presence of antiphospholipid antibodies (lupus anticoagulant, anticardiolipin antibodies and anti-β2-glycoprotein-1). The presence of at least 1 clinical and 1 laboratory criterion allows definitive diagnosis of APS. Primary APS is diagnosed in patients without features of connective tissue disease; secondary APS is diagnosed in patients with clinical signs of autoimmune disease. A high frequency of catastrophic APS as well as a high tendency to evolve from primary APS to secondary syndrome during the course of lupus and lupus-like disease is a feature of pediatric APS. The most characteristic clinical presentation of APS in the pediatric population is venous thrombosis, mainly in the lower limbs, and arterial thrombosis causing ischemic brain stroke. Currently, no diagnostic criteria for pediatric APS exist, which probably results in an underestimation of the problem. Similarly, no therapeutic procedures for APS specific for children have yet been established. In the present literature review, we discussed data concerning APS in children and its role in cerebrovascular diseases, including pediatric arterial ischemic stroke, migraine and cerebral venous thrombosis.

Pediatric antiphospholipid syndrome

Despite its potential to cause significant morbidity in children, pediatric antiphospholipid syndrome (APS) is an understudied condition. In this review, we will cover what is known about pediatric APS epidemiology and how the clinician might approach the diagnosis of pediatric APS. We will highlight similarities and differences with the adult disease, both for primary APS and in the context of lupus. Clinical manifestations beyond thrombosis, especially neurologic and hematologic in nature, will be discussed. We will also consider what unique implications antiphospholipid antibody-positivity may have for children with lupus and for neonates born to mothers with APS. The approach to treatment will be covered, including the unique impact of APS medications on children as compared with adults. Finally, the importance of future mechanistic research is emphasized as physicians endeavor to provide the personalized care that children with APS clearly deserve.

The Differences Between Childhood and Adult Onset Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is a rare autoimmune disease of unknown etiology that represents a leading cause of acquired thromboembolism and recurrent miscarriage. It is characterized by the persistent elevated presence of pathogenic antiphospholipid auto-antibodies directed against cardiolipin, ß2-glycoprotein-I, and/or a positive lupus anticoagulant test. As with many autoimmune disorders, the pathogenesis of APS is believed to be the result of a complex interaction between environmental triggers and genetic predisposition. Although more common in adults, APS occasionally manifests in the neonatal period and throughout childhood. Adut-onset APS classification criteria are poorly validated to the pediatric population (in which pregnancy related complications are seldom seen) and as a result, assessment of the prevalence of the disease in childhood is difficult. Thromboembolic events seen in children include deep venous thrombosis in addition to stroke and pulmonary embolism, which can lead to significant long-term disability. The disease can be classified as either primary (when occurring in isolation) or secondary, in which the disease is diagnosed in the context of another underlying disease, most commonly systemic lupus erythematosus. A variety of laboratory and clinical difference are seen between pediatric and adult-onset APS. The marked female predominance seen in adult-onset disease is less evident in childhood where the gender split is more evenly spread. In addition, children with APS are at a higher risk of recurrent thromboembolism than adults. The treatment of childhood-onset APS is challenging due to a lack of large-scale prospective studies in the pediatric population. Therapeutic options are often based upon treatment guidelines that have been based upon literature from the adult-onset form of the disease. In the majority of cases, treatment is focused on the prevention of further thrombosis through treatment with long-term anti-coagulation therapy. The evidence for the use of antiplatelet agents (such as aspirin) and hydroxychloroquine is inconclusive. It is important to remember that anti-coagulation can have significant lifestyle implications for the child with APS and it is essential to consider potential implications relating to school and recreational activities, with contact sports often discouraged due to the increased risk of bleeding.

Clinical characteristics and thrombosis outcomes of paediatric antiphospholipid syndrome: analysis of 58 patients

The study aims to analyse the clinical and immunological manifestations of paediatric antiphospholipid syndrome (APS) in patients, based on the 2006 revised classification criteria of definite APS. Fifty-eight paediatric patients with APS were enrolled and analysed retrospectively. A total of 37 female and 21 male patients with a mean age of 14 ± 3 years at disease onset were included. Fourteen (24%) cases were primary APS, and 40 (69%) cases were secondary to systemic lupus erythaematosus (SLE). Anti-nuclear antibody (ANA) positivity and hypocomplementemia were more common in secondary APS than in primary APS. The most common manifestations of thrombosis were deep vein thrombosis of the lower extremities (25 cases, 37%). Non-thrombotic manifestations were mainly immunologic thrombocytopenia, autoimmune haemolytic anaemia, skin lesions, arthritis, pulmonary hypertension, heart valve vegetations and spontaneous abortion. LA, ACL and anti-β2GPI were positive in 42 (95%), 28 (64%) and 34 (77%) cases, respectively. Over half (23 cases, 52%) of the patients were triple-positive for antiphospholipid (aPL) antibodies. Among patients with single-positive LA and anti-β2GPI, the proportion with venous thrombosis was 100% (5 cases) and 0% (0 cases), respectively. The arterial thrombosis proportions were 22% (5 cases), 21% (3 cases) and 14% (1 case) in the triple-, double- and single-aPL-positive groups, respectively (P > 0.05). Fifty-three (91%) cases were followed up for 3 to 140 months, with a median time of 32 months. Seven (13%) cases had recurrences or appearances of thrombosis during follow-up, all of which were double- or triple-aPL positive. APS in the paediatric patients is mostly secondary to SLE. ANA positivity and hypocomplementemia are more common in secondary APS, but there are no differences in the other clinical manifestations between the primary and secondary APS groups. Deep vein thrombosis is the most common thrombotic event. Positive LA may increase the risk of venous thrombosis. Multiple-aPL positivity does not increase the proportion of thrombosis. Long-term anticoagulant or antiplatelet therapy is needed to prevent thrombosis recurrence in double- or triple-positive aPL cases.