From the Guidelines
A positive anti-cardiolipin antibody IgM is a significant finding that may indicate the presence of antiphospholipid syndrome (APS) when accompanied by clinical symptoms such as recurrent venous or arterial thrombosis or pregnancy morbidity, and requires confirmation with a second positive test at least 12 weeks after the initial result, along with clinical manifestations, as stated in the most recent guidance from the ISTH-SSC subcommittee on lupus anticoagulant/antiphospholipid antibodies 1. The presence of antiphospholipid antibodies is associated with an increased risk of blood clots and pregnancy complications.
- The antibodies interfere with normal clotting mechanisms by binding to phospholipids and associated plasma proteins, disrupting the balance between pro-coagulant and anticoagulant pathways, which explains the increased thrombotic risk.
- For patients with confirmed APS, treatment typically involves anticoagulation therapy with medications like warfarin, heparin, or direct oral anticoagulants, depending on the clinical scenario, with recent guidance suggesting that direct oral anticoagulants (DOACs) should be avoided in patients with APS, especially if positive for lupus anticoagulant, anti-cardiolipin, and anti-b2-glycoprotein-I antibodies (ie, “triple-positive”), and in those with arterial thrombosis, with vitamin K antagonists (VKAs) being the preferred first-line therapy 1.
- During pregnancy, low-dose aspirin plus prophylactic heparin is often recommended. It is essential to differentiate between classification criteria and assessment of aPL in clinical care, as classification criteria are strict and meant for participant inclusion in studies and trials, while laboratory detection for APS diagnosis in daily practice is broader, meant to diagnose each APS patient to optimize their management 1.
From the Research
Significance of Positive Anti-Cardiologist Ab, IgM
- The presence of IgM anticardiolipin antibodies is one of the criteria for the diagnosis of antiphospholipid syndrome (APS) 2, 3.
- Studies have shown that patients with isolated IgM anticardiolipin antibodies are at a higher risk of stroke and may require different treatment approaches compared to those with IgG antibodies 3.
- The detection of anticardiolipin and anti-β2-glycoprotein I antibodies can vary between different platforms and assays, which may affect the diagnosis and management of APS 4, 5.
- A positive result for IgM anticardiolipin antibodies may indicate an increased risk of thrombotic events, and patients with this result should be closely monitored and managed accordingly 2, 3.
- The clinical significance of low titers of IgM anticardiolipin antibodies is still debated, but studies suggest that these patients may not be at a significantly increased risk of antiphospholipid antibody-related disorders 6.
Clinical Implications
- Patients with positive IgM anticardiolipin antibodies should be evaluated for the presence of other antiphospholipid antibodies and undergo a thorough clinical assessment to determine the risk of thrombotic events 2, 3.
- The management of patients with isolated IgM anticardiolipin antibodies may involve the use of antiplatelet agents or anticoagulants, depending on the individual risk factors and clinical presentation 3.
- Repeat testing for anticardiolipin antibodies may be necessary in patients with low-positive results or those who develop new clinical symptoms 6.