A lupus anticoagulant neutralization procedure using the patient's own platelets

Area of Science:

• Hematology
• Clinical Chemistry
• Immunology

Background:

• Lupus anticoagulants (LA) are autoantibodies that prolong phospholipid-dependent coagulation tests.
• Accurate identification of LA is crucial for managing thrombotic and bleeding risks.
• Existing diagnostic criteria can be complex and may require multiple assays.

Purpose of the Study:

• To describe and evaluate a novel auto platelet neutralization procedure (APNP) for lupus anticoagulant (LA) identification.
• To determine the diagnostic utility of APNP in differentiating LA-positive from LA-negative individuals.
• To assess the correlation between APNP results and established LA diagnostic markers.

Main Methods:

• The auto platelet neutralization procedure (APNP) involves freezing and thawing patient platelet-rich plasma (PRPF).
• Activated partial thromboplastin time (aPTT) is performed on both platelet-poor plasma and PRPF.
• The percentage of APNP is calculated based on the degree of aPTT correction between the two plasma types.

Main Results:

• Normal volunteers and LA-negative patients showed mean APNP values of 7.7% and 10.0%, respectively.
• LA-positive patients exhibited significantly higher mean APNP values (39.0%), with 28 cases > 25%.
• Patients with factor deficiency had low APNP (< 25%), and some cases with normal aPTT but elevated APNP (21-28%) were suspected for LA.

Conclusions:

• APNP > 25% is a strong indicator for suspected lupus anticoagulant (LA).
• The APNP assay demonstrates potential utility in LA detection, even in cases with normal aPTT.
• This procedure offers a valuable adjunct for identifying LA, potentially simplifying diagnosis.