Value of Isolated IgA Anti–β₂‐Glycoprotein I Positivity in the Diagnosis of the Antiphospholipid Syndrome

Isolated IgA anti-β2 GPI-positive titers may identify additional patients with clinical features of APS. Testing for these antibodies when other antiphospholipid tests are negative and APS is suspected is recommended. IgA anti-β2 GPI antibodies directed to domain IV/V of β2 GPI represent an important subgroup of clinically relevant antiphospholipids.