PNN antibodies, commonly referred to in the context of antiphospholipid syndrome (APS), are autoantibodies targeting phospholipid-binding proteins, particularly β₂-glycoprotein I (β₂GPI) and prothrombin. First identified in the 1980s, these antibodies are associated with thrombotic events, recurrent pregnancy loss, and thrombocytopenia. Their name derives from the "phospholipid-dependent" tests (e.g., lupus anticoagulant) used in detection, though "PNN" isn’t a standard abbreviation and may reflect regional or contextual terminology.
Pathogenically, PNN antibodies disrupt phospholipid-protein complexes on cell membranes, promoting hypercoagulability by activating endothelial cells, platelets, and complement pathways. They are clinically significant in APS, often coexisting with systemic lupus erythematosus (SLE). Laboratory diagnosis involves ELISA for anticardiolipin antibodies, anti-β₂GPI antibodies, and functional coagulation assays for lupus anticoagulant.
Research highlights their role in obstetric complications, such as placental thrombosis and inflammation. Management includes anticoagulants (e.g., heparin) and immunosuppressants, though therapeutic efficacy varies. Ongoing studies explore molecular mechanisms and targeted therapies to mitigate antibody-mediated damage. Despite advances, challenges remain in understanding their heterogeneous profiles and optimizing diagnostic criteria.