The search results extensively discuss anti-PF4 antibodies (Platelet Factor 4), which are central to conditions like heparin-induced thrombocytopenia (HIT) and vaccine-induced immune thrombotic thrombocytopenia (VITT). These antibodies target PF4, a chemokine involved in coagulation and platelet activation. Key findings include:
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Pathophysiology
Anti-PF4 antibodies form complexes with heparin or polyanions, activating platelets and causing thrombosis. In COVID-19, similar antibodies correlate with disease severity and microthrombi.
Diagnostic Testing
ELISA and chemiluminescence assays detect anti-PF4 antibodies, though specificity varies. Platelet activation assays (e.g., serotonin release) confirm pathogenicity.
Vaccine Association
Adenovirus-vectored COVID-19 vaccines (e.g., AstraZeneca, J&J) rarely induce anti-PF4 antibodies, leading to VITT. Most individuals show no seroconversion post-vaccination.
Potential Confusions with Prohibitin (PHB) Proteins
Search result discusses prohibitin (PHB) proteins (PHB1, PHB2), which are mitochondrial inner membrane proteins. No antibodies against PHB4 are mentioned, and PHB4 itself is not a recognized entity in the literature. Key points:
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Prohibitin Function
PHB1 and PHB2 form complexes critical for mitochondrial membrane stability and stress responses. Their localization is enriched in crista membranes.
Antibody Use
Anti-PHB1 and PHB2 antibodies (e.g., EP2803Y, EPR14523) are used in immunogold electron microscopy and Western blotting to study prohibitin distribution and interactions.