Platelet-Derived Microparticles Bearing PF4 and Anti-GAGS Immunoglobulins in Patients with Sepsis

PF4 is a megakaryocyte-derived cationic chemokine that plays a part in innate immunity through its activity on the macrophages. In bacterial sepsis, PF4 binds to glycosaminoglycans (GAGs) on the surface of aerobic bacteria, giving rise to an antigenic complex that induces the early formation of anti...

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Bibliographic Details
Published in:Diagnostics (Basel) 2020-08, Vol.10 (9), p.627
Main Authors: Sartori, Maria Teresa, Zurlo, Chiara, Bon, Maria, Bertomoro, Antonella, Bendo, Raffaele, Bertozzi, Irene, Radu, Claudia Maria, Campello, Elena, Simioni, Paolo, Fabris, Fabrizio
Format: Article
Language:English
Subjects:
anti-heparin/PF4 antibody
Antibiotics
Antibodies
Antigens
Bacteria
Bacterial infections
Blood
Blood platelets
Chemokines
Consent
Gram-positive bacteria
Hospitalization
Infections
Intensive care
platelet
platelet microparticles
Sepsis
Thrombocytopenia
Values
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Summary:PF4 is a megakaryocyte-derived cationic chemokine that plays a part in innate immunity through its activity on the macrophages. In bacterial sepsis, PF4 binds to glycosaminoglycans (GAGs) on the surface of aerobic bacteria, giving rise to an antigenic complex that induces the early formation of anti-PF4 IgG-IgA-IgM. This triggers the immune response in patients receiving heparin therapy who develop heparin-induced thrombocytopenia (HIT). These antibodies have also been identified in patients with chronic Gram-negative infections. Given the complexity of this innate immune response network, our study on 45 patients with sepsis focused on the immune response mediated by platelet PF4. We analyzed the role of IgG-IgA-IgM against PF4-GAGs, and the presence of specific PF4-bearing platelet microparticles (PMPs). Anti-GAGs/PF4 IgG-IgA-IgM levels were significantly higher in septic patients than in control groups (healthy controls or acute patients without sepsis, p < 0.001). PF4-bearing PMP levels were only significantly higher in septic patients (p < 0.001). The occurrence of IgG-IgA-IgM against PF4-GAGs and PF4+ PMPs correlated with an improvement in patients’ sepsis. In conclusion, we demonstrated that, in the course of bacterial sepsis, platelet activation leads to the formation of specific PF4-bearing PMPs. These specific microparticles bind to polyanionic sequences on the surface of aerobic bacteria, giving rise to an antigenic complex that induces the early formation of IgG-IgA-IgM against PF4-GAGs as an innate immune response to infection.
ISSN:2075-4418
2075-4418
DOI:10.3390/diagnostics10090627