Abstract
Background: Antibodies against cationic platelet chemokine, platelet factor 4 (PF4/CXCL4), have been described in heparin-induced thrombocytopenia (HIT), but also in patients positive for antiphospholipid antibodies (aPL) even in the absence of heparin treatment and HIT-related clinical manifestations. Anti-PF4 antibodies have been recently described also in subjects who developed thrombosis with thrombocytopenia syndrome (TTS) in association with adenoviral vector-based, but not with mRNA-based, COVID-19 vaccines.
Objective: To investigate whether COVID-19 vaccination affects the production of anti-PF4 antibodies in aPL-positive patients and in control groups.
Methods: Anti-PF4 immunoglobulins were detected in patients’ and controls’ serum samples by ELISA and their ability to activate normal platelets was assessed by the platelet aggregation test.
Results: Anti-PF4 were found in 9 of 126 aPL-positive patients, 4 of 50 patients with COVID-19, 9 of 49 with other infections, and 1 of 50 aPL-negative patients with systemic lupus erythematosus. Clinical manifestations of TTS were not observed in any aPL patient positive for anti-PF4, whose serum failed to cause platelet aggregation. The administration of COVID-19 vaccines did not affect the production of anti-PF4 immunoglobulins or their ability to cause platelet aggregation in 44 aPL-positive patients tested before and after vaccination.
Conclusions: Heparin treatment-independent anti-PF4 antibodies can be found in aPL-positive patients and asymptomatic carriers, but their presence, titre as well as in vitro effect on platelet activation are not affected by COVID-19 vaccination.
Keywords: COVID-19; antibodies; antiphospholipid; vaccination.
【저자키워드】 COVID-19, antibodies, vaccination, Antiphospholipid, 【초록키워드】 Treatment, platelet activation, COVID-19 vaccine, vaccination, thrombosis, antibody, systemic lupus erythematosus, in vitro, heparin, ELISA, chemokine, clinical manifestations, serum, COVID-19 vaccines, infections, COVID-19 vaccination, Immunoglobulin, Patient, Asymptomatic carriers, Control, Platelet, patients, association, administration, heparin-induced thrombocytopenia, clinical manifestation, subject, syndrome, control groups, titre, aggregation, positive, Affect, tested, described, absence, not affect, activate, not affected, cationic, mRNA-based, patients with COVID-19, 【제목키워드】 Production, antibody, COVID-19 vaccination, Patient, not affected,