Objective To explore whether inactivated COVID-19 vaccine influences the profile of prothrombotic autoantibodies and induces thrombotic events in primary antiphospholipid syndrome (APS) patients. Methods We enrolled 39 primary APS patients who received two doses of inactivated SARS-CoV-2 vaccine (BBIBPCorV, Sinopharm, Beijing, China) voluntarily in this prospective cohort. Prothrombotic autoantibodies were determined before vaccination and four weeks after the 2nd dose of vaccination. Thrombotic disorders were evaluated via hospital site visits and assessments. Results There was no significant difference in the presence of all eleven autoantibodies detected before and four weeks after vaccination: for aCL, IgG (14 vs. 16, P= 0.64), IgM (13 vs. 19, P= 0.34), IgA (2 vs. 3, P= 0.64); anti-β2GP1, IgG (12 vs. 12, P= 1.00), IgM (5 vs. 8, P= 0.36), IgA (4 vs. 3, P= 0.69); aPS/PT IgG (13 vs. 16, P= 0.48), IgM (17 vs. 22, P= 0.26); LAC (22 vs. 28, P= 0.16); aPF4-heparin (0 vs. 0, P= 1.00), and antinuclear antibody (ANA) (23 vs. 26, P= 0.48). Notably, the distribution of aPL profile in pre- and post- vaccination cohort was not affected by SARS-CoV-2 vaccination: for patients with low-risk aPL profile (11 vs. 10, P= 0.799) and patients with high-risk aPL profile (28 vs. 29, P= 0.799), respectively. Furthermore, no case exhibited symptoms of the thrombotic disorder during a minimum follow-up period of 12 weeks. There was no adjustment to the ongoing treatment regimens following SARS-CoV-2 vaccination. Conclusions Inactivated SARS-CoV-2 vaccine does not influence the profile of antiphospholipid antibodies and anti-PF4-heparin antibodies nor induces thrombotic events in primary APS patients.

BACKGROUND: Anti-β2GP1 (β2-glycoprotein 1) antibodies are the primary pathogenic antibody to promote thrombosis in antiphospholipid syndrome (APS), yet the underlying mechanism remains obscure. We aimed to explore the intracellular pathway that mediated platelet activation. METHODS: Platelets were isolated from patients with APS and subjected to RNA sequencing. Platelet aggregation, the release of platelet granules, platelet spreading, and clot retraction were detected to evaluate platelet activation. We purified anti-β2GP1 antibodies from patients with APS and the total IgG from healthy donors to stimulate platelets with/without FcγRIIA (Fcγ receptor IIA) blocking antibody or Akt inhibitor. Platelet-specific Sin1 (stress-activated protein kinase–interacting protein) deficiency mice were established. The thrombus model of inferior vena cava flow restriction, ferric chloride–induced carotid injury model, and laser-induced vessel wall injury in cremaster arterioles model were constructed after administration of anti-β2GP1 antibodies. RESULTS: Combined RNA sequencing and bioinformatics analyses suggested that APS platelets exhibit increased levels of mRNA associated with platelet activation, which was in line with the hyperactivation of APS platelets in response to stimuli. Platelet activation in APS platelets is accompanied by upregulation of the mTORC2 (mammalian target of the rapamycin complex 2)/Akt pathway and increased levels of SIN1 phosphorylation at threonine 86. Anti-β2GP1 antibody derived from patients with APS enhanced platelet activation and upregulated the mTORC2/Akt pathway. Moreover, the Akt inhibitor weakened the potentiating effect of the anti-β2GP1 antibody on platelet activation. Notably, Sin1 deficiency suppresses anti-β2GP1 antibody–enhanced platelet activation in vitro and thrombosis in all 3 models. CONCLUSIONS: This study elucidated the novel mechanism involving the mTORC2/Akt pathway, which mediates the promotion of platelet activation and induction of thrombosis by the anti-β2GP1 antibody. The findings suggest that SIN1 may be a promising therapeutic target for the treatment of APS.

Objective A succession of cases have reported flares of adult-onset Still’s disease (AOSD) after vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), raising concerns. We aimed to investigate the impact of inactivated SARS-CoV-2 vaccines on disease activity in patients with AOSD. Methods We prospectively enrolled clinically inactive AOSD patients visiting the outpatient clinics of our department. The patients received SARS-CoV-2 vaccines (BBIBPCorV, Sinopharm, Beijing, China) voluntarily. The occurrence of relapse in the participants was recorded during the follow-up period and a propensity score matching (PSM) method was used to compare the relapse rates between vaccinated and unvaccinated patients. Localized and systemic symptoms were assessed in the vaccinated patients. Results A total of 122 patients with inactive AOSD were included, of which 49.2% (n = 60) voluntarily received the inactivated SARS-CoV-2 vaccine. The relapse rate did not increase significantly in vaccinated patients in comparison with unvaccinated patients (after PSM: 6.8% versus 6.8%), and no relapse occurred within one month after vaccination. No obvious adverse reactions were reported in 75.0% of the participants, and none of the patients reported severe reactions. Conclusion Increased disease activity or relapse following vaccination with inactivated SARS–CoV-2 were rare in patients with inactive AOSD. Local and systemic adverse reactions were found to be mild and self-limiting. These safety profiles of inactivated SARS–CoV-2 vaccines in patients with AOSD may assist in eliminating vaccine hesitancy and increase the vaccination rate against SARS-CoV-2.