Evidence of immune response to BNT162b2 COVID-19 vaccine in systemic lupus erythematosus patients treated with Belimumab.

Abstract

To evaluate humoral and cell-mediated response after three doses of BNT162b2 SARS-CoV-2 vaccine in patients with systemic lupus erythematosus (SLE) treated with Belimumab (BLM). SLE patients were vaccinated with three doses of BNT162b2-mRNA vaccine (two-dose primary vaccination, third booster dose after 6months). The humoral immune response was assessed one and 6months after the second dose (T1, T2), and 6months after the booster dose (T3). Serological assay was performed (The Liaison® SARS-CoV-2 TrimericS IgG chemiluminescent). Spike-specific T-cell response was monitored 6months after the second vaccine dose and the percentage of cytokines producing T cells was assessed by flow cytometry. Twelve patients [12F; median age 46years (IQR 8.25); median disease duration 156months (IQR 188)] were enrolled. At T1, all patients showed seroconversion (median anti-Spike IgG levels 1610 BAU/mL, IQR 1390). At T2--day of the third dose--a significant reduction of median anti-Spike IgG antibodies levels was observed [214 BAU/mL (IQR 94); p = 0.0009]. Anti-Spike IgG were significantly increased at T3, reaching a median value of 1440 BAU/mL (IQR 1316; p = 0.005). Despite declining humoral immunity, almost 60% of patients mounted a virus-specific CD4 + T-cell response 6months after primary vaccination. BLM does not impair humoral response to primary BNT162b2 SARS-CoV-2 vaccination. During the follow-up, a decline in antibody levels is evident and the third dose is crucial to increase the specific immune response. Finally, we observed a recall T-cell response to the Spike antigen 6months after the first vaccination cycle.