ABSTRACT
Objective. To evaluate seroreactivity and disease biomarkers after 2 or 3 doses of COVID-19 mRNA vaccines in a cohort of patients with rheumatic diseases. Methods. We collected biological samples longitudinally before and after 2-3 doses of COVID-19 mRNA vaccines from a cohort of patients with systemic lupus erythematosus (SLE), psoriatic arthritis, Sjogrens syndrome, ankylosing spondylitis, and inflammatory myositis. Anti-SARS-CoV-2 spike IgG and IgA and anti-dsDNA concentration were measured by ELISA. A surrogate neutralization assay was utilized to measure antibody neutralization ability. Lupus disease activity was measured by Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Expression of type I interferon signature was measured by real-time PCR. The frequency of extrafollicular double negative 2 (DN2) B cells was measured by flow cytometry. Results. Most of the patients generated high SARS-CoV-2 spike-specific neutralizing antibodies comparable to those in healthy controls after 2 doses of mRNA vaccines. The antibody level declined over time but recovered after the third dose of the vaccine. Rituximab treatment substantially reduced antibody level and neutralization ability. Among SLE patients, no consistent increase in SLEDAI scores was observed post-vaccination. The changes in anti-dsDNA antibody concentration and expression of type I IFN signature genes were highly variable but did not show consistent or significant increases. Frequency of DN2 B cells remained largely stable. Conclusion. Rheumatic disease patients without rituximab treatment have robust antibody responses toward COVID-19 mRNA vaccination. Disease activity and disease-associated biomarkers remain largely stable over 3 doses of vaccines, suggesting that COVID-19 mRNA vaccines may not exacerbate rheumatic diseases.