Tu53 - Rapid Waning and Unique Response Kinetics of Humoral and Cellular Immune Responses to SARS-CoV-2 Vaccination in Patients on Immunomodulatory Drugs

Abstract Text: Autoimmune diseases such as rheumatoid arthritis (RA) and scleroderma (SSc) are often treated with immunomodulatory drugs, reducing the strength and longevity of immune responses. Given the vulnerability of these populations to SARS-CoV-2 infections, understanding the efficacy of SARS-CoV-2 vaccination in patients with RA and SSc is critical for their protection. We examined the longevity and magnitude of serum antibody and memory T cell responses following SARS-CoV-2 vaccination in patients with RA or SSc, who are on immunomodulatory drugs, compared to age- and sex-matched controls. Blood and serum were collected from participants. SARS-CoV-2 spike- and receptor binding domain (RBD)-specific antibodies were quantified by ELISA. Spike-specific memory T cell responses were quantitated by flow cytometry using an activation induced marker assay. Following the second COVID-19 vaccination, participants with RA trended towards lower levels of spike-specific antibodies and CD4+ T cells than controls. Before dose 3, participants with RA exhibited rapidly waning antibody levels, which were rescued by the third COVID-19 vaccination. One month after dose 2, half of participants with SSc had low anti-RBD and anti-spike IgG, a deficit not observed in their spike specific T cells. By 3 months after dose 2, 3/4 participants with SSc who previously had low antibody levels exhibited increases in anti-spike IgG. In conclusion, participants with RA, who are on immunomodulatory drugs, may require shorter intervals between booster doses to maintain sufficient protection. Participants with SSc respond to two doses of a COVID-19 vaccine but can take longer to reach adequate antibody levels.