Analysis of T-cell and Humoral Immune Response to SARS-CoV-2 Antigens in Rituximab-Treated Patients with Rheumatoid Arthritis Vaccinated with Combined Vector Vaccine Gam-COVID-Vac.

The COVID-19 pandemic has brought significant changes in managing of patients with rheumatoid arthritis. Rituximab-treated patients were more susceptible to severe infection. This required a "switch" to another genetically engineered drug in the patients with high risk of adverse COVID-19. In this study, we assessed the severity of immune response to SARS-CoV-2 antigens in rituximab-treated patients with rheumatoid arthritis vaccinated with the combined vector vaccine Gam-COVID-Vac. Insufficient formation of the humoral response and a high level of T-cell response to SARS-CoV-2 antigens in this group of patients were revealed. An imbalance of cellular and humoral response may play a role in more severe COVID-19 in rituximab-treated patients with rheumatoid arthritis.