Humoral and Cellular Immunity after Vaccination against SARS-CoV-2 in Relapsing-Remitting Multiple Sclerosis Patients Treated with Interferon Beta and Dimethyl Fumarate

The impact of vaccines against SARS-CoV-2 on immunity of patients with multiple sclerosis (PwMS) is still not fully known. Its elucidation may be helpful in resolving medical concerns associated with the maintenance of immunosuppressive and immunomodulatory medications known as disease modifying therapies (DMTs) at PwMS, as well as obtaining accurate protection against severe COVID-19 outcomes. Therefore, the aim of our study was to evaluate the humoral and cellular immune response in PwMS treated with DMTs. The concentrations of IgG Spike (S) anti-SARS-CoV-2 antibodies, and IgG Nucleocapsid (N) anti-SARS-CoV-2 antibodies as well as Interferon gamma (IFN-γ) titers were analyzed in PwMS groups treated with dimethyl fumarate (DMF), interferon beta (IFN), and healthy control group. Almost 100% of PwMS experienced seroconversion. Additionally, there were no significant differences between the study and control groups in terms of IgG (S) and (N) anti-SARS-CoV-2 antibody levels. However, interferon gamma titers were lower in both PwMS groups which may indicate adequate humoral and decreased cellular response of examined PwMS. Additionally, after division of the whole study group into two subgroups according to the time since last vaccination, IgG (S) anti-SARS-CoV-2 and IFN-γ concentrations were significantly lower in case of patients who were immunized more than 200 days before sample collection. No differences were observed in case of subgroups in which sample collection was less than 200 days after vaccination when compared to the control group. This could indicate a time-related and decreased immunity in PwMS treated with DMTs.